FIRE AND RESCUE NSW - BA/Hazmat

FIRE AND RESCUE NSWRECOMMENDED PRACTICE

FOUR-HEAD GAS DETECTORMSA ORION

VERSION 02, ISSUED: FEBRUARY 2011, CID: 06553

© State of New South Wales through Fire and Rescue NSW, 2011.

This work may be freely reproduced and distributed for most purposes, however some restrictions apply. See the General Copyright Notice on www.fire.nsw.gov.au or contact Fire and Rescue NSW (FRNSW).

This Recommended Practice contains information, data, documents, pages and images prepared by FRNSW for training, occupational health and safety, and reference purposes. The material it contains may be incomplete, inaccurate, or out of date. The State of NSW accepts no responsibility or liability in relation to the use of any information contained in this document.

Published by:Specialised OperationsFire and Rescue NSW

Amarina Avenue(Locked Bag 13)

Greenacre NSW 2190

Telephone: (02) 9742 7155Facsimile: (02) 9742 7380

Document Control:Version A, Jan 2005Version 02, February 2011. (Comprehensive review, update contact details, revisions to troubleshooting and risk management.)

Supply Catalogue CID:06553

Acknowledgements:Mine Safety Appliance CompanySenior Firefighter Daren EllenStation Officer Stuart HarveyStation Officer Timothy ClimoSenior Firefighter Matt DahlbergSenior Firefighter Glenn JacksonSenior Firefighter Andrew JohnsonSenior Firefighter Richard Neville

Filing:NFB/08514Working file located at Equipment Development Unit, Greenacre (filed by CI number)

This document rescinds:Operations Bulletin 2008/07: Orion gas detector extension probe, Ver 01.Recommended practice: Orion four-head gas detector, Ver A.

Has this document been printed or copied?Check you have the most recent version by comparing the version number and the issue date on the footer with those of the document on station portal on the Intranet. The online document is the master.

This document was produced using Adobe Framemaker™ version 8.0. It is intended for release as an electronic PDF document for online viewing. It is formatted for double-sided printing on station printers. Copies are available through the Electronic Supply Catalogue.

http://www.fire.nsw.gov.au/

Four-Head Gas Detector: MSA Orion iii

D.I. Recommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\OrionTOC.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

CONTENTS

Using this Document vWarnings, Cautions and Notes vElectronic navigation vDocument control vi

Specific Equipment Warnings vii

Section 1 Introduction 11.1 Manual structure 11.2 General 11.3 Limitations 21.3.1 Intrinsic safety 31.4 Reading 31.5 Contact 3

Section 2 Equipment Fact Sheet 42.1 Kit contents 42.2 Main features 52.3 Control layout 62.3.1 The LCDs 62.3.2 Control buttons 82.4 Specifications 92.4.1 Calibration / challenge test gas specification 92.4.2 Orion specifications 92.4.3 Sensor specifications 102.5 Principles of operation 112.5.1 The Orion 112.5.2 Principles of calibration 112.5.3 Explosive limits 11

Section 3 Operations 123.1 Safety 123.1.1 Risk management 123.1.2 Protective clothing 133.2 Navigating LCD pages 143.3 Before operations 153.3.1 Assembling the wand 153.3.2 Turning on and pre-operational checks 163.3.3 Zero the Orion 173.3.4 Challenge test 183.3.5 Field calibration 203.3.6 Clearing peaks 213.3.7 Clearing STEL and TWA 223.3.8 Test the pump 23

iv Four-Head Gas Detector: MSA Orion

D.I. Recommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\OrionTOC.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

3.4 Operations 243.4.1 Operational hints 243.4.2 Heartbeat indicator 243.4.3 Alarms – general 243.4.4 Gas concentration alarms 253.4.5 Battery condition and alarm 263.4.6 Datalogging 273.5 Turning Off 27

Section 4 Maintenance 284.1 Maintenance schedule 284.2 After use 294.3 Changing batteries 294.4 Changing filters 314.4.1 External water stop 314.4.2 Dust filter 314.4.3 Internal water stop 324.5 Changing time and date 324.6 Downloading data 334.7 Troubleshooting 334.8 Resupply 344.8.1 Calibration gas 344.8.2 Other consumables 34

Appendix A Principles of Gas Detection 35A.1 Short Term Exposure Limit 35A.2 Time Weighted Average 36A.3 Combustible gas sensor 36A.4 Oxygen and toxic gas sensors 37A.5 Orion sensor configuration 38A.6 Orion LEL correlation factors 38A.7 Cross sensitivity 40A.8 Temperature class 40

Glossary 41

References 43

Index 44

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D.I. Recommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\How to Use.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

USING THIS DOCUMENT

Warnings, Cautions and Notes

Throughout this manual, the reader will find statements titled: WARNING, CAUTION or NOTE. These consist of a short piece of information highlighting a hazard or providing additional clarification, or both. Each of these statements has a particular meaning, as follows:

WARNINGPERSONAL INJURY MAY RESULT if warnings are not carefully heeded. Warnings give you precautions for avoiding injury. While the emphasis of warnings is on avoiding injury, the situations described may also involve damage to equipment.

CAUTIONEQUIPMENT MAY BE DAMAGED if these recommended procedures are not carefully followed. Cautions tell you what to do to avoid such damage. Personal injury is not expected.

NOTEOPERATIONAL PROCEDURES are clarified. Neither personal injury nor equipment damage is involved.

Electronic navigation

This document has been produced in PDF format. The electronic document has a number of features which aid navigation.

• In the left frame of the Acrobat Reader window are bookmarks which replicate the contents page. Click the bookmark to go to that heading.

• To expand a bookmark to a list of subheadings, click the ‘ ’ beside the bookmark.

• In the body of the document you will find cross references. For instance: See ‘Electronic navigation’, highlighted in blue. Your cursor icon will change to a pointing finger when over a link. Click these to go to the referenced section, table or figure.

Figure: Selecting bookmarks

+

vi Four-Head Gas Detector: MSA Orion

D.I. Recommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\How to Use.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

• The contents page has live links to the referenced pages. Your cursor icon will change to a pointing finger when over a link. Click the heading to go to that page.

• The index is arranged alphabetically and has live links to the source text. Your cursor icon will change to a pointing finger when over a link. Click the page number to go to the text.

• To return to either the index or contents page, click any other bookmark, and then click the index or contents bookmark.

Document control

This Recommended Practice is a Fire and Rescue NSW managed document. This document will become uncontrolled if printed, saved, copied or emailed.

Wherever possible, users should refer to the Fire and Rescue NSW Intranet: Station Portal for Recommended Practices.

NOTEIf this document has been printed, copied or emailed, check the validity by confirming the version number and the issue date in the footer with the those of the document on Station Portal on the Intranet. Station Portal will always display the most recently approved document.

Four-Head Gas Detector: MSA Orion vii

D.I. Recommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\Equip Warnings.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

SPECIFIC EQUIPMENT WARNINGS

This is a summary of important warnings and cautions regarding the Orion four-head detector. It is not an exhaustive list of all the warnings and cautions you will find as you read the recommended practice.

WARNINGAlways wear breathing apparatus (BA) when there is any possibility of a hazardous atmosphere.

WARNINGThe Orion must only be used by personnel trained in its operation.

WARNINGBefore use:

• zero the Orion

• conduct challenge test

• clear peaks, TWA and STEL

• test the pump.

WARNINGThe Orion can only detect and measure:

• combustible gases and certain combustible vapours

• oxygen concentration

• carbon monoxide

• hydrogen sulphide.

Do not attempt to measure other gases with the Orion.

WARNINGChanging batteries is not intrinsically safe. Do not change batteries in a potentially flammable atmosphere.

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Four-Head Gas Detector: MSA Orion 1

D.I. Rec-ommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\Orion.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

SECTION 1: INTRODUCTION

1.1 Manual structure

This manual consists of five sections:

Section 1: Introduction

Section 2: Equipment Fact Sheet

Section 3: Operations

Section 4: Maintenance

Appendix: Principles of Gas Detection

Index

1.2 General

This Recommended Practice instructs firefighters in the use of the Mine Safety Appliances Company Orion four-head gas detector (Orion). For how you will use the Orion at an incident, refer to your training material.

Figure 1 The Orion four-head gas detector

Sampling wandSampling hoseOrion, in protective

rubber boot

Carry strap Attached quick start instructions

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D.I. Recommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\Orion.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

WARNINGThe Orion must only be used by people trained in its operation.

The Orion has a simple, two button operation. It is powered by three AA alkaline cells. It features an automatic datalogging facility. The Orion uses four sensors to detect:• oxygen (O2) percentage in the atmosphere• carbon monoxide (CO), in parts per million• hydrogen sulphide (H2S), in parts per million• combustible gases and some combustible vapours as a percentage of the Lower

Explosive Limit (LEL).

The Orion continuously monitors these four conditions. The instrument alarms when any one condition reaches preset alarm levels. These levels are given in Table 6: Gas concentration alarms, on page 25.

In addition, the oxygen concentration shown by the Orion can be used as an indicator of other contaminants. See Section 3.4.1: ‘Operational hints’ on page 24 for more information.

Use the Orion when your dynamic risk assessment indicates one of the above hazardous atmospheres might exist and that atmospheric monitoring is a suitable control measure. Atmospheric monitoring is mandatory in confined spaces.This monitoring helps determine:• the hot zone boundary• safe OHS limits for the use of respiratory and personal protective equipment for

these hazards• render safe.

Consider adequate fire protection.

If a toxic gas alarms sounds, notify the Incident Controller (IC) and continue monitoring.

When operating in an ambient temperature above 40 oC and your 10% LEL alarm sounds, stop your activity and reassess your dynamic risk assessment and incident action plan. If required, exit and/or seek specialist advice from HMRU on the nature of the contaminant.

When operating at any ambient temperature in an environment which may contain carbon disulphide, exit the area if the 10% LEL alarm sounds.

See A.8: ‘Temperature class’, on page 40, for temperature classes of gases.

1.3 Limitations

The Orion indicates the presence of, but does not identify, combustible gases.

The Orion does not measure the toxicity of combustible gases.

Response time is 30 to 45 seconds.



If the atmosphere is rich or deficient in oxygen, the Orion’s combustible and toxic gas readings can be affected.

High humidity can lessen oxygen readings over time.

The Orion should not be used to monitor:• reducing atmospheres, such as ammonia,• atmospheres containing combustible mists or airborne dusts.

A high sample temperature, such as when a sample is drawn from inside a furnace stack, will affect the readings. This is not recommended.

Battery consumption is high when the unit alarms, for instance during the challenge test. Acknowledge alarms quickly and keep spare batteries on hand.

1.3.1 Intrinsic safety

The Orion meets:• AS/NZS 60079.11:2000 for intrinsic safety, within the temperature limits of

–20 °C to 40 °C• AS/NZS 61779.1:2000 for intrinsic safety• AS/NZS 61779.1:2000 and 61779.4:2000 for performance of electrical

apparatus for the detection and measurement of flammable gases in environments with a potentially explosive atmosphere, other than mines where high over-range %LEL readings can occur.

See Section 2.4: ‘Specifications’ on page 9 for details of intrinsic safety.

1.4 Reading

This Recommended Practice must be read in conjunction with the following documents:

1.5 Contact

Any queries regarding the equipment or procedures described in this document should be directed to Gas Help on 0407 663491.

• Standard Operating Guidelines, Section 9: Respiratory protection, Fire and Rescue NSW, Greenacre, Australia.

• Hazardous Materials SOG 10.1: Guidelines for all hazardous materials incidents, Fire and Rescue NSW, Greenacre, Australia.

• Firefighters Training Manual Vol 2, ‘Topic Six: Breathing Apparatus’, Fire and Rescue NSW, Greenacre, Australia.

• Recommended practice: Wearing of uniforms and personal protective equipment (PPE), CI:06745, Fire and Rescue NSW, Greenacre, Australia.



SECTION 2: EQUIPMENT FACT SHEET

2.1 Kit contents

Figure 2 Orion kit contents

Table 1: Orion kit contents

Item

1 Hose for connecting to regulator and calibration gas (black).

2 Sampling hose, with wand connection and water stop filter

3 Calibration/challenge test gas.

4

Tool kit with:• calibration nozzle• 3 x spare water stop filters• spare internal dust filters• 3 x spare batteries (Duracell MN1500 available through ESCAT, CI:00017) as well as

the three in the Orion.• screw driver with Phillips head and two sizes of Allen key• quick reference card.

5 Regulator for calibration gas.

6 Orion, with rubber boot, carry strap and quick start guide.

7 Sampling wand.

Recommended practice (not shown).

1

2

3

5

4

6

7



2.2 Main features

Figure 3 Orion gas detector main features

Table 2: Orion main features

Part Explanation

1 Alarm lights Flash red during alarm conditions.

2 Pump cap The pump cap covers the sensors.

3 LCD This section of the LCD displays date, time, battery charge, and alarm indicators.

4 LCD This section of the LCD displays gas concentrations.

5 On/Off/Page button Power on and off, and scroll through displays.

6 Gas inlet/probe connection

For connection of the sampling probe and calibration nozzle for calibration/challenge gas.

7 Gas outlet Gas outlets are located in both sides of the pump cap.

8 Inlet filters Dust filter and internal water stop.

9 Change/Reset button To change values, and acknowledge alarm conditions.

10 Speaker Issues audible alarms.

11 Battery pack screws Remove to change batteries.

12 Unit ID Fire and Rescue NSW identification chip.

13 Battery pack For 3 x alkaline batteries.

14 Belt clip For attaching to belt, if required.

3

4

12

95

8

6

11

1410

13

17

2



2.3 Control layout

2.3.1 The LCDs

The layout of the Orion liquid crystal display (LCD) flags is given below.

Table 3: LCD flag explanation

Flag Explanation

Zero Zero flashes at start-up or during calibration, giving the option to zero the instrument.

Cal Cal shows when the calibration option is selected, and flashes when calibration can be initiated.

Time Time shows, and the current time is displayed in a 24 hour format on the main LCD.

MM, DD, YY MM, DD, YY show, and the current date is displayed in the US format on the main LCD.

Change Change shows when it is possible to change values. To accept a value, press On/Off/Page.

Pump Pump flashes when the gas sampling circuit is blocked. The unit goes into pump alarm.

PeakPeak shows. Peak readings are displayed in the relevant locations of the main LCD. These are the highest gas concentrations recorded by each of the four sensors since the instrument was last turned on or peaks were cleared.

Min Min shows, and the minimum O2 value recorded since the instrument was last turned on or reset is displayed in the O2 section of the main LCD.

STEL

Shows the current Short Term Exposure Limit for the CO and the H2S sensors, as calculated by the Orion from instant readings. The STEL flag comes on, and the values appear in the relevant parts of the LCD. See A.1: ‘Short Term Exposure Limit’, on page 35 for an explanation of STEL.

TWA

Shows the current Time Weighted Average for the CO and the H2S sensors, as calculated by the Orion from instant readings. The TWA flag comes on, and the values appear in the relevant parts of the LCD. See A.2: ‘Time Weighted Average’, on page 36 for an explanation of TWA.

Please wait until the Orion is ready.

Battery indicator: Displays continuously. Segments disappear with battery use. The indicator shows battery time remaining.

Displayduring

start-up



Figure 4 The Orion LCD showing the instant reading display in clean air

The battery flag displays at all times. Instant readings for %LEL, %O2, ppm CO, and ppm H2S are displayed.

Heartbeat. This flag flashes every 30 seconds to the left of the battery detector to confirm the instrument is on and operating.

%LEL The instant reading for combustible gases is shown here. Peak value is displayed here when that option is chosen.

%O2The instant reading for oxygen is shown here. Peak and Min values are displayed here when those options are chosen.

PPM CO The instant reading for carbon monoxide is shown here. Peak, STEL, and TWA values are also displayed here when those options are chosen.

PPM H2S The instant reading for hydrogen sulphide is shown here. Peak, STEL, and TWA values are also displayed here when those options are chosen.

Table 3: LCD flag explanation

Flag Explanation

Displayduring

start-up



2.3.2 Control buttons

The Orion is operated by two buttons:• On/Off/Page• Change/Reset.

On later models, the words on the On/Off/Page and Change/Reset buttons have been replaced by symbols. See Figure 5: ‘The control buttons’ for details. The function of the buttons is unchanged.

Either button can be:• pressed and released (press)• pressed and held for three to five seconds (press and hold).

Figure 5 The control buttons

Using the On/Off/Page button:• Press On/Off/Page to turn the unit on.• Once on, press On/Off/Page to scroll through instrument displays.• When the Change flag shows, press On/Off/Page to accept the change• In the Calibration menu press On/Off/Page to initiate zeroing or calibration.• Press and hold On/Off/Page for five seconds to turn the unit off.

Using the Change/Reset button:• Press Change/Reset to acknowledge alarm conditions.• Press and hold Change/Reset for three seconds to initiate a change of values.• Press and hold Change/Reset for three seconds to enter Calibration menu.• Press Change/Reset to refuse options given by the Orion.

At all times, leaving the control buttons returns the Orion to instant reading mode.

Old style New style



2.4 Specifications

2.4.1 Calibration / challenge test gas specification

2.4.2 Orion specifications

Combustible gas: 58% LEL (1.45% by volume methane, to simulate the pentane reading)

Oxygen: 15%

Carbon Monoxide: 300 ppm

Hydrogen Sulfide: 10 ppm

Dimensions (wand removed): 10.2 x 6.8 x 17.3 cm

Dimensions carry case: 15.5 x 48.5 x 37.5 cm

Weight (with wand and hose): 1 kg

Weight whole kit: 4.0 kg approx

Temperature range: 0 to 40 °C (when calibrated at room temp)

Extended temperature range: –20 to 50 °C (when calibrated at temperature of use)

Warm-up time: 25 seconds

Battery: 3 x AA (LR6) alkaline cells. Use only Duracell MN1500 Available on ESCAT, CI:00017), or Energizer E91

Battery duration: 10 hours (non-alarming)

Regulator flow rate: 0.25 litres per minute

Protection rating: IP54

Intrinsic safety: Ex ia s Zone 0 1/IIC T4, –20 ºC < Ta < 40 ºC

This means the Orion is safe in environments, including underground, with atmospheres of < 20.8% oxygen and:• Ambient temperatures between –20 ºC and 40 ºC.• Explosive concentrations of any gas having an

ignition point above 135 ºC.• Non-explosive concentrations of gas and/or dust.• Explosive concentrations of methane and coal dust

continuously present.• Explosive concentrations of gas groups IIA, IIB

and IIC continuously present.

For ambient temperatures between 40 ºC and 50 ºC, the Orion is rated at T3, and is safe in an explosive concentration of any gas having an ignition point above 200 ºC.



2.4.3 Sensor specifications

The following table gives the specifications for the Orion sensors, given normal operating temperatures and sampling hose of 3 metres.

WARNINGIf the start-up challenge test gives a result outside ± 10% of the challenge gas specifications, the unit must be calibrated before use.

NOTEOxygen response time is up to 3 minutes if the Orion is calibrated outside the normal temperature range.

Table 4: Sensor specifications

Oxygen – O2 Combustible Toxic – CO Toxic – H2S

Sensor type Electrochemical Catalytic Electrochemical Electrochemical

Response time(with hose)

90% of final reading in 35 – 40 seconds




Range O2 as 0% to 25% of atmosphere 0% to 100% LEL 0 – 999 ppm 0 – 200 ppm

Resolution 0.1% 1% LEL 1 ppm 1 ppm

Accuracy ± 10% of the reading – only applicable when the challenge test has been passed and within specified operating temperatures



2.5 Principles of operation

2.5.1 The Orion

A pump draws the gas sample into the instrument through a sampling wand. Filters remove water and dust particles. A set of four sensors then test the gas for combustibles, oxygen content, carbon monoxide and hydrogen sulphide.

NOTEIf necessary, the Orion can be used without the wand and sampling hose.

Combustible gases are tested by a catalytic sensor. See A.3: ‘Combustible gas sensor’, on page 36 for details.

Oxygen and toxic gases are measured by electrochemical sensors. See A.4: ‘Oxygen and toxic gas sensors’, on page 37 for details.

The Orion is protected by a series of three filters:• a water stop filter in the wand,• a dust filter located on the rear of the Orion,• an internal water stop located in the body of the Orion under the dust filter.

2.5.2 Principles of calibration

Calibrating the Orion involves these concepts:a) The instrument is first zeroed. This means that the response of the instrument in

clean air is registered.b) Calibration gas of a known concentration is applied to the instrument. The

response to this known concentration is registered.c) The difference between the zero gas response and the known concentration

response is the span. Instrument readings for concentrations from zero to this known concentration are set according to this span.

An unknown concentration of a gas is determined by comparing the response of the instrument to the unknown, with the span value.

2.5.3 Explosive limits

To sustain combustion, there must be an appropriate mix of fuel (in this case a flammable gas) and oxygen. If the mix is too lean and there isn’t enough fuel, the reaction can’t sustain itself. If the mix is too rich and the fuel starts to displace the oxygen, the reaction will once again stop.

The Lower Explosive Limit (LEL) is the lowest percentage of fuel in the mix for combustion to take place.

The Upper Explosive Limit (UEL) is the highest percentage of fuel in the mix for combustion to take place.



SECTION 3: OPERATIONS

3.1 Safety

WARNINGAt all times, observe the following safety precautions when operating the Orion multi-gas detector.

3.1.1 Risk management

Use the Orion when your dynamic risk assessment indicates one of the following hazardous atmospheres might exist and that atmospheric monitoring is a suitable control measure:• oxygen enriched or deficient atmospheres• presence of CO and/or H2S• the explosive hazard presented by combustible gases.

In addition, the oxygen concentration shown by the Orion can be used as an indicator of other contaminants. See Section 3.4.1: ‘Operational hints’ on page 24 for more information.

This monitoring helps determine:• the hot zone• safe OHS limits for the use of personal protective equipment for these hazards• render safe.

Atmospheric monitoring is mandatory in confined spaces.

The Orion must only be operated by personnel trained in its use.

WARNINGThe Orion does not measure the toxicity of combustible gases. Always be aware of the toxic hazard as well as combustibility. Always wear BA when conducting atmospheric monitoring.

Only monitor gases for which sensors have been fitted. Do not attempt to monitor other gases.

Consider adequate fire protection.

If a toxic gas alarms sounds, notify the Incident Controller (IC) and continue monitoring.

When operating in an ambient temperature above 40 oC and your 10% LEL alarm sounds, stop your activity and reassess your dynamic risk assessment and incident action plan. If required, exit and/or seek specialist advice from HMRU on the nature of the contaminant.

When operating at any ambient temperature in an environment which may contain carbon disulphide, exit the area if the 10% LEL alarm sounds.

See A.8: ‘Temperature class’, on page 40, for temperature classes of gases.



3.1.2 Protective clothing

While using the Orion, firefighters must wear a minimum of:• BA• structural firefighting ensemble• general purpose gloves.

If required, firefighters must wear a higher level of chemical protective clothing suitable to protect against the hazard.



3.2 Navigating LCD pages

Scroll through the Orion’s LCD pages by pressing On/Off/Page.

Figure 6 Orion display page flowchart

Instant reading

Wait10 secs

PressPage

Peak

Min

STEL

TWA

Time

Date

PressPage

PressPage

PressPage

PressPage

PressPage

Wait10 secs

Wait10 secs

Wait10 secs

Wait10 secs

Wait10 secs

PressPage

HoldReset

PressOn/Off

ClearPeak?

HoldReset

HoldReset

HoldReset

ClearMin?

ClearSTEL?

ClearTWA?

PressOn/Off

PressOn/Off

PressOn/Off

To change or clear values:a) Press and hold Change/Reset until:

• the chosen page flag flashes• the Change flag stays on.

b) Press On/Off/Page to confirm the change.c) At any time, return to instant reading mode

by waiting.



3.3 Before operations

3.3.1 Assembling the wand

Figure 7 Assembling the sampling wand

To assemble the wand:a) Dismantle the handle.b) The water stop should already be fitted. Check that it is tight. If required, twist

the water stop into the connection lug to ensure a tight fit.c) Fit the metal end of the wand into the water stop. You may need to twist the

wand to ensure an air-tight fit. See Section 4.4.1: ‘External water stop’ on page 31.

d) Thread the tube through the spring in the other end of the handle.e) Reassemble the handle.

CAUTIONAlways use a water stop filter. This filter protects the internal workings of the Orion from water and water mist. Without using the filter, the wand assembly won’t be airtight, and the Orion will fail the pump test.

When stowing the Orion, disassemble the wand and leave the water stop connected inside the handle for protection.

It may be possible for a nut in the handle of the wand to come loose. This nut connects the gas sample line from the Orion body to the handle of the extension probe, and is at the opposite end of the handle to where the water stop is fitted. The Fire and Rescue NSW has a program of securing these nuts by applying a thread locker. Until your Orion is fitted with a thread locker, you must check this connection before use.a) Unscrew the connector cover on the probe closest to the detector.

Line up the bayonet fitting, bring the halves of the handle together, and twist to connect

Tube goes through the internal spring

Water stop should be inserted into metal

connection lug

Fit the metal end of the wand into the water stop



b) Check if you can undo the connection with finger pressure. If you can’t, the connection is okay. Go to step (d).

Figure 8 Wand connection to hose

c) If the connection is loose, screw the female connector on the probe handle to the male connector until firmly bedded.You’ll feel some resistance as the female connector contains an O-ring.

CAUTIONDo not over tighten as you can damage the O-ring or strip the thread.

d) Replace the connector cover.

Figure 9 The sampling wand, correctly assembled

3.3.2 Turning on and pre-operational checks

Turn on the Orion by pressing On/Off/Page.

The following steps must be performed before operations:a) Assemble the wand and check all connections.b) Zero the Orion.c) Conduct a challenge test to confirm calibration.d) If the challenge test fails, conduct a field calibration.e) Clear peak readings.f) Clear TWA and STEL.g) Test the pump.

Check this connection!

Female connector

Probe

Connection to Orion

Connector cover

Male connector



3.3.3 Zero the Orion

Zero the Orion:• at start-up• as required during operations.

WARNINGZero the Orion in clean air only. If the Orion shows contaminants are present, DO NOT zero the instrument. Investigate.

To zero at start-up:a) Turn on the Orion in known clean air, away from truck exhausts, etc.b) The Orion will go through warm-up. Then for 10 seconds the Zero flag flashes,

offering the option of zeroing.c) Ensure readings are stable, with %LEL, CO and H2S reading zero, and O2

reading 20.8%. If initial Orion readings do not match these values, you may not be in clean air. Do not zero the Orion. Investigate.If clean air is confirmed, but the Orion still shows readings, proceed to field calibration. (See Section 3.3.5: ‘Field calibration’ on page 20.)

d) To accept zeroing, press On/Off/Page. (If you don’t accept zeroing, the Orion goes into instant reading mode.)

e) The Zero flag stays on. The Orion automatically sets the zero point for the sensors. (The oxygen sensor is spanned and calibrated at this point.)

f) When zeroing is complete, the Zero flag disappears. The Orion enters instant reading mode.

To zero during operations:a) Push and hold Change/Reset until the Cal flag comes on and the Zero flag

flashes.b) Press On/Off/Page to accept zeroing.c) The Zero flag stops flashing while the Orion is zeroed.d) When zeroing is complete, the Zero flag disappears and the Cal flag flashes.

To return to instant reading mode, press Change/Reset, or wait 45 seconds. To continue with calibration, press On/Off/Page.



3.3.4 Challenge test

The challenge test challenges the response of the Orion against a known concentration of gas. This confirms that the instrument calibration is valid. To perform the challenge test:a) Use the gas cylinder provided in the Orion kit. Check the gas expiry date.b) Begin with the Orion turned on and the sample hose removed.c) Screw the calibration nozzle to the gas inlet port.d) Connect the regulator to the cylinder.e) Attach the black calibration hose to the regulator.

CAUTIONWhen connecting the calibration hose to the nozzle, don’t hold the hose within 1 cm of the end. The nozzle can damage the internal bore of the hose.

f) Connect the calibration hose to the Orion, and fully open the regulator.

Figure 10 Connecting gas for both challenge test and calibration

NOTEThe Orion may go into pump alarm at this point. Acknowledge the alarm by pressing Change/Reset and continue.

Connect gas. Don’t hold the hose within

1 cm of the end.

Fully open the regulator

Gas specifications

Cylinder Id chip

Screw down the calibration nozzle

Expiry date is on the white section

on the rear of the label.



g) Wait until readings stabilise. This should take no longer than 2 minutes. The Orion must display readings within the limits indicated in Table 5. These limits are also printed on the gas cylinder.

NOTEThe Orion will alarm for all gases. Acknowledge the alarms as they occur and continue.

h) Turn off the regulator and disconnect the hose.i) Wait until the readings recover and show clean air.

If the calibration challenge readings are within the tolerances in Table 5, move on to clearing peaks as described in Section 3.3.6: ‘Clearing peaks’ on page 21, and TWA and STEL readings as described in Section 3.3.7: ‘Clearing STEL and TWA’ on page 22. You can then fit the wand, test the pump as described in Section 3.3.8: ‘Test the pump’ on page 23, and the Orion will be ready for operation.

If the readings are not within these tolerances, the Orion has failed the challenge test. Perform a field calibration.

Table 5: Calibration challenge results

Gas Concentration

Combustible 58% LEL optimum (52 – 64% allowable)

Oxygen 15% (13 – 17% allowable)

Carbon monoxide 300 ppm (270 – 330 ppm allowable)

Hydrogen sulphide 10 ppm (9 – 12 ppm allowable)



3.3.5 Field calibration

The Orion is equipped with an easy-to-use autocalibration feature. This feature zeroes the Orion and adjusts sensor calibration.

NOTEEnsure the Orion is in clean air before zeroing and calibrating.

To field calibrate the Orion:a) Have the calibration gas ready, with regulator and black calibration hose

attached.b) Start with the unit turned on, the sample hose removed, and the calibration

nozzle attached.c) Press and hold Change/Reset until the Cal flag shows and the Zero flag

flashes.d) Confirm zeroing by pressing On/Off/Page. The Zero flag stops flashing and

remains on.

NOTEThe oxygen sensor is calibrated as part of the zeroing procedure.

e) Once the instrument is zeroed, the Zero flag disappears, and the Cal flag flashes. You have 45 seconds to begin calibration, otherwise the unit will return to instant reading mode.

f) Connect calibration gas, as shown in Figure 10: ‘Connecting gas for both challenge test and calibration’ on page 18.

g) Confirm calibration by pressing the On/Off/Page button. (Cal flag shines solid.)

h) Open the regulator.

NOTEIf the unit goes into pump alarm, acknowledge the alarm and continue.

The Orion will now automatically calibrate the H2S, CO and LEL sensors against the calibration gas.

i) When calibration is complete, the Cal flag will disappear and the Orion returns to instant reading mode. Remove the calibration hose and close the regulator on the cylinder. Wait until the readings recover and show clean air.

j) The next steps are to clear peaks, TWA and STEL.

If the Orion fails calibration, it will alarm and show the Autocalibration Failure screen. Sensors which could not be calibrated are indicated by dashed lines. Calibration for these sensors is left unchanged.

Acknowledge the alarm by pressing Change/Reset. Do not use the instrument. Ring Gas Help.



3.3.6 Clearing peaks

Clear peak readings before beginning operations. Operators can then be confident that peak values shown during operations represent their exposure. Don’t clear peaks unless the Orion shows you are in clean air.

NOTEPeak readings will include the challenge test and/or calibration you have just completed. To have meaningful results during operations, peaks must be cleared.

To clear peaks, start with the instrument turned on, and in instant reading mode.a) Press On/Off/Page.b) The Peak flag shows, and the display gives the peak readings for O2, LEL, H2S

and CO recorded since the unit was turned on, or since peaks were last cleared.c) If necessary, record the values. Go forward a step and record the O2 minimum

reading. Press On/Off/Page until you return to the Peak screen.d) Press and hold Change/Reset until the Change flag shows and the Peak flag

flashes.e) Press On/Off/Page to confirm. Peaks will be reset to zero, and the unit will

return to instant reading mode.

NOTEClearing peaks also clears the oxygen minimum reading. Clearing the oxygen minimum also clears the peaks. Turning the Orion off clears both the peaks and O2 minimum.

Peak readings are recorded in the datalog. Clearing peaks does not effect the datalog. If you need to record peak and O2 minimum readings for operational needs, do so before clearing, or before turning the unit off.



3.3.7 Clearing STEL and TWA

Clear STEL and TWA before beginning of operations. Operators can then be confident that peak values shown during operations represent their exposure.

NOTETWA and STEL readings will include the challenge test and/or calibration you have just completed. To have meaningful results during operations, TWA and STEL must be cleared.

NOTETurning the Orion off clears TWA and STEL. If you need to record TWA and STEL readings for operational needs, do so before clearing, or before turning the unit off.

To clear STEL, start with the instrument turned on, and in instant reading mode.a) Press On/Off/Page and scroll through the displays to STEL.b) The STEL flag shows, and the display gives the measurement for STEL since

the unit was turned on, or since STEL was last cleared.c) Press and hold Change/Reset until the Change flag shows and the STEL flag

flashes.d) Press On/Off/Page to confirm. STEL will reset to zero, and the unit returns to

instant reading mode.

Repeat for TWA.



3.3.8 Test the pump

Testing the Orion’s internal pump confirms pump operation, and that the gas sampling circuit, including the wand and hose, is airtight. You must test the pump before use. You can also test the pump at any time.

WARNINGIf the gas circuit leaks, then gas other than that being sampled can be drawn into the sensors, diluting the results.

The unit must be fully assembled with the wand and hose, otherwise the hose and wand assembly will not be tested.

To test the pump:a) Start with the Orion turned on and the wand connected.b) Block the end of the sampling wand with your finger.

The unit should go into alarm within a few seconds:• the red alarm lights will flash• the Pump flag will show• the audible alarm will be issued.

Remove your finger and acknowledge the alarm by pressing Change/Reset.

NOTEIf you turn on the Orion and then connect the sample hose, the unit may go into pump alarm. This does not constitute a pump test. Acknowledge the alarm and repeat the pump test.

If the unit doesn’t alarm:a) Check all connections.b) Check the wand is assembled correctly. (See Section 3.3.1: ‘Assembling the

wand’ on page 15.)c) Repeat the test.

NOTEFailure is most often caused by an incorrectly fitted water stop, or by a split hose.

If the instrument still doesn’t alarm, try to isolate the problem. Remove the wand only, and keep the hose fitted. Repeat the test by blocking the hose.

If necessary, remove the hose and repeat the test by blocking the gas inlet.

NOTEIf necessary, the Orion can be used without the hose and wand.

If the Orion itself fails, replace the internal dust filter. (See Section 4.4: ‘Changing filters’ on page 31.) Ensure filter cover screws and pump cap screw are tight. Repeat the test by blocking the gas inlet.

If the pump alarm continues, see Table 8: ‘Troubleshooting matrix’, on page 33. If the unit continues to fail, remove from service.



3.4 Operations

3.4.1 Operational hints

After the challenge test, calibration, and clearing peaks, TWA and STEL, the Orion returns to instant reading mode.

Always wait for the display to stabilise before taking readings. This can take up to 45 seconds.

Keep the probe tip above liquid surfaces.

If you’re comparing readings over time, make sure you always take subsequent readings at exactly the same location as the first reading.

The oxygen concentration shown by the Orion can be used as an indication of other contaminants. The O2 reading is normally about 20.5 to 21%. If the O2 level drops between clean ambient air and the atmosphere being monitored, it is usually caused by one of the following:• The O2 has been consumed by fire.• The O2 has been consumed by a chemical or biochemical reaction. Eg, in a

confined space such as a sewer.• The O2 has been displaced by another contaminant.

Therefore any unexplained drop in oxygen concentration must be investigated. If in any doubt contact the Hazardous Materials Response Unit (HMRU) or Science Advisor.

CAUTIONAlways leave the rubber boot fitted. This helps protect the Orion from impact.

Use the Detector Use Record if required by the IC.

3.4.2 Heartbeat indicator

Once switched on, every thirty seconds, the Orion:• beeps• heartbeat flag flashes.

This indicates to the operator that the unit is switched on and functioning.

3.4.3 Alarms – general

When the Orion goes into alarm:• the red alarm lights flash• an 85 dB alarm is issued• the relevant flag displays, such as the Pump flag showing or the TWA, STEL,

%O2, %LEL, or battery flag flashing.

Acknowledge the alarm by pressing the Change/Reset button.

http://its1/ois_portal/content/forms/Orion%20Assessment%20Form.pdf



3.4.4 Gas concentration alarms

The Orion alarms in the following gas concentration conditions:

WARNINGSome combustible gases are toxic at concentrations less than the LEL alarm level. Always be aware of the toxic hazard as well as combustibility. Wear BA when conducting atmospheric monitoring.

NOTEWhile the Orion alarms at 100 ppm for carbon monoxide STEL, there is no established STEL for carbon monoxide. Safe Work Australia recommends excursion limits of 100 ppm for a sum of 30 minutes, or 60 ppm for a sum of 60 minutes exposure in an eight hour day which assumes the worker will have no further exposure to carbon monoxide. This is not a conventional STEL.

Combustible alarm

The combustible gas alarm sounds when combustible gas levels reach 10% LEL. Acknowledge the 10% LEL alarm by pressing Change/Reset. The alarm reissues every 10 seconds until gas concentrations drop below 10% LEL.

WARNINGLeave the area immediately and report.

When combustible gases reach 100% LEL, the alarm latches on. This alarm can only be reset by turning the Orion off and back on again.

WARNINGExplosion danger. Leave the area instantly.

Once clear of the hot zone:a) If necessary, record peaks, O2 minimum, TWA and STEL, as these values will

be cleared by turning off.b) Turn the Orion off and back on again to reset the alarm.

NOTEThe Orion does not identify combustible gases. If the gas has been identified, use the correlation factors in A.6: ‘Orion LEL correlation factors’, on page 38 to determine LEL.

Table 6: Gas concentration alarms

Sensor Alarm concentration TWA STEL

Combustible 10% LEL N/A N/A

CO 30 ppm 30 ppm 100 ppm

H2S 10 ppm 10 ppm 15 ppm

%O2 Low: 19.5%, High: 23.5% N/A N/A



Oxygen alarm

The oxygen alarm sounds when:• O2 levels drop below 19.5%• O2 levels rise above 23.5%.

Acknowledge the alarm by pressing Change/Reset. The alarm sounds every 10 seconds until O2 concentrations return to the 19.5% – 23.5% range.

NOTEChanges in pressure, humidity and temperature will cause the oxygen sensor readings to fluctuate.

To deal with O2 sensor fluctuations:• Pressure: wait for readings to stabilise.• Humidity: no action required. The effect is gradual, over a period of hours.• Temperature: zero the Orion in the new temperature.

Toxic gas alarm

The toxic gas alarm sounds when:• CO concentration reaches 30 ppm,• H2S concentration reaches 10 ppm.

Acknowledge the alarm by pressing Change/Reset. The alarm sounds every 10 seconds until gas concentrations drop below the alarm concentration.

STEL and TWA alarms sound when toxic gas concentrations averaged over time reach STEL or TWA levels. See A.1: ‘Short Term Exposure Limit’, on page 35, and A.2: ‘Time Weighted Average’, on page 36, for details.

Acknowledge the alarm by pressing Change/Reset.

NOTEThe alarm will sound again if the condition continues.

3.4.5 Battery condition and alarm

Full battery life is 10 hours (non-alarming). Battery condition is indicated by the battery icon.

Figure 11 Battery icon, showing half charge

Segments within the icon disappear as battery life is used up. Each segment represents 25% of battery life. When 20 minutes of nominal battery life remains, the Orion will alarm and the battery icon will flash. Acknowledge the alarm by pressing Change/Reset.



When the battery alarm sounds, move to clean air and replace all three batteries. See Section 4.3: ‘Changing batteries’ on page 29.

WARNINGChanging batteries is not intrinsically safe. Do not change batteries in a combustible atmosphere.

If batteries are not changed, the Orion will re-alarm every five minutes.

When the batteries can no longer operate the unit, the Orion will go into battery shutdown:• the battery indicator remains on,• the alarm sounds continuously,• the alarm lights flash,• all other displays disappear.

The instrument switches off after about five minutes.

3.4.6 Datalogging

Datalogging is automatic. These records are kept:• date of calibration• date and time• TWA• STEL• peak readings (oxygen, toxic gases, combustible gases)• oxygen minimum reading• instant readings once a minute.

3.5 Turning Off

To turn off the Orion:a) Press and hold On/Off/Page for five seconds.

All flags disappear. The sandglass time flag then appears, and displays until the instrument switches off.

b) Release On/Off/Page.



SECTION 4: MAINTENANCE

4.1 Maintenance schedule

Station Commanders are to ensure station personnel carry out after use, weekly, and ‘as required’ maintenance.

The Orion is exchanged annually for preventative maintenance and laboratory calibration. This is initiated by MSA. MSA will issue an exchange unit. Instructions for the return of the original unit are included with the exchange unit.

MSA issues an Instrument Calibration Report for all Orions in service.

Table 7: Maintenance Schedule

Maintenance item After use Weekly As required Cross reference

Cleaning Clean Clean 4.2: ‘After use’

Batteries Confirm spares within expiry date Change 4.3: ‘Changing

batteries’

Challenge test Test Test 3.3.4: ‘Challenge test’

Field calibration Calibrate 3.3.5: ‘Field calibration’

Dust filter Check Change 4.4: ‘Changing filters’

Water stop filter Check Change 3.3.1: ‘Assembling the wand’

Inventory Check Check 2.1: ‘Kit contents’

Workshop maintenance Return to MSA

4.1: ‘Maintenance schedule’



4.2 After use

Clean with a soft damp cloth.

If the pump alarm keeps activating, replace the dust filter and external water stop.

Any of the following conditions can cause the sensors to be desensitised:• the Orion is subjected to physical shock• the 100% LEL alarm has latched on• hydrogen sulphide exposure over 200 ppm, or over 50 ppm for one minute• organic silicones are monitored• silicates are monitored• carbon monoxide sensor goes over-range• any compound containing lead is monitored• if formaldehyde, acrylonitrile, styrene, or carbon disulphide are monitored.

If any of these conditions is experienced, carry out the following procedure:a) Run the Orion in known clean air for 15 minutes, acknowledging any alarms as

they occur.b) Conduct a challenge test to confirm the sensor has returned to normal readings.

If the Orion fails this challenge test, call Gas Help.c) Zero and field calibrate the Orion.d) Confirm the calibration by conducting a challenge test.

If the Orion fails this calibration, call Gas Help.

4.3 Changing batteries

The Orion is powered by 3 AA size alkaline batteries. Only use Duracell MN1500 available through ESCAT; CI: 00017.

NOTEWhen replacing batteries, always:

• discard old batteries,• replace all three batteries at the same time.• order new replacement batteries.

To change batteries:a) Begin with the Orion turned off.b) Locate the battery pack screws on the bottom rear of the unit. Use a Phillips

head screwdriver and fully undo the screws.



Figure 12 Battery cover in place

c) Lift the base of the pack and gently pull it away from the Orion.d) Turn the pack over. A cover is held in place by a single clasp with an Allen key

head.

Figure 13 The battery pack

e) Use the Allen key provided. Give the clasp a quarter turn counter-clockwise and lift off the cover.

f) Check the battery pack gasket is intact, and in place. This is essential for the intrinsic safety of the detector.

Figure 14 Replacing Orion batteries

g) Replace all batteries. Be careful to maintain polarity.

Battery pack

screws

A ridge on the battery pack slots into the body of

the Orion

Cover clasp.Give a

quarter turn only

Battery pack terminals

Battery pack gasket

Replace all three

batteries

Maintain battery

polarity as indicated on battery pack



WARNINGIt is important to replace all three batteries. The Orion assumes all batteries have been replaced when calculating battery alarms and duration times. Failure to observe this can result in unexpected battery failure.

When the battery terminals connect with the Orion, the Orion will switch on. Proceed with operational start-up, or wait until warm-up is complete and turn the Orion off.

h) Reassemble cover onto battery pack.i) Insert the ridge on the battery pack into the Orion, and push the battery pack into

place. Screw the battery pack down.

4.4 Changing filters

Check all filters after use and replace as required.

4.4.1 External water stop

To replace the external water stop:a) Disassemble the wand.b) Untwist the old water stop from the wand and the connection lug, and discard.c) Replace from the spares provided in the tool kit. The water stop can fit in one

direction only. You may need to twist the water stop onto the connection to ensure an air-tight fit.

d) Reassemble the wand. See Section 3.3.1: ‘Assembling the wand’ on page 15.e) Conduct a pump test of the Orion and assembled wand. The Orion must alarm.

Figure 15 Replacing the water stop

4.4.2 Dust filter

The dust filter is about 3 millimetres thick. It is fibrous, and has a smaller diameter than the internal water stop.

To replace the dust filter:a) Use a Phillips head screwdriver. Undo the four screws on the backing plate.b) Lift the backing plate. The dust filter is attached to the plate.c) When lifting the filter out of the backing plate, ensure any trapped dust and

debris does not fall into the Orion.d) Confirm the internal water stop is in place under the dust filter.

The thicker end of the filter fits over the metal

end of the wand



e) Replace the filter from the spares provided in the tool kit. Discard the old filter.f) Set the backing plate in place, and screw down.g) Conduct a pump test of the Orion only by holding your finger over the air inlet.

The Orion must alarm.

Figure 16 Replacing the dust filter

4.4.3 Internal water stop

If the internal water stop is dirty or wet, call Gas Help.

4.5 Changing time and date

To change the time:a) Begin in instant reading mode, and scroll through pages to the Time screen.b) Hold down Change/Reset until the Time flag flashes. c) Press On/Off/Page to confirm.d) The hour figure displays. Press Change/Reset to advance the hour.e) When correct hour displays, press On/Off/Page to confirm.f) The minute figure displays. Press Change/Reset to advance minutes.g) When the correct minute figure displays, press On/Off /Page to confirm.

The Orion returns to instant reading mode.

To change the date:a) Begin in instant reading mode, and scroll through pages to the Date screen.b) Repeat the above process for month, day and year.

NOTEDate is given in the US format: month, day, year.

Remove screws and lift backing plate.Replace the dust filter

Screws

Filter backing

plate

Internal water stop

O-ring gasket

Dust filter



4.6 Downloading data

If the Orion is used at an incident where there is a fatality, injury or near miss, the Orion must be quarantined. Do not attempt to download data. Ensure no data is lost.

If you require data to be downloaded, contact Gas Help or the HMRU Technical Service Centre. A replacement will be issued.

4.7 Troubleshooting

The Orion displays an error code if it detects a problem during start-up, or while in operation. See the table below for corrective action.

Table 8: Troubleshooting matrix

Symptom Remedy

Orion doesn’t turn on Replace batteries.

Fails pump test(The Pump alarm doesn’t appear when it should)

a) Check filters have been correctly fitted.b) Check sampling hose has no leaks.c) Check all connections.d) Check filter backing plate is correctly screwed down.

If the problem persists, call Gas Help.

Pump keeps alarming

Systematically remove components from the gas circuit until the blockage is found. After you remove each component, press Change/Reset to acknowledge the alarm. If the alarm persists, continue.• Dismantle wand and remove external water stop.• Remove sampling hose.• Replace the dust filter.

If the problem persists, call Gas Help.

Error code 7 Check fresh AA size alkaline batteries have been fitted.

Error code 1 Remove and reconnect battery pack. If problem persists, call Gas Help.

Any other Error message Call Gas Help.

Does not complete Self-Tests at start-up Call Gas Help.

Desensitisation of sensors indicated by unusual or negative readings

a) Run the Orion in clean air for 15 minutes.b) Challenge test. If the Orion fails this challenge test, call Gas Help.c) Zero and field calibrate the Orion.d) Confirm the calibration by conducting a challenge test.

NOTEOne situation where this can occur is if batteries fail while the Orion is in use.

Any sensor fails calibration Call Gas Help.



4.8 Resupply

4.8.1 Calibration gas

Calibration gas is automatically supplied by MSA before the cylinder expiry date. Contact Gas Help if:• you haven’t received a new cylinder by the expiry date on the old cylinder• your cylinder runs out before the expiry date.

Return empty and expired calibration gas cylinders to MSA after you have received a replacement. This is a one-for-one swap. Before transport, take the cylinder outside – away from doors and windows – and bleed it empty. Then the cylinder won’t require dangerous goods documentation.

NOTEEmpty cylinders are required for quality control and equipment management purposes.

4.8.2 Other consumables

Batteries are available through Fire and Rescue NSW Electronic Supply Catalogue (ESCAT), A.E. Baker, or from local suppliers. See Section 2.4.2: ‘Orion specifications’ on page 9 for battery specifications.

Filters and other Orion parts are listed on ESCAT. Contact Gas Help for advice.


D.I. Recommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\Appendix.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

APPENDIX A: PRINCIPLES OF GAS DETECTION

A.1 Short Term Exposure Limit

The Short Term Exposure Limit (STEL) is the gas concentration an unprotected worker can be continuously exposed to for 15 minutes without adverse health effects.

This limit should not be repeated more than four times per working day of eight hours. There should be a break of at least one hour between each exposure.

The equation below shows how the Orion calculates your short term exposure. To calculate STEL:

Example 1: Assume the Orion has measured a H2S concentration of 45 ppm for 15 minutes:

Compare this with the STEL for H2S of 15 ppm published in the Hazardous Substances Information System (HSIS) database. To work in this environment, this worker must wear respiratory protection.

Example 2: Assume the Orion has measured a CO concentration of 15 ppm for 10 minutes and 10 ppm for 5 minutes:

Due to its persistence in the blood stream – with a biological half life of 3 to 4 hours – carbon monoxide doesn’t have an established STEL. However the time weighted average (TWA) published by HSIS is 30 ppm. This worker doesn’t need respiratory protection.

NOTEFor carbon monoxide, Safe Work Australia recommends excursion limits of:

• 100 ppm for a sum of 30 minutes exposure in an eight hour day

• 60 ppm for a sum of 60 minutes exposure in an eight hour day.

These excursion limits assume the worker will have no further exposure to carbon monoxide. This is not a conventional STEL.

(Exposure time in minutes) x (Exposure concentration in ppm)

15 minutesOrion STEL reading =

(15 minutes) x (45 ppm)

15 minutes

= 45 ppm

Orion STEL reading =

(10 mins x 15 ppm) + (5 mins x 10 ppm)

15 minutes

= 13.3 ppm

Orion STEL reading =



A.2 Time Weighted Average

The TWA is the concentration of gas a worker can be continuously exposed to for an eight hour working day, repeated over five days for a forty hour working week.

The equation below shows how the Orion calculates your time weighted exposure. To calculate TWA:

Example 1: Assume the Orion has measured a 2 hour exposure of H2S concentration of 16 ppm:

The published TWA for H2S is 10 ppm. While the two hour exposure averaged across an eight hour day gives an Orion TWA reading of 4 ppm, the actual exposure is 16 ppm – above the published STEL of 15 ppm for H2S. This worker requires respiratory protection.

Example 2: Assume in a 10 hour operation, the Orion has measured a CO concentration of 45 ppm for 3 hours and 30 ppm for 7 hours:

The TWA for carbon monoxide published by HSIS is 30 ppm. This worker requires respiratory protection.

A.3 Combustible gas sensor

Combustible gases are detected by a catalytic sensor. This kind of sensor relies on these concepts:• the gas can be burnt• different combustible gases have different flammability characteristics• an increase in the temperature of a coil carrying a current results in a change in

the electrical resistance of the coil.

The gas to be tested is passed over a heated metal coil. The coil burns the gas, resulting in an increase in temperature of the coil. This change in temperature causes a change in the electrical resistance of the coil, which is measured.

The greater the concentration of gas, the more gas is burned, resulting in a greater change in temperature and electrical resistance.

The result is interpreted and displayed on the LCD as a percentage of LEL.

(Exposure time in hours) x (Exposure concentration in ppm)

8 hoursOrion TWA reading =

(2 hours) x (16 ppm)8 hours

= 4 ppm

Orion TWA reading =

(3 hours x 45 ppm) + (7 hours x 30 ppm) 8 hours

= 43 ppm

Orion TWA reading =



The instrument is calibrated to a standard concentration of a known combustible gas. Concentrations of other gases can be determined by comparing the extent to which they are combustible, to the standard. This conversion is done manually after identifying the gas being measured. See A.6: ‘Orion LEL correlation factors’, on page 38.

WARNINGFor any comparison to work, the combustible gas being measured must first be identified. Otherwise the Orion can only indicate the presence or absence of a combustible gas, and not an accurate concentration.

The combustible gas sensor measures the concentration of combustible gases only. The toxicity of combustible gases is not measured. Wear BA.

NOTEFor a catalytic sensor to work, there must be sufficient oxygen in the atmosphere for combustion to take place.

Some gases, such as formaldehyde, can inhibit the catalytic process, or coat the heated coil, reducing the sensitivity of the sensor. To clear this condition, see the procedure in Section 4.2: ‘After use’ on page 29.

A.4 Oxygen and toxic gas sensors

Oxygen and toxic gas concentrations are determined by electrochemical sensors. These sensors work in a similar manner to batteries, and rely on the following processes:• Chemical reactions can generate an electric current (such as in a battery).• A chemical reaction is chosen that uses the gas to be measured.• The sensor is designed so that everything needed for this reaction to proceed is

present except the gas to be measured.• Gas is allowed to diffuse into the cell, allowing the reaction to take place.• The reaction generates a current which is measured.

Electrochemical sensors are designed to be sensitive to one particular compound. However reactions can occur with different compounds, resulting in cross-sensitivity. The Orion’s carbon monoxide sensor, for instance, will also detect ethylene, hydrogen and nitric oxide, giving false positives.

NOTEElectrochemical sensors have a service life. Like any battery, the compounds in electrochemical sensors will be slowly used up.



A.5 Orion sensor configuration

The sensors are located below the pump cap on the upper front body of the Orion. The configuration is as below.

Figure 1 Orion sensor configuration

A.6 Orion LEL correlation factors

Not all combustible gases behave identically. The Orion is calibrated to a pentane (C5H12) standard at 58% LEL. The reaction of the Orion to other gases of known concentration and known LEL can be compared to this standard. This gives a correlation factor.

To determine the concentration of a gas, multiply the correlation factor given in Table A.1: LEL correlation factors, below.

Example:

You have determined that the leaking gas is carbon disulphide. The Orion gives an LEL reading of 12%. What is the actual LEL of the carbon disulphide (CS2)?

NOTEThe use of correlation factors is subject to an error of + 25% of the result.

NOTEThe correlation factor for carbon disulphide is an extreme example. The Orion’s 10% LEL alarm kicks in at 22% LEL for carbon disulphide, still well below the lower explosive limit.

Alarm light

The sensors

are located under the pump cap

LCD

CO O2

LEL H2S

%LEL CS2 = (Orion %LEL reading) x (carbon disulphide correlation factor)

%LEL CS2 = 12% x 2.2

%LEL CS2 = 26.4 ± 7%



WARNINGCorrelation factors can only work if the gas has been identified. If in doubt, always follow the Orion’s 10% LEL alarm.

Table A.1: LEL correlation factors

Combustible gasMultiply %LEL reading by:

Combustible gasMultiply %LEL reading by:

Acetone 1.1 Isopropyl alcohol 1.1

Acetylene 0.7 LPG Autogas (butane + propane) 0.9

Acrylonitrile * 0.8 Methane 0.5

Benzene 1.1 Methanol 0.6

Butane 1.0 Methyl isobutyl ketone 1.1

1,3 Butadiene 0.9 Methylcyclohexane 1.1

n-Butanol 1.8 Methyl ethyl ketone 1.1

Carbon disulphide * 2.2 Methyl tertiary butyl ether 1.0

Cyclohexane 1.1 Mineral spirits 1.1

2,2 Dimethylbutane 1.2 iso-Octane 1.1

2,3 Dimethylpentane 1.2 n-Pentane 1.0

Ethane 0.7 Petrol (unleaded) 1.3

Ethyl acetate 1.2 Propane (LPG) 0.8

Ethyl alcohol (ethanol) 0.8 Propylene 0.8

Ethylene 0.7 Styrene * 1.9

Formaldehyde * 0.5 Tetrahydrofuran 0.9

Heptane 1.1 Toluene 1.1

Hydrogen 0.6 Vinyl acetate 0.9

n-Hexane 1.3 VM & P naptha 1.6

Isobutane 0.9 0-xylene 1.2

Isobutyl acetate 1.5

* These gases can inhibit the sensor. To clear this condition, see the procedure in Section 4.2: ‘After use’ on page 29.



A.7 Cross sensitivity

Some sensors react against gases other than those for which they have been designed. For instance, the carbon monoxide sensor will show a reading when hydrogen is present.

The following table gives the major cross-sensitivity values for the given sensors.

Other gases can also cause small readings on the toxic gas sensors. Do not be alarmed if the CO and H2S sensors show small readings while detecting combustible gases with the %LEL sensor. This is neither a positive nor a negative identification. Treat the environment as toxic, and wear BA.

A.8 Temperature class

To be intrinsically safe in a particular atmosphere, the maximum temperature the surface the Orion can reach must be less than the ignition temperature of the gas or vapour.

With alkaline batteries fitted, the Orion is rated for temperature class T4 (including T1, T2, and T3) for ambient operating temperatures up to 40 oC, and T3 (including T1 and T2) for ambient operating temperatures between 40 oC and 50 oC.

Some gases with a low ignition temperature are listed in Table A.3.

Table A.2: Sensor cross-sensitivity

Gas at 100ppm CO sensor reading H2S sensor reading

Nitric oxide (NO) 70 + 10 ppm –

Ethylene (C2H4) 80 + 9 ppm –

Hydrogen (H2) 70 + 26 ppm –

Sulphur dioxide (SO2) – 10 ± 3 ppm

Nitrogen dioxide (NO2) 2 + 6 ppm –20 ± 2 ppm, or the sensor failure reading of ‘- - -’

Table A.3: Some gases with low ignition temperatures

Gas or vapour Ignitiontemp.

Temp.class

Operational implication

Carbon disulphide (CS2) 90 oC T6 Always exit on reaching low LEL alarm.

Acetaldehyde 140 oC T4

For ambient operating temperatures between 40 oC and 50 oC, exit on reaching low LEL alarm.

Diethyl ether 180 oC T4

Diethylene glycol dimethyl ether 188 oC T4

Any gas or vapour with an ignition temperature between 135 oC and 200 oC T4



Glossary

auto-ignition temperature: See ignition temperature.

calibration gas value: A known concentration of gas against which the Orion is calibrated and spanned.

carbon disulphide: Carbon disulphide (or carbon bisulphide) is an industrial chemical used as a solvent, fumigant, and in mining and manufacturing. Chemical formula is CS2 and CAS No is 75-15-0. Its ignition temperature is 90 oC, flash point is –30 oC, it has a low ignition energy, and it is heavier than air.

carbon monoxide: A colourless, odourless gas produced by the incomplete combustion of fossil fuels. Carbon monoxide is lethal because it reacts with the oxygen-carrying substance in the blood, haemoglobin. The haemoglobin is then unavailable to react with oxygen in the lungs, causing asphyxiation. Carbon monoxide is present in smoke, including bushfire smoke, is often present after fires, in exhausts from internal combustion engines, and is used in the steel industry. CO is combustible, with an LEL of 12.5% by volume.

datalog: Record of measured gas concentrations, including time and date, stored in the instrument’s electronic memory.

Gas Help A 24 hour, seven day a week help service for the Orion gas detector (and some other gas detectors). Use the number listed on the Online Phone Book page on the Intranet. Call for advice on using, maintaining, problem solving and ordering spare parts for the Orion 4-head gas detector. Spare parts queries are best sent during daylight hours.

hydrogen sulphide: A colourless, poisonous gas with the odour of rotten eggs. Often produced by decaying animal or vegetable matter.

ignition temperature: The temperature of a gas or vapour is the temperature at which it will ignite without a flame or spark being present.

Immediately Dangerous to Life and Health (IDLH):

The maximum concentration of gas (in ppm) from which a worker could escape within 30 minutes without experiencing any escape-impairing or irreversible health effects.

Lower Explosive Limit (LEL):

Sometimes referred to as Lower Flammable Limit (LFL). The minimum concentration of a gas – in a mixture of that gas and air – which will ignite. A common unit of measurement is a percent of the LEL.

mist: A suspension of finely divided liquid particles suspended in the atmosphere. Examples are an oil mist produced during cutting and grinding operations, acid mists from electroplating, acid or alkali mists from pickling operations, and paint spray mist in painting operations. Fog and cloud are both examples of mists that occur when water vapour in the atmosphere condenses.

parts per million (ppm): A common unit of measurement for toxic gases. This term literally means one part out of one million possible parts. 10,000 ppm is 1% by volume for gases.

Short Term Exposure Limit (STEL):

The average amount of gas (in ppm) a worker can be exposed to in a 15 minute period with no long term health effects. This may occur 4 times a shift with one hour between 15 minute exposures.

Threshold Limit Value (TLV):

A term used to signify limits in gas exposure. TLV is a proprietary term and is not normally used by Fire and Rescue NSW. TLV is usually expressed as a TWA.



Time Weighted Average (TWA):

The average amount of gas (in ppm) a worker can be exposed to over a certain time period. This time is defined as 8 hours to represent a normal work day.

Upper Explosive Limit (UEL):

Sometimes called the Upper Flammable Limit (UFL). The maximum concentration of a gas – in a mixture of that gas and air – which will ignite.

vapour: Effectively, a vapour is a gas. Humidity in the atmosphere is a vapour, but when it condenses as cloud or fog, it is a mist. Technically, there is a critical temperature below which a gas can be compressed to form a liquid. Below this temperature, the gaseous form of the substance is called a vapour.



References

Chemwatch, 2010, Chemfxx MSDS Database and Chemicals Management System, Version 2010/3, Chemwatch, Glen Huntly, Victoria. Viewed 9 Nov 2010 [http://jr.chemwatch.net/chemffx/?X].

Clugston, M. J., 2004, The New Penguin Dictionary of Science, 2nd Edition, Penguin London, England.

Mine Safety Appliance Company, 2003, Orion Multigas Detector Operation Manual, Part No 10021555, (L) Rev 5, 2003, MSA, Pittsburgh, USA.

National Occupational Health and Safety Commission, 2001, Guidance Note on the Interpretation of Exposure Standards for Atmospheric Contaminants in the Occupational Environment [NOHSC:3008(1995)] 3rd Edition, Work Safe Australia, Braddon ACT.

National Pollutant Inventory, n.d., Carbon disulphide overview, Department of Sustainability, Environment, Water, Population and Communities. Viewed 4 Nov 2010 [http://www.npi.gov.au/substances/carbon-disulfide/index.html]

FRNSW, 2005, Recommended practice: Orion four-head gas detector, Version A, Fire and Rescue NSW, Greenacre.

FRNSW, 2005, Recommended practice: Wearing of uniforms and personal protective equipment (PPE), Version A(01), Fire and Rescue NSW, Sydney.

FRNSW, 2007, MSA Orion gas detector: Detector use record, Ver 01, Fire and Rescue NSW Alexandria. Viewed 22 Dec. 2012 [http://its1/ois_portal/content/forms/Orion%20Assessment%20Form.pdf]

FRNSW, In Orders 2007/8, MSA Orion gas detector use record, Fire and Rescue NSW, Sydney.

Safe Work Australia, 2009, Hazardous Substances Information System (online database), Safe Work Australia, Braddon, ACT. Viewed 4 August 2009 [http://hsis.ascc.gov.au/SearchHS.aspx].

Safe Work Australia, no date, Carbon monoxide, Safe Work Australia, Braddon, ACT. Accessed 4 August 2009 [http://hsis.ascc.gov.au/DocumentationES.aspx?ID=111#ref].

Test Safe Australia, 2004, Certificate of conformity, AUS Ex 01.3730X, Issue 3, Test Safe Australia, Londonderry.


D.I. Recommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\OrionIX.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

INDEX

Aaccuracy 10alarms

acknowledging 24alarm lights 5, 24gas concentrations 25oxygen 26STEL 26toxic gases 26TWA 26volume 24

atmospheres detected 2autocalibration 20

BBA vii, 37, 40battery

battery icon 6, 26battery pack 30battery pack gasket 30battery pack screws 5, 29consumption 3polarity 30spare 3

Ccalculating

STEL 35TWA 36

calibrating the oxygen sensor 20calibration 20

calibration gas 11, 18calibration gas specification 9nozzle 18principles of 11span 11

carbon monoxide 41catalytic sensor, see combustible gas sensorcaution, meaning vchallenge test 18

calibration gas specification 19clearing TWA and STEL 22peak readings 21results 19

Change icon 6Change/Reset button 8clearing peaks 21

effect on datalog 21oxygen minimum 21

clearing STEL and TWA 22combustible gas sensor

oxygen content of air 37poisoning 37principles of operation 36

combustible gasesalarm 25correlation factors 25, 37, 38correlation factors list 39explosive limits LEL and UEL 11toxicity of 25

connecting sample hose 23control buttons 8correlation factors 25, 37, 38

combustible gas list 39error 38

Ddatalogging 2

records kept 27dust filter See filtersdynamic risk assessment 2, 12

Eelectrochemical sensors 37

cross sensitivity 37false positives 37principles of operation 37

exposure limitsalarms 25STEL 35TWA 36

Ffield calibration 29

See also calibration 20filters 11

changing dust filter 31replacing water stop 31

furnace stack readings 3

Ggas concentration alarm points 25Gas Help 3, 41gas inlet location 5gas outlet location 5gas sampling circuit, testing 23

Hheartbeat indicator 7hydrogen sulphide 41

Iidentification chip

cylinder 18Orion 5


D.I. Recommended Practice Version 02 Issued February 2011FILE: W:\NB\RP HMRU\Orion\Frame Ver 02\OrionIX.fm © Copyright State of NSW (Fire and Rescue NSW) 2011

instant readingcarbon monoxide 7flowchart 14hydrogen sulphide 7LEL 7operations 24oxygen 7

Instrument Calibration Report 28intrinsic safety 3, 9

batteries 27

Kkit contents 4

LLCD icons, location and explanation 6LEL 11, 38

See also combustible gasesLEL sensor, see combustible gas sensor

Mmist, definition 41

Nnote, meaning v

OOn/Off/Page button 8oxygen minimum 21oxygen sensor 37

PPPE 13pre-operational checks 16pump cap 5pump test 23

Qquick start instructions 1

Rrubber boot 24

Ssampling wand, assembling wand 15scrolling LCD pages 14sensors

accuracy 10combustible gases 36electrochemical 37response time 10

speaker 5specifications

calibration gas 9Orion 9sensors 10

STEL 25, 35

Ttesting the pump 23toxic gas sensors 37toxicity of combustible gases 37TWA 25, 36

UUpper explosive limit 11

Vvapour, definition 42

Wwarmup time 9warning, meaning vwater stop

external 31See also filters

Zzeroing 11, 17

in clean air 17

FIRE AND RESCUE NSW - BA/Hazmat

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