09 operation and maintenance

OPErATION ANd MAINTENANCE 433433

UPONOR INFRASTRUCTURE

OPErATION ANd MAINTENANCE

434 OPErATION ANd MAINTENANCE

Operation and Maintenance of Uponor Infrastructure Pipe Solutions

9.1 General ....................................................................................................283

9.2 Pipe System User Instructions...............................................................284

9.3 Inspection of pipe lines ..........................................................................286

9.4 Maintenance and Servicing of Sewer and Storm Drains ......................289

9.5 Maintenance and Servicing of Chambers ..............................................291

9.6 Maintenance and Servicing of Pressure Sewer Systems......................292

9.7 Maintenance and Servicing of Pressure Pipe Systems ........................293


9.1 General

regular maintenance plays a crucial part

in ensuring the trouble-free operation

of municipal pipe systems. Preventive

maintenance measures reduce pipe

system damage as well as repair costs.

Appropriate system-specific instructions

must be provided for the operation and

maintenance of pipe systems.

Provision of operation and

maintenance instructions

In accordance with environmental and

health laws, regulations and guidelines,

operation and maintenance instructions

must be provided for water and drain-

age systems. Legislation also stipulates

the penalties for failure to observe the

required operation and maintenance

measures. These regulations apply to

designers, installers, owners and users

of pipe systems.

System designers are responsible for

drawing up the required instructions.

In turn, contractors are responsible for

supplementing them, by appending

product-specific information and any

text changes which arise during the

construction phase.

Operation and maintenance instructions

must serve the following objectives:

•ensured water supply

•waste- and stormwater removal using

the appropriate methods

•appropriate use of public resources

•minimisation of drawbacks and hazards

•human and animal health and safety

provision

•minimisation of risks to property


A well-functioning, properly built and

maintained pipe system is invisible to the

user. As stated in their connection agree-

ment, users are nevertheless obliged to

observe the instructions and regulations

issued by those responsible for building

and maintaining the network.

Wastewater and stormwater drains

users of waste- and stormwater drainage

networks must be informed that it is

forbidden to discharge harmful waste-

waters or other substances, which may

cause damage or be detrimental to trunk

sewers, treatment facilities or receiving

watercourses, into the sewer network.

Such instructions may also inform users

that sewer networks can be damaged

if substances such as paints, solvents,

medicines, fats or other materials not

contained in normal household wastewa-

ter, are discharged into the wastewater

sewer. Authorities are required to provide

users with clarification of where these

and other harmful substances can be

delivered for appropriate disposal.

Instructions on sewer network opera-

tion and use must include an operational

description of the network, including up-

dated drawings. These drawings must be

updated with any changes made during

construction or subsequent repair work,

and must show the locations and sizes of

all pipes and chambers. If, for example,

during repair work, pipes or piping com-

ponents made from something other than

the original material are connected to

the pipe system, such a change must be

noted on the drawings. This information

is important, because the durability of

the pipe system, particularly with respect

to pressure flushing, is determined based

on its material type.

Instructions must also include the

following:

•the maximum allowable flow rate into

the system, for example when emptying

basins or tanks

• information on which substances

may or may not be discharged into

the system

•wastewater temperature limits

•operating instructions for backflow

valves and other components

•operating instructions for pumps,

separators etc. in emergency situations.

Operating instructions for any system

components affecting personal safety,

or which might cause damage that is

difficult to repair, must be located in the

immediate vicinity of the component

concerned.

9.2 Pipe System User Instructions


In accordance with environmental regula-

tions, whenever companies are required

to obtain a licence for wastewater dis-

charge into public sewer networks, such

a licence may include specific wastewater

management instructions in line with

national legislation such as:

•maximum wastewater volumes

•maximum levels of specified substances

• inspection procedures

• inspection intervals

Waste- and stormwater

pipe chambers

With respect to maintenance and general

servicing, it is important that the location

of all chambers and any other related

key information, such as material type,

connection sizes and possible special

features, are marked on the drainage lay-

out drawings. For information purposes,

the drawings must also be fully updated

with any subsequent changes, such as

additional pipe connections. The instruc-

tions can also indicate any points in the

network requiring closer or more regular

monitoring.

Pressure systems

Critical inspection and maintenance

points in water and sewerage pressure

networks include pump houses, check

valves, vent valves and vacuum release

valves. The pump house or pumping sta-

tion supplier is responsible for providing

pump operating and service instructions,

normally delivered as part of the hand-

over documents.


The most common condition inspection

methods for pipelines are visual inspec-

tion via pipe chambers and TV inspection.

Visual inspection, e.g. with an optical

square, is possible where the line of view

between chambers is straight, or where

the point of inspection only includes the

pipe section immediately adjacent to a

single chamber. Joint tightness and crack

testing of a pipeline can also be carried

out by smoke testing.

Cleaning hatches and inspection

chambers

regulation-compliant sewer networks

are equipped with cleaning hatches and

inspection/cleaning chambers with de-

tachable covers, through which the sewer

can be accessed for maintenance.

Sanitary lines must be equipped, for

example, with separable bottom valves

and a water trap, as well as a removable

grating for access to the pipe system.

Older systems also have cleaning plugs

located on the water traps, through which

the system can be cleaned.

Maintenance of underground pipe sys-

tems is primarily carried out via inspection

chambers and inspection pipes installed

along the network.

9.3 Inspection of pipe lines

Figure 9.3.1

Figure 9.3.2


Displaced joint materials

Separated jointHard deposit

Obstacle

Figure 9.3.3

TV inspection

ClosedCircuitTVinspection(CCTV)isthe

most commonly used and effective pipe-

line inspection method. It enables high-

precision assessment of pipe damage, by

using a self-driven robot camera to carry

out close, in-situ inspection of pipeline

details, including pipe junctions. A key

benefit of TV inspection is that it provides

highly detailed condition reports for sub-

sequent maintenance and repair purposes,

based on video post-analysis and precision

mapping of points of damage. To achieve

reliable video data, the pipeline must be

pressure flushed prior to inspection.


Smoke testing

Smoke testing is an effective technique

for identifying faulty joints and large

cracks in storm drains, house drains and

foul sewers. This method can also be used

to identify possible storm drain connec-

tions to foul sewers as well as unmapped

drain lines and inspection chambers.

Testing is carried out by releasing smoke

canisters in the test pipe section and

raising the air pressure in the pipeline,

causing the smoke to seep out through

the open pipe ends, pipe chambers and

possible pipe faults. Suitable for soil-

covered pipes only, this method is not

effective for street areas, since asphalt

and dense gravel pavings prevent the

smoke from filtering out. The smoke used

is non-toxic and non-staining.

Underwater pipelines

during the condition inspection of under-

water pipelines, particular attention must

be paid to the condition of the ballast

weights. The location of underwater pipes

must also be determined and checked

against the drawings. regular points of

inspection for wastewater pipes include

gas valves.

Figure 9.3.4. Smoke test

Pipeline location

The precise location of pipelines belonging

to old networks is sometimes unknown. To

locate and accurately position pipelines,

a transmitter is fed into the line and its

progress is monitored above ground with a

receiver. Metal detectors are often used to

locate buried manhole covers.


Minor operational faults occur in all sewer

networks from time to time; these can

usually be remedied through provisional

intervention. If, however, the cause

of the disorder is a blockage recurring

frequently at the same location, the fault

will need to be investigated and proper

repairs carried out. recurring blockages

are normally caused by faults in the pipe-

line and usually first appear soon after

installation. Typical causes include an

insufficient pipe gradient, poorly installed

joints, or pipe damage during installation.

Another common cause is contamination

of the line with construction waste during

installation, e.g. through open-ended

drains or pipe ends. It is therefore ex-

tremely important to keep drainage point

socket junctions and open ends plugged

throughout the build stage. In addition,

sewer networks must be carefully flushed

after installation or before commission-

ing, to enable the early detection of

possible faults.

Fat drained into the sewer from kitchen

sinks is also a common cause of block-

ages. Hot fat easily drains past the sink

trap, only to solidify upon contact with

the cold drain. Most build up occurs

inside the building, but will eventu-

ally also accumulate in the horizontal

underground drain. Blockages like this

often occur after years of use, indicating

that the pipe system was fully functional

9.4 Maintenance and Servicing of Sewer and Storm Drains

after installation. Fat deposits can usually

be removed by cleaning the pipe system

with special fat removal tools. If the

system cannot be effectively cleaned,

the pipes must be replaced. drainage

water from dishwashers equipped with

descaling systems, together with other

wastewater, can cause lime scaling that

is so dense, particularly in concrete pipe

systems, that it is difficult to remove.

The most common maintenance proce-

dures required for stormwater systems are

pipe cleaning and the unblocking of fro-

zen pipes and chambers. root penetra-

tion through broken joints can also cause

blockage problems.

Pipe cleaning

The most common cleaning method is

pressure flushing, which is used for both

foul and storm drains. In cases of root

blockage or hard deposits, the appropri-

ate mechanical tools are used.

Pipe thawing

Thawing of frozen pipes and chambers

is normally carried out using hot steam

and/or water. When using this technique,

it is important to remember that differ-

ent plastics have different temperature

resistances. When thawing pipes, care

must be taken that the pipe is not heated

in any one place for too long, as this can

damage the pipe material and the seal.


The maximum operating temperatures per

material type are given in Table 2.2 of the

Materials and Service Life chapter.

The thawing temperatures per plastic

type are as follows:

PE + 80 °C

PP + 80 °C

PVC + 70 °C

The same temperatures apply to pipe

chambers and chamber materials.

Mechanical tools are not recommended

for unblocking frozen pipes, since they

can damage the pipes. Thawing is most

commonly required for stormwater sys-

tems, particularly culverts.


Waste- and stormwater pipe chambers

perform an important function in network

maintenance. regular maintenance and

servicing of chambers can considerably

reduce the need for pipe cleaning and

repair work. In the case of wastewater

sewer inspection chambers and inspec-

tion pipes, items requiring regular inspec-

tion normally include the chamber covers

and the tightness of the risers and other

joints.Keymaintenanceproceduresfor

storm and land drain chambers include

cover condition inspection and regular

emptying and cleaning of the silt trap.

The cover sections of chambers located

in trafficable areas are subject to high

mechanical stress. Cover sections are

also susceptible to displacement by frost

heave, and should therefore be regularly

inspected. Proper re-adjustment of pipe-

line covers must also be ensured during

road pavement work. The installation

instructions provided for the chamber

must be followed whenever corrective

maintenance is carried out.

9.5 Maintenance and Servicing of Chambers

Stormwater chambers

In the case of stormwater chambers,

the most important maintenance task

is emptying the silt trap. This prevents

solids from being washed into the pipe

system and ensures free drainage flow.

The condition of grate covers must

also be monitored and damaged covers

replaced as soon as possible.

If a chamber freezes due to cold air

circulation in the pipe system, thawing

must be carried out using the appropriate

measures, such as steaming. Mechanical

ice removal can damage the chamber.

Freezing can be prevented by equip-

ping the chamber with the appropriate

freeze protection.

Land drain chambers

The most important maintenance task for

land drainage pipe chambers is empty-

ing the silt trap. Since land drains must

be kept separate from other drainage

water, chamber covers must be regularly

inspected for damage.


Effective pressure sewer system operation

depends on having the pump discharge

head, flow rate, pipe sizes, pump run-

ning time and pumping frequency at the

correct ratios. In long pressure sewers,

air venting and vacuum release must be

managed effectively. Vent valves and re-

lease valves should be regularly condition

monitored and serviced. Faulty valves

must be replaced as necessary.

9.6 Maintenance and Servicing of Pressure Sewer Systems

Wastewater pressure sewers are mainly

cleaned by pressure flushing, combined

with pigging. In special cases, TV inspec-

tion is also required.

The above instructions apply to both

wastewater and stormwater pressure

systems.


In municipal water supply networks,

sediment accumulates on pipe bottoms

over time, while deposits can build up on

the inside walls. Both of these must be

removed at regular intervals, using the

following methods:

•flushing in the flow direction

•counter-flow flushing

•compressed air pulse cleaning

•pigging

•chemical cleaning and shock

chlorination

9.7 Maintenance and Servicing of Pressure Pipe Systems

The above maintenance aspects must be

accounted for during the design stage,

to ensure that the network is adequately

furnished with flushing branches, flushing

valves, water and fire hydrants and water

holding tanks.

In long pressure systems, provision must

also be made for either manual or auto-

matic air venting. In addition, vacuum

release valves must be installed at suf-

ficiently regular intervals.

The cleaning methods used are the same

as for pressure sewers.

09 operation and maintenance

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