JTL Suite of Pool Plant Operator Training Programmes

© Johnson Training Ltd: Unit 4 ONLINE V4 03 2021

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JTL Suite of Pool Plant Operator Training Programmes

Unit 4: The processes and procedures required to ensure good pool water quality Unit Content Section 1: How to maintain good pool water quality

Section 2: The impact that the incoming mains water has on pools

Section 3: Legislation, regulations and guidance

Section 4: Pool related emergencies and procedures

Section 5: Infections associated with poor pool water quality and hygiene

Section 6: Microbiological testing

Section 7: Pool water hydraulics

Section 8: Heating and ventilation of swimming pools

Section 9: Problem solving activities

The unit will be subdivided into sections and activities have been devised in order to help you understand the topic better. At the end of each section there will be a Question time, answering these questions will help you to prepare for the unit assessment. The assessment for this unit is the completion of a multiple-choice question paper.

NOTE: Ensure that you read the Covid-19 update and listen to the presentation. The standards referred to in this programme relate to normal operations, but there are some changes which you need to be aware of as a result of Covid-19.


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Section 1: How to maintain good pool water quality Disinfection Maintaining good pool water quality starts by getting the disinfection right. We have already considered disinfection processes in the earlier units but now we are going to explore the subject in greater detail. As we already know, swimming pools are disinfected as a means of removing the risk of infection. Disinfection is achieved by maintaining the correct concentration of disinfectant in the pool water, referred to as the ‘residual’ disinfectant, although it should be noted that filtration also plays an important part in keeping pools safe. The commonest disinfectants are chlorine based. There is a link between the efficiency of disinfection and the pH value of the water. The ability of chlorine to kill bacteria is directly related to the pH of the water. As the pH increases, the efficiency of chlorine decreases. This effectively means that the pool operator will use more chemicals if they allow the pH to continue to run at high levels. The following diagram illustrates the link between pH and active disinfectant within the pool. The yellow line relates to hypochlorous acid (HOCl), which is the effective disinfectant when using chlorine and the red line relates to hypobromous acid (HOBr) which is the active ingredient when the pool is disinfected with a bromine compound. At a pH of approximately 7 active ingredient levels of hypochlorous acid are approximately 62%. However, this drops to 22% at pH 8.

Source: PWTAG


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Chlorine and ammonia compounds added by bathers Chlorine has no problem in killing bacteria but it goes through a complicated process when dealing with the ammonia compounds which are introduced by bathers in the form of urine and sweat. The product of chlorine and a ammonia is the formation of a group of chemicals called chloramines and these are measured as combined chlorine when pool water tests are carried out. When hypochlorous acid combines with ammonia it produces a form of chlorine known as monochloramine. Monochloramine does have some disinfecting properties, but is not as effective at killing bacteria and in dealing with pool pollution as free chlorine is. When hypochlorous acid is added to monochloramine it forms a new compound known as dichloramine. Dichloramine is an irritant and can cause discomfort to bathers in the form of sore eyes and irritation of the nasal passages. Dichloramine can be removed by additional chlorine providing that the pool water pH is within the range of 7.2 - 7.4 and that there is an adequate supply of free available chlorine. A third combination of chlorine is nitrogen trichloride which is caused when the hypochlorous acid reacts with the dichloramine. Nitrogen trichloride is an extreme irritant, and along with the dichloramine content, can create smelly pool conditions and can affect the bathers and staff by causing sore eyes and breathing difficulties. A further complication is the creation of what is referred to as organic chloramines, which occurs when chlorine reacts with the organic carbon-based nitrogen compounds found in urine and sweat. Organic chloramines are not removed by excessive chlorine. They can only be removed by the dilution process, although ultraviolet and ozone have been found to be effective in removing them. In well managed pools combined chlorine levels are kept as low as possible, ideally less than 0.5mg/l; they should always be ideally less than half the value of the free chlorine and always less than 1.00 mg/l. If the combined chlorine levels have not been reduced by the addition of more chlorine, then this is an indication that the level of dilution in the pool is inadequate and as a consequence it will be necessary to increase the dilution level by stepping up the amount of backwashing carried out on the filtration system. The most efficient tool in keeping combined chlorine levels to an absolute minimum is to ensure that:

• all bathers engage in efficient pre-swim hygiene, • pH levels are maintained between 7.2-7.4 • the relationship between the free chlorine and the combined chlorine is correct, and • the dilution regime of the pool is adequate.


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Activity The following chart shows chlorine levels and pH values from a series of pools. Make comments about how well these readings match up with what could be considered as best industry standards. No DPD1

1 DPD3 pH Comments

1 2.00 2.50 7.8 2 5.00 6.00 7.8 3 0.40 2.00 7.5 4 1.00 2.00 7.4 5 1.00 1.30 7.3

6 1.60 2.00 7.2

7 1.00 1.40 7.4 8 10.00 12.00 8.0 9 0.90 1.20 7.2 10 0.20 2.00 7.4

Question Time

1 Why should swimming pools be kept at a pH of 7.2-7.4?

2 What forms can combined chlorine take?

3 Which is the most troublesome form of combined chlorine?

4 How are organic chloramines removed?


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The variables in maintaining good pool water quality Pool water must kept free from bacteria, comfortable for bathers, but also needs to be in good condition. In this section we will consider how to maintain good pool water quality One way of deciding whether or not the water is in good condition is to establish if the water is ‘balanced’ or not. We have already considered balanced water in the earlier units but now we are going to explore the subject in greater detail. There are a number of variables which have a bearing upon whether the pool water is balanced or no, the variables are: § pH § Total alkalinity § Calcium hardness § Total dissolved solids § Temperature In this section, we are going to describe the terms, explain why they are important in maintaining good quality pool water. Finally, we will be discussing how each of the parameters can be altered and which chemicals should be used. pH The term pH was explained in detail in Unit 1, so, for the purpose of revision we will confirm the following points:

• The pH of a chemical will indicate whether the chemical is an acid or an alkaline. • It is measured on a scale of between 0 and 14 • The mid- point on the scale is 7 which is neutral • pH values of less than 7 indicate that the fluid is an acid • A pH value above 7 indicates that the fluid is alkaline • The pH scale is a logarithmic scale which means that the difference in value between

each full number and the next is x 10 The pH of the pool should be maintained between 7.2 and 7.4 when chlorine is used to disinfect the pool. Bromine based disinfectants can run at pH values of up to 8.2. If the pH value is maintained between 7.2 and 7.4: § The chlorine based disinfectant will be efficient § Coagulants work well at this level § Levels are compatible with the human body, so avoiding discomfort of bathers § pH is the most important aspect in determining whether the water is balanced or not Every time chemicals are added to the pool the pH will change, similarly every time dilution takes place, as would be the case of the backwashing of the filters, will cause a change in the pH of the pool water because the pH of the incoming mains water may well be different to that of the pool.


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Adjusting pH levels

• pH can be raised by adding sodium carbonate

• pH can be reduced by adding an acid, for example, hydrochloric acid, sodium bisulphate, sulphuric acid, or CO2 .

Total alkalinity Total Alkalinity of water is defined as a measure of the alkaline salts dissolved in it – e.g.. bicarbonates and carbonates. High total alkalinity makes the water more resistant to pH change, sometimes referred to as a ‘buffer’. Low levels of total alkalinity do not contain this buffer and consequently it can be difficult to maintain control of the pH. This is referred to as “pH bounce”. The total alkalinity of the pool water will also be affected by incoming mains water and can be lowered by the use of aggressive pH reduction chemicals. PWTAG recommends that the total alkalinity in the pool should be maintained above 80mg/l, but less than 200mg/l. Chemical manufacturers indicate the best parameters for use with their chemical and so, for example, calcium hypochlorite pools tend to run with a total alkalinity of between 80 and 120mg/l, whereas sodium hypochlorite pools tend to run between 120 and 150mg/l. It is important to maintain the correct level of total alkalinity in a pool because it leads to better control over the pH, which can then lead to more efficient use of chemicals. Total alkalinity also has an impact upon the water balance. Total alkalinity can be increased by the addition of sodium bicarbonate and can be lowered by dilution, if the pool is served with water from a soft water source with low alkalinity, or alternatively, total alkalinity can be lowered by the use of an acid, such as Sodium bisulphate Calcium hardness The total hardness of water is a measure of all its calcium and magnesium salts such as carbonates, bicarbonates, sulphates and chlorides. Water supply companies use the term ‘total hardness’ when defining water standards. Calcium hardness is the part of the total hardness which consists of calcium salts, and it is this which is used because it is the parameter most relevant to swimming pools. Low levels of calcium hardness is likely to be corrosive to the fabric of the pool plant and erosive to the pool itself. It is generally accepted that by approximately 80mg/l a protective layer begins to form. In order to protect the pool tank from erosion, SPW makes the recommendation that the calcium hardness should be maintained above 80mg/l. The upper level is determined by the incoming water supply. Calcium hardness is raised by the use of calcium chloride and can only be lowered by dilution. Calcium Hardness is a contributory factor to pool water balance.


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Total Dissolved Solids Total Dissolved Solids (TDS) is defined as the sum of the weight of soluble material in water. When disinfectants and other chemicals are added to the water this raises the TDS level, and it is controlled by dilution. PWTAG recommend that the TDS should not be allowed to rise more than 1000 mg/l above the source water. High levels of TDS tend to make the pool look unattractive and can lead to creating a corrosive environment in terms of pool water balance. The TDS levels may look acceptable, but it may be necessary to carry out additional testing to see whether or not there are high levels of sulphated and chlorides present, as may be the case when certain chemicals are used. Sulphates: Sulphates occur naturally in many waters. Sulphates are introduced into treated waters by the use of such chemicals as aluminium sulphate, sodium bisulphate (dry acid) and sulphuric acid. The presence of high levels of sulphate can be undesirable for a number of reasons. In water containing sulphates localised corrosion of iron, steel and aluminium in plant and pipe work can occur through the action of sulphate-reducing bacteria. These bacteria, which generate sulphides, cause a characteristic pitting of the metal surface. High sulphate levels can also cause damage to concrete and cement based materials through the formation of calcium sulphoaluminate. This causes expansion and crumbling of the cement. It can also affect concrete structures and pipes in water distribution systems carrying sulphate-bearing ground waters; and can attack grouting in tiled swimming pools using sodium bisulphate for pH adjustment. The maximum level for sulphates is 360mg/l, but the lower the better. Chlorides Chlorides are introduced into the water by the use of chemicals such as sodium hypochlorite, especially if it is generated on site from salt. Chlorides form part of the TDS. The maximum level for chlorides is 600mg/l, but the lower the better. Additional pool water testing techniques The ‘Turbidity’ method of testing The ‘Turbidity’ method of testing can be used to test for sulphates and also used for testing cyanuric acid levels. The Turbidity Test Tube usually comprises of two tubes, one inside the other. The outer tube has markings to enable the operator to easily add the correct amount of sample water to test. The reagent is then added, which causes the sample to become cloudy. The degree of cloudiness or Turbidity is dependant on the level of the chemical being tested in the


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sample. The inner tube has graduations on the side, a black spot or similar on the inside bottom of the tube, and a small hole at the bottom of one side. This inner tube is slowly lowered into the cloudy sample in the outer tube. The sample water enters the inner tube through the small hole, and as the tube is lowered further into the sample, the inner tube steadily fills. The operator carefully looks down the centre tube at the black spot which, due to the cloudy sample slowly becomes more difficult to see. At the point where the black spot just disappears, the inner tube movement is stopped and a note taken of where the water sample surface is in relation to the inner tube. The graduations on the inner tube are numbered and this gives an indication of the level of the chemical being tested. There are variations on this method where the sample is mixed with the reagent in one bottle and the cloudy solution slowly poured into a graduated cuvette with the black spot on the base. Again, the operator carefully monitors the visibility of the black spot and when it just disappears, the level of sample water in the cuvette is compared to the graduations on the side to determine the particular chemical level. Sulphates testing The maximum level for sulphates is 360mg/l, but the lower the better. Method - Proportional Turbidity Equipment Required - Turbidity Test-Tube kit, crusher/stirrer, sulphates turbidity test reagent Separate the Double Tube Turbidity Tester assembly, and fill the outer tube to the top line with sample water. Add 1 Sulphates Turbidity test tablet, crush and mix thoroughly. When thoroughly mixed, a cloudy solution indicates the presence of Sulphates. Slowly insert the square graduated inner tube into the round outer tube ensuring the friction cap is in position, so that the inner tube slowly fills with the cloudy sample water. Viewing from above, adjust the inner tube up and down until the black spoy on the base of the tube is "just" not visible. Read the number from the graduations level with the surface of the solution in the inner tube and multiply this number by 2 to determine the Sulphates level in ppm or mg/l NOTE: If the solution is too cloudy to obtain an accurate reading, then dilute the sample by filling the outer tube to the bottom line with fresh sample water and making up to the top line with distilled water. Carry out the test as before and multiply the result by 4. If the solution is still too cloudy further dilution should be effected until an accurate reading is obtained


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Chlorides Testing The maximum level for chlorides is 600mg/l, but the lower the better. Method - Colour titration Equipment Required 10 ml test cells or 100 ml shaker tube, crusher/stirrer, Chlorides test reagent

• Fill a 10 ml test cell to the mark with sample water. • Add 1 chlorides test tablet and crush and stir to disintegrate and mix the tablet. The

sample should become bright yellow. Keeping a note of the number of tablets used, continue to add and mix tablets one at a time until the sample changes from yellow to brown. You can now calculate the chlorides level in mg/l from the formula: (Number of tablets x 100) - 100 Example: Sample takes 4 tablets to titrate (change colour). 4 x 100 = 400 and 400 - 100 = 300. So, the Chlorides level is 300mg/l NOTE 1: For low levels a greater accuracy can be achieved by using a 100 ml sample and

the formula (Number of tablets x 10) - 10 NOTE 2: High levels of chlorine or bromine can bleach the indicator colour, making the

colour change difficult to detect. Cyanuric Acid Where pools are treated with stabilised chlorine, since these chemicals contain cyanuric acid, there is a need to test for cyanuric acid levels in the pool on a weekly basis. The maximum SAFE level and the maximum OPERATIONAL level are two entirely different standards. Research has shown that with levels above 50mg/l the tendency for chlorine to 'lock' progressively increases. Although swimming pools are often found to be crystal clear despite having excessively high CYA levels, a maximum of 200mg/l has been determined for health reasons. Chlorine 'Lock' occurs at an indeterminate level of CYA and is dependant of the overall water chemistry. We have documented evidence of one pool being 'locked' at 70mg/l CYA, whilst another was still crystal clear at 200mg/l CYA. High levels (over 50mg/l of CYA also attack copper, stainless steel and other metals, and therefore the Cyanuric level should always be maintained below 50mg/l)


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Recommended Cyanuric Acid Levels: • Min – 0mg/l (indoor pools) • Min - 20mg/l (outdoor pools only) • Ideal - 0mg/l (indoor pools) • Ideal - 30mg/l (outdoor pools only) • Max - 50mg/l (operational, to avoid chlorine 'lock') • Max - 200mg/l Maximum safe level for health Test Method - Proportional Turbidity Equipment Required - Turbidity Test-Tube kit, crusher/stirrer, cyanuric acid turbidity test

reagent

• Separate the Double Tube Turbidity Tester assembly, and fill the outer tube to the top line with sample water.

• Add 1 cyanuric Acid test tablet, crush and mix thoroughly. • When thoroughly mixed, a cloudy solution indicates the presence of Cyanuric Acid. • Slowly insert the square graduated inner tube into the round outer tube ensuring the

friction cap is in position, so that the inner tube slowly fills with the cloudy sample water.

• Viewing from above, adjust the inner tube up and down until the black spot on the base of the tube is "just" not visible.

• Read the cyanuric acid level in mg/l from the graduations level with the surface of the solution in the inner tube.

NOTE: If the solution is too cloudy to obtain an accurate reading, then dilute the sample by filling the outer tube to the bottom line with fresh sample water and making up to the top line with distilled water. Carry out the test as before and multiply the result by 2. If the solution is still too cloudy further dilution should be effected until an accurate reading is obtained Temperature Hydrotherapy and spa pools operate at a higher temperature than swimming pools and this does have an impact on the balanced water conditions. There is no virtue in running the pool at a higher temperature than needed as this can impact in higher energy costs and condensation problems.


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Water balance calculations It is possible to calculate whether or not the water is balanced and there are two methods which can be adopted - the Palin method and the Langelier method. The Palin method involves pH, total alkalinity and calcium hardness, whereas the Langelier method involves pH, temperature, calcium hardness, total alkalinity and TDS, and for this reason most pool operators tends to use the Langelier method. It should be noted that the water balance indices were not developed for the conditions found in swimming pools, but having said that, they do provide an indication of the balanced water condition. The Langelier Index This method requires the use of a factor table and the application of simple formula to determine the balanced water index. The formula is: Langelier Index = TF + CF + AF + pH - TDSF Where: TF = temperature factor CF = calcium hardness factor AF = total alkalinity factor pH= value (not factor) TDSF = total dissolved solids factor The factor table is as follows:

Temp. TF Calcium hardness

mg/l

CF Total alkalinity

mg/l

AF TDS TDSF

19 0.5 75 1.5 50 1.7 1,000 12.1 24 0.6 100 1.6 100 2.0 2,000 12.2 29 0.7 150 1.8 150 2.2 3,000 12.3 34 0.8 200 1.9 200 2.3 41 0.9 300 2.1 300 2.6

400 2.3 800 2.5

When the calculation is completed the results will either be positive (plus) or negative (minus). A positive index indicates that the pool is scale forming, a negative result indicates the pool is corrosive. An index of zero would indicate that the pool is balanced, providing that all of the tests are within the agreed range for the tests. It is generally considered acceptable to have an index of between 0 and +0.5. A balanced water test is normally carried out on a weekly basis.


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An example of how to carry out the balanced water calculation if given below: Test Test result Factor Temperature 29oC 0.70 Calcium Hardness 75mg/l 1.50 Alkalinity 50 mg/l 1.70 pH 7.1 7.10 Sub Total 11.00 TDS 1000 12.10 Langelier Index -1.1

The results of the above test indicate that the pool is corrosive and therefore out of balance. In order to correct this, the following action is recommended: • Raise the pH to 7.4 • Raise the total alkalinity to 100mg/l • Raise the calcium hardness to 150mg/l Possible actions required to correct pools which are out of balance

• Raise /lower pH • Raise /lower TA • Raise /lower CH • Lower temperature • Lower TDS

By knowing the characteristics of the incoming water, dilution may well achieve some of the above.


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Activity From the information given below, work out whether the pool is balanced or not, and what action may be needed to restore the pool water to balance. The pool is in a soft water area and the chemical treatment is sodium hypochlorite as the disinfectant with CO2 as the pH correction agent. Test Test result Factor Comments Temperature 34oC Calcium Hardness 300mg/l Alkalinity 50 mg/l pH 7.8 Sub Total TDS 3000 Langelier Index

Question Time

1. List the components which contribute to balanced water?

2. What is the acceptable value for a Langelier index balanced water result?

3. Are balanced water calculations carried out at your pool? If so, how often?

4. What is the most influential parameter to decide upon whether the pool water is balanced or not?

5. What is the maximum recommended sulphate level in swimming pool water?

6. What is the maximum recommended chloride level in swimming pool water?

7. What is the maximum recommended cyanuric acid level in swimming pool water?


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The Traffic Light System (RAG Rating) Some pool operators have found it helpful to interpret the pool water readings based upon a traffic light type of system. The pool readings will either fall within the Green, Amber or Red zone i.e. a RAG rating The interpretation is as follows: The pool operator should always strive to keep all values within the Green Zone Green Zone: These Results are within the acceptable range and no corrective action is necessary.. No action is required. Amber Zone: These Results are allowable but not ideal, and so corrective action needs to take place to ensure that the result return to the green zone. If the reading falls within the amber zone for chlorine levels and pH, then take corrective action and repeat the tests in 30 minutes, if the reading is again in amber range then act accordingly. If results fail to return to the green zone, this could lead to the situation entering the Red Zone. Red Zone: These Results are no longer within an acceptable range. This Pool should be closed and corrective action should take place. The Pool should not be open until results are at least within the amber Zone. There are some test results which need immediate action but which would not normally lead to closure see the above table for guidance. The following example was produced for caretakers looking after school pools. Please note that it is only an example and if you adopt the process, you will need to adjust the figures to reflect the risk assessment carried out on your own pool.

© Johnson Training Ltd: Unit 4 V4 03 2021

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Pool Water Testing Parameters TEST

GREEN ZONE

AMBER ZONE

RED ZONE

Free chlorine (DPD1)

1.0 – 3.0mg/l

0.50 -1.00mg/l 3.1 – 5.00mg/l

Higher than 5.0mg/l Below 0.50mg/l

Combined chlorine (Total chlorine – free)

chlorine)

No more than half the value of the free up to a maximum of 1.00mg/l

1.1 -1.50mg/l

If the combined chlorine level goes above 1.50mg/l, take appropriate action to reduce e.g. dilution. As long as this is done, there is no need to close the pool

Total chlorine (DPD3 + DPD1)) Total chlorine

Total chorine has no recommended value, it is used to calculate the combined chlorine level. The actual test must be carried out and the value noted.



pH

7.2 – 7.4

7.0 – 7.1 7.5 – 8.0

8.0+ less than 7.0

Clarity All tiles are visible All tiles are still visible but there are minor clarity issues e.g. slight cloudiness but you can still see all the steps

You cannot see the bottom of the pool

Swimming Pools: Pool water

temperature

29-31°C 27°C - 28°C 32°C - 35°C

Lower than 27°C Higherthan36°CThere is no need to close the pool, but immediate action should be taken to bring it back to the green zone.


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TEST GREEN ZONE AMBER ZONE RED ZONE

Hydrotherapy pools Pool water temp

32-36°C 30°C - 31°C or 37°C

Lower than 290C Higher than 37°C There is no need to close the pool, but immediate action should be taken to bring it back to the green zone.

Total alkalinity: weekly

80-200mg/l 60 - 79mg/l 201-250mg/l

Less than 60mg/l Above 250mg/l There is no need to close the pool, but immediate action should be taken to bring it back to the green zone.

Calcium hardness: tested weekly

80- 200mg/l 60 - 79mg/l 151 -500mg/l** Determined by incoming mains water levels

Less than 60mg/l Above 500mg/l There is no need to close the pool, but immediate action should be taken to bring it back to the green zone.

TDS: tested weekly 0 - 1100 1101-1500mg/l Above 1500mg/l There is no need to close the pool, but immediate action should be taken to bring it back to the green zone. This will necessitate dilution of the pool

Frequency of testing: Chlorine tests and pH: Before the pool is opened to bathers and then every three hours during the hours of operation whilst the pool is in the green zone. If the reading falls within the amber zone for chlorine levels and pH, take corrective action, then repeat the tests in 30 minutes, if the reading is again in amber range, take further corrective action, and report to the site manager. Tests for total alkalinity, calcium hardness and TDS should be undertaken weekly and corrective action taken if the results are not in the green zone.


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Section 2: The impact that the incoming mains water has on pools

In this section, we are going to consider the implications of the incoming mains water supply in the treatment of swimming pool water. In order to understand the make-up of incoming mains water it is necessary to trace the water back to its origins – i.e. obviously rainfall, but where did the rain fall? and, was it merely collected in a lake? or did it pass through the ground to create, what is in effect, an underground lake? The properties of the incoming mains water will be dependent on the geographical location of the pool. The number of minerals and chemicals in the mains water will determine the characteristics of the water, and so every time the pool is drained, or every time the pool water filters are backwashed the incoming water supply will have an effect on the chemistry of the pool itself. In addition to the “natural” minerals contained within water, depending upon the location from which it came, there will also be other chemicals that have been added to the water by the chemical utility companies as they treat it, in order for them to provide a safe water supply. When water supplies emanate from mountainous areas which feed the lakes, there tends to be very few minerals contained within it, and such water will often have a low pH, low total alkalinity, low calcium hardness level and very few totally dissolved solids. We will be discussing the implications of the above later, but, put simply, if the incoming water supply has such a low chemical content this will have the effect of lowering pH, total alkalinity, calcium hardness and total dissolved solids every time the mains water replaces water used for the backwash process. This type of water is referred to as surface water and is described as being ‘soft’. Soft water has a tendency to cause corrosion of equipment within the plant room and can also damage the pool water tank by dissolving the grout around the tiles; this process is called ‘erosion’. Soap lathers easily in soft water. When water emanates from deep wells and boreholes which have been sunk into the ground in order to capture underground water supplies, the water tends to be rich in minerals and often such water will have high pH, total alkalinity, calcium hardness and high total dissolved solids. This type of water is referred to as Ground Water. Consequently, when this water is introduced into the pool, the above parameters will rise within the pool, and corrective action will need to be taken. Ground water is described as ‘hard’ water, which, unlike soft water, which tends to cause corrosion, actually lays down chemicals within the pipework which can reduce the pool diameter. This is referred to as ‘scaling’ and such waters as ‘scale forming’. Soap does not lather easily in hard water and this can lead to cleaning difficulties caused by lime scale build up. Before deciding on the most appropriate type of disinfection system to be employed within a swimming pool, it is worth carrying out an investigation into the chemical make-up of the incoming mains water. If the pool operator is aware of the characteristics of the incoming water supply, it makes good sense to use disinfectants and chemicals which would be compatible with the incoming water supply, and in doing so this is an indication that the minimum number of chemicals will be used and there is more chance that the water will be balanced – i.e. neither corrosive nor scale forming.


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The impact of geography on incoming mains water Differing characteristics by location: Light green: soft Deep blue: Hard Purple: Medium


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Hard or soft: testing the incoming mains water supply In order to confirm whether the incoming mains water is hard or soft, the tests which need to be carried out are:

• pH • Total alkalinity • Calcium hardness • Total dissolved solids

The principles and practices of pool water testing were discussed in detail in Unit 2 and you may wish to refer back to this when carrying out the tests. It would be useful to use this information to compare with the readings taken in the pool itself in order for you to make a comparison between the incoming water supply and the water conditions prevalent in the pool as a result in the pool water chemical regime being used. The following table summarises the impact of the incoming mains water.


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The effect of incoming mains water on pools Parameter

Effect

pH Incoming mains pH levels below 7.2 will lower the pH of the pool water when dilution takes place (after backwash) and may make the water corrosive. Incoming mains pH levels above 7.4 will raise the pH of the pool water when dilution takes place (after backwash) and may make the water scale forming

Total alkalinity Total alkalinity levels in pool are determined by the disinfectant used, but are usually between 80-200mg/l If the total alkalinity is lower than 80mg/l it will lower the total alkalinity of the pool water when dilution takes place (after backwash) and may make the water corrosive. If the total alkalinity is higher than 200mg/l this will raise the TA of the pool water when dilution takes place (after backwash) and may make the water scale forming

Calcium hardness If the calcium hardness is lower than 75mg/l it is an indication that the incoming water supply may be soft and the calcium hardness will need to be increased. If the calcium hardness is higher than 150mg/l it is an indication that the incoming water supply may be hard. (Calcium hardness levels in pool are usually kept between 200-300mg/l)

TDS TDS levels in pools should be no higher than the incoming mains level plus 1000mg/l

Mains water supply standards There are water quality standards in the water supply industry and these are contained within the Water Supply (Water Quality Regulations 2000 (in England) and Water Supply (Water Quality Regulations 2001 (in Wales) and both of these are in line with the 1998 EU directive on the Quality of Water Intended for Human Consumption. There are different, but similar regulations, which are applicable in Scotland and Northern Ireland. The World Health Organisation (WHO) Drinking Water Guidelines give a global view and are the basis of the EU directive. Mains water may have to be transported over long distances, so it is possible that a region may receive soft water from distant uplands source and hard water from a local underground or impounded source, and sometimes, the water can be a blend of the two. It goes without saying, that water supplies must be safe and secure, in line with the Private Water Supply Regulations 2006. The Water Authorities filter the water in order to remove solids, use a coagulant to remove colour and some of the smaller tiny chemicals in the water and then they add a disinfectant,


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which is usually chlorine based. Clearly, the disinfectant is to make sure that the water arrives at the tap safely free from harmful bacteria or contamination. All water suppliers are required by regulations to maintain a public record of the quality of water supplied to each supply zone, and users have a right to inspect the record and have a free copy of it for their water supply records. Dependent on where the water supply came from, the standard values for pH value are between 5.5 and 9.5, which means that it can be significantly different to the pH required in the pool. The hardness level measured as ‘total hardness’ is normally maintained at a standard minimum value of 60 mg Ca//litre where the water is softened at the water works. Total alkalinity is normally maintained at a minimum of 30mg/l, again, where this is treated at the water works. Question Time

1 If the incoming water supply has low pH, low total alkalinity and low calcium hardness, is it likely to be soft water or hard water?

2 Which type of water tends to cause a build up of scale within pipes? Soft water or

hard water?

3 Have tests been carried out on the incoming mains water at the pool at which you work? If so, is the disinfectant and chemical regime compatible with it?


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Section 3: Legislation, regulations and guidance As we saw in Unit 1, pool operators, and all those who are responsible for management and operation of swimming pools have a legal responsibility to provide a safe pool environment, one which will not be harmful to, or damage either bathers, staff, spectators or visitors. The Health and Safety at Work etc. Act 1974 (HASAW) places a legal duty on pool operators to ensure a safe working environment and safe working practices. This is referred to as a ‘Duty of Care’. The HASAW 1974 Act was further reinforced by the European based, Management of Health and Safety at Work Regulations 1999 which requires managers and operators to carry out risk assessments and produce documents which underpin safe working practices. These documents are referred to as Normal Operating Procedures (NOP’s) and Emergency Action Plans (EAP’s). Normal operating procedures apply to the working environment when everything is working normally, and therefore would apply most of the time. Emergency Action Plans (EAPs) come into play when things go wrong. There are a number of other regulations and also codes of practice which relate to pool plant operations and these will be discussed later; for now though, it is sufficient to state that the pool operator must be aware of these regulations and ensure that the requirements of the law are fully met. Should anyone be hurt or damaged as result of non-compliance with the law there will be an investigation which will lead to the prosecution of individuals and organisations, and as a result, there will invariably be claims for compensation by the damaged party, spurred on by the advertising campaigns of claims management companies advertising constantly on television, radio and in the media generally. Guidance publications There are a number of publications which provide guidance on the operation of pools. Examples of relevant publications are:

• Managing Health and Safety in Swimming Pools (HSG 179, published by the HSE). • Swimming Pool Water Treatment and Quality Standards in Pools and Spa Pools

(Pool Water Treatment Advisory Group (PWTAG). • PWTAG Code of Practice: The Management and Treatment of Swimming Pool Water • Guidelines for Safe Recreational Water Environments: Volume 2, Swimming Pools

and similar environments (World Health Organisation 2006). • BS EN 13451-1. Swimming pool equipment. Part 1. General safety requirements and

test methods • BS EN 15288-2:2008: Swimming pools. Safety requirements for operation • BS EN 15288-1:2008 Swimming pools. Safety requirements for design

Additionally, the following organisations have produced a number of technical publications which are also helpful to pool operators:

• The Pool Water Treatment Advisory Group (PWTAG) • The Institute of Swimming Pool Engineers


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Although, as can be seen, there are a number of guidance documents, it should be noted that the industry have adopted Managing Health and Safety in Swimming Pools HSG179 and the Pool Water Treatment Advisory Group publication Swimming Pool Water Treatment and Quality Standards in Pools and Spa Pools as being the key authoritative texts and it will be found that most normal operating procedures and emergency action plans for swimming pools are based upon these two documents. Both of these documents have been referred to constantly throughout the course of this manual with the Managing Health and Safety in Swimming Pools document referred to as HSG179, and the PWTAG publication ‘Swimming Pool Water Treatment and Quality Standards in Pools and Spa Pools’ will simply be referred to as SPW. The importance of HSG179 cannot be overstated. It is generally accepted that this is the way that the Health and Safety Executive interpret health and safety law in relation to swimming pools, and the document is often quoted in court. It is the key publication used by Health and Safety Executive Officers and Environmental Health Enforcement Officers. HSG179 clearly lays out what the law actually requires of pool operators, which put simply is, that every pool operator is responsible for health and safety. It then goes on to make specific references to the Health and Safety at Work etc Act 1974, confirming that the Act places duties on employers, employees and self employed people and that it also protects those undertaking voluntary work and the public who may be effected by work activities. PWTAG Code of Practice: The Management and Treatment of Swimming Pool Water The purpose of this Code of Practice (CoP) is to provide pool managers and operators with the fundamental principles of good practice in swimming pool operation. It reinforces the principles expounded in their book Swimming Pool Water Treatment and Quality Standards in Pools and Spa Pools, and the associated technical updates to be found on the PWTAG website. The code is to be reviewed at intervals not exceeding two years and any amendments arising from the review will be published in an amended CoP and published on the PWTAG website. The code contains general operational and safety recommendations for the management of swimming pool water treatment systems and associated water treatment plant, heating and ventilation systems. The code sets out how the technical operation of the pool should function and focuses clearly on good practice. It provides firm guidelines for public pools; which can be applied apply to other types of pools not covered by the code. The code is based principally on published guidance from PWTAG, but also on material from the Health and Safety Executive, the Health Protection Agency, Public Health Wales and the World Health Organisation; also on BSEN standards. The code can be downloaded free of charge from the PWTAG website.


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Current regulations which affect the health and safety management of a pool environment Current regulations which affect the health and safety management of a pool environment include the following:

• Health and Safety at Work etc. Act 1974 • Management of Health and Safety at Work Regulations 1999 • Workplace (Health, Safety and Welfare) Regulations 1992 • Provision and Use of Work Equipment Regulations 1998 • The Personal Protective Equipment Regulations 2002 • Construction (Design and Management) Regulations 2007 • Electricity at Work Regulations 1989 • Manual Handling Operations Regulations 1992 • The Personal Protective Equipment Regulations 1992 • Control of Substances Hazardous to Health Regulations 2002 (COSHH) • Reporting of Injuries, Diseases and Dangerous Occurrence Regulations 1995

(RIDDOR) • Health and Safety (Safety Signs and Signals) Regulations 1996 • Diving at Work Regulations 1997 • Employer’s Liability (Compulsory Insurance) Act 1969 • Regulatory Reform (Fire Safety) Order 2005 • Health and Safety (Enforcing Authority) Regulations 1998 • Confined Spaces Regulations 1997 • Registration, Evaluation, Authorisation and Restriction of Chemicals Regulations

2007 (REACH) • Biocidal Products Regulations 2001(BPR) • Biocidal Products EU Directive • Work at Height Regulations 2005 (WAHR)

Although the list of legislation is vast, there are some of the above which are worthy of further comment; The Health and Safety (Safety Sign and Signals) Regulations 1996 and COSHH were covered in some detail in Unit 3, but it is important to recognise the importance of the Reporting of Injuries, Diseases and Dangerous Occurrence Regulations 1995 (RIDDOR) How then can the pool operator meet their legal responsibilities? The answer to this is to ensure that there are policies and procedures in place, devised by a competent person and based upon thorough risk assessment. The policies and procedures must be: • Appropriate • Sufficient • Available, • Trained to, • Enforced by managers and: • Accurate records kept confirming to the authorities that the legal requirements are being complied with. It is important that lifeguards, caretakers, duty officers, physiotherapists, teachers, and all those who are involved with the operation of pools, have an appropriate level of understanding of how the pool water is treated, appropriate to their level of responsibility and know when the pool is safe to use.


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Activity Make a list of five ways in which a pool operator could demonstrate to the authorities that they are taking their legal obligations and responsibilities seriously. Your suggestions: 1 2 3 4 5

Question Time 1. List the two key pieces of legislation which apply to swimming pools?

2. Name two key guidance documents relating to pool management

3. What do pool operators have to do in order to comply with the Management of Health and Safety at Work Regulations 1999?


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Principal pool related legislation The Health and Safety at Work etc. Act 1974 The Health and Safety at Work etc. Act 1974 was discussed in Unit 1 and also earlier in this section. We are now going to explore the ways in which this Act has a significant effect on safe working practices employed within a swimming pool. At this stage it is worth looking at HSG179 in respect of what the law requires from pool operators. The Health and Safety at Work etc. Act of 1974 places duties on employers, employees and self employed people. It protects not only people at work, including those undertaking voluntary work, but also the general public who may be effected by work activities. Many of the requirements in this legislation are qualified with ‘so far as is reasonably practicable’. The general requirements under The Health and Safety at Work etc. Act are that equipment and plant are safe, the workplace is safe, there are safe systems of work and there is the provision of information, instruction, training and supervision needed to ensure that safety (HSG179 paragraph 16). Employees must do all that is reasonably practicable to take care of their own health and safety and that of others, including those undertaking voluntary work, who may be affected by their acts of emissions at work and they must co-operate with their employers in complying with statutory health and safety obligations. Manufacturers and those installing equipment have a duty under Section 6 of this Act to ensure that their products do not cause harm and are safe to use, including the provision of instructions on use and maintenance of equipment provided. The term ‘so far as reasonably practicable’ basically means that the degree of risk in a particular job or workplace needs to be balanced against the time, trouble, cost, benefit and physical difficulty of taking measures to avoid or reduce the risk. However, HSG179 makes it clear that it should not be used as an excuse to avoid taking safety measures, and if unsure, the pool operator should always err on the side of caution. So then, the Act impacts on a swimming pool in respect of: • Safe equipment and plant • Safe workplace • Safe systems of work • Provision of information • Provision of instruction and training • Provision of supervision in order to ensure safety Question Time

1. Who does The Health and Safety at Work etc. Act 1974 apply to? 2. Which buildings does it apply to? 3. List 4 ways in which the Act impacts on swimming pools


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RIDDOR Under the regulations, pool operators must: notify the enforcing authority without delay (for example by telephone), followed by a completed accident form (F2508) within 10 days, if an employee is killed, or suffers a ‘major’ injury (including as a result of physical violence); or a member of the public is killed or taken to hospital; or there is a ‘dangerous occurrence’ as defined in the regulations.

• Send a completed accident form (F2508) to the enforcing authority within 10 days, if there is a work related accident and, if an employee or self employed person does not suffer a major injury, but is unable to do their normal work for more than 3 days (including as a result of physical violence);

• Send a completed disease form (F2508a) to the enforcing authority as soon as they receive notification from a doctor that an employee is suffering from one of the work related diseased set out in RIDDOR.

Examples of reportable incidents could include: • Pool user is resuscitated and is taken to hospital • Lifeguard is injured as a result of violence by another person • Pool operator is splashed with chemicals causing injury The term ‘major injury’ is defined in RIDDOR and can include injuries such as: certain fractures and dislocations; unconsciousness; admittance to hospital for more than 24 hours; an acute illness caused by absorption of any substance. ‘Dangerous occurrences’ are serious incidents accidents which do not lead to reportable injury. They include the failure of lifts and lifting equipment; electrical short circuit or over-load causing fire or explosion; and the result of any substance with the potential to damage health. In this context it is important to note that pool operators work with chemicals which are potentially highly dangerous. It is essential that all pool operators record and monitor all accidents and incidents, particularly successful rescues. If this is done, it will help:

• to ensure effective risk assessment • to identify possible problem areas and • in possible cases of civil legal action at a later date

Control of Substances Hazardous to Health (COSHH) Regulations 2002 Under the COSHH Regulations every employer has a responsibility to assess the risk associated with hazardous chemicals used or stored in the workplace and to take adequate steps to eliminate or control those risks. These regulations cover the majority of swimming pool chemicals, hence the need for special care when choosing and using such materials. The regulations also cover the risks arising from microorganisms, bacteria, for example. Having carried out the risk assessment, the next stage is to prevent or control exposure to hazardous substances. Prevention is obviously best.


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The pool operator will need to consider whether prevention can best be achieved by substituting a less harmful substance, or one that is compatible with other chemicals on site. This will definitely reduce the risk to health due to fire, explosion, or the production of toxic gases. When prevention is not reasonably practicable, it is then appropriate for the pool operator to turn to other control measures, such as personal protective equipment (PPE). The COSHH Regulations require suppliers of chemicals to provide a Material Safety Data Sheet (MSDS) for each chemical. It should be noted that it is also the installer’s responsibility to provide relevant information on plant, safety, etc. which may include MSDS’s. There will be a need for MSDS sheets for all the chemicals used for all the chemicals used in the plant room, including test reagent chemicals, cleaning chemicals, chemicals used in maintenance programmes etc. The COSHH Regulations require that staff involved in the handling and use of chemicals should receive appropriate training and instruction. HSG179 makes the point that only competent people should handle chemicals.


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Written systems of work Management of Health and Safety at Work Regulations 1999 Under the Management of Health and Safety at Work Regulations 1999, pool operators must carry out an assessment of the risks which may affect employees and others as a result of the work activity done. These requirements also take into account members of the public using the pool and action needs to be taken to eliminate or reduce risks, as far as is reasonable practicable. These regulations place an obligation on pool operators to carry out risk assessments which lead to the formulation of the Normal Operating Procedures (NOP) and Emergency Action Plans (EAP) Risk assessment of swimming pool operations A hazard is defined as anything that may cause harm. The first stage of carrying out a risk assessment is to look for the hazards. A hazard is defined as anything that may cause harm. So then, what are the hazards associated with ineffective pool water treatment? Well, the obvious one is that the bather could become ill as a result of bacteria present in the water because of inadequate levels of disinfection. All swimming pools must be safe to swim in, as confirmed by pool water testing, which is backed up by bacteriological testing. Bathers can also be harmed as a result of pool operators introducing chemicals directly into the pool. This is dangerous practice and should not be done. If the filtration system is not adequately maintained and backwashed frequently enough, it is possible for the water to become cloudy and of poor quality. Lifeguards are trained to close the pool in the event of them not being able to see the bottom of the pool. This is an unfortunate occurrence which should have been rectified well ahead of the pool cloudiness occurring. Question Time

1. What is a hazard? 2. What is the staffing structure at your pool? 3. Who carries out the risk assessment related to pool plant?


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Factors to be considered when writing polices and procedure The factors to be considered when writing polices and procedure Include: • Bathers • Staff • Environmental • Design • Temperature • Management structure • Age of building Bathers and staff It is important for the pool operator to understand how the swimming pool is programmed and for whom. Clearly, there will be a significant difference in the way that the pool is managed dependent upon whether the pool is, for example, a hotel pool, or whether it’s a school pool, a large leisure centre, or a holiday park. The human factors therefore include the type of bather (age, disability etc), the number of bathers and the type of activity which they will be involved in. The more bathers there are, the more pollution there will be. As we saw in Unit 1, bathers introduce a significant amount of pollution into the water and it was recognised that a significant way of reducing this pollution would be by ensuring a pre-swim hygiene culture, implementing the 5 stage plan/procedures, which is then implemented and enforced by the centre staff. Environmental There is a link between environmental conditions and design, in that, older buildings tend to have poorer ventilation systems, and consequently the pool hall air environmental conditions can be less than ideal. Some pools are traditional internal pools, which of course are in the majority in the UK, whilst other pools are outside pools, which of course is very much the domain of the overseas holiday resorts such as the Mediterranean countries. There are a large number of outside pools within the UK, some of which are on holiday parks, and some of which are in schools. Outside pools present particular challenges for the pool operator, especially in relation to levels of physical pollution. The geographical location of the centre also has a bearing on the environmental issues in terms of incoming mains water supply. This was discussed in Section 2. Design ‘Design’ covers a number of factors, including the type and size of the building itself and also the age of the building. Some UK pools are in excess of 100 years old and design conditions at the time when those buildings were built are entirely different to those which currently apply.


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Engineering services have to be properly designed to ensure that pumps, filters, etc are adequately sized to provide the design turnover for the pool. It is important to ensure that there is a streamline flow of water within the pool itself, ensuring that there are no ‘dead-spots’ in the pool, i.e. areas where the water does not move. Designers need to ensure that hazards are not created in the pool as a result of sunlight and glare, which obviously would impact negatively on the lifeguard’s ability to do their job. Temperature The temperature of the pool is dependent upon the activity which takes place there and the type of bathers which use the pool. Pool water temperatures were discussed in Unit 1. Management Structure The management structure employed within the pool will depend upon the type of pool and whether or not the pool is in the control of the local authority, a private sector organisation or a school or college. In some cases, pools are tested and operated by, for example, caretakers, as would be the case in a school, in other pools, water testing may be carried out by lifeguards, but the plant maintained by a technical officer. In other pools, the duty officer would be required to test the water and take care of the plant. Every member of staff who is involved in the operation of the swimming pool should realise and understand what is required of them, and appropriate training should be provided for all members of staff and team members, appropriate to their level of experience. Where there have been prosecutions as a result of people being damaged by unsafe pool water, it has been invariably identified that it was a ‘management failure’ which caused or allowed this to happen, so it is important for pool operators to understand that it is the facility manager who will be held responsible in the event of an incident.


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Pool Safety Operating Procedures (PSOP) All pools should have a Pool Safety Operating Procedures (PSOP). The PSOP combines together the NOP and the EAP in a pool context. HSG 179 sets out in detail what should be included in the procedure. Normal Operating Plan (NOP) (a) Details of the pool(s) - dimensions and depths, features and equipment and a plan of the building. The plan of the building may include positions of pool alarms, fire alarms, emergency exit routes and any other relevant information. (b) Potential risk - an appreciation of the main hazards and of users particularly at risk is required before safe operating procedures can be identified. (c) Dealing with the public - arrangements for communicating safety messages to customers, customer care, poolside rules for the public and for lifeguards, controlling access. (d) Lifeguards’ duties and responsibilities and special supervision requirements for equipment, etc; lifeguard training; and numbers of lifeguards for particular activities. (e) Systems of work including lines of supervision, call-out procedures, work rotation and maximum poolside working times. (f) Operational systems - controlling access to a pool or pools intended to be out of use including the safe use of pool covers. (g) Detailed work instructions including pool cleaning procedures, safe setting up and checking of equipment, diving procedures and setting up the pool for galas. (h) First aid supplies and training, including equipment required, its location, arrangements for checking it, first aiders, first aid training and disposal of sharps. (i) Details of alarm systems and any emergency equipment, maintenance arrangements - all alarm systems and emergency equipment provided, including operation, location, action to be taken on hearing the alarm, testing arrangements and maintenance. (j) Conditions of hire to outside organisations. Emergency Action Plan (EAP) Action to be taken in the event of a foreseeable emergency, for example: (a) overcrowding; (b) disorderly behaviour (including violence to staff); (c) lack of water clarity; (d) outbreak of fire (or sounding of the alarm to evacuate the building); (e) bomb threat; (f) lighting failure; (g) structural failure; (h) emission of toxic gases; (i) serious injury to a bather; (j) discovery of a casualty in the water. The procedure should make it clear, if it becomes necessary, how to clear the water or evacuate the building. To ensure the effectiveness of emergency procedures management should ensure: (a) all staff are adequately trained in such procedures; (b) notices are displayed to advise the general public of the arrangements; (c) exit doors, signs, fire-fighting equipment and break-glass call points where provided, should be checked regularly to ensure they are kept free from obstruction; (d) all fire exit doors are operable without the aid of a key at all times the premises are occupied.


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Pool Technical Operation Procedures (PTOP) The requirements for a Pool Technical Operation Procedures (PTOP) document are detailed both in SPW and also the PWTAG Code of Practice. The document contains the policy and procedures for the general operation of the pool water treatment, it forms a part of the risk assessment process for the whole pool facility, sets out how the plant should function and be operated safely, and also contributes to the formulation of pool safety operational procedures (PSOP). The first step in preparing a PTOP is to establish a policy for water quality, safety, and hygiene and to have a strategy for its implementation. There should be clear objectives and a good management plan to achieve them. Learning from experience is important. You should review the outcomes and if necessary make changes to improve things. SPW states that the policy and strategy should:

• demonstrate the commitment of senior management to the quality and safety of pool water

• integrate the quality and safety of pool water management with other relevant policies and management activities throughout the organisation.

• clearly set out how the organisation is structured to deal with the quality and safety of pool water issues

• show how that organisation might usefully change, and set out the steps to get there • identify the resources, both financial and staff time, necessary to achieve the

objectives. The PTOP should contain monitoring measures for the safe and effective performance of

their pool operation. Such measures would include the monitoring of: • plant and pool water treatment systems • pool water testing • bacteriological monitoring and interpretation • feedback from regulatory authorities and users of the pool • actions taken or required to ensure compliance with operational plans and

procedures • any corrective and preventive actions • responding to incidents and other emergencies • pursuit of the industry recognised awards. • staff training

As with any management process, the PTOP should be reviewed on a regular basis. The review would be informed by: • Customer feedback: users of the pool, suppliers, regulators and other external parties • action taken to restore or to improve water quality • incidents or emergencies impacting upon water quality • follow-up actions from previous management reviews • changes that could affect the water treatment system, including changes in pool plant or

chemicals • changes in regulations or national standards


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Question Time 1. What is the purpose of the PTOP? 2. Has a PTOP been developed for your pool? 3. If so, how importantly is it viewed as a management tool? 4. How often is it reviewed? and who by? 5. If a PTOP has not been developed for your pool, who could you discuss it with to put it

on the management agenda?


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Section 4: Pool related emergency procedures It is essential that the pool operator be able to identify an emergency as such and be aware of the procedures to follow in order to respond appropriately in the event of such an event occurring.

The key document here is the PSOP and, in particular, the EAP elements of it. The key guidance is found in HSG 179 and SPW.

Typical emergencies in a pool environment would include:

• Chemical incidents • Bomb alerts • Structural failure • Fire • Pool related accident • Drowning • Faecal release into the pool • Blood release into the pool • Bather vomiting into the pool • Poor pool water clarity

Each of the above would have its own detailed procedure which must be followed.

The identification and implementation of the emergency procedures listed above are relatively self-evident, but it is useful to note that on the whole, the type of emergency tends to be either bather related or facility related.

In all case, bathers would have to be instructed to get out of the pool whilst the procedure is followed; and in some cases they may even have to be evacuated from the building.

The pool operator must know when evacuation of a pool environment would be necessary and what to do if this should be required.

The procedure for evacuating the pool environment

The procedure for evacuating the pool environment must be detailed in the PSOP and the procedures must be followed exactly. Evacuations must be practiced regularly and monitored for compliance by the centre management team, so that when the real incident occurs the various team members know what to do and do not panic.

The pool operator has a legal duty to ensure the health and safety of pool users during an evacuation

Although the PSOP should contain details of what to do in an emergency evacuation it rarely provides the detailed information which is required to ensure that the pool users are looked after and the level of customer care which is required.

An example of this would be in the event of an emergency, which leads to the bathers having to be instructed to get out of the pool and to evacuate the building. In this case, the bathers would need to be provided with foil blankets and they will need to be evacuated to a safe place, which may be another adjacent building or possibly to a car park assembly point.

If this is to be achieved there needs to be sufficient foil blankets to accommodate the maximum bathing load as detailed in the NOP. Team members need to know where they are kept and ensure the orderly distribution of them.

As you can imagine, this could be extremely uncomfortable, disconcerting and possibly distressing to some bathers, therefore a member of staff will need to stay with the evacuees to reassure them, deal with their concerns and keep them informed.


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After the event, the foil blankets will need to restocked and made available for future use. An inventory will need to be kept to ensure that they are available when needed.

Activity

Research the PSOP for the pool that you work at and look in particular for the procedure to be followed in the event of a pool evacuation requiring the evacuation from the building.

If the document lacks the requited detail in relation to the use of foil blankets etc. find out from your manager what the procedure actually is.


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Pool contamination emergencies There are specific procedures which must be to be followed in the event of the following contamination related incidents in the pool:

• Faecal release into the pool

• Blood release into the pool

• Bather vomiting into the pool It is important that the pool operator can distinguish between low risk emergency action and high risk emergency procedures, such as dealing with a diarrhoea incident in the pool. In all cases, given the seriousness of these types of incident, the guidance provided by PWTAG should be followed The following procedures are in line with the current guidance provided by PWTAG. Faecal release into the pool

If a pool is contaminated with faeces, the pool operator must decide quickly on an appropriate course of action in order to prevent any possible illness in users. This is particularly important with diarrhoea, which may contain the chlorine-resistant organism Cryptosporidium. All faeces contain potentially harmful microorganisms. The actual risk to pool users depends on whether the faeces are solid or runny. It should be noted that the following emergency procedures are followed where sand filters are installed at the facility. Solid faeces Solid faeces are relatively easy to deal with. The procedure to follow is:

1. Clear the pool of bathers 2. The stools should immediately be removed from the pool using a scoop or fine mesh

net and flushed down the toilet (not put in any pool drains). 3. There must be certainty that all the faeces have been captured and disposed of. If

not, and there is possible widespread distribution of the faeces in the pool, then the pool should be closed and the advice given for runny faeces considered.

4. All equipment that has been used in this process should be disinfected using a 1% solution of hypochlorite.

5. If the pool is operating properly with appropriate disinfectant residuals and pH values, no further action is necessary.

6. Allow the bathers back into the pool. Pool operators should consider clearing the pool of bathers for, say, 30 minutes whilst the above procedure is followed. This would certainly be necessary if the faeces has broken up. In which case, bathing should not resume until all the faeces have been removed.


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Runny faeces (Diarrhoea) If the stool is watery, runny or soft (diarrhoea), the risk of infection is greater. The pool operator must know the type of filtration system being used on the pool since the emergency procedure to be followed depends on whether the filters are medium rate or high rate Since the perpetrator is more likely to be carrying enteric pathogens which may spread through the pool water, it will certainly be impossible to remove the faecal material as it is with solid stool. The infectious causes of diarrhoea include viruses, bacteria and protozoa. (Other causes include alcohol, emotion, diet and medicine side effects.) Most of the bacteria and viruses that cause diarrhoea – E coli, Shigella, norovirus, for example – are killed within minutes in a satisfactorily disinfected pool water. But if the diarrhoea contains oocysts of the chlorine-resistant protozoa Cryptosporidium, normal levels of chlorine will not be effective. Crypto is a significant cause of relatively serious gastroenteritis, particularly in pools. Young children are both the likeliest sources of the infection, and those worst affected (along with the immunocompromised). In most cases of diarrhoea in a swimming pool, the operator will not know if Crypto is involved. So the safest option is to assume that it is and immediately close the pool. There are in principle three procedures that will in time remove Crypto – coagulation/filtration, UV and superchlorination. The procedures to be followed primarily depend on the efficiency of the pool’s filtration. These procedures are endorsed by Public Health England and the national Cryptosporidium Reference Unit which is part of Public Health Wales. Pools with medium-rate filtration (up to 25 metres per hour) These are the type of filters which should be installed in public pools. The main emphasis is here is on filtration. Coagulation is critical in this: it should be continuous, and the residence time (that between the injection of coagulant and treated water reaching the filter) must be long enough for flocculation to happen – at least 10 seconds at a flow velocity no more than 1.5m/sec. Secondary disinfection (UV or ozone) and superchlorination are also relevant. How long it takes for all the pool water to pass through the filter will depend on two factors. First is the pool hydraulics – crucially, how well mixed the pool water is. Dead spots will delay the passage of all the pool water through the filters. The second factor is the turnover period – the length of time it takes for a volume of water equivalent to the pool water volume to go from pool to plant room and round to the pool again. It might take as long as 24 hours for all the pool water to pass through the filters – based on the 3 to 4-hour turnover period common to many pools. The procedure for use with medium rate filters is as follows: 1 Close the pool – and any other pools whose water treatment is linked to the fouled pool. If people transfer to another pool, perhaps from a teaching pool to a main or leisure pool, they should shower first using soap and water. 2 Hold the disinfectant residual at the top of its set range for the particular pool (e.g. 2.0mg/l free chlorine if the range is 1.0 to 2.0mg/l) and the pH value at the bottom of its range (e.g. pH 7.2-7.4). This will maintain the normal level of microbiological protection. 3 Ensure that the coagulant dose is correct – for continually dosed PAC, 0.1ml/m3 of the total flow rate.


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4 Filter for six turnover cycles (which may mean closing the pool for a day). This assumes good hydraulics and well maintained filters with a bed depth of 800mm and 16/30 sand. This applies also to pools with secondary disinfection. 5 Monitor disinfection residuals throughout this period 6 Vacuum and sweep the pool. Cleaning equipment, including automatic cleaners should be disinfected after use, this will at least move faecal contamination off surfaces and into the main pool water circulation, for eventual removal. 7 Make sure the pool treatment plant is operating as it should (filters, circulation, disinfection) 8 After six turnovers, backwash the filters. 9 Allow the filter media to settle by running water to drain for a few minutes before reconnecting the filter to the pool. 10 Circulate the water for 8 hours. This will remove any remaining oocyst contamination of the pool and allow the filters to ripen. It is optional, depending on the pool operator’s confidence in backwashing procedures. 11 Check disinfection levels and pH. If they are satisfactory re-open the pool. 12 Any moveable floors and booms should be moved around from time to time during the whole process. Pools with high-rate filtration (over 25 and up to 50 metres per hour) In the case of high-rate filters the main emphasis is on superchlorination. PWTAG make the point that high-rate filters without coagulation remove as little as 10% of Cryptosporidium oocysts in each pass. Even with coagulation, and perhaps 50% removal, it could take two days to be safe. The procedures below also apply to tier filters. 1 Close the pool – and any other pools whose water treatment is linked to the fouled pool. If people transfer to another pool, they should shower first using soap and water. 2 If coagulation is not the norm, a supply of polyelectrolyte coagulant should be available so it can be hand-dosed in these circumstances, following manufacturers’ instructions. 3 Superchlorinate to 20mg/l adjusting the pH to 7.2-7.4 and leave for 13 hours (or 50mg/l for 5 hours). Procedures and supplies must be in place for this. 4 Vacuum and sweep the pool. 5 Make sure the pool treatment plant is operating as it should. 6 Backwash the filters. 7 Allow the filter media to settle by running to drain for a few minutes (rinse cycle) before reconnecting the filter to the pool. 8 Reduce the free chlorine residual to normal by dilution with fresh water or using an approved chemical. This may mean using the chemical gradually; procedures and supplies must be in place for this. See Technical note 21 for details. 9 When the disinfectant residual and pH are at normal levels for the pool, re-open. 10 Superchlorination should remove any current contamination but will not guarantee future water quality. So it is important to review procedures for the control and removal of contamination by Crypto. Pools with no filtration (fill and empty pools) Here there is the possibility of emptying the pool altogether. This might apply to a paddling or plunge pool, for example. For any pool, if operators are confident that they can safely empty the pool, this is the procedure that should be followed. 1. Close the pool – and any other pools whose water treatment is linked to the fouled pool. 2. Superchlorinate the pool to 20mg/l for 13 hours or 50mg/l for 5 hours. 3. Vacuum and sweep the pool. 4. Drain, rinse and refill. 5. Re-treat and when disinfectant residual and pH are at normal levels for the pool, reopen

the pool.


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Secondary disinfection Secondary disinfection using UV is strongly recommended by PWTAG – partly to counter the threat from Cryptosporidium and partly for its other water quality benefits, including allowing pools to operate with lower disinfectant residuals. UV plus good coagulation and filtration provides a multi-barrier defence against Cryptosporidium. Pool operators should carry out a risk assessment to determine whether secondary disinfection is required. The risk assessment should take into account the hydraulic and filter characteristics of the pool, as well as the risk from routine unseen contamination. It is particularly recommended for hydrotherapy pools and pools used by young children. Their users are likely to be more vulnerable to – and to be carriers of – Cryptosporidium. Where used, UV should be applied to the full flow and be capable of a 3log (99.9%) reduction in viable Cryptosporidium oocysts. UV installations should be medium pressure, 60mJ/cm2 and monitored to ensure an effective dose rate. Superchlorination The US Center for Disease Control (CDC) recommends high chlorine concentrations alone (e.g. 20mg/l for 13 hours) to inactivate Cryptosporidium if any swimming pool is contaminated. In practice, many pools would find achieving and maintaining such residuals difficult with standard dosing equipment. Then there is the possibility of generating unwelcome disinfection by-products as a result. And finally there is the challenge of reducing residual levels afterwards – either chemically or by water replacement. The effectiveness of this approach is difficult to monitor, and is no quicker than the coagulation and filtration method above. Coagulation, filtration and backwashing are certainly also needed. And any UV (or ozone) plant should be switched off and by-passed during superchlorination. Operators may wish to consider superchlorination, either on its own or alongside PWTAG’s filtration method – belt and braces. Operators should be confident that the pool plant , including valves etc, will withstand superchlorination. PWTAG Technical Note 23 has details of superchlorination and de-chlorination.


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Be pro-active, not reactive: Prevention methods Because pool operators are unlikely to know what the cause is of any contamination with diarrhoea, and because it can get into a pool unnoticed, the best defence against infections including Cryptosporidium is good Hygiene, Hydraulics and Filtration. Secondary disinfection with UV is a good second line of defence. Investigations of Crypto outbreaks linked to pools frequently reveal inadequate design, operation and management issues which would have made the pool vulnerable to an outbreak following contamination with diarrhoea. Attention to these issues is vital. Prevention can be summarised.

• Control bather entry using notices at reception saying that people with diarrhoea must not swim – then, or for 48 hours afterwards. Those who have been diagnosed with cryptosporidiosis must not swim for 14 days after diarrhoea has stopped, as infective Cryptosporidium oocysts can still be released in that period.

• Encourage bathers to wash and shower before swimming. • Pre-swim showering is good for water and air quality in any case, as it minimises

combined chlorines. • Encourage bathers to use the toilets before they swim, and wash their hands

afterwards. Children should be offered frequent toilet breaks. • Young children should ideally have their own pools. There should be good baby

changing facilities, and babies should wear special swimming nappies (but not swim if they have diarrhoea). There should be provision for safe disposal of soiled nappies.

• Continuous low-level dosing of a coagulant is recommended for all pools to improve the filtration efficiency and increase the removal of any contaminants from the pool. This procedure significantly reduces the risk associated with any unseen faecal release.

• Backwashing protocol is critical; when neglected, for example, it can be a factor in outbreaks of cryptosporidiosis. Backwashing must not take place when the pool is being used and should be done at the end of bathing for the day, normally in the evening. This is because after backwashing and rinsing it can take several hours for the filter to fully ripen – a process whereby the media settles back down and re-compacts to provide an efficient filtration system. Repeated backwashing throughout the day when the pool is in use is therefore wrong.

• Backwashing of medium-rate filters should be done at least once a week or more frequently as the filter pressure differential dictates and according to the manufacturer’s literature for the filters installed.

• Avoid high-rate filters if possible. If they are in place, they may need to be backwashed more often than once a week (as the pressure difference dictates) but this should never be more than once a day, and only when bathing has finished for the day.

• Ensure there is an effective disinfectant residual, and an appropriate pH, at all times. • The pool hydraulics should ensure appropriate turnover periods and good mixing of

water in the pool; short circuits and ‘deadlegs’ should be avoided. ‘Deadlegs’ are pipes containing water which does not circulate, but rather travels to an end point and stays there.


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Blood and vomit Blood and vomit are unlikely to cause illness, because they are less likely to be infected than faeces and skin. Pool disinfectants should kill any bugs that there are, provided disinfectant residuals and pH values are within recommended ranges, but there are some precautions to take.

Blood

Small amounts of blood, from a nose bleed say, will be quickly dispersed and any germs present killed by the disinfectant in the water.

If significant amounts of blood are spilled into the pool, it should be temporarily cleared of people, to allow the pollution to disperse and any infective particles to be neutralised by the residual disinfectant. Operators should confirm that disinfectant residuals and pH values are within the recommended ranges; bathing can then resume.

Any blood spillages on the poolside should not be washed into the pool or poolside drains and channels. Instead, like blood spillage anywhere in the building, it should be dealt with using strong disinfectant – of a concentration equivalent to 10,000mg/l of available chlorine.

A 10:1 dilution of the sodium hypochlorite in use may be convenient. Using disposable latex gloves, the blood should be covered with paper towels, gently flooded with the disinfectant and left for at least two minutes before it is cleared away. On the poolside, the affected area can then be washed with pool water (and the washings disposed of not in the pool). Elsewhere, the disinfected area should be washed with water and detergent and, if possible, left to dry. The bagged paper towels and gloves are classed as offensive/hygiene waste and in only small quantities can be disposed of with the general waste.

Vomit

It is not unusual for swimmers to vomit slightly. It often results from swallowing too much water, or over-exertion, and so is very unlikely to present a threat through infection.

But if the contents of the stomach are vomited into a pool, the bather may be suffering from a gastrointestinal infection. And if that is cryptosporidiosis, infective, chlorine-resistant Cryptosporidium oocysts will be present. This is a rather theoretical, unevaluated risk, and there is some disagreement about how it should be dealt with.

PWTAG recommends that vomit in the pool should be treated as if it were blood (ditto vomit on the poolside). See above for details. In the US, the Centers for Disease Control and Prevention suggests treating vomit in the pool like solid stool, which amounts to the same thing. But the World Health Organisation currently recommends responding as if it were diarrhoea (potentially closing the pool for six turnovers etc.). The WHO pool guidelines are currently being revised.

Meanwhile, pool operators need to decide what their response will be, and have written procedures in place. If they follow PWTAG guidelines, vomiting would result in temporarily clearing the pool of people, scooping up vomit where possible and allowing the pollution to disperse and any infective particles to be neutralised by the residual disinfectant. Operators need to confirm that disinfectant residuals and pH values are within the recommended ranges; bathing can then resume.

Question Time

1. What is the procedure for dealing with diarrhoea at your pool? 2. What is the procedure for dealing with vomit/blood spillage on the poolside at your pool?


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Section 5: Infections associated with poor pool water quality and hygiene There are a number Infections which are introduced by bathers and there are some which are associated with poor pool water quality and poor levels of hygiene. In this section we will be exploring these issues and we will also consider the importance of microbiological monitoring.

How infections are transmitted in a pool environment As we consider the types of Infections associated with poor pool water quality and hygiene we will also consider how they are transmitted. On the whole the infections are transmitted:

• By touching contaminated surfaces e.g. dirty floors, biofilms etc. • In the pool water itself normally caused by inadequate levels of disinfectant • By breathing in, as is the case with Legionnaire Disease.

Measures used to control the transmission of infections A pool which is well managed, with good hygienic cleaning schedules with good pre-cleanse facilities and which is properly disinfected, whilst consistently operating at the appropriate pH level, should be a pool which is generally free from infection. However, is spite of the above, there are a number of waterborne diseases which are associated with swimming pools and they are discussed in this section. Infections associated with poor pool water quality and hygiene Gastro-Intestinal Infections If the pool is well managed, the microorganisms responsible for diarrhoea should be dealt with by the disinfectant. However, there are bacterial infections that can cause diarrhoea, and these include Shigella and Escherichia coli (E coli). There are other diseases such as enteroviruses which include poliovirus, echovirus and coxsackievirus. Some enteroviruses have caused pool related incidents as have adenoviruses, astroviruses, Hepatitis A virus and noroviruses. There are particular problems where the organisms are resistant to chlorine and this is particularly true of Cryptosporidium and Giardia. These are microscopic protozoa (unicellular organisms), which are found throughout the environment and often in animals. They are resistant to disinfectants such as chlorine, but can be removed by coagulation and filtration. Foot Infections Foot infections are not passed on in pools but can be transmitted via changing room floors, which reinforces the need for regular scrubbing, cleaning and disinfection of changing rooms and pool surrounds. Athletes Foot is a typical foot infection associated with pool environments it is a ringworm infection caused by contact with contaminated floor surfaces. Verrucae can also be acquired through contact with contaminated floor surfaces.


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Eye Irritation Eye irritation in swimming pools is mostly caused by combined chlorine, which is a disinfectant bi- product, but it is possible that the free chlorine residuals may be too high and this can also contribute to eye irritation. pH values which are outside the recommended range are also a factor in eye irritation, as can be the pool chemicals themselves, particularly where chemicals are manually dosed into the pool, where they have been inadequately mixed with the circulation water. It is also possible for irritation of the eye to take place simply by prolonged immersion under the water. Viruses Viruses are generally not spread in well managed and adequately disinfected pools, although there have been some incidents of adenoviruses which can cause nose and eye irritation where the pool has been inadequately disinfected.. SPW notes that people who wear soft contact lenses can occasionally get corneal ulcers. Acanthanoeba is the organism usually involved, which is commonly found in pool water and in spas, and its cysts are resistant to chlorine. The recommendation is that if bathers cannot swim without their soft lenses, (or wear goggles), they should remove them after swimming and clean them with a lens fluid. Aids and Hepatitis The human immunodeficiency virus (HIV) and Hepatitis B are susceptible to the action of disinfectant and therefore are not a hazard in swimming pools. Because HIV and Hepatitis B viruses can be blood borne, blood spillages should be taken very seriously, wherever they occur. Skin Rashes The most important safeguard against skin problems is good water management, disinfectants and adequate dilution. Skin rashes associated with pools are mainly due to § Chemical irritation § Allergic reactions § Pseudomonas aeruginosa § Wetting and de-greasing of skin due to prolonged exposure Ear and Sinus Infections High levels of P. aeruginosa in a swimming pool may cause severe cases of Otitis Externa (swimmers ear), but the risk of infection is minimised if adequate disinfection is in place. Many swimmers report suffering from ear and sinus infections following bathing in outside pools in overseas holiday resorts.


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Naegleria Fowleri Naegleria Fowleri is a very rare cause of meningitis associated with swimming. It has been found that, in most cases, the pool is in untreated natural water, which is usually kept warm. It is therefore possible for incoming water supplies to be infected and as a consequence circulation systems, including balance tanks, should be kept clean and designed to avoid long periods of water stagnation. Legionnaires Disease Legionnaires disease is a severe form of pneumonia caused by the Legionella bacterium. Although not associated with swimming pools, it is associated with spa pools and showers. The disease is contracted by breathing in the bacterium contained within aerosols which are found in fine sprays. Pool water features with spray effects should be checked for scale and other deposits, the heads cleaned and regularly disinfected by soaking with 10 milligrams per litre of chlorine. Showerheads and associated flexible hoses should be similarly treated. In summary: When seeing such a list of illnesses and diseases, which could be associated with swimming pools, it reinforces the fact that every care should be taken to ensure that the disinfectants and pH levels are kept within the recommended range, because basically, most of these diseases only occur in pools where the chemical levels are wrong. In order to ensure that pools are kept bacteriologically safe, it is necessary for them to be bacteriologically tested as discussed earlier. Question Time

1. List 3 ways in which pool infections are transmitted 2. List 3 causes of bather rashes in pools 3. In what way does Legionella differ from other pool related disease?


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Section 6: Microbiological testing and monitoring It is recommended that a routine monthly microbiological test should be carried out. The testing should be carried out independently by a UKAS registered laboratory. Swimming and spa pools should be tested once a month for microbiological quality. Spot checks will be necessary if there are problems with the plant, after contamination (or as part of an investigation into an outbreak of illness) or if the pool has been shut down for any reason. Adverse results will also involve further tests. PWTAG recommend that hydrotherapy pools – including those not in a healthcare setting – should be tested once a week. Sampling should be taken with the pool in use, preferably when heavily loaded or immediately afterwards. The deep end is the best place, and away from inlets. Leisure pools with complex water flows to different areas may demand several samples. Pool staff may be trained to do the sampling, although the testing itself must be done at a UKAS laboratory. Sample containers should be of a material that will not affect the sample either microbiologically or chemically. A 500ml plastic sample bottle is the norm. The bottle should be sterile and contain an agent that neutralises the pool disinfectant: sodium thiosulphate (18mg/l) is the agent for chlorine and bromine-based disinfectants.

Typical bacteriological sampling bottle To take the sample, the stopper or cap is first removed, making sure that nothing touches the inside of the bottle or cap. While the bottle is being plunged into the water the long axis should be kept approximately horizontal but with the neck pointing slightly upwards to avoid loss of the neutralising agent. The bottle is then quickly immersed 100-300mm below the pool surface, at which point the bottle is tilted upwards to allow it to fill with an air space at the top. On removal from the water, the cap is immediately replaced, the sample shaken to disperse the neutraliser, and then sent to the laboratory without delay to arrive there ideally within 4 hours of sampling. Bacteriological samples must be analysed as quickly as possible and in any event within 24 hours of the sample being taken. Between sampling and dispatch samples should be stored away from the light at 5±3°C. They should ideally travel in refrigerated vehicles, or at least in a freezer box with ice blocks. (The sample container should not come in direct contact with the freezer packs.)


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Water samples for Legionella determination should preferably be analysed within 24 hours of sampling, and not exceeding 48 hours. Samples should be stored in the dark at room temperature if immediate analysis is not possible. Samples submitted for analysis must be clearly labelled with the client’s name, site, sample point, date and time and the analysis required. They should be accompanied by the on-site test results taken at the time of sampling – free chlorine, combined chlorine and pH. These are necessary for the correct interpretation of bacteriological results. It is recommended that samples should also be taken:

• before a pool is used for the first time, • before it is put back into use after it has been shut down for repairs or cleaning • after an emergency/incident and • if there have been difficulties with the treatment system.

Microbiological testing should include the following:

• Aerobic Colony Count (ACC) sometimes referred to as Total Viable Count (TVC) • Coliform organisms and Escherichia coli (E coli) • Pseudomonas aeruginosa (P. aeruginosa)

Aerobic Colony Count (ACC) sometimes referred to as Total Viable Count (TVC) The aerobic colony count is sometimes referred to as a ‘total viable count’ (TVC) or a ‘plate’ count, is an indication of the number of bacteria present, without differentiating in detail between the different kinds. It identifies the bacteria capable of forming visible colonies under certain laboratory conditions. Samples are incubated at 37oC for 24 hours. Aerobic colony counts are usually expressed as colony forming units (cfu) per millilitre of water. They do not necessarily give an indication of microbiological safety, but give valuable information on the general quality of the pool water and, in turn, whether the filtration and disinfection systems are operating satisfactorily. Coliform Organisms

Coliform bacteria are widely used as an indicator of water quality. They are found in animal intestines (included human) but are also widespread in the environment including the surfaces of plants and in soil. The presence of coliforms may indicate faecal pollution.


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E. coli

The most dangerous of the coliforms is E coli (Escherichia coli). When E coli are present in swimming pools, this is an indication that faecal matter has entered the water and the pool water disinfectant system has failed to remove it. E coli is potentially fatal to bathers. Pseudomonas Aeruginosa

Pseudomonas aeruginosa is capable of growing in water even at relatively low temperatures, and they can readily form colonies of bacteria in filters and have been associated with pool water play inflatables, tubing and pool covers. P. aeruginosa can cause skin and ear infections, so its presence in pool water is undesirable. Bacteriological sampling: Interpreting the results: In order to ensure that the pool is operating safely, acceptable levels for bacteria results are as follows: Aerobic colony count (ACC)/Total viable count (TVC) The aerobic colony count (ACC) should normally be 10 or less colony forming units per millilitre of pool water. If the colony count is above 10cfu/ml, and it is the only unsatisfactory microbiological results, providing the residual chlorine and pH values are within recommended range, it is recommended that the water should be re-tested. Total Coliforms Coliforms are sensitive to disinfectant and should be absent, in other words zero, in 100 ml of pool water. A coliform count of up to 10cfu/100 ml is acceptable provided that: 1. Coliforms are not found in the repeat sample 2. The aerobic colony count is less than 10cfu/ml 3. There are no E coli present 4. The residual disinfectant and pH values are within recommended ranges


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E. coli E. coli should be absent (i.e. zero) in 100 millilitre sample. Pseudomonas Aeruginosa Well-operated pools should not contain P. aeruginosa. If the count is over 10 per 100 ml repeat the test. Where repeated samples contain P. aeruginosa the filtration and disinfectant processes should be examined to determine whether there are areas within the pool circulation where the organism is able to multiply. Where counts exceed 50, pool closure should be considered. Gross contamination Pools should be closed following a routine microbiological test if the results suggest gross contamination, or if there is other evidence that the pool disinfection system is not operating correctly. Gross contamination therefore can be considered as:

• E coli over 10 per 100 ml PLUS either colony count over 10 cfu per ml or P aeruginosa over 10 per 100 ml (or, of course, both)

• P aeruginosa over 50 per 100 ml PLUS colony count over 100 per ml. Acting on failures/pool closure The PWTAG Code of Practice provides the following guidance in the event of poor microbiological results being received:

1. If a result is unsatisfactory, a preliminary investigation should be undertaken and the test should be repeated as soon as practicable.

2. If the second result is also unsatisfactory, the pool's management and operation

should be investigated and the test repeated.

3. If the third result is still unsatisfactory, immediate remedial action is required, which may mean closing the pool.

4. The pool should be closed if there is chemical or physical evidence of unsatisfactory

disinfection.

5. The pool should be closed if microbiological testing discloses gross contamination. Question Time

1. What is the procedure at your pool for carrying out bacteriological testing of the pool water?

2. Is the testing carried out independently by a UCAS registered laboratory? 3. What are the three main areas covered in a bacteriological test? 4. Who is responsible for the monitoring of the bacteriological test results at your pool?


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Section 7: Pool design and hydraulic flow

Hydraulic flow is about the movement of water through the filtration system and the distribution of water within the pool. The hydraulic flow of pool water should ideally be streamlined, delivering good quality, disinfected pool water to all areas of the pool and avoiding areas of stagnant water. At the time of the design, the hydraulic flow will have been designed with due regard to the suction velocity (1.5 m/s delivery capacity to 2.5 m/s and the design turnover of the pool) and for this reason, a flow meter should be installed, capable of measuring the circulation rate, which in turn, can confirm the turnover. The circulation rate, measured in cubic metres per hour (m3/h), can be calculated by dividing the water volume in cubic metres by the turnover period in hours. Consequently, given the circulation rate and the water volume, it is a simple matter to work out the turnover period. There are several different designs of pool water circulation systems and various types of systems. In the traditional design of swimming pools, disinfected, treated and heated pool water would travel from the plant room and enter the pool at the inlets, usually in the shallow end and usually three of them. Pool water would then leave the pool at the deep end through pool outlets protected by a grille.


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Traditional swimming pool hydraulic flow As pool designs began to develop, pools then started to have water introduced along the long walls of the pool or even through a series of inlets through the pool floor. Once again, outlets would be provided at the deep end. It has been stated previously that the most polluted pool water is that which sits on the surface of the water and occupies the top 150mm, and for this reason, it is absolutely essential that there be adequate surface water draw off facilities. Surface Water Removal The traditional method of removing the polluted surface pool water was to use overflow channels, which were located around the perimeter of the pool. In order for these to work it is essential that the pool water level reaches the lip of the overflow channel and overflows gently into the channel and back to the filtration system. If the pool water level is too low, this has the effect of locking in the pollution, which will then sit on the face of the water and look unsightly. Unfortunately, it will also lock in the rest of the bacteria as well as creating a tidemark. Since the top 150 millimetres of pool water contains the vast majority of the pollution within the pool, it is absolutely essential that the pool is fitted with a suitable surface water removal system. There are three types of surface removal systems: § Overflow channels § Deck level surface water removal § Skimmers Overflow Channels This is the traditional type of surface water removal system based around a ceramic trough system, which runs around the perimeter of the pool. In this system, it is essential that the water level be maintained at the level of the trough so that the water runs over the trough and back into the filtration system. Where water levels operate below this level it creates unsightly tide marks, surface water pollution is trapped on the surface, making the pool unattractive and creating problems for the pool operator in terms of how it is removed. A typical overflow channel is shown below:

Inlets Outlets


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Typical overflow channel Deck Level This is far and away the best type of pool water surface water removal. In this system the pool is filled to overflowing and the pool water level is the same as the surround. The overflowing water runs over into a surface channel and back to the filtration system. A properly designed system will therefore be removing surface water pollution all of the time.

Deck level pools Skimmers Skimmers incorporating skimmer baskets, are often installed in hotel pools, smaller school pools and are very popular in outside swimming pools. In some cases, the skimmer basket is used as a receptacle for chemicals, such as, slowing dissolving chlorine tablets and if this is the case, extreme caution must be exercised when adding any chemical in this way, as it is easy for an accidental mixing of chemicals to take place, which could result either in the production of chlorine gas or even an explosion.


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Pool Outlets There are British Standards which relate to the size of apertures in grille openings, whether they by inlet or outlet grilles. The size of the aperture should not exceed 8mm (BSEN13451). It is also recognised that excessive suction at the outlet may cause entrapment, injury and drowning, and for this reason, there should be a minimum of two outlets from the pool, and they need to be sufficiently spaced apart to prevent a body being drawn or trapped by the two suction outlets. Where a single outlet is installed in the pool it is necessary to install a protective grid cover which increases the surface area of the grille, but at the same time stops the possibility of a bather being sucked onto the outlet. These devices are referred to as ‘anti-vortex covers’.

Anti –vortex cover Question Time

1. What sort of surface water removal system is employed at your pool? 2. Which of the three methods of surface water removal is considered to be the best? 3. How does the swimming pool water circulate from the inlets to the outlets in your own

pool? 4. How many inlets are there? 5. Where are they? 6. How many outlets? 7. Why are single outlets a problem? 8. How is this problem addressed in practice?

Activity Draw a sketch of your own pool indicating where the water enters and leaves the pool and the place where sample water is taken for testing


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Section 8: The principles of heating and ventilating the pool environment Pool Water Heating The pool water is heated by passing the water through a ‘non-storage’ calorifier or heat exchanger. There are two types used in swimming pools, one is the traditional type of calorifier, sometimes referred to as a ‘shell and tube heat exchanger’, this is where water generated from the boiler system passes through a series of tubes within the calorifier and water directed from the pool passes around those tubes and is heated, usually by 0.5oC per hour. The plate type heat exchanger is an alternative form of heating pool water and is now the preferred method. This design is based upon hot water circulating between the plates of the heat exchanger and the pool water passing around those plates. Heating and Ventilation of the Pool Environment It is essential to maintain satisfactory environmental conditions in the pool hall itself in order to provide comfortable conditions for bathers, lifeguards, staff, and spectators, and for the building to operate successfully over its projected life. The swimming pool environment is heated and ventilated by passing incoming air through air filters, and over a heat exchanger by the use of a centrifugal fan. Air may be mixed with return air from the pool hall through a mixing box. Energy may be recovered from air removed by extraction air handling units and transferred to the incoming air using cross over heat exchangers, run around coils, thermal wheels or heat pumps. The air handling system introduces heated and filtered air into the building is responsible for:

• Controlling pool hall air quality in terms of temperature, humidity and dealing with evaporation from the pool water surface

• Maintaining comfortable environmental conditions • Preventing condensation • Removing chlorine-like odours from the air caused by the disinfection process and

chemicals within the pool itself. It is recommended that the pool hall temperature should be equal to, or 1o C above that of the water temperature, although air temperatures above 30oC should be avoided. In order the keep the conditions within the pool hall comfortable, relative humidity should be maintained between 50/70% throughout the whole of the pool hall area. It is necessary to introduce some outside fresh air into the pool hall; this would normally be 30% of the total volume of air which is circulated, but this was changed to 100% in 2020 in response to the Covid-19 pandemic Ideally, the pool hall area, which includes both the pool itself plus any wet surrounds, should be ventilated at a rate of greater than 10 litres of ventilation air per second for every square metre of total pool hall area (10l/s/m2).


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Another way of calculating the amount of fresh air required would be to provide 12 litres per second of fresh air for each occupant of the pool hall, and this includes bathers, staff and spectators. Ventilation rates are expressed in ‘air changes per hour’ and it is recommended that the ventilation rate in a typical swimming pool should be in the order of 6 air changes per hour, but this may be increased between 8 and 10 air changes if the pool has extensive water features. It is usual recirculate air, but typically 30% of the air should be fresh outside air, but it may be necessary to increase this to 100% fresh air when necessary, for example, when bathing loads are particularly high, or where there is a high level of contaminants in the pool atmosphere. By using a heat pump it is possible to dehumidify – i.e. remove the moisture out of the air in a pool hall and reintroduce it drier; this type of system is particularly appropriate for hydrotherapy pools, where the water temperature is higher. There are a number of options available for recovering energy from the air which would normally be discharged away out of the building. Installing pool covers would also make good sense, and will enable the lowering of the ventilation rate and air temperature. Pool operators go to a lot of trouble to try and ensure that the pool water conditions are good, but if the air conditions are not addressed, this can be uncomfortable for bathers and very damaging to the building as a result of the chlorinated condensation which will damage the building structure etc. Question Time

1 What is the link between water temperature and air temperature?

2 Which piece of equipment raises pool water temperature?

3 What is the recommended relative humidity level in a swimming pool hall?

4 How is the swimming pool environment heated and ventilated?


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The importance of encouraging the efficient use of energy How can pool operators can improve energy efficiency? Pool operators should understand the importance of encouraging the efficient use of energy and the part that they can play in achieving this. There are many issues to consider when addressing energy efficiency in pools, not all of which are in the domain of the pool operator, so this section has been written from the perspective of the pool plant operator in terms of what impact they can have on energy use. Good housekeeping If the pool plant operator is responsible for a pool in an older building there may not be any installed energy saving measures to speak of, and so the only thing that they need to do is to embrace good housekeeping. This would include:

• turning off lights when not needed • closing windows to conserve heat • repairing (or reporting) leaks • ensuring that controls are set to the correct level • knowing and keeping within the parameters for all chemical tests • ensuring that only the required amount of chemicals are used for pool water

treatment • ensuring that faulty controls are replaced to avoid excessive water and air

temperatures • replacing air filters as necessary on air handling plant • keeping air handling plant intakes free of debris • listening for excessive or unusual noises in plant (e.g. whining motors, slipping fan

belts etc. and then reporting the fault etc. Systems that can be used to run an economic, energy efficient and effective pool facility Low cost solutions can be found to some of the above including:

• Motion controlled lighting sensors • Time controlled water taps (properly maintained so as to avoid wasting water by

excessive run times) • Tamper-proof controls to stop unauthorised changing of settings • Password control of automatic dosing units to stop unauthorized changing of settings

In general, specialist contractors design, install and maintain the energy saving equipment, the pool operator may never been involved in the discussions, but they do need to know what has been installed and what are the expectations of the pool plant operator. The following systems can be used to run an economic, energy efficient and effective pool facility. They can be classified into three main areas:

• Heat recovery • Heat retention • Other energy saving technologies


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Heat retention Heat retention describes the measures we put into place to avoid wasting energy from evaporation and heat loss etc., and such measures would include:

• Fitting, using and maintaining pool covers. Installing pool covers would also make good sense and would enable the lowering of the ventilation rate and air temperature.

• Ensuring that all exposed pipework is efficiently insulated • Reporting when insulation is missing or in poor condition

Heat recovery Heat energy can be recovered from both the air and water that we discard to waste, such measures can be very costly and most would need to be installed when the building is being constructed or where there is a major refurbishment of the site. Heat recovery from air handling plant can include:

• Re-cycling pool air (mixed with fresh air) • Run around coils/ Cross-over heat exchangers: There are a number of options

available for recovering energy from the air which would normally be discharged away out of the building.

• Heat pumps: By using a heat pump, it is possible to dehumidify the air (i.e. remove the moisture from the air in a pool hall before reintroducing it); this type of system is particularly appropriate for hydrotherapy pools where the water temperature is higher.

• Heat can also be recovered from waste water and this would involve the use of heat pumps.

Other energy saving technologies Other energy saving technology can include:

• Rain water harvested to provide water for flushing toilets etc. • Variable speed drives on pool water circulating pumps • Variable speed drives on air handling systems

Pumps with variable speed drives


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Recording and reviewing energy usage to improve energy performance The facility manager should ensure that energy usage is measured, recorded and monitored, however, it is the responsibility of the plant operator to collect the data and record it in such a way that it can be monitored with a view to improve energy performance. This will involve reading meters on a regular basis and inputting the data into the centre’s energy recording system, identifying any unusual patterns of use (e.g. spikes in power use, excessive water loss etc.) and bringing this to the attention of the centre management team. Consideration could then be given to benchmarking energy costs for your building against similar sized buildings in the sector. It is good management practice to constantly review energy usage with a view to improve energy performance where this can achieved without compromising on pool water quality. An example of this would be to reduce water use by not backwashing filters in line with best practice. You could achieve the reduction in water use, but this would impact on pool water quality; what would be the effect on pool water quality? So, what is the role of the pool plant operator in energy efficiency?

• Be aware of the energy efficiency measures employed in the building • Good housekeeping • Being observant and reporting faults • Know what is expected from them and when to contact specialist contractors • Liaise with contractors • Being observant and reporting faults • Recording and monitoring gas, electricity and water usage • Consider benchmarking energy costs against similar buildings

End of section: Learning check 1. List 4 ways in which energy savings can be achieved by good housekeeping 2. List 4 ways in which the pool operator can play a role in energy efficiency 3. What is meant by the term ‘heat retention’? 4. How involved are you in the efficient use of energy at your pool?


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Section 9: Problem solving activities These exercises and activities should help to consolidate your learning and give you practice in correctly interpreting pool water readings and in finding solutions to pool related problems. They are not part of the assessment.


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Pool water readings. Exercise 1 Pool Type: School pool Time chlorine and pH readings were taken: 0700hrs

Test Results Comments Rec. remedial action RAG

Free Cl2 1.00mg/l

Combined Cl2 0.75mg/l

Total Cl2 1.75mg/l

pH 7.8

Total alkalinity 40mg/l

Calcium hardness

340mg/l

Temperature 300C

Sulphates 300mg/l

Chlorides 500mg/l

TDS 2000mg/l

Cyanuric acid N/a

Clarity 7/10


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Pool water readings: Exercise 2 Pool Type: School pool Time chlorine and pH readings were taken: 0700hrs

Test Results Comments Rec. remedial action RAG Free Cl2 3.00mg/l


Total Cl2 4.75mg/l

pH 7.0


Calcium hardness 40mg/l

Temperature 280C

Sulphates (Not measured)

x

Chlorides (Not measured)

x

TDS (Not measured)

x

Cyanuric acid (Not measured)

x

Clarity 5/10


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Pool water readings: Exercise 3 Pool Type: Council-run leisure centre Time chlorine and pH readings were taken: 0700hrs

Test Results Comments Rec. remedial action RAG Free Cl2 1.50mg/l


Total Cl2 2.25mg/l

pH 7.3


Calcium hardness 100mg/l

Temperature 290C

Sulphates (Not measured)

x

Chlorides Not measured)

x

TDS 800mg/l

Cyanuric acid N/a

Clarity 9/10


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Problem Pools: Exercise 4 The pool water is dull, it lacks sparkle and just doesn’t look right. What are the probable causes?

How would you correct it?

Problem Pools: Exercise 5 The free chlorine reading is 0.4mg/l. the combined chlorine reading is 1.80mg/l, it is 4.30pm. The pool is busy and expected to remain so for the next three hours What would you recommend? What are the probable causes?

What would you recommend?


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Problem Pools: Exercise 6 A pool is treated with sodium hypochlorite and the correcting acid is carbon dioxide. In order to reduce chemical costs, the operator was told to run at a pH of 7.8. What advice would you give? Advice:

JTL Suite of Pool Plant Operator Training Programmes

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