/ Petroleum Development Oman LLC / Revision: 4.0
Effective Jul-11


Petroleum Development Oman L.L.C.

Document Title: Entry into a Confined Space

Document ID / PR-1148
Document Type / Procedure
Security / Unrestricted
Discipline / Engineering and Operations
Owner / Functional Production Manager (UOP)
Issue Date / July 2011
Revision / 4.0

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i Document Authorisation

Authorised For Issue – July 2011

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. / Author / Scope / Remarks
4.0 / July-11 / Robin Norman UOP6 / Refer to Addendum 2 for changes
Apr-11 / Added Section 1.9 - ALARP
Rev 3.1 / Nov-09 / Robin Norman UOP6/ Del Ellbec UOP7 / For minor changes refer to Addendum 1
Rev 3.0 / Feb-09 / Robin Norman UOP6 / Revised Sections 2.1 & 2.2.
Added “use of Dragger Tubes” for testing prior to Confined Space Entry
Added Appendix 1 “Reference Material”
Rev 1 / Nov-98 / UOP/1 / SI-19 re-written in new format.

iii Related Business Processes

Code / Business Process (EPBM 4.0)
EP.71.02 / Operate Wells and Facilities

iv Related Corporate Management Frame Work (CMF) Documents

The related CMF Documents can be retrieved from the CMF Business Control Portal.

TABLE OF CONTENTS

1Introduction......

1.1Background......

1.2Purpose......

1.3Distribution / Target Audience......

1.4Changes to the Document......

1.5Step-out Approval......

1.6ALARP......

2Roles and Responsibilities......

3Confined Space Entry Procedure......

3.1Preparation for Confined Space Entry......

3.1.1Potential Hazards Associated with Confined Space Entry......

3.1.2Planning and Risk Assessment......

3.1.3Gas Freeing and Flushing......

3.1.4Working Atmosphere......

3.1.5Ventilation......

3.1.6Positive Isolation......

3.1.7Use Naked Flames and Arc......

3.1.8General......

3.2Confined Space Entry Process......

Appendix 1 – Narcotic Effect of Hydrocarbons......

Appendix 2 – Abbreviations......

Appendix 3 – Reference Material......

Appendix 4 – User Feedback Page......

Addendum 1 – Changes at Revision 3.1......

Addendum 2 – Changes at Revision 4.0......

1 Introduction

1.1 Background

The nature of industry in which PDO operates frequently requires personnel to enter ‘Confined Spaces’ to carry out inspections and / or maintenance and repair work. A confined space:

  • Has limited or restricted means of entry or exit
  • Is large enough for an employee to enter and perform assigned work, and
  • Is not designed for continuous occupancy by the employee.

A “permit-required” confined space is one that meets the definition of a confined space and has one or more of these characteristics:

  • Contains or has the potential to contain a hazardous atmosphere,
  • Contains a material that has the potential for engulfing the entrant,
  • Has an internal configuration that might cause an entrant to be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross section, and/or contains any other recognised serious safety or health hazards. These shall include but are not limited to:
  • Process vessels i.e. separators, pressure vessels
  • Storage tanks
  • Compressor enclosures
  • Heaters and boilers
  • Flare and vents systems
  • Cellars and pits
  • Culverts

1.2 Purpose

The purpose of this procedure is to provide all personnel, PDO or contract, with clear and concise instructions for entering or working within a confined space.

1.3 Distribution / Target Audience

This procedure is intended for use production and maintenance personnel and any other parties tasked with carrying out work covered by this procedure on behalf of PDO.

1.4 Changes to the Document

Responsibility for the upkeep of the Document shall be with the Functional Production 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 Requests shall be forwarded to the Custodian using the “User Feedback Page” provided in this Document.

The Document Owner and the Document Custodian shall ensure review and re-verification 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 approval must be obtained from the Asset Manager - using the PR-1001e – Operations Procedure Temporary Variance, prior to any changes or activities associated with the procedure being carried out.

1.6 ALARP

ALARP is the acronym for ‘As Low As Reasonably Practicable’ which simplified means, ‘reducing the risk to a level at which the cost and effort (time and trouble) of further risk reduction are grossly disproportionate to the risk reduction achieved’. Full Compliance to PDO Standards and Procedures is a key element in achieving ALARP.

For more details refer to ALARP Definition

2 Roles and Responsibilities

Asset Holder /
  • Accountable for ensuring all HSE Procedures are implemented within the asset

Production Coordinator /
  • Responsible for ensuring that HSE Procedures and Risk Assessments are conducted and are adhered to in the area

Responsible Supervisor /
  • Inspect work site with Permit Applicant
  • Check Job Safety Plan and ensure Risk Assessments are completed for each Confined Space Entry.
  • Authorise the Permit to Work (PTW)
  • Check Section 2 of the ‘Confined Space Entry Certificate’
  • Authorise the isolation on Mechanical Isolation Certificate
  • Authorise ‘Entry’ to confined space

Area Authority /
  • Validates PTW
  • Check Job Safety Plan and ensure Risk Assessment controls are adhered to
  • Conduct isolations
  • Inspection of work site on completion when PTW is closed
  • Check Section 2 of the ‘Confined Space Entry Certificate’[1]
  • Authorise ‘Entry’ to confined space[2]

Permit Applicant /
  • Applicant for PTW
  • Conduct safety checks of site and Risk Assessment with Responsible Supervisor prior to any works being carried out

Permit Holder /
  • Carry out ‘toolbox’ talks prior to works being carried out
  • Oversee safety of personnel and work within ‘confined space’
  • Ensuring strict adherence to all Safety Procedures, Job Safety Plan, Risk Assessments and Work Instructions
  • Checking condition of work site on completion of all works

Standby Personnel[3] /
  • Maintain register of entry / exit of personnel during work in confined space
  • Maintain communication and visual contact with all personnel in the confined space
  • Maintain emergency rescue equipment at all times during work in the confined space
  • Record any incidents during work process

3 Confined Space Entry Procedure

3.1 Preparation for Confined Space Entry

CAUTION: Entry into confined spaces exposes personnel to risk in addition to those associated with the work / task. Entry into a ‘Confined Space’ should only be considered if the work cannot be accomplished from an external location.

3.1.1 Potential Hazards Associated with Confined Space Entry

Potential hazards associated with confined space entry are recognised. These hazards can be any or all of the following:

  • Oxygen deficiency or enrichment
  • Flammability (fire and / or explosion)
  • Residual liquids, or solids and associated toxic or other noxious gases
  • Chemical hazards
  • Physical hazards
  • Number of personnel working within the confined space
  • Restricted entry / exit
  • Narcotic and anaesthetic effect of hydrocarbon gas and vapours

3.1.2 Planning and Risk Assessment

The first priority is to consider if the work in the confined space can be limited or avoided. Alternatives may be:

  • Residues may be removed from the outside using water jetting or in place cleaning systems.
  • In some cases it may be possible to see inside without entering by using a boroscope.
  • Use of non invasive inspection techniques

If the work is to be carried out in a confined space a risk assessment shall be completed covering all activities that will be carried out both inside and outside of the space.

Personnel selected for confined space entry shall have the correct level of competence, experience and knowledge as indicated by the risk assessment. It will be necessary to include Vendors / 3rd parties or HSE professionals in this task.

The risk assessment will consider but is not limited to:

  • Previous contents of the confined space
  • Internal temperature and humidity of confined space
  • Ingress of substances
  • Oxygen deficiency or oxygen enrichment
  • Residues
  • Contamination
  • Physical dimensions including internal structures or obstacles
  • Nature of any work itself, including concurrent activities.
  • The maximum number of personnel required to work in the confined space

The outcome of the risk assessment process shall be a Job Safety Plan approved by the Responsible Supervisor, who shall determines what mitigation must be put in place based on the Risk Analysis.

Where the risk assessment indicates that properly trained individuals can work for periods without supervision, it should be ensured that they are competent to follow the established safe system of work and have been provided with adequate information and instruction about the work to be done.

The Permit Applicant shall prepare a rescue plan as part of the Risk Assessment Process suitable for the agreed maximum number of personnel and covering each entry. This document should be reviewed and approved by the Responsible Supervisor. Some examples of possible inclusions to the rescue plan are:

  • Number of personnel required to provide effective rescue.
  • The equipment required for immediate use
  • Contingency plans for loss of communication
  • Safest route of access and egress with respect to casualty handling
  • Removal of unnecessary obstacles, which will hinder rescue operations

NOTE: These issues may limit number of people in confined space

The Permit Applicant must appoint a trained rescue team before work begins. For efficient functioning, a rescue team must consist of at least two persons. The Permit Applicant must be sure that the designated rescue team can be deployed quickly in an emergency and that they will be able to function effectively. If assistance is required this shall be provided by the Area Fire Service.

The rescue team must be equipped with suitable personal protective equipment to enable them to function efficiently.

Rescue plans covering the maximum permitted number of personnel will be agreed and practiced before any entry takes place. If it is not possible or practicable to perform training exercises before entry, it is the Permit Applicant responsibility to ensure all parties with responsibilities under this plan are competent in their roles.

Entry into a confined space shall be controlled by a PTW.

All persons holding safety competent roles e.g. gas tester, must be have valid PDO Passports showing their qualifications.

Personnel required to work safely in confined spaces must have had adequate training and experience in the particular work involved. Training standards must be appropriate to the task, and to the individual's roles and responsibilities, so that work can be carried out.

In order to achieve the above the following conditions require being satisfied and / or detailed in the Job Safety Plan prior to entry into a confined space:

  • All entries into a confined space shall be controlled by the PTW system
  • When entry is required, the confined space shall be physically isolated from all sources of hazardous substances, and from all sources of energy or motive power
  • Hazardous substances contained within the confined space shall be displaced, and the space suitably cooled and ventilated;
  • The confined space shall be tested for the presence of hazardous substances and for acceptable oxygen content. If conditions for safe entry cannot be achieved or guaranteed, additional precautions to be applied, e.g. the use of breathing apparatus

CAUTION: Additional to the use of Portable Multi-Gas Testers confined spaces that have contained hydrocarbons shall be tested using a Photo-Ionization Detector (PID – e.g. Draeger tube) to confirm that Occupational Exposure Levels are complied with before an entry is made. This is particularly important for the very low exposure limits of the carcinogenic compounds such as Butane, Pentane and Benzene.

  • Provision of personal protective clothing and equipment (personal gas detectors if required), access and egress, standby personnel, and rescue plans
  • When a person is in a confined space a standby person shall be in attendance at all times and the responsible supervisor shall ensure that this person is authorised and fully briefed on the activity to be undertaken
  • Additional hazards, including concurrent activities in the vicinity of, or within, the confined space are considered
  • When entry to a confined space is required using breathing apparatus, only those persons trained and deemed competent in the use of the breathing apparatus shall be allowed to enter the confined space
  • All personnel involved in the confined space entry shall made aware of the hazards

3.1.3 Gas Freeing and Flushing

Tanks, towers and vessels that have contained hydrocarbon or toxic materials shall require gas freeing and ventilation before entry[4] can be made.

Gas freeing shall be in accordance with PDO Procedures, PR-1073 - Gas Freeing, Purging & Leak Testing of Process Equipment (Excluding Tanks) and PR-1079 - Gas Freeing and Purging of Tanks Procedure. Once gas freed and drained[5] the confined space can be opened and ventilated. This method may be employed where high concentrations of toxic gases are encountered.

Flushing with water (produced if available) shall be used on pipework, tanks, towers and vessels to remove heavy hydrocarbon deposits before opening for cleaning and / or maintenance and repair.

3.1.4 Working Atmosphere

Gas testing of confined spaces shall only be carried out by an Authorised Gas Tester and shall be as specified on the PTW and recorded on the Confined Space Entry Certificate and the Additional Gas Test Record form (if required).

OXYGEN

Confined spaces may only be entered when the atmosphere inside has been certified as having a safe oxygen (between 20%-21%) content as indicated by approved PDO detection apparatus.

WARNING: If the oxygen content is less than 20% the vessel MUST not be entered.

FLAMMABLE

Entry into confined spaces where there is any possibility of flammable vapours, gas testing with an approved PDO explosive meter shall be carried out and recorded. This meter must be capable of measuring hydrocarbons in an inert atmosphere if the confined space has been subjected to gas freeing using nitrogen. (examples are Ray Systems MX6 or MSA Tankscope.) The frequency of subsequent testing shall be stipulated on the PTW. If a reading greater than 0% is indicated the Responsible Person or his delegate must be notified and any required restrictions or precautions to be taken shall be entered on the "Confined Space Entry Certificates".

Flammable process hydrocarbon vapours are also hazardous due to their potential narcotic / anaesthetic effects, and can result in irrational behaviour, loss of consciousness, or even death. Hazardous concentrations can be related to flammability limits (Refer to Appendix 1). Continuous ventilation shall be established within these spaces where possible.

TOXIC

Where toxic vapours may be present and continuous ventilation is not considered possible or feasible, each man entering the confined space shall wear positive pressure respiratory[6] protection.

If NORM or Mercury is suspected then the necessary external and internal tests MUST be carried out by competent persons and the results checked and confirmed by the Production Chemists. If the tests are outside the specified limits, the confined space should be ventilated continuously and re-tested at regular intervals until acceptable. Further information on NORM and Mercury can be obtained in:

SP-1170 - HSE Specification - Naturally Occurring Radioactive Materials (NORM)

PR-1515 - Control of HSE Risks of Dealing with Mercury in PDO Facilities

INTERNAL TEMPERATURE & HUMIDITY

For entry to spaces like Waste Heat Recovery Units of gas turbines, additional hazards may exist. These hazards exist due to the operational service where the space has been subjected to high temperature. Hazards such as internal temperature, humidity and hot surfaces should be included in the risk assessment, and suitable controls put in place. These controls could for example, result in work duration being reduced accordingly.

BREATHING APPARATUS

For entry in to a confined space without the use of breathing apparatus, tests may include but are not limited to:

  • Oxygen (between 20%-21%)
  • H2S shall be no greater than 1ppm
  • Benzene shall be less than 1ppm, but preferably zero
  • Hydrocarbons in air less than 2% LEL but preferably zero (see Table)

<2% / Entry allowed without BA
≥2% and <10 or atmosphere unsustainable / Entry only with BA
≥ 10% / No entry allowed

CAUTION: If it is considered that the breathable atmosphere cannot be guaranteed then entry shall be completed wearing breathing apparatus.

3.1.5 Ventilation

Ventilation shall be employed to make the atmosphere inside of the confined space able to ‘support life’. Where the atmosphere in the confined space is flammable or toxic, forced ventilation will be employed to extract and clean air be allowed to replace that extracted by natural circulation from a low point.

WARNING: Outside air shall not be forced in to expel the flammable atmosphere as this may cause an explosive mixture being formed.

When dealing with vessels and tanks etc, that are have a risk of pyrophoric deposits being present within the internals reference should be made to PR-1077 – Preparation of Static Equipment for Internal Maintenance and Inspection Section 4.2 Confined Space Entry.

3.1.6 Positive Isolation

Before any entry is permitted to a confined space positive isolation shall be carried out as required.

Process equipment and systems shall be positively isolated as detailed in PR-1076 – Isolation of Process Equipment.

MECHANICAL

Mechanical isolations shall be carried out using ‘spades and blind’ where applicable, or removal of spool pieces where applicable.

ELECTRICAL

Electrical shall be isolated at the MCC or switchboard. All isolations should be carried out by a ‘competent person’ and be tagged in accordance with SP-1104 - Electrical Safety Rules and the issue of an Electrical Isolation Certificate which shall be attached to the PTW.

3.1.7 Use Naked Flames and Arc

Strict control shall be exercised on the use of ‘naked flames or arc welding’ equipment inside or in the vicinity of confined spaces where flammable vapours are or could be present. Such works shall require a ‘Hot Work Permit’ to be in force.