Petroleum Development Oman L.L.C.
Document Title: Hydrogen Sulphide (H2S) Management
Document ID
Document Type
Security
Discipline
Owner
Issue Date
Revision
PR-1078
Procedure
Unrestricted
Engineering and Operations
UOP – Functional Operations Manager
May 2012
4.1
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this document may be disclosed to others or reproduced, stored in a retrieval system, or transmitted in
any form by any means (electronic, mechanical, reprographic recording or otherwise) without prior
written consent of the owner.
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i
Revision: 4.1
Effective: May-12
Document Authorisation
Authorised For Issue – May 2011
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ii Revision History
The following is a brief summary of the 4 most recent revisions to this document. Details of all
revisions prior to these are held on file by the issuing department.
Revision No.
Date
Author
Scope / Remarks
4.1
May-12
Robin Norman
UOP61
See Interim Amendment 1078_0512_01
4.0
Apr-11
Tom Moffat
UOP95
Update, revise, reformat in conjunction with
UOP, HSE, UEP
3.0
Jul-07
Robin Norman
UOP6
Reformat and revision in conjunction with HSE
Engineers.
2.0
Feb-01
UOP1
Minor Revision of 2.2.5 & 2.8 to incorporate
user feedback comments
1.0
Sep-98
UOP1
SI-02 rewritten to new format and merged with
SI-10.
iii Related Business Processes
Code
Business Process (EPBM 4.0)
EP.71
Produce Hydrocarbons
EP.72
Maintain & Assure facilities Integrity
iv Related Corporate Management Frame Work (CMF)
Documents
The related CMF Documents can be retrieved from the CMF Business Control Portal.
Refer to Appendix 2
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TABLE OF CONTENTS
i
Document Authorisation ......................................................................................................... 3
ii
Revision History ..................................................................................................................... 4
iii
Related Business Processes ................................................................................................. 4
iv
Related Corporate Management Frame Work (CMF) Documents ........................................ 4
1
Introduction ............................................................................................................................ 7
2
3
4
1.1
Background ...................................................................................................................... 7
1.2
Purpose ............................................................................................................................ 7
1.3
Key Rules regarding H2S ................................................................................................. 7
1.4
Changes to the Document ............................................................................................... 8
1.5
Step-out Approval............................................................................................................. 8
H2S Hazards, Classification and Access Control .................................................................. 9
2.1
Physiological Properties ................................................................................................... 9
2.2
Physical Properties of H2S .............................................................................................. 9
2.3
Facility Classification and Area Controls ........................................................................ 10
2.4
Area H2S Classification within a Sour Facility ................................................................ 11
2.5
Access Prerequisites ...................................................................................................... 11
2.6
Numbers Permitted to Enter (at any one instance) ........................................................ 12
2.7
Departure ....................................................................................................................... 13
2.8
Work Outside of Facility Perimeter Fences .................................................................... 13
2.9
Formal H2S Training Courses ........................................................................................ 14
H2S Safety and Emergency Response ................................................................................ 15
3.1
Activities requiring BA .................................................................................................... 15
3.2
H2S Detection ................................................................................................................ 15
3.3
Alarms and Mustering .................................................................................................... 16
3.4
Rescue ........................................................................................................................... 16
3.5
Emergency Procedures and Drills.................................................................................. 16
Safe Worksite Practices in H2S Facilities ............................................................................ 17
4.1
Job Planning, Hazard Identification and Assessment .................................................... 17
4.2
Permit to Work................................................................................................................ 18
4.3
Isolation Procedures ...................................................................................................... 18
4.4
Purging and Returning Equipment to Service ................................................................ 18
4.5
Sample Points and Safe Sampling................................................................................. 18
Appendix 1 - Abbreviations ......................................................................................................... 19
Appendix 2 – Reference Material ................................................................................................ 20
Appendix 3 - User Feedback Page ............................................................................................. 21
Interim Amendment 1078_0512_01 ............................................................................................ 22
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1
Introduction
1.1
Background
Revision: 4.1
Effective: May-12
Hydrogen Sulphide (H2S) is an extremely dangerous substance and can cause fatalities
if not managed properly. H2S is present in more of PDO’s operations as existing fields
begin to sour and as high sour developments are brought on stream. This procedure
deals with the identification and assessment of the hazards and the management of the
associated risk for “sour gas”, or gas containing H2S.
H2S in the upstream oil and gas industry comes from:
1.2

the original reservoir, as a result of the hydrocarbon source material and the
conditions under which it was converted to oil and gas. If this is the case then
H2S will be produced with the fluids

the reservoir after prolonged injection of water with oxygen (brackish or
formation water) which may result in 'souring' of the fluids within it due to the
action of sulphate reducing bacteria (SRB) introduced during the injection
process. Any H2S will be subsequently produced with fluids.
Purpose
The purpose of this procedure is to outlines the hazards associated with H2S and the
steps required to assess and manage the associated risk, and protect personnel within
Production Operations.
1.3
Page 7
Key Rules regarding H2S
a)
Facilities are classified as either sweet, low sour, high sour or critical sour (refer
to Section 2 - Classification). Unless facilities are classified as sweet, H2S
management procedures shall be followed at all times. Additional rules apply to
high or critical sour facilities.
b)
When dealing with sour gas, the primary focus should be on the controls that
prevent release or exposure, and a secondary but also important focus should
be on the recovery measures. These are illustrated in the bow-tie diagram
below:
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1.4
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c)
Strict access control requirements are mandated for sour facilities
d)
Personnel shall have specific training to work in or visit sour facilities
e)
Breathing apparatus shall be worn for specific activities
f)
Emergency response plans are established for all facilities, and sour facilities
shall have Emergency Response Procedures (ERP’s) which specifically
address the sour aspects of the operation. Drills shall be conducted regularly to
keep personnel trained on the ERP’s.
g)
A combination of fixed and portable H2S detection systems shall be used to
provide warning of the presence of H2S in the atmosphere.
h)
Risk assessments shall be done for sour activities, and the job procedures,
hazards and controls shall be identified to ensure the work is done safely
i)
Sour equipment shall be properly isolated, gas freed and made safe prior to
breaking of containment. When returning to service, proper assembly,
tightening, purging and leak testing shall be carried out to ensure integrity.
j)
Sampling of sour fluids will be strictly controlled and managed, using
engineered sample points, breathing apparatus and the buddy system.
Changes to the Document
Responsibility for the upkeep of the Document shall be with Functional Operations
Manager UOP, the Owner. Changes to this document shall only be authorised and
approved by the Owner.
Users of the Document who identify inaccuracy or ambiguity can notify the Custodian or
his/her delegate and request changes be initiated.
The Document Owner and the Document Custodian should ensure review and reverification of this procedure every 3 years.
1.5
Step-out Approval
This procedure is mandatory and shall be complied with at all times. Should compliance
with the procedure be considered inappropriate or the intended activity cannot be
effectively completed or safely performed, then step out authorisation and approval
shall be obtained in accordance with PR-1001e – Operations Procedure Temporary
Variance, prior to any changes or activities associated with the procedure being carried
out.
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2
H2S Hazards, Classification and Access Control
2.1
Physiological Properties
Revision: 4.1
Effective: May-12
H2S has acute effects on people, as follows:
Level of Concern
H2S concentration in air
Unpleasant Odour
0.13 ppm
8 Hour Threshold Limit Value (TLV)
5 ppm
Immediately Dangerous to Life and
Health (IDLH)
100 ppm
Onset of significant health effects
300 ppm
Immediate unconsciousness, onset of
worker fatalities
650 ppm
NOTE: 1% H2S equates to 10,000 ppm
2.2
Physical Properties of H2S

H2S is extremely toxic and can cause death at very low concentrations

H2S, also known as sour gas, is a colourless toxic, corrosive and flammable
gas, which is heavier than air and tends to collect in low-lying areas such as
trenches, sumps and confined spaces.

H2S reacts with the internal surfaces of carbon steel vessels in the absence of
oxygen to form pyrophoric iron sulphide. Pyrophoric iron sulphide can autoignite when exposed to air.
Property
Characteristic
Colour
Colourless
Odour
H2S concentration, when:
<100 ppm - has a distinctive, offensive smell – similar to rotten
eggs
>100 ppm - impairs the sense of smell; therefore, the nose cannot
be relied upon to detect the presence of H2S
Vapour Density
1.189 – heavier than air
Explosive limits
and flammability
4.3 to 46 percent – by volume in air
H2S explodes over a very wide range, when:
 mixed in the right proportions with air (oxygen), and
 there is a source of ignition.
Burns readily (with a distinctive blue flame)
Produces Sulphur Dioxide (SO2) – another toxic gas
Page 9
Auto Ignition
Temperature
260ºC
Reactivity
Can react with carbon steel, in the absence of oxygen – forming
Pyrophoric Iron Sulphide (on the internal surfaces of vessels), which
in turn can react upon contact with air (oxygen) – auto igniting
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Water Solubility
H2S is:
 Readily dissolved in both water and hydrocarbons
 Dependent on temperature and pressure to be soluble
 Quickly released, by simply agitating the fluid
Corrosives
H2S forms a corrosive mixture with water
Boiling Point
 60ºC at normal pressure
 Liquefied H2S boils at a very low temperature and is normally
found as a gas
2.3
Facility Classification and Area Controls
Facilities in PDO are classified as follows:
1.
Sweet
2.
Low Risk Sour
3.
High Risk Sour
4.
Critical Sour (currently only applies to Harweel 2AB, Birba and Al Noor
facilities)
Each facility in PDO is classified according to criteria set out in SP-1190 - Design For
Sour Service Specification. Operations staff at each facility shall understand the
classification of their facility and the appropriate level of controls that apply:
Facility Classification
Sweet
No additional requirement to base standards
Low Risk Sour

Company/Contractor personnel shall be made
aware of the hazard and the appropriate actions to
escape or shelter from a credible release of the
hazard.

Competencies in H2S, breathing apparatus, and
sour work practices
High Risk Sour And Critical
Sour
Page 10
Basic Requirements
As stated above plus:

Company/Contractor personnel shall be provided
with suitable equipment and knowledge to selfescape to a place of safety in case of a credible
release.

Work (or rest) that could reasonably be completed
further from the hazard source shall not take place.

Activities requiring
large maintenance or
construction work forces shall be subject to
Quantitative Risk Assessment and Bow-Tie
assessment.

A SIMOPs plan should be in force for simultaneous
operations under different lines of command.

Emergency Planning Zone (based on toxic risk)
and Emergency Response Plans to be established
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2.4
Area H2S Classification within a Sour Facility
Within a sour facility, some facilities are zoned on the level of toxic gas risk present in
accordance with SP-1190 - Design For Sour Service Specification. This is typically
determined by quantitative risk assessment considering the partial pressure of H 2S in
the process units, the layout/spacing of the unit, and the nature of the work activities
there. Sour facilities shall have the zones identified in consultation with Corporate MSE
and marked by Operations, and personnel shall be trained accordingly. Rules which
apply to the zones are as follows:
Zone
Description
Controls
Green
Low toxic H2S gas hazard
No additional controls
Yellow
A credible release of H2S could result in a
concentration in air above IDLH levels in the
vicinity of the process units or in the vicinity of
the well.
As High Risk Sour Facility
Classification plus:
H2S is expected to be present in the breathing
zone for an area (confined space, ground
level or elevated working platform) as part of
normal operations at a concentration in air
above the 8 hour TLV.
As Yellow Zone plus:
Red
OR
A credible release of H2S could result in a
concentration in air above 650 ppm in the
process units or in the vicinity of the well.
 The number of persons
present shall be actively
minimised
(reference
Section 2.6)
 Area / activity specific
sour operating
procedures including
wearing Respiratory
Protective Equipment at
all times.
 Specific area access
control.
AND
The perceived operational risk is higher than
in normal operations e.g. operational risk may
be perceived to be higher during start up or
during periods when a facility is operating with
uncertain static integrity, and therefore Red
Zone operating rules may be enforced.
2.5
Access Prerequisites
Access to H2S designated areas shall only be allowed provided the following have been
adhered to:
Page 11

Area Authority or Approved Gas Tester has completed a gas test of the area at
the start of the shift and after scheduled breaks, and the recorded results
indicate < 5 ppm of H2S in air.

Valid Permit to Work has been issued, authorised by the Responsible
Supervisor, validated by the Area Authority and specifying clearly the reasons
for entry.

Valid H2S Entry Permits are held by all persons entering the sour classified
facility and that they have been hung on the numbered slot board in the Control
Room.

Persons entering the restricted area have the correct safety equipment for that
area which shall include personal H2S monitors.
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
All persons entering the restricted area are fully conversant with the ‘Buddy’
system and are aware of the escape routes and Area Muster Points.

All persons entering the restricted area have completed and signed the Station
Entry logbook i.e. Name, Department, Entry Pass Number and Time In.
Mandatory requirements for personnel entry to sour facilities are shown below.
Facility H2S Category
Low Risk Sour
High Risk Sour and
Critical Sour
Required for Entry
Permit to Work
Or
Access
Authorisation
Form
Or
Asset Holder Exemption
And
H2S Entry Permit
As for Low Risk Sour
And
Buddy System to be in
force (PR-1081 – The
Buddy System)
Training Required
Safety Induction.
As for Low Risk Sour
And
H2S
Awareness
Escape Course.
Safety Equipment
Required
and
Personal H2S Gas Detector
(PDO Approved)
As for Low Risk Sour
And
Respiratory Protective
(Escape) Equipment (RPE).
2.6
Numbers Permitted to Enter (at any one instance)
As a general rule the numbers of personnel that shall be allowed to be in a high risk
sour facility at any one instance shall be limited to 20. However this shall be governed
by the number of personal monitors and escape sets held at site.
Where the work is classed as ‘non-routine work’ i.e. major overhaul of equipment,
additional personnel may be permitted on site provided the following criteria are met:
A documented Risk Assessment has been carried out
And
The extra manning levels have been sanctioned by the Area Production
Coordinator
And
Required supervision is present and adequate for each team working in the
restricted area
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And
An Activities Coordinator1 has been appointed when the number of persons in the
restricted area exceeds 20.
Non-essential work should be done offsite or deferred until a shutdown opportunity
when the facility has been purged free of H2S.
2.7
Departure
On completion of any work or access or visit to an H 2S designated location the
station operator and the person(s) leaving shall ensure:

The station entry register has been signed correctly

H2S Entry Permit or ID has been removed from the control board

Access authorisation form has been cancelled (if required)

Permit to Work has been signed off and work status updated
Failure to comply may result in unnecessary extensive rescue operations may be
initiated if there is an emergency.
2.8
Work Outside of Facility Perimeter Fences
Construction or modification work may require to be undertaken outside of the facilities
boundary fences and in these instances due consideration shall be given to protecting
the workforces from the effects of exposure to H2S in the event of an incident.
All work conducted inside the Emergency Planning Zone shall be covered by a Permit
to Work and effective communication methods with the main control room shall be
maintained.
Prior to the work commencing the Job HSE Plan (JHSEP) shall be completed which
should consider the ‘worse case scenario’ of an H 2S leak. The plan should consider the
area that would be affected ‘down wind’ of such an incident and the nature of the work
being undertaken. Based on the JHSEP the following should be established:

H2S monitoring of the area identified ‘at risk’ by the JHSEP

An emergency response contingency plan

Provision of rescue facilities if required

Safety Awareness briefings for all staff at the start of each shift
1
The Activities Coordinator shall be responsible for continuous monitoring of the work being
undertaken and shall STOP the work and evacuate the work site if unsafe conditions or
practices are observed.
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2.9
Revision: 4.1
Effective: May-12
Formal H2S Training Courses
Two mandatory training courses for personnel at sour facilities are:
H2S Awareness and Escape
The course shall be required for all staff that enter H2S designated areas. The course
addresses hazards associated with H2S, occupational exposure limits, detection and
alarm systems and appropriate action to be taken should a personal or facility alarm
sound.
Self Contained Breathing Apparatus (SCBA) Training
Provides personnel with knowledge and skills to be competent in the use of Breathing
Apparatus2 (BA) and in search and rescue techniques.
For more details refer to SP-1157 - HSE Specification – HSE Training.
2
A medical test declaring the person physically fit for the use of a SCBA should be completed in
advance to SCBA training. Results should be shown to the trainer in advance.
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H2S Safety and Emergency Response
3.1
Activities requiring BA
Revision: 4.1
Effective: May-12
BA is required to be worn in a sour facility when performing any breaking of system
containment until the work area has been tested for H2S and declared safe to proceed
without BA (e.g. breaking flanges, opening of vessels, opening of pump casings,
pipelines, etc). For any BA activity, the Buddy System shall apply (Refer to PR-1081 –
The Buddy System) and the Buddy must remain at a safe vantage point to provide aid
or response.
BA is also required to be worn when:
3.2

Entering any Red Zone

Any gas leak occurs, BA should be worn until mustered in a safe location

Working in an area where the concentration of H2S in air has been tested > 5
ppm or where a build-up of H2S could exceed the TLV (e.g. bunded areas and
low-level areas). Refer to PR-1148 – Entry into a Confined Space.

Performing wellhead activities, e.g. bleeding down to a pit, flowline operations
etc. where H2S may be present in gaslift systems.

Performing any sour sampling activity (refer to PR-1096 - Sampling of Oilfield
Liquids and Gases Procedure)
H2S Detection
H2S detection is used to provide early warning to personnel to the presence of H2S in a
facility or workplace. Either of the following H2S detection methods can be selected for
the activity and hazards:

Continuous gas monitoring in the immediate vicinity of the work using a
properly calibrated and maintained H2S monitoring device (personal, portable or
fixed).

Intermittent measurements taken before and periodically during the work using
a properly calibrated and maintained electronic H2S monitoring device or
colorimetric detector tubes suitable for the range expected to be encountered.
This method is also typically used during turnarounds when multiple concurrent
activities may be executed in an area without fixed H2S detection.
Fixed Systems
Fixed detection systems are recommended when hazard assessment indicates a
potentially high H2S risk. The location and installation of fixed systems are governed by
SP-1190 - Design For Sour Service Specification
A fixed system does not in itself provide protection for personnel. It should not therefore
be considered a substitute for normal entry precautions to a high-risk area.
Portable Detectors (Personal H2S monitors)
These are used to alert the worker of a pre-set concentration of H2S, usually 10 ppm.
They shall be used in an area where it is not practical to install fixed detectors and/or as
a backup to fixed systems. They shall have an audible and visual alarm, which activates
if the pre-set limit is exceeded and shall continuously display the current concentration.
Personal monitors must be calibrated every 6 month in order to function properly.
Users shall verify the unit is not out of calibration and perform the function test prior to
use. Refer to requirements in SP-1234 - HSE Specification - Personal Protective
Equipment
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3.3
Revision: 4.1
Effective: May-12
Alarms and Mustering
All personnel in the restricted area shall respond as follows in the event of a
personal H2S alarm being activated:
1.
The person wearing the affected personal monitor shall evacuate the area
immediately and don their escape equipment if available.
On leaving the area the station operator shall be informed immediately of the
incident.
2.
The station operator shall:

Activate the facility H2S alarm

Initiate the H2S emergency response

Notify the CCR of the H2S emergency by dialling 5555

Alert his ‘Buddy’

Collect the Station Entry logbook and all IDs / H2S Entry Permits

Proceed to designated Muster Point to perform head count, identify
persons at the Muster Point and return their Entry Permits / ID cards.
Should any permits remain, he shall check with the logbook to verify
their presence within the station, and initiate rescue procedures

Return to the station control room as quickly as possible to coordinate
and lead any emergency response activity required
3.
On hearing H2S alarm or the ‘personal monitor alarm’ all personnel in the
restricted area shall proceed immediately to designated Muster Point (upwind
or across the wind from the leak source) and adhere to any instructions given
to them by the station operator.
4.
The station operator and an assistant in full 35-minute breathing apparatus
shall affect any required rescue.
In the event that trained personnel (e.g. Fire and Safety) are already affecting
the search and rescue, station operator and an assistant (still wearing full BA)
shall attempt to locate the leak and isolate it. If this cannot be done quickly and
safely the plant must be shut down completely. Consultation with the LEBC is
first required to determine the safest course of action.
Emergency Response procedures are outlined in CP-123 - Emergency
Response Documents Part I - CoP.
3.4
Rescue
Rescue procedures are outlined in CP-123 - Emergency Response Documents Part I CoP.
3.5
Emergency Procedures and Drills
Emergency Response Drills shall be conducted regularly to give all affected personnel
the opportunity to practice the emergency response procedures. The requirement for
Drills is outlined in CP-123 - Emergency Response Documents Part I - CoP.
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Safe Worksite Practices in H2S Facilities
4.1
Job Planning, Hazard Identification and Assessment
Revision: 4.1
Effective: May-12
It is the responsibility of the Permit Applicant and Responsible Supervisor to ensure a
Job HSE Plan is produced to identify the activity related hazards.
It is the responsibility of the Permit Holder to ensure a quality Toolbox Talk and Risk
Identification (TRIC) discussion takes places where the Job Safety Plan is discussed
with the work party, and any additional hazards recorded on the TRIC form.
The Job HSE Plan shall include but not limited to:

Sequential analysis of the task execution and the potential hazards involved

The potential sources of H2S under normal and upset conditions (planned and
unplanned or emergency releases),

Events that might release H2S into the work area,

The maximum concentration of H2S in the process stream(s) and the maximum
concentration that might result in the work area, in the event of accidental or
anticipated releases,

System integrity, reliability, and safeguards, including monitoring and alarm
systems,

The volume and H2S content of material that could be released,

Process and monitoring data, and the validity of such data, especially in light of
any changes,

The activities involved in the planned work, their complexity, and duration, as
well as any other relevant factors.
The TRIC discussion should include the contents of the Job HSE Plan together with:

Any potential where workers may be exposed to H2S in the course of their
work.

Warning signs and/or barricades at each point of access where there is a
potential for H2S exposure.

Testing and/or monitoring requirements.

Compliance to relevant Corporate Procedures

Emergency response in the event of H2S release.

Access/egress – situations with limited access/egress and the potential for H2S
exposure in confined spaces.

The need for safety person(s), rescue equipment (including resuscitators), and
hazard warning signs shall be considered when carrying out work involving H2S

Careful attention shall be given to details, such as equipment checks, access /
egress (escape) routes, and obstacles.
In cases where the hazards have not been fully assessed and understood the job
should not proceed
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4.2
Revision: 4.1
Effective: May-12
Permit to Work
All work planned and executed in a sour facility shall be carried out in accordance with
the Permit to Work (PTW) system. Refer to PR-1172, Permit to Work Procedure.
Any activity involving Simultaneous Operations, or SIMOPS, shall be properly risk
assessed and coordinated between the Permit Holders of the respective activities, with
each attending the TRIC discussion for each activity. The following conditions shall be
established as a minimum:
4.3

Coinciding events shall be analyzed by both job coordinators in advance and
the agreed activities and control measures shall be captured on the PTW’s

Separation distances between the simultaneous activities shall be established.
Consult with the Technical Safety group if guidance is required

A method of communication between the two simultaneous jobs shall be
maintained to ensure awareness of hazards and progress at each site
Isolation Procedures
PR-1076 - Isolation of Process Equipment outlines the isolation requirements. Sour
service equipment shall be properly isolated from service, all toxic fluids drained to a
safe location, gas freed with inert gas, and checked for residual sour gas content prior
to opening. Breathing apparatus shall always be worn when breaking any system
integrity until the system has been deemed safe.
Note that sour service equipment can contain an iron sulphide layer on the inner pipe
wall, vessel wall, or internal components. Iron sulphide is pyrophoric, meaning it can
spontaneously combust in the presence of oxygen, therefore attention shall be paid to
managing this hazard. PR-1077 - Preparation of Static Equipment for Internal
Maintenance and Inspection provides further details
4.4
Purging and Returning Equipment to Service
Following any breaking of integrity, equipment to be returned to service shall:
4.5

Have all flanges correctly assembled and torque in accordance with SP-2020

Be purged with inert gas to remove any oxygen, and a reinstatement leak test
carried out in accordance with PR-1073 - Gas Freeing, Purging & Leak Testing
of Process Equipment
Sample Points and Safe Sampling
Sampling of sour fluids requires a properly designed sample point that allows a trained
technician to safely draw a sample. Requirements for sour sampling and sample points
are detailed in PR-1096 Sampling of Oilfield Liquids and Gases Procedure
Page 18

Breathing apparatus and the buddy system shall always be used when
sampling

Proper access and egress shall be provided for the sample location to enable
safe work practices and minimize hazards
PR-1078 - Hydrogen Sulphide (H2S) Management
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Revision: 4.1
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Appendix 1 - Abbreviations
CCR
Central Control Room
ERP
Emergency Response Procedure
IDLH
Immediately Dangerous to Life and Health
JHSEP
Job HSE Plan
LEBC
Local Emergency Base Controller
PTW
Permit to Work
SCBA
Self Contained Breathing Apparatus
SIMOP
Simulaneous Operations
SRB
Sulphate Reducing Bacteria
TLV
Threshold Limit Value
TRIC
Toolbox Talk and Risk Identification
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Appendix 2 – Reference Material
Code of Practice
CP-123 - Emergency Response Documents Part I - CoP
Specification
SP-1157 - HSE Specification – HSE Training
SP-1190 - Design For Sour Service Specification
SP-1234 - HSE Specification - Personal Protective Equipment
Procedures
PR-1001e – Operations Procedure Temporary Variance,
PR-1073 - Gas Freeing, Purging & Leak Testing of Process Equipment
PR-1076 - Isolation of Process Equipment
PR-1077 - Preparation of Static Equipment for Internal Maintenance and Inspection
PR-1081 – The Buddy System
PR-1096 - Sampling of Oilfield Liquids and Gases Procedure
PR-1148 – Entry into a Confined Space
PR-1172, Permit to Work Procedure
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Appendix 3 - User Feedback Page
PR-1078 – Hydrogen Sulphide (H2S) Management User Feedback Page
Any user who identifies an inaccuracy, error or ambiguity is requested to notify
the custodian so that appropriate action can be taken. The user is requested
to return this page fully completed, indicating precisely the amendment(s)
recommended.
Name:
Ref ID
Page Ref:
To:
Date:
Brief Description of Change Required and Reasons
UOP 6
Custodian of Document
Page 21
Date:
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Interim Amendment 1078_0512_01
This procedure has been aligned with SP-1190 – Design for Sour Services last updated
September 2011. The key reference is Section 2.2 Levels of Concern.
The changes at this interim amendment shall be incorporated when the procedure is next
updated.
The key change is the lowering of the Threshhold Level value (TLV) from 10ppm to 5ppm. It will
be noted that this exposure change only effects the limit allowed for the standard working day
which is taken to be 8 hours.
The change does not affect the setpoint alarm of the personal H2S detector which still remains
at 10ppm.
The Short Term Exposure Level (STEL) shall also remain at 10ppm.
This change will be will reflected in all other documentation where it occurs.
Page 22
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