City West Water
QES Management System
Issue Date: 24/12/2014
Confined Space Entry & Associated Works Procedure
CONTENTS
1.
PURPOSE ................................................................................................................... 2
2.
SCOPE ...................................................................................................................... 2
3.
REFERENCES.............................................................................................................. 2
4.
DEFINITIONS ............................................................................................................. 2
5.
LEGAL AND OTHER REQUIREMENTS .............................................................................. 3
6.
PROCEDURE ............................................................................................................... 3
6.1
EMERGENCY PROCEDURES ....................................................................................... 3
6.1.1 REPORTING OF ALL SAFETY RELATED OCCURRENCES ............................................... 4
6.2
RESPONSIBILITIES .................................................................................................. 4
6.3
GENERAL PROCEDURES............................................................................................ 5
6.3.1 TRAINING ............................................................................................................ 5
6.3.2 MEDICALS ........................................................................................................... 5
6.3.3 ENTRY/ACCESS PERMITS ....................................................................................... 6
6.3.4 SAFE WORK METHOD STATEMENT (SWMS) ............................................................. 7
6.3.5 WORK GROUP SIZES ............................................................................................ 7
6.3.6 PROTECTIVE EQUIPMENT ...................................................................................... 7
6.3.7 IGNITION SOURCES.............................................................................................. 9
6.3.8 TESTING THE ATMOSPHERE ................................................................................... 9
6.3.9 VENTILATION ..................................................................................................... 11
6.3.10
COMMUNICATIONS .......................................................................................... 12
6.3.11
DISTRESS PROCEDURES .................................................................................. 12
6.3.12
PERSONAL HYGIENE ........................................................................................ 12
6.3.13
ISOLATION OF SEWERS ................................................................................... 13
6.4
SPECIAL INSTRUCTIONS/PROCEDURES .................................................................... 13
6.4.1 SEWER EXCAVATIONS ........................................................................................ 13
6.4.2 LIFTING MANHOLE COVERS ON LIVE SEWERS (Non Entry/Visual Inspections/CCTV/Jet
Cleaning) .................................................................................................................... 14
6.4.3 SEWERS SERVING INDUSTRIAL AREAS OR SURCHARGED SEWERS .......................... 15
6.4.4 PUMPING STATIONS, TANKS, VALVE PITS, UNCOMMISSIONED SEWERS ................... 16
6.4.5 WORK PROCEDURES FOR ENTRY CLASSIFIED AS LOW RISK (RESTRICTED ENTRY) .... 16
6.4.6 WATER SUPPLY TANKS ........................................................................................ 17
6.4.7 WATER PIPELINES .............................................................................................. 18
6.4.8 OTHER MANNED OPERATIONAL SITES .................................................................. 19
APPENDIX A ...................................................................................................................... 20
APPENDIX B ...................................................................................................................... 22
APPENDIX C ...................................................................................................................... 27
APPENDIX D ...................................................................................................................... 28
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Confined Space Entry & Associated Works Procedure
1.
PURPOSE
This document has been prepared as a generic document for use by persons undertaking Confined
Space associated works on City West Water assets.
This procedure is designed to meet the requirements of Part 3.4 of the Occupational Health &
Safety Regulations 2007. Although generic in nature, the document also outlines specific matters
that need to be considered in fulfilling Duty of Care responsibilities under the Occupational Health
and Safety Act 2004.
2.
SCOPE
This document has been prepared for all City West Water staff and contractors engaged to
undertake any confined space associated activities, be they entry or non-entry for the purpose of
construction, operation, inspection and maintenance of assets owned by City West Water. It is also
to be used by consultants and contractors engaged in the construction of new assets as part of the
Development process.
It is important to mention at this point that prior to entering into any confined space, the need for
the entry must be seriously evaluated. Alternative methods to complete a task that don’t require
entry into the confined space or at least minimise the number of entries must be considered.
3.
REFERENCES
Occupational Health & Safety Act 2004
Occupational Health & Safety Regulations 2007
WorkSafe Victoria Compliance code - Confined Spaces
AS 2865: Confined Spaces
AS 1657: Fixed platforms, walkways, stairways and ladders
AS/NZS 1715: Selection, use and maintenance of respiratory protective equipment
AS/NZS 1716: Respiratory protective devices
Management of Confined Space Works (PRO-140)
Requirements on Undertaking Works in Sewer Affected by Trade Waste (WI-120)
Explosive Gases in Sewers (PRO-198)
4.
DEFINITIONS
For the purpose of this document, confined spaces may include spaces such as those in a tank,
pit, pipe, duct, underground sewer, shaft, trench, tunnel or other similar enclosed or partially
enclosed structure, if the space:
(a) is, or is intended to be, or likely to be entered* by any person;
(b)has a limited or restricted means for entry or exit that makes it physically difficult for a person
to enter or exit the space;
(c) is, or is intended to be, at normal atmospheric pressure while any person is in the space;
(d)contains, or is intended to contain, or is likely to contain(i)
an atmosphere that has a harmful level of any contaminant; or
(ii)
an atmosphere that does not have a safe oxygen level; or
(iii)
any substances, that could cause engulfment.
Refer to Appendix C – Confined Space Definition Table for examples.
Authorised persons: Personnel appropriately trained to undertake confined space entry and
nominated by the Responsible Manager to plan and direct work activities
undertaken in confined spaces.
Competent persons: All City West Water personnel and authorised contractors trained to undertake
and control confined space entry.
CSE:
Confined space entry
CWW:
City West Water
Contaminant:
Any substance that may be harmful to the health &/or safety of people
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Entered*:
Entry Permit:
Hazard:
OCC:
TWA:
STEL:
Competent:
Manhole:
SWMS:
5.
When a person’s head or upper body is within the boundary of the confined
space
Written approval of an employer to enter or access a confined space
The potential to cause harm, injury or illness
Operational Control Centre - CWW 24 hour emergency communication centre
Time Weighted Average
Short Term Exposure Limit
The specification of knowledge and skill and the application of that knowledge
and skill within an occupation or industry level to the standard of performance
required in employment.
Also known as access chamber, is a chamber with a removable cover through
which a person can gain access to an underground structure or installation,
e.g. sewer pipe, pump station wet well etc.
Safe Work Method Statement
LEGAL AND OTHER REQUIREMENTS
It is a requirement of CWW that all activities in confined spaces be carried out in accordance with
the Occupational Health & Safety Regulations 2007, particularly Part 3.4 – Confined Spaces,
WorkSafe Victoria’s Compliance Code for Confined Spaces, Australian Standard AS 2865 –Confined
Spaces, and the procedures detailed within this document to ensure as far as reasonably
practicable the health and safety of all personnel involved in confined space entry and related
activities.
6.
PROCEDURE
This procedure shall apply in all circumstances that warrant entry into a confined space or access
without entry. Prior to undertaking any such works, appropriate notification/approval must first be
sought (refer to Section 6.3.3 – Entry/Access Permits).
6.1
EMERGENCY PROCEDURES
Appropriate procedures must be established for the control and management of an emergency in a
confined space, including procedures for:
 the rescue of any person from the confined space
 first aid to be provided to any person in the confined space and after rescue.
When establishing emergency procedures, the following must be taken into account:
 the nature of the confined space
 any hazards associated with the level (or change in level) of oxygen &/or atmospheric
contaminants
 the work to be done and the work method
 work done outside the confined space
 the means of entry and exit.
The preparation of the emergency procedure is the responsibility of the employer in conjunction
with the actual personnel/contractors entering the confined space.
Rehearsal – The emergency procedures must be rehearsed with relevant employees to
demonstrate that the specific rescue plan for the space is effective.
If a worker is overcome:
1. Do not attempt a rescue if you cannot protect yourself from the same hazard(s) that has
overwhelmed your workmate;
2. Where prepared, follow the emergency rescue procedures detailed in the Safe Work Method
Statement (SWMS) which must be specific to the activity being undertaken (refer to
Appendix D for sample ‘Emergency Procedure’ SWMS.
3. Summon help:
(a) from the rest of the working party
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(b)from the Ambulance Service and/or Fire Brigade Phone 000 (who you call will be
dependant on the situation at hand). You may need to ring 112 on your mobile
phone if you are in an ‘out of service’ area.
(c) from CWW’s Operational Control Centre. Contact No 9313 8499
4. Apply first aid as quickly as possible;
5. Obtain medical treatment:
(a) If victim is unconscious or showing significant symptoms, summon ambulance
(b)Medical opinion must be obtained in every case of gas attack or suspected gas attack
(c) Gassing victims must never be permitted to drive until declared fit by a doctor
Once the needs of the patient have been attended to, report the circumstances to your supervisor
to allow the incident to be fully investigated and the cause identified. The incident may also need to
be reported to WorkSafe. If so, ensure that this is undertaken.
6.1.1 REPORTING OF ALL SAFETY RELATED OCCURRENCES
(e.g. injury/illness, near miss, unmanageable working atmosphere etc. to City West Water)
Where a safety related occurrence takes place, it is the contractor’s/worker’s responsibility to
advise CWW at the earliest convenient time. This is to allow CWW an opportunity to either
investigate, restrict future access, monitor future access, review current protocols or whatever
other action may be required in order to prevent any future reoccurrence from taking place.
In such instances, CWW must be advised by the contractor/worker via a direct call to CWW’s
Operational Control Centre (OCC will refer to appropriate personnel for follow up) or CWW Project
Manager associated with the activity being performed (who will also refer to appropriate personnel
for follow up)(refer to PRO-140 Management of Confined Space Works).
6.2
RESPONSIBILITIES
Responsible Managers (e.g. Departmental, Project Managers, Contract Managers etc.)
shall:
(a) Ensure that all appropriate actions are taken to implement this procedure.
(b) Ensure equipment is available and in good working order
(c) Ensure that training facilities are available to enable training to be carried out at required
frequency.
(d) Provide a visible commitment to the procedure by undertaking regular on-site visits and
participating in checking on-site conditions.
(e) Hold managers/authorised personnel under their direction accountable for meeting the
objectives of this procedure.
(f) Nominate Authorised Persons
Authorised Persons (e.g. Coordinators, Supervisors, Project Managers etc.) shall:
(a) Ensure that all personnel undertaking confined space entries and associated works under
their direction or management have the latest information (particularly CWW requirements)
on confined space work.
(b) Monitor the effectiveness of safety training.
(c) Arrange for specialist atmospheric testing to be conducted in areas identified as high risk
by Competent Persons during normal work activities.
(d) Arrange safety training and medical examinations for employees under their control at the
specified frequency.
(e) Ensure that:
Where sub contractors are used to undertake works with or on behalf of a primary
contractor, evidence of their knowledge and qualifications must be demonstrated. This
should include evidence of current in-date confined space training, knowledge of the
intended works, as well as a signed documented form stating that the sub contractor
has been advised of and is aware of CWW’s confined space entry and associated works
procedures. This must be available on site. The sub contractors in these situations form
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part of the primary contractor’s structure and therefore require appropriate supervision
whilst undertaking the works.
Competent Persons (e.g. Employees, Contractors) shall:
(a) Ensure that a current copy of this procedure is available on site at all times and that it is
followed by all persons entering/accessing any confined spaces.
(b) Record the results of atmospheric testing when required and advise the relevant Authorised
Person of any dangerous atmospheres detected.
(c) Attend training and medical examinations as directed.
(d) Wear the correct safety gear for the task being performed.
(e) Ensure that the safety equipment is in good order and is only used for the designed task
and is not willfully damaged.
(f) Report any defective safety equipment and prevent it from being used for confined space
work.
(g) Ensure access/entry permit and if required the confined space entry record/permit is
completed prior to any persons entering/accessing the space.
6.3
GENERAL PROCEDURES
6.3.1 TRAINING
Confined Space Entry
All personnel involved in confined space entry work groups must have achieved a certificate of
competency from a registered/endorsed training provider.
Training must be competency based and attended at the nominated frequency of 12 monthly. For
personnel who are expected to utilise airline or Self Contained Breathing Apparatus (SCBA), specific
training on these items must also be undertaken.
For personnel who are required to utilise a six gas detector, specific training on the use of a gas
detector and each of these gas sensors must also be undertaken. This shall be provided by the
training provider and proof of such may be requested by City West Water from time to time.
The Responsible Manager may deem more frequent training intervals appropriate in some
situations. Situations where this may apply include those with little or no previous experience in
working in confined spaces or where the frequency of confined space entry is minimal.
All personnel not previously trained in CSE shall be required to undertake initial training in confined
space entry to meet the Occupational Health and Safety Regulations 2007 – Part 3.4 Confined
Space as well as CWW specific requirements. Reference to this procedure should be included in the
training and evidence of such must be made available through the training provider if requested.
Personnel who are also required to access Melbourne Water assets may be required to undertake
Melbourne Water specific CSE training.
OH&S Construction Induction Training
The Occupational Health & Safety Regulations 2007 – Part 5.1 Construction: requires that all
personnel involved in construction activities (of which confined space is considered to be) have
been provided with OH&S Construction Induction Training.
Records of training undertaken must be maintained by a nominated person and also available on
request.
6.3.2 MEDICALS
All persons undertaking confined space entry shall undergo a medical examination on a 2 year
cycle to determine physical capacity for carrying out activities during CSE.
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The medical examination is to assess the medical fitness of the person for work in confined spaces,
its associated hazards, including the use of respirators. Working in confined spaces and the wearing
of respirators and some other personal protective equipment imposes a burden on the cardiac,
respiratory and muscular -skeletal systems. AS/NZS 1715: Selection, use and maintenance of
respiratory protection equipment, recommends medical screening is conducted for any person who
uses any type of respirator.
A Certificate signed by a Registered Medical Practitioner confirming they are fit to work with the
hazards with due consideration being given to:
(a) Demands arising from working under stressful conditions (such as high temperature
environment)
(b) Variable atmospheric conditions, including possible exposures to irritant gases.
(c) Ability to maneuver in cramped conditions.
(d) Microbiologically active environments (waste water organisms)
(e) Immunisation status
(f) Demands arising from wearing air supplied or self rescue respirators from time to time.
(g) Demands arising from the wearing of extra personal protective equipment, e.g. waders,
safety harness, lifeline, helmets, safety boots, etc.
(h) The physical fitness of the person carrying out work in the confined space.
These Certificates are valid for 2 years from the day they have been signed by the Registered
Medical Practitioner unless a review is needed with the person becoming ill in the interim. Where
required, CWW’s records are to be kept by its medical practitioner and a copy of certificate placed
in the employee’s personnel file held in Human Resources. Contractors are required to produce
medical certificates as soon as practical on request from the CWW representative.
The Authorised/Competent Person on site controlling the CSE shall also look for obvious signs
relating to the individual members of the work group and their suitability to undertake activities in
a confined space. Where it appears that a worker(s) is not in a suitable condition, their position in
the work group should be replaced.
CWW employees who are CSE trained for project management and awareness reasons and would
not be expected to neither enter a high risk confined space nor utilise breathing apparatus are not
generally required to undertake a medical examination.
6.3.3 ENTRY/ACCESS PERMITS
Application for Permit
Prior to undertaking any confined space related activities, a Permit Number must first be applied
for and received. To do this, an Application to Access/Enter Confined Space (FOR-159) must first
be completed and submitted to CWW’s Operational Control Centre (fax 9313 8108), or to the
relevant CWW Project Manager.
CWW/Maintenance Contractor personnel are excluded from this requirement, particularly for
emergency works, and are able to process their own confined space entry application via the
creation of a Focus Service Request. This entails completion of the CSE checklist therein and the
resultant Service Request Number becomes the Entry/Access Permit number.
Communications to OCC
Entry/Access Call
After obtaining a permit number and on the day of the intended entry/access, one hours* notice
must be given to CWW’s Operational Control Centre (9313 8499) prior to the entry/access taking
place.
*One hours notice is not required for works undertaken directly for or by CWW, i.e. maintenance
contractor, Trade Waste/Operations personnel, capital works, scheduled sewer cleaning/CCTV etc.
A Competent person on site responsible for controlling the work must complete an Entry Permit
before any person is permitted to enter the confined space.
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Exit/Completion Call
Once works are completed, CWW’s Operational Control Centre must again be contacted to advise
that all have exited the confined space or completed the confined space associated works. Note
that the Operational Control Centre must be notified in advance, if it is anticipated that the exit
time nominated on the entry/access permit is going to be exceeded.
Availability and Retention of Permits
The completed CSE permit must be available on site during the currency of the works and copies of
completed permits must be retained for at least one month from time of issue.
6.3.4 SAFE WORK METHOD STATEMENT (SWMS)
In accordance with the Occupational Health and Safety Regulations 2007 – Part 5.1 Construction,
confined space activities are considered ‘high-risk construction work’ which are therefore required
to comply with additional aspects including the preparation of a SWMS.
A SWMS is a document that:
 Lists the type of high-risk construction work being done e.g. confined space entry
 States the health and safety hazards and risks arising from the work
 Describes how the risks will be controlled, and
 Describes how the risk control measures will be put in place.
A SWMS must be undertaken and understood by all relevant workers prior to any works taking
place. On site, works must be performed in accordance with the SWMS. If circumstances relating to
the activity change, the SWMS must be reviewed to ensure that it remains adequate.
6.3.5 WORK GROUP SIZES
The work group size of at least 3 persons (refer below) relates to entries into the sewerage system.
There must be at least three people in the working group, two must remain at the surface to help
the one below if needed. Where there is more than one person below, there must be an equal
number at the surface (refer to table below).
Number of Persons below
1
2
3
4
Number of Persons required above
2
2
3
4
Communication between the surface parties and those below must be maintained at all times.
One of the surface party must remain at the access chamber, and another must remain within hail
or hearing distance of any distress signal.
The work group size for activities associated with sewer dig outs, visual inspections (CCTV),
vacuum sewer lines, jet cleaning and other specialist activities may be reduced provided the risk
assessment can adequately demonstrate a lower risk which can be controlled with less people
(refer also to Section 6.4).
6.3.6 PROTECTIVE EQUIPMENT
Safety Helmets
A safety helmet must be worn when working in confined spaces where practicable. Safety helmets
must be worn when work is being performed above the person in the confined space. This is for
protection from objects being lowered or accidentally dropped from above, and to protect from
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bumping the head in confined spaces. Safety helmets should be replaced as per the manufacturer
specifications or when damaged.
Warning Signs and Barricades
A temporary sign must be placed at the entry point of confined space to signify that the area is
potentially dangerous and the entry can only be undertaken with appropriate authorisation.
The sign should contain the following details:
When working in roadways or other traffic areas, erect warning signs and barricades. Follow the
guidelines in Road Management Act 2004 Worksite Safety – Traffic Management Code of Practice
and AS 1742.3: Traffic control for works on roads, and any Local Council Traffic Guidelines.
When working in footpaths or unfenced private property, erect barricades or install covers at
unattended open access chambers or shafts. Covers should be fixed to prevent removal where the
site has been vacated e.g. overnight or if crew has left to attend other site or obtain supplies etc.
In the event that the excavation, e.g., shaft, is located in a roadway, suitable solid plate covers
must be installed to allow vehicular traffic to pass over safely.
At night place barricades and lights at all open access chambers or shafts.
Fall Prevention
Safety Lines and Fall Arrest Devices for persons entering a confined space
Any person working in a confined space must wear an approved harness with a safety line attached
where practicable. If there is potential for the safety line to tangle in equipment while working in a
confined space, the safety line may be disconnected but must remain at the base of the access
ladder or point of ascent and be reconnected before ascent out of the confined space. In such
circumstances, a rescue plan detailing how a person (who has disconnected from the safety line)
would be reconnected and removed if they were suddenly overcome or collapsed needs to be in
place.
The standby person should constantly control the safety line whilst people are working below and
connected to the safety line, this includes controlling the ascent and descent of personnel below to
prevent falling.
When working in manholes greater than 2 metres in depth, and/or where a fall of greater than 2
metres is possible, a winch/fall arrest device must be used to control the safety line where
reasonably practicable. Risk control measures associated with the use of a winch/fall arrest device
must be undertaken in accordance with the Occupational Health and Safety Regulations 2007 –
Part 3.5 Plant.
Do not use safety lines or harnesses for anything other than their designed purposes.
Fall Prevention for surface personnel
Personnel exposed to a possible fall of two meters or greater must comply with the Occupational
Health and Safety Regulations 2007 – Part 3.3 Prevention of Falls. Furthermore, the following
requirements must also be complied with:
(a) Personnel undertaking works must detail fall preventative controls on the work specific
Safe Work Method Statement (SWMS) prior to works being undertaken; and
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(b) SWMS must be known and understood by all relevant personnel and available on site and
upon request at all times.
Self Rescue Breathing Sets
Self rescue breathing sets meeting the requirements of AS/NZS 1715 and AS/NZS 1716, must be
available for each person working below and carried within easy reach to provide immediate access
if required.
Protective Clothing
The selection of the appropriate protective clothing to be worn within a confined space depends
upon both the type of confined space and the work being performed. In the job planning these
factors are to be considered. Equipment to be considered for use includes overalls, waders, hard
hat, long sleeve shirts, long pants, gloves, eye and ear protection, buoyancy vest, industrial
clothing, and safety or gum boots.
Clean all contaminated work clothes and equipment at work. Never take contaminated clothing
home.
6.3.7 IGNITION SOURCES
Do not smoke, weld, use grinders, light fires or have other naked lights in, or within 6 metres of
the entrance to any confined space.
Do not carry matches or cigarette lighters while working in, or inspecting sewers, access chambers,
drains, wells or tanks.
If hot works or chemical usage is required to be performed in the confined space, a specific Risk
Assessment must be completed. Works should not be undertaken unless an additional Hot Work
Permit record has been completed.
Lighting & Electrical Equipment
Lighting and other electrical equipment used in areas determined as Confined Spaces should be
classified as approved for use in Hazardous Areas Class 1 Zone 1 or Class 1 Zone 2 (Intrinsically
Safe). Refer to Australian Standards AS 2380 and AS 2430 for further information.
Mobile phones and pagers are not to be taken into areas assessed as Confined Spaces.
6.3.8 TESTING THE ATMOSPHERE
The atmosphere shall be tested and results recorded prior to entry to any confined space or
restricted space. For confined spaces, the space shall be air monitored continuously during
occupancy.
Equipment
Air testing shall be conducted using an electronic gas detection meter. Gas detection meters must
be fitted with a minimum of six gas sensors, these comprising of Explosive Gas, Oxygen, Hydrogen
Sulphide, Carbon Monoxide, Ammonia and Volatile Organic Compounds (VOCs).
In the case of entering/accessing CWW confined spaces that are not sewer related (e.g. water
assets, recycled water/stormwater assets etc.), a gas detector fitted with a minimum of four gas
sensors, these comprising of Explosive Gas, Oxygen, Hydrogen Sulphide and Carbon Monoxide
must be used. The risk assessment of the specific task shall determine if any additional gas sensors
are required.
Note: Atmospheric testing equipment must be calibrated in accordance with manufacturers’
recommendations.
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Routine Tests
Lower the gas detection meter or its sample lead if fitted slowly to the proposed working level and
test the atmosphere for 5 minutes. This slow lowering of the meter will assist to detect pockets of
contaminated air. The peak levels should be checked to ensure they comply with the following
conditions:
GAS
Oxygen
Explosive gas
Hydrogen sulphide
Carbon monoxide
Ammonia
Volatile Organic Compounds (VOC)
CONCENTRATION
between 19.5% and 23.5%
less than 5% of its LEL
less than 10 ppm
less than 30 ppm
less than 25 ppm
Less than 10 ppm
If any of these levels are exceeded, DO NOT ENTER the confined space, increase the ventilation
and repeat the routine test. If the second test fails to pass, record the concentrations and advise
the Authorised Person to determine what further action to take. This could involve further
ventilation or the use of respiratory protection.
Keep the gas detector or its sample lead in the confined space at all times when working to
continuously monitor the work atmosphere and be alert for any alarms.
Where a safe atmosphere still cannot be achieved, escalation to CWW via the OCC or CWW Project
Manager associated with the activity being performed must be undertaken. OCC
representative/CWW Project Manager will refer this to the relevant internal personnel for advice
and/or action. OCC representative/CWW Project Manager may advise field personnel to close up
job until further notice (refer to Section 6.1.1 Reporting of All Safety Related Occurrences to
CWW).
Explosive Gases
If explosive gases are found to be present at concentrations greater than 5% of their LEL after 10
minutes venting report immediately to the City West Water Project Manager or Sewer Operations
Engineer (via OCC) and await advice for further action. The City West Water Project Manager or
Sewer Operations Engineer will determine what course of action is required in accordance with
Procedure PRO -198 (Explosive Gases in Sewers).
Confined space entry shall NOT be permitted if explosive gas concentration is greater than 5% of
its LEL.
Once the confined space has been entered and providing it is continuously monitored for LEL,
evacuation must occur if the LEL of the gas reaches 10%.
Other Contaminants
In some confined spaces it will be necessary to monitor for atmospheric contaminants in addition to
those listed above.
This may be because the atmosphere may be affected by:
(a) non-compliant industrial discharges – particularly sewerage assets
(b) tasks being performed by other persons around the space
(c) observation of abnormal conditions by the work crew
(d) spillages / discharges into drains
(e) the task performed requires the use of materials containing volatile solvents etc.
A guide to the levels of contaminants that are of concern can be found in ‘Exposure Standards for
Atmospheric Contaminants in the Occupational Environment’, published by the Australian Safety
and Compensation Council. Assistance can also be sought from qualified occupational hygienists if
required.
Note: Human senses may also indicate unsuitable atmospheric conditions.
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Notification Of Change In Confined Space Conditions
Authorised Persons/Competent Persons shall notify the relevant asset owner/controller immediately
of any change in the conditions, e.g., colour and gas levels that may indicate that dumping into the
confined space or associated system may have occurred.
6.3.9 VENTILATION
Other than isolation of incoming sources of contaminant, ventilation is the major control used to
protect persons in confined spaces from harmful atmospheres. If air quality within the confined
space is not suitable for entry, then ventilation to the space should be increased.
The two most common types of ventilation are natural and forced.
Natural Ventilation
Natural ventilation involves the opening of an appropriate number of covers on the confined space
to create a draft that allows fresh air to enter through natural circulation. In the case of sewers, the
minimum requirement is to open the immediate downstream and upstream manhole covers.
Not all confined spaces can be adequately vented using natural means due to either insufficient
covers being available to open or levels of contaminant require an increase in the volume of fresh
air entering the confined space.
If suitable air quality cannot be obtained using natural ventilation, then forced air ventilation should
be used.
Forced Ventilation
Forced ventilation involves either blowing fresh air into the confined space or extracting air from
the space by using a mechanical fan to force the air movement.
Forced ventilation has advantages in that the volume of air flow can be more controlled than for
natural ventilation, and also the direction of air flow can be controlled.
The use of mechanical blowers/extractors will require consideration of the following factors:
(a) Noise in urban areas, noisy mechanical ventilation can disturb the public, particularly
during the night. Use “quiet” blowers in sensitive areas.
(b) Location - in selecting where the blower is to be located, choose a site that will minimise
the introduction of vehicle exhaust gases or other contaminants into the confined space.
With extractors, choose a site to minimise odours for local residents.
(c) As blowers can be required to operate continuously for many hours, sites should also be
selected to minimise traffic disruptions, this may require work to be performed outside
of the busy traffic times.
(d) Security - incidents have occurred in the past where the operation of blowers/extractors
has been compromised by members of the public, either because they object to their
operation creating noise or odours, or in extreme cases by the fan being stolen. Measures
must be put in place to monitor the fan to ensure its operation is not compromised in this
way.
(e) Public Safety - warning signs and appropriate barricades should be installed around the
fans to protect members of the public from both the mechanical energy of the fan and any
gases that may be exhausted from the confined space.
Breathing Apparatus
If the methods outlined above cannot establish a safe working atmosphere, then suitable airline
equipment meeting AS/NZS 1715 requirements may be considered in order to work within the
confined space (except in circumstances where the atmospheric hazard relates to high
explosive/flammable gases).
Airline equipment may also be considered in circumstances where smell and dust cause comfort
problems.
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6.3.10 COMMUNICATIONS
Radio or telephone communication must be available on site at all times to enable contact with
Operational Control Centre and Emergency Services.
Maintain regular and continuous communication between the surface and those below by using for
example:
 Voice
 Visual
 Torch signals
 Whistles
 Approved radio communication equipment (intrinsically safe)
 Signals on the safety line e.g.:
o One tug - stop (when in motion)
o Two tugs - lower
o Three or more tugs - to attract attention.
It is essential to maintain communication between the surface attendant and the work-site inside
the space so that help can be given when someone indicates distress. Distress should be indicated
using any of the above communication methods.
Some examples of when distress signals may be generated by the party inside the space include
the gas detector alarming, a person feeling ill, a person injuring themselves whilst working in the
confined space.
A distress signal may also be generated by the surface attendant when they become aware of
hazards that exist to persons inside the space that have not yet been detected by the party
working inside the confined space.
6.3.11 DISTRESS PROCEDURES
Person Below
If the gas detector alarms because of high concentrations of a dangerous gas, or you suspect a
dangerous gas, feel eye irritation, headache, dizziness, shortness of breath or nausea:
(a) put on the self rescue respirator;
(b)signal to the observer;
(c) move immediately to exit confined space;
(d)if unable to exit by yourself, signal distress to the observer to initiate emergency rescue
procedures.
Surface Attendant
If someone working below gives a distress signal follow the emergency procedures contained within
this procedure (refer to Section 6.1), or those developed as part of the site specific safe work
method statement. Where possible;
(a) Assist as far as practicable the exit of the confined space without placing yourself or other
members of the work group at risk.
(b) If necessary, immediately make contact with emergency services via Phone 000 or the
Operational Control Centre to arrange urgent assistance. Give all relevant site details and
known conditions.
(c) Notify the relevant Responsible Manager/Authorised Person
6.3.12 PERSONAL HYGIENE
Confined spaces can be soiled workplaces, either due to contaminants normally contained within,
e.g. sewage, or through dirt build up due to infrequent access. Good personal hygiene is critical to
work in proximity to these types of spaces.
The following are particularly important for working in soiled confined spaces:
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Risk of Infection
Minimise the risk of infection by wearing gloves and keeping hands away from your face. Wash
hands thoroughly before eating or smoking.
Inoculations for Tetanus, Hepatitis A and Hepatitis B are recommended for all personnel required to
work in soiled confined spaces.
Protective Creams and Disinfectants
Use barrier cream and hand cleaner on hands and forearms. Disinfectants may also be used after
activities to ensure hands are clean.
Clothing
Clean all contaminated work clothes and equipment at work. Never take contaminated clothing
home.
Abrasions and Cuts
Treat abrasions and cuts immediately. Report any injuries to your supervisor and follow appropriate
procedures for injury/incident reporting and investigation.
6.3.13 ISOLATION OF SEWERS
In some instances, isolation of sewers may be required to prevent sewage and/or contaminant
gases entering the working environment. Isolation of sewers may be undertaken with the use of
plugs, shut off valves or other means. To reduce the risk the following is to be carried out in all
cases:
(a) SWMS to be carried out to determine if sewer can be diverted, plugged or educted
upstream of entry. This is to be undertaken in conjunction with the Project Manager
responsible for the works.
(b) The SWMS will require a contingency plan and details of isolated sewers.
(c) The SWMS must be provided to CWW’s works Project Manager prior to any works taking
place.
(d) Entry permits and isolation documentation must be available on site at the time works are
carried out.
(e) The plugs isolating the sewer must be recorded against the CSE number.
(f) Plugs must comply with relevant standards for isolation of gasses and not necessarily
flows.
(g) The plug manufacturers’ recommendations must be considered when preparing the SWMS.
6.4
SPECIAL INSTRUCTIONS/PROCEDURES
This section gives special procedures that apply to CWW’s assets.
The following provides examples of how CWW expects particular activities to be assessed and
undertaken in line with the aforementioned procedure and general instruction.
6.4.1 SEWER EXCAVATIONS
When a shaft or trench is excavated to repair or break into a sewer or access chamber, the
following points are to be considered during the period the sewer is open/unsealed.
A SWMS shall be undertaken prior to any works commencing and shall be made available on site.
All members of the work group shall be familiar with the SWMS and a form of verification by
members of the work group shall be documented.
If there is a change in conditions from the initial preparation of the SWMS (e.g. contaminated
ground encountered) or if clarification is needed, enquiries should be directed to the responsible
manager/authorised person to plan and direct work activities undertaken in the confined space.
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The following should be used in determining safe systems of work, and considered whilst
completing the SWMS:
(a) Ensure all personnel have received appropriate training in relation to Confined Space Entry
and OH&S Construction Induction Training (Red Card equivalent);
(b) All employees must be fit for the proposed work;
(c) Complete an Entry Permit on site, having previously received a Permit Number from CWW;
(d) Determine and detail work group size considering the activity at hand, remoteness of site,
emergency procedures/resources etc.;
(e) Wear a full body safety harness at all times with safety lines connected where practicable;
(f) Conduct initial atmospheric testing followed by continuous atmospheric monitoring;
(g) Use fall arrest system if practicable and consider fall protection for those above;
(h) Have self rescue breathing sets in close proximity at all times;
(i) Consider possible ignition sources and eliminate where possible;
(j) Ensure communications systems are understood and operable.
6.4.2 LIFTING MANHOLE COVERS ON LIVE SEWERS (Non Entry/Visual
Inspections/CCTV/Jet Cleaning)
Personnel must be appropriately trained in relation to the types of works performed and meet the
requirements of the Occupational Health and Safety Regulations 2007 – Part 3.4 Confined Space as
well as CWW specific requirements. Proof of appropriate confined space entry training for this type
of work shall be made available on site if requested.
Personnel must ensure adherence to the Occupational Health and Safety Regulations 2007 – Part
3.3 Prevention of Falls whilst undertaking these activities.
The following should be used in determining safe systems of work, and considered whilst
completing the SWMS:
(a) Ensure all personnel have received appropriate training in relation to Confined Space
Entry and OH&S Construction Induction Training (Red Card equivalent);
(b)Complete an Entry/Access Permit on site, having previously received a Permit Number
from CWW;
(c) Determine and detail work group size considering the activity at hand, remoteness of
site, weight and size of manhole cover, emergency procedures/resources etc.;
(d)Consider atmospheric testing, particularly in industrial areas;
(e) Utilise fall protection measures whilst above the opening;
(f) Consider possible ignition sources and eliminate where possible;
Application must be made to CWW and approval granted prior to any works commencing in
accordance with Clause 6.3.3.
Non Entry Activities on Sewers in Industrial Areas
The following points must be considered when undertaking non entry type activities (e.g. visual
inspections, jet cleaning, CCTV, sampling etc.) on sewers in industrial areas:
(a) Where practicable, atmospheric testing (via gas detection) should be undertaken inside
the manhole at all times whilst activity is in progress.
(b)If advised by CWW’s Trade Waste Group that Ammonia levels may be elevated due to
the industrial discharges, consider the use of an Ammonia gas detection device in
conjunction with standard gas detector.
(c) When approaching to inspect or working from the top of a manhole which cannot for
practical purposes have a gas detector placed in it, the person should wear a personal
detector and approach with the wind on their back (where possible).
(d)When jet cleaning/CCTV, persons should keep well away from the manhole once the jet
hose/camera has been placed far enough up the chase and into the pipe to enable jet
cleaning/CCTV to commence and only approach when there is a problem or when there
is the need to check progress.
(e) Extraction ventilation may need to be installed at the up or downstream manhole to
ensure air flow is into the manhole or, air flow out is minimised when jet cleaning.
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(f) For operations such as jet cleaning where a permanent gas detector cannot be
positioned at the top of the open manhole (due to the outward expulsion of water &
material) inspection of the process from the open manhole should only be undertaken by
a person wearing a personal gas detector.
(g)If the gas detector alarms on approach, or offensive odours are present which contribute
to a nauseous reaction, the person should back away immediately and consider the
operational activities which may be contributing to the unfavourable conditions.
Operational activities (e.g. jet cleaning) potentially causing the unfavourable conditions
should be ceased (where possible) to reduce the immediate risk to personnel e.g. cease
jet cleaning. After ten minutes the manhole should be approached again and, if safe to
do so, equipment removed and the manhole closed.
If an operator is not feeling well as a result of work near the manhole, other operator(s)
must not continue with the work and cease operation as outlined above.
Upon closure of the manhole, or if the condition remains unsafe and the manhole cannot
be closed, the project supervisor must be contacted. Supervisors may determine that
additional controls such as the following may be necessary to continue working:
(i) Air purifying respirators (e.g. Half face mask with organic vapour filter complying
with AS/NZS 1716 - 2012).
(ii) Mechanical Ventilation
(iii) BA Sets
(iv)Cease discharge of upstream customer(s) impacting on manhole(s)
6.4.3 SEWERS SERVING INDUSTRIAL AREAS OR SURCHARGED SEWERS
When working in sewers located in industrial areas, be aware that trade waste may be discharged
into the sewer at irregular intervals.
Possible Trade Waste Discharges
Prior to working in sewers in an industrial area, obtain information on the likely discharges, and
any specific implications for working near them. Information regarding trade waste discharges can
be obtained from the controllers of trade waste licensing, CWW’s Trade Waste Group.
Information regarding known non-compliant discharges will be advised by the OCC at time of
application or prior to entry into a sewer. You may be advised to seek assistance from the
controllers of trade waste licensing, CWW’s Trade Waste Group. The isolation of incoming lines or
the closing down of known sources of contamination could be requested to be investigated.
Ventilation
Forced ventilation should be used whenever practicable. If natural ventilation has to be used, open
the work access chamber and additional access chamber covers, upstream or downstream, until a
draft of air can be felt entering or leaving the work access chamber. Once established, proceed with
atmospheric testing.
Surcharged Access chambers
For surcharged access chambers, or jobs with short duration, use a blower at the work access
chamber for approximately five minutes, before testing the air.
Normal Flow
For sewers flowing normally, an exhaust blower can be used and is best located at a convenient
downstream access chamber. After the blower has been operating for 10 minutes, test the air in
the work access chamber. If satisfactory proceed with the work, keeping the blower running for the
duration of the job.
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6.4.4 PUMPING STATIONS, TANKS, VALVE PITS, UNCOMMISSIONED SEWERS
Risk Assessment
All Sewer and Water Pumping Stations under the control of CWW have had extensive risk
assessments undertaken. These assessments may also contain information pertaining to confined
space risk. For sites that have been assessed as having a high risk, a HIGH RISK sign has been
positioned on or within close proximity to the entry point.
Copies of the risk assessments are available via the relevant CWW Contract/Project Manager or by
following this link N:\OHS Risk Register\Risk Assessment. These are proposed to be moved over to
City West Water’s Quality, Environment, Safety (QES) Management System in the future.
Prior to undertaking works, be sure to reassess these taking into consideration (and modifying if
necessary) the previously completed risk assessments.
Wet Pump Wells or Covered Tanks
For pumping station wet wells or covered tanks which contain sewage, ensure that any fixed
ventilation equipment is switched on and operating for 10 minutes before commencing to test the
air.
For pumping stations serving industrial areas, also consider the instructions detailed above for
sewers in Industrial Areas.
Atmospheric testing must also be undertaken at the surface of all wet wells once the cover is
opened.
Dry Pump Wells, Valve Pits And New Manholes
Entries which have no direct contact with sewage such as dry pump wells and valve pits (both
sewer and water) will normally present a lower occupational health risk to personnel required to
enter them. This also applies to manhole entry on sewers that have yet to be connected to the live
sewerage system, i.e. land development works.
An assessment of the dry well, valve pit or new manhole is required to determine what control
procedures are required. The procedure for conducting this assessment is described in Appendix B.
Once the assessment has been completed the entry will be classified into one of the following three
categories:
Low Risk (Restricted Entry),
Medium Risk, or
High Risk.
Work procedures for entries classified as Low Risk (Restricted Entry) are described in the
appropriate sections below.
Work procedures for confined space entries classified as Medium or High Risk are the same as
those for work in contact with live sewage and detailed within the general body of this procedure,
as well as specific requirements detailed in relevant risk assessments.
6.4.5 WORK PROCEDURES FOR ENTRY CLASSIFIED AS LOW RISK (RESTRICTED ENTRY)
Spaces classified as Low Risk utilising the flowcharts in Appendix B would indicate that the space
does not meet the specific requirements of a confined space under the Occupational Health &
Safety Regulations 2007 – Part 3.4. In such instances a SWMS must be developed prior to
undertaking any works. CWW still requires that some of the confined space processes be followed
due to the potential for conditions to change without notice.
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This section describes the work procedures to be followed for all entries that have been classified
and labeled as Low Risk (or Restricted Entry) e.g. Sewerage Pumping Stations.
Site Specific Procedures
If site specific procedures have been developed, these are to take precedence on the following and
be followed accordingly. If not, the following should be adhered to:
Permits
Entry/Access Permit procedures as described in Section 6.3.3 must be followed.
Atmospheric Monitoring
Before entry, the atmosphere must be tested as described in Section 6.3.8.
The atmosphere must be continuously monitored during occupancy with gas detection meter.
Ventilation
Natural ventilation should, where possible, be maximised by opening another access cover furthest
from the access point to create a draught of air through the space.
If mechanical ventilation is available, turn it on and keep it running for period of occupancy.
Work Group Size
As detailed above, works classed as Low Risk are not considered to be ‘confined space’ works.
These works will however be required to have appropriate SWMS prepared and depending on the
controls in place, may reduce the work group, providing it is safe to do so.
Communication
The person undertaking the Low Risk Entry is to communicate to CWW’s Operational Control Centre
(9313 8499) one hour before entering and after exiting.
6.4.6 WATER SUPPLY TANKS
Procedure PRO-66 Carrying Out Reservoir and Tank Cleaning must be adhered to when undertaking
works on water tanks.
A Risk Assessment must first be undertaken to determine whether the entry is required, and if so,
what the safe work group size shall be.
Top Entry
Entry through the top may be required with water present in the tank, so extra precautions to
prevent unintentional fall into the tank are required.
(a) Open all available top covers, if tank is empty then bottom covers are also removed.
(b) Check that air quality is satisfactory and fill in entry permit.
(c) A harness, lifeline and fall arrester must be worn by the person entering the tank.
(d) An observer is to remain on the top for communication, and to control the lifeline.
(e) Where internal combustion engines are used to assist with the cleaning they must be
external to the confined space and sited down wind from the opening. Only electrical
pumps should be used within the space. In such circumstances, electrical hazards should
also be considered and eliminated as far as reasonably practicable.
Bottom Entry
Open top covers before removing bottom entry hatches to provide best possible natural ventilation.
(a) Perform initial gas test by holding gas detector inside entry point, then fill in entry permit.
(b) All persons entering tank must wear a harness. A safety line should be readily available.
(c) The tank is to be entered by a person carrying a gas detector and self rescue respirator
and the area of the tank be generally traversed while checking for gases which may be
emitted from any disturbed debris or silt on the floor.
(d) All persons entering these spaces must be confined space entry trained.
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(e) If any atmospheric contamination is detected, all additional personnel entering must be
confined space entry trained and carry a gas detector and self rescue respirator.
(f) Any inlet pipe, outlet pipe, scour pipe, or sumps which are present as floor openings that
personnel could step into must be clearly marked or barricaded off.
For all water supply tanks requiring confined space entry, a gas detector fitted with a minimum of
four gas sensors, these comprising of Explosive Gas, Oxygen, Hydrogen Sulphide and Carbon
Monoxide must be used. The risk assessment of the specific task shall determine if any additional
gas sensors are required.
6.4.7 WATER PIPELINES
The following sections apply only to internal inspections and minor works inside water pipelines.
Works Planning & Execution
In planning a pipeline entry the Authorised Person must investigate and limit the risks, which may
be present from the following:
(a) Pipeline gradient - Entry should only be made into areas where gradients are near to flat.
Harnesses and lifelines must be worn where gradients exceed 1 in 100 and the pipeline
invert remains slippery.
(b) Slippery surfaces - Wet internal surfaces of enamel lined pipelines are extremely
slippery. The addition of non-slip matting at the access point and the sweeping of the
invert with a broom should be considered.
(c) Ponded water at low points - The possibility of personnel slipping down into water at
low points must be prevented.
(d) Any pipe branches into which personnel could step down or slide into, must be identified.
(e) The work/inspection party size, entry duration, works to be performed, and the volume of
available air must be considered.
(f) Where natural ventilation is to be used its effectiveness must be monitored throughout the
period of occupation for any airflow changes which can occur due to external air
temperature and prevailing wind changes.
(g) If any materials are to be used to undertake minor coating repair works the potential for
contamination of the atmosphere by gases given off by the material or as a result of
reactions with other materials or the curing process should be considered.
(h) Entry to Unsafe areas - The Authorised Person is to ensure that all persons entering are
instructed as to which part of the space must not be entered because it has not been air
tested or there are unsafe pipeline gradients or pipe branches. Consideration should be
given to erection of barriers or signs to prevent inadvertent entry to potentially unsafe
areas.
Ventilation
Provided gas detection shows the air quality to be satisfactory, ventilation is not required for a
pipeline inspection of duration no longer than two hours, if it has been dewatered and fresh air
introduced to the space within the previous eight hours.
Where it has been more than eight hours since the space was dewatered then natural or forced
ventilation should be used to achieve a minimum air velocity of 0.2 m/s.
When natural ventilation does not achieve the minimum air velocity, the space is to be entered by
an air testing party. Where possible the party members are to wear harness and lifeline and remain
in contact with the person stationed in the pipeline at the access point. Air testing should be done
near invert, spring line and crown levels throughout the length of pipeline to be inspected. Only
after the air in the space has been tested and found to be uncontaminated may the inspection
party enter.
Where natural ventilation is used its effectiveness must be monitored at 30 minute intervals during
the period of occupation for any air flow changes which can occur due to external air temperature
and prevailing wind changes.
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Permits
Entry/Access permit procedures as described in Section 6.3.3 must be followed for all confined
space entries into water pipelines.
Safety Equipment
A gas detector shall operate inside the space for the duration of the occupancy.
For all water pipelines requiring confined space entry, a gas detector fitted with a minimum of four
gas sensors, these comprising of Explosive Gas, Oxygen, Hydrogen Sulphide and Carbon Monoxide
must be used. The risk assessment of the specific task shall determine if any additional gas sensors
are required.
Where the minimum of air velocity is not achieved for sufficient time to produce two air volume
change overs prior to entry, then self rescue breathing apparatus must be carried.
Work group size
A minimum work group size of three is required with at least two persons stationed outside the
access point.
6.4.8 OTHER MANNED OPERATIONAL SITES
(e.g. ALTONA TREATMENT PLANT, WERRIBEE RECYCLED WATER PLANT etc.)
Prior to any works being planned or undertaken at these sites, Site Management will need to be
consulted to determine what tasks are required and what specific procedures need to be followed.
Procedures that need to be adhered to may include site specific Permit To Work Systems and task
specific SWMS. There may also be a need to develop task specific SWMS at the time.
A number of areas within these sites may have been assessed as Restricted Spaces which if
entered must be done so in accordance with their particular assessments. Further details relating
to such assessments can be obtained via Site Management.
For all works requiring confined space access/entry at these sites, a gas detector fitted with a
minimum of four gas sensors, these comprising of Explosive Gas, Oxygen, Hydrogen Sulphide and
Carbon Monoxide must be used. The risk assessment of the specific task and site specific
requirements shall determine if any additional gas sensors are required.
All other confined space activities must be undertaken in accordance with the requirements
detailed in Clause 6.3.3.
7.
REVIEW
This procedure shall be reviewed bi-ennially or when a legislative change arises. Changes to
legislation are flagged to the OH&S Coordinator for the organisation via ANSTAT Services, LAWLEX,
Safetylaw and Workcover Authority Documentation.
8.
DOCUMENTATION
Confined Space Entry Checklist Form FOR-95
Application to Access/Enter Confined Spaces FOR-159
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APPENDIX A
DANGEROUS GASES
There
1.
2.
3.
are three main gas hazards in a confined space environment:
Lack of oxygen
Explosive gases
Toxic gases
Following is a brief description of some gases that may be encountered in the sewer environment.
A1.1
HEAVY GASES
HYDROGEN SULPHIDE
Relative density 1.19 (air = 1)
Exposure standard TWA 10 ppm
STEL 15 ppm
Gas characteristics - Distinctive odour (rotten eggs) but not evident at high concentrations.
Colourless, explosive, very poisonous, inflammable (5% LEL = 2,150 ppm).
Effects on the body - This gas is rapidly fatal even in low amounts, a concentration of 0.2%
(2000 ppm) causing death in a few minutes.
In low (but dangerous) concentrations the gas will be initially detectable by its distinctive rotten
eggs odour however the gas will quickly paralyse the sense of smell and it may be mistakenly
believed that the gas has dispersed.
In high concentrations paralysis of the sense of smell will occur after only seconds of contact. It will
cause irritation of the eyes and nose slightly less intense than that due to chlorine.
Testing method - Electronic gas detection meter (H2S sensor), Draeger tube.
PETROL VAPOUR
Relative density 2.50 to 4.00 (air = 1)
Exposure standard TWA 900 mg/ M3
Gas characteristics - Distinctive odour, colourless, flammable, explosive
Effects on the body - Suffocating. A concentration of 1 - 2% is dangerous and over 2% is rapidly
fatal.
Testing method - Electronic gas detection meter (LEL and VOC sensors), Draeger tube.
CARBON DIOXIDE
Relative Density 1.53 (air = 1)
Exposure standard TWA 5000 ppm STEL 30,000 ppm
Gas Characteristics - Odourless, colourless, non flammable, will not support combustion.
Effects on the body - This gas has no odour. It acts as a stimulus to the respiratory nerves,
which will increase the breathing, possibly up to the gasping stage. If present in large quantities it
may cause an acid taste. Causes ears to ring. 10% concentration (100,000 ppm) cannot be
endured for more than a few minutes. Collapse or death will be caused by asphyxiation due to lack
of oxygen.
Testing Method - Draeger Tubes, Electronic gas detection meter (O2 sensor indicating low
oxygen).
CHLORINE
Relative Density 2.49 (air = 1)
Exposure standard 1 ppm (peak limitation)
Gas Characteristics - Yellowish-green gas, choking odour (concentrations as low as 0.02 ppm can
be detected by smell), non flammable
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Effects on the body - Irritates eyes, nose, throat causing coughing and pain in the chest. In liquid
form it irritates the skin. Will kill quickly even in very low concentrations.
Testing Method - Draeger tubes
A1.2
LIGHT GASES
AMMONIA
Relative Density 0.60 (air = 1)
Exposure standard TWA 25 ppm
STEL 35 ppm
Gas Characteristics - Colourless, strong characteristic odour (concentrations from 5 ppm can be
detected by smell), irritating, explosive.
Effects on the body - Irritant to respiratory system, eyes and skin
Testing Method - Draeger tubes, Electronic gas detection meter
CARBON MONOXIDE
Relative Density 0.97 (air = 1)
Exposure standard TWA 30 ppm
STEL 200 ppm
Gas Characteristics - Odourless, colourless, tasteless, flammable (5% LEL = 6,250 ppm),
explosive, non irritating, very poisonous.
Effects on the body - Exceedingly poisonous when inhaled. The symptoms are dizziness,
headache, drowsiness, weakness of legs, dimness of vision, loss of hearing and palpitations all
leading to complex collapse. The victims must be moved into the open air, kept warm and must not
exert themselves
Testing Method - Electronic gas detection meter (NH3 sensor), Draeger tubes.
METHANE
Relative Density 0.55 (air = 1)
Gas Characteristics -Odourless, colourless, flammable (5% LEL = 2,500 ppm).
Effects on the body - Deprives tissue of oxygen, does not support life.
Testing Method - Electronic gas detection meter (LEL sensor), Draeger tubes
SLUDGE DIGESTION TANK GAS
Relative density – variable
Gas Characteristics - May be practically odourless, colourless, flammable. Consists principally of
methane and carbon dioxide with smaller amounts of hydrogen sulphide, nitrogen and sulphuric
compounds.
Effects on the body - will not support life.
Testing methods - Electronic gas detection meter (flammable gas, hydrogen sulphide), Draeger
tubes.
NITROGEN
Relative Density 0.97 (air = 1)
Gas Characteristics - Colourless, odourless.
Effects on the body - high concentrations are associated with a lack of oxygen.
Testing Method - Electronic gas detection meter (O2 sensor indicating low oxygen levels).
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APPENDIX B
CONFINED SPACE RISK ASSESSMENT PROCEDURES
GENERAL
This procedure has been prepared to assist in the assessment of confined spaces typically found in
the Water Industry environment.
Confined spaces can be grouped into three main risk categories, being High Risk, Medium Risk and
Low Risk. Steps involved in determining the level of risk are:
1.
Is the area a confined space?
2.
Assess the atmospheric risk.
3.
Assess the access/egress risk.
Assessment flow charts are included as Diagrams 1 and 2 and are to be used to aid determining
the risk level for atmospheric and access/egress hazards. The risk category for the confined space
is the highest category evaluated for either atmospheric or access/egress risk.
Confined Space assessments are to be carried out by assessment teams of at least two persons,
preferably one representative nominated by the asset owner and one representative nominated by
groups required to work on the asset.
Determining if the Area is a Confined Space
The Occupational Health and Safety Regulations 2007 clearly define a confined space as detailed
earlier within Section 4 of this document. Generally sewers, drains, wet wells, some dry wells and
valves pits meet the definition of a confined space.
More difficult to categorise are buildings over wet wells and dry wells, where although there may be
only one way in, ventilation may be plentiful and therefore the potential for a hazardous
atmosphere to be present is minimal. Each building will need to be assessed against the above
criteria and if the assessment team cannot reach a decision, further advice should be sought from
the relevant Contract Supervisor (representing the asset owner).
Assessing Atmospheric Risk
The following notes are intended to assist in using the flowchart (Diagram 1) for determining the
atmospheric risk category.
Ventilation - Mechanical Ventilation
If the confined space is mechanically vented, the ideal is at least one complete change of air every
6 minutes, i.e. 10 changes per hour.
To calculate the actual number of air changes per hour, the fan flow rate and the volume of the
confined space should be determined. The number of air changes per hour is the fan flow rate per
hour divided by the volume of the confined space.
Ventilation - Natural Ventilation
Two factors will have an influence on the effectiveness of natural ventilation:
1.
Is it possible to open more gatics or covers than the one being used as the entry point
into the confined space? Air is much more likely to flow if vents are available at the
extremities of the confined space.
2.
The width to depth ratio of the confined space - If the confined space is shallow and
relatively wide then natural ventilation of the entire space is relatively easy. If the
confined space is relatively deep and narrow then natural ventilation is likely to be poor
at the bottom of the confined space.
A shallow pit is defined as having a width to depth ratio greater than 2:1 i.e. a pit 2 metres deep
would need to be more than 4 metres in width to qualify as a shallow pit.
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QES Management System
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Confined Space Entry & Associated Works Procedure
A deep pit is defined as having a width to depth ratio less than 1:3. That is, for a pit 2 metres
wide, it would not qualify as a deep pit for ventilation assessments unless it was more than 6
metres deep.
The assessment flow chart incorporates the width to depth ratio into the risk determination.
Shallow Pit
Width/Depth > 2
Medium Depth Pit
Width/Depth < 2 and > 1/3(0.33)
Deep Pit
Width/Depth < 1/3(0.33)
Some worked examples to determine the depth category of a pit follow:
A pit 6 metres deep is 4 metres wide
Width/Depth = 4/6
= 2/3 (0.66)
i.e. medium depth pit
A pit 8 metres deep is 2 metres wide
Width/Depth = 2/8
=1/4 (0.25)
i.e. deep pit
A pit 2 metres deep is 8 metres wide
Width/Depth = 8/2
=4
i.e. shallow pit.
Hazardous Gases
To determine if there is a possibility of hazardous gases present in the confined space, the
condition of the confined space itself plus the surrounding environment need to be assessed.
Possible sources of hazardous gases in the confined space include, but are not limited to:
 Rotting vegetation
 Sludge/sewage
 Any substances being used in the confined space
Possible sources of hazardous gases from the surrounding environment include:
 Vents from wet wells
 Traffic fumes
 Leaks from nearby gas mains, chlorine cylinders
 Exhaust gases from plant and machinery being used on site
Oxygen Depletion
Oxygen depletion is likely to occur in any confined space that is sealed for extended periods of time
due to its uptake by rotting vegetation, rust and absorption by concrete.
The risk of oxygen depletion can be minimised by keeping the confined space clean and dry and
continuously vented.
Historical Data
Historical data can be used to support the categorisation of a confined space in a lower risk
category even if the ventilation does not appear to be sufficient.
It is suggested that a minimum of 6 gas detector readings be recorded over an extended period of
at least one year to show that the air in the confined space is consistently of a high quality.
If the following readings are equaled or bettered over this period, a low atmospheric risk is
indicated:
Oxygen >20%
Flammable gas<1% Hydrogen sulphide <1ppm Carbon monoxide <5ppm
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Document PRO-69
Rev 7
4
Y
2
Natural
HIGH RISK
Y
Possible
hazardous gases or
oxygen depleting
conditions
N
Can an
u/s or d/s pit be opened
to provide natural
ventilation?
None
3
N
N
Y - Shallow
MEDIUM RISK
Y
2
MEDIUM RISK –
Not a CS, prepare
SWMS
N
Width/depth ratio
greater than 2:1?
Possible
hazardous gases or
oxygen depleting
conditions
LOW RISK - Not a
CS, prepare SWMS
Mechanical
What type of ventilation
is available?
CHECK
VENTILATION
START
LOW RISK - Not a
CS, prepare SWMS
Y
Does historical data
show low risk?
N
N
HIGH RISK
N
Does historical data
show low risk?
Y
Possible
hazardous gases or
oxygen depleting
conditions
Y - Medium
Width/depth ratio
greater than 1:3?
LOW RISK - Not a
CS, prepare SWMS
MEDIUM RISK
Y
Y
Does historical data
show low risk?
N
Possible
hazardous gases or
oxygen depleting
conditions
N - Deep
N
HIGH RISK
MEDIUM RISK –
Not a CS, prepare
SWMS
Y
4
N
Y
Y
Y
CS:
SWMS:
U/S:
D/S:
HIGH RISK
N
Is fan capacity
adequate?
DETERMINE FAN
CAPACITY
Y
Possible
hazardous gases or
oxygen depleting
conditions
N
LOW RISK
Confined Space
Safe Work Method Statement
Up Stream
Down Stream
Definitions:
MEDIUM RISK
Can fan be turned
on when required?
N
Does the fan continually
operate?
3
City West Water
QES Management System
Issue Date: 24/12/2014
Confined Space Entry & Associated Works Procedure
DIAGRAM 1 – FLOWCHART FOR ASSESSING ATMOSPHERIC RISK
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Confined Space Entry & Associated Works Procedure
ASSESSING ENTRY/EXIT RISK
The following notes are to be used in conjunction with the flowchart (Diagram 2) to determine the
entry/exit risk for the confined space.
The factors to be considered in determining the entry/exit risk are:
1.
2.
3.
4.
5.
Depth of the pit
Are step irons/ladders designed/installed to an acceptable standard
Is there sufficient head clearance
What is the risk of slipping?
Pit depth
The pit depth has been broken into three categories, the deeper the pit the greater the potential
risk. The categories are:
1.
Less than 2 metres deep
2.
Between 2 and 5 metres deep
3.
Greater than 5 metres deep.
The pit depth should be determined by measurement or referring to the relevant construction
drawings.
Step Compliance with AS 1657
To assess the risk of falling and the severity of injuries that may occur, Australian Standard AS
1657 –Fixed Platforms, Walkways, Stairways and Ladders – Design, Construction and Installation is
the standard to be used for the assessment. Each assessment team must have a copy of this
standard with them when conducting an assessment. The key points to observe with the
assessments are:
Stairways (Section 4, AS 1657)
 No more than 18 rises per flight
 No more than 36 rises without a change in direction
 Rises between 150 and 215 mm
 Goings between 215 and 305 mm
Ladders (Section 5.6, AS 1657)
 200 mm between ladder and wall
 Cage required for ladders greater than 6 metres in height between landings
 Step spacing between 250 and 300 mm
 Ladder never to overhang the person climbing
Step irons (Section 5.7, AS 1657)
 Rungs evenly spaced between 250 and 350 mm apart
 If climb greater than 750 mm, rung to be 200 mm from wall
Step ladders (Section 5.5 AS 1657)
 Slope 60 and 70 degrees
 Treads and risers uniform
 Treads between 200 and 250 mm
 Width not less than 450 mm
 Slipping Risk
The risk of slipping off the provided steps when entering or vacating a confined space is affected by
the design or by wet and slippery surfaces. If the confined space and the access steps are wet
and/or slippery, then the risk of falling increases and the use of fall protection devices such as
lifeline and winch may be required. This then indicates a high entry/exit risk.
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Document PRO-69
Y
Rev 7
HIGH RISK
N
MEDIUM RISK
N
Do the steps conform
to AS 1657
HIGH RISK
LOW RISK
Is some form of step
access available?
N
Y
N
Is pit depth greater
than 2 metres?
CHECK DEPTH
N
N
Y
Y
MEDIUM RISK
Y
Y
Is the risk of
slipping low?
CHECK FOR
SLIPPERY
SURFACES
Y
Does ladder conform
to AS 1657
Is pit depth greater
than 5 metres?
Is the risk of
slipping low?
LOW RISK
HIGH RISK
N
N
LOW RISK
Y
Y
HIGH RISK
Does ladder conform
to AS 1657
N
Is pit depth greater
than 5 metres?
Ladder
CHECK FOR
SLIPPERY
SURFACES
N
Step Irons
Is access via ladder
or step iron?
N
Y
Is the risk of
slipping low?
CHECK FOR
SLIPPERY
SURFACES
N
Do step irons conform
to AS 1657
Y
LOW RISK
2
Y
Do the steps conform
to AS 1657
Y
Is pit depth greater
than 5 metres?
Y
Is it a stairway?
N
2
N
City West Water
QES Management System
Issue Date: 24/12/2014
Confined Space Entry & Associated Works Procedure
The risk of slipping within the confined space itself should also be assessed. If walking surfaces are
wet and unclean, the risk of slips, trips and falls within the confined space are increased.
DIAGRAM 2 – FLOWCHART FOR ASSESSING ENTRY/EXIT RISK
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Confined Space Entry & Associated Works Procedure
APPENDIX C
CONFINED SPACE DEFINITION TABLE
The table below applies the confined space definition to a number of work space scenarios and
provides the criteria for assessing whether the work space is a confined space.
Is the space a confined space?
Description
of space or
activity
A
Is the
space
enclosed
or
partially
enclosed?
B
Is it likely
to be
entered and
is it at
normal
atmospheric
pressure?
Confined space criteria
C
D
Does the
Is the space likely to contain:
space
atmospheric
an unsafe
substances
have a
contaminants oxygen
that could
limited or
level
cause
restricted
engulfment
entry or
exit?
Sewer
manhole
access via a
vertical
ladder
Dislodging a
sludge
blockage in
a drain pit
Construction
of new
branch off
sewer retic
line and/or
sewer retic
repair in
trench
Inspection
of a shallow
water valve
pit
Entering an
above
ground
building
structure
associated
with a
sewerage
pump
station
Confined
space?
If the
answer to A,
B, C and at
least one of
D is yes,
then the
space is a
confined
space.
Yes
Yes
Yes
No
No
If YES, follow confined space procedure, if NO, develop safe work method statement (SWMS).
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Confined Space Entry & Associated Works Procedure
APPENDIX D
SAMPLE OF SWMS FOR EMERGENCY PROCEDURES FOR A VARIETY OF CSE ACTIVITIES
No
Relevant Safety Issue
Risk Control Measure
.
List the control measures required to eliminate or
minimise the risk arising from the potential hazard.
Activity/ Job Step
Potential Hazard
Risk Level
Use the Control Hierarchy Process
List the tasks required to
Against each task, list the
From
perform the activity in the
hazards that could cause
Risk
sequence they are carried
injury when the task is
Assessm
out.
performed
ent
1
Emergency Procedure for:
Entering an Above
Ground Sewer Pump
Station Structure
Not Specified – not confined
space related
E5 Significant
*As per CWW PRO-69, this
scenario does not meet the
definition of a confined
space. It is recommended
that a SWMS be developed
for the activity and site at
hand.
2
Emergency Procedure for:
Entering a Shallow
Water Valve Pit
A SRBA may also be considered for the works (to be detailed
in overall SWMS).
Not Specified – not confined
space related
E5 Significant
*As per CWW PRO-69, this
scenario does not meet the
definition of a confined
space. It is recommended
that a SWMS be developed
for the activity and site at
hand.
3
Emergency Procedure for:
Working on Live Sewer
in a trench/manhole –
Document PRO-69
Entry and exit from an above ground pump station structure
requires time limited confirmation from site with the
operations communications centre (Failure to advise
departure will instigate site investigation and or emergency
response).
Entry and exit from a shallow water valve pit requires time
limited confirmation from site with the operations
communications centre as part of a confined space
entry/access permit process (failure to advise departure will
instigate site investigation and or emergency response).
A SRBA may also be considered for the works (to be detailed
in overall SWMS).
Unsafe Environmental
Atmosphere
D5 Significant
A SRBA must be on person or within reach at all times whilst
in confined space in order to initiate self rescue.
Observer to utilise attached lifeline to remove
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Confined Space Entry & Associated Works Procedure
No
.
Relevant Safety Issue
Activity/ Job Step
List the tasks required to
perform the activity in the
sequence they are carried
out.
with life line attached
4
Emergency Procedure for:
Working on Live Sewer
manhole – with life line
detached
Potential Hazard
Against each task, list the
hazards that could cause
injury when the task is
performed
Risk Level
From
Risk
Assessm
ent
Risk Control Measure
List the control measures required to eliminate or
minimise the risk arising from the potential hazard.
Use the Control Hierarchy Process
injured/affected employee from the confined space with the
assistance of a retrieval device, application of first aid to be
provided by the Observer, Emergency Services to be
contacted if required.
Unsafe Environmental
Atmosphere
D5 Significant
A SRBA must be on person or within reach at all times whilst
in confined space in order to initiate self rescue.
SCBA, airline or similar to be available to initiate rescue
response from outside the space if required.
Standby staff/Initial Responder to be wearing harness at all
times in preparation for emergency rescue if required.
Observer to alert standby staff of an emergency, Standby
staff to confirm contact with Emergency Services 000 pre
initiation of site rescue plans.
Standby staff/Initial Responder to utilise SCBA, airline or
similar to allow safe entry into the space to connect the
affected CSE member and allow the Observer to initiate
retrieval of the affected CSE member utilising a retrieval
device (Tripod - SAD - Davit).
Observer to apply first aid to the affected CSE member if
required.
Standby staff/Initial Responder to exit the space when safe to
do so with the assistance of the Observer if required.
5
Emergency Procedure for:
Working on Live Sewer
Document PRO-69
Unsafe Environmental
Atmosphere
D5 Significant
Rev 7
A SRBA must be on person or within reach at all times whilst
in confined space in order to initiate self rescue.
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Confined Space Entry & Associated Works Procedure
No
.
Relevant Safety Issue
Activity/ Job Step
List the tasks required to
perform the activity in the
sequence they are carried
out.
excavation – with life
line detached
Potential Hazard
Against each task, list the
hazards that could cause
injury when the task is
performed
Risk Level
From
Risk
Assessm
ent
Risk Control Measure
List the control measures required to eliminate or
minimise the risk arising from the potential hazard.
Use the Control Hierarchy Process
SCBA, airline or similar to be available to initiate rescue
response from outside the space if required.
Standby staff/Initial Responder to be wearing harness at all
times in preparation for emergency rescue if required.
Observer to alert standby staff of an emergency, Standby
staff to confirm contact with Emergency Services 000 pre
initiation of site rescue plans.
Standby/Initial Responder to enter the space (utilising SCBA,
airline or similar where atmospheric contaminants have
caused the issue) and connect the affected CSE member and
allow the above ground Observer to initiate retrieval of the
affected CSE member utilising a retrieval device (Tripod SAD - Davit). Observer to apply first aid to the affected CSE
member if required.
Standby/Initial Responder to apply first aid to the affected
CSE member if required when safe to do so.
Observer outside CSE to apply first aid to the affected CSE
member if required.
Initial Responder to exit the space when safe to do so.
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