Safe Working on the Roof of a Floating Roof Tank



Petroleum Development Oman L.L.C.

Safe Working on the Roof of a Floating Roof Tank

|Document ID |PR-1083 |

|Document Type |Procedure |

|Security |Unrestricted |

|Discipline |Engineering and Operations |

|Owner |Functional Production Manager |

|Issue Date |May December 2015 |

|Revision |4.0 |

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i. Document Authorisation

Authorised For Issue May 2015

|Document Authority |Document Custodian |Document Controller |

| | | |

| | | |

| | | |

| | | |

| | | |

| | | |

|Ali Harrasi |Derek Ellbec |Said Harmali |

|UOP - Functional Production Manager |UOP6 – Surface Operations and |UEOI211 - Document Controller |

| |Integrity Team Leader | |

|Date: |Date: |Date: |

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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 |

|4.0 |MayDec-15 |Philip Hatherton UOP61 |Regular Review and Revalidation |

|3.1 |Apr-11 |Robin Norman UOP6 |Added Section 1.7 ALARP |

|3.0 |May-10 |Robin Norman UOP6 |Review and Revalidation. See Addendum 1 for changes |

|2.0 |Mar-07 |UEV11 |Reformatted and revised. |

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.

|CP-115 |Operate Surface Product Flow Assets CoP |

See also Appendix 2

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 56

1.1 Background 56

1.2 Purpose 56

1.3 Distribution / Target Audience 56

1.4 Structure of this Document 56

1.5 Changes to the Document 56

1.6 Step-out Approval 57

1.7 ALARP 57

2 Roles and Responsibilities 58

3 Safe Working on the Roof of a Floating Roof Tank 59

3.1 Precautions for Safe Working on Floating Roof Tanks 59

3.1.1 General 59

3.1.2 Safety 59

3.2 Process for Safe Working on the Roof of a Floating Roof Tank 511

Appendix 1 – Abbreviations 513

Appendix 2 – Reference Material 514

Appendix 3 - User Feedback Page 515

Introduction

1 Background

Work on the roof of a ‘floating roof‘ storage tanks has a potential for danger to personnel and assets if not carried in with consideration of the associated risks. Primary risks associated with floating roofs are:

• Explosive and toxic mixtures accumulating around rims and unventilated areas of the tank roof space

• Confined spaces being formed when the roof drops below the level of the tank sides

• Incorrect operations when lowering the roof of the tank.

2 Purpose

The purpose of this procedure is to provide a safe and consistent method for ensuring that all safety precautions are observed prior to commencing work on a floating roof tank, and that they are maintained during and on completion of all works.

NOTE: Any tank maintenance, repair work or inspection should make reference to this procedure whether the tank has a floating roof or not. .

3 Distribution / Target Audience

This procedure is intended for the use or reference of ;

• Operations and Maintenance personnel;

• Area Engineering ;

• Inspection Teams and;

• Contractor personnel undertaking work on behalf of PDO

4 Structure of this Document

This document is structured to provide clear and concise instructions for ensuring that all safety precautions have been addressed and safe working environment is maintained. The procedure shall comprise the following:

• Roles and responsibilities of all key personnel

• Flow chart of action and response

• Description of key procedural steps to be followed

5 Changes to the Document

Responsibility for the upkeep of the Document shall be with the Functional Production Team Leader 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 should ensure review and re-verification of this procedure every 3 years.

6 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 must be obtained in accordance with PR-1001e – Operations Procedure Temporary Variance, prior to any changes or activities associated with the procedure being carried out.

7 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

Roles and Responsibilities

|Production Coordinator |Accountable for all works undertaken within his / her area of control[1] |

|Production Supervisor |Responsible Supervisor for PTW system |

| |Conduct ‘work site’ visit with Permit Applicant to identify and agree hazards. |

|Permit Applicant |Applicant for PTW |

| |Carryout ‘work site’ inspection with Responsible Supervisor |

| |Conduct safety checks of site with Area Authority and Permit Holder prior to |

| |any works being carried out |

|Area Authority |Area Authority for PTW system |

| |Ensure that all safety equipment required by Job HSE Plan is provided, |

| |including self contained breathing apparatus and rescue breathing sets |

| |Ensures ‘TRIC’ discussions are conducted prior to works being carried out |

| |Perform and / or check any isolations that are required prior to works being |

| |carried out |

| |Perform frequent audits[2] and safety checks and ensure PTW system is adhered |

| |to |

|Permit Holder |Ensure that all work complies to the requirements of the PTW and the Job HSE |

| |Plan |

| |Prepares TRIC and carries out discussions before the work is commenced |

| |Ensures appointed Security Sentry is competent and fully understands his roles |

| |and responsibilities |

|Security Sentry (Job Watcher) |Maintain surveillance of all personnel on tank roof while works are in progress|

| |Maintain communication[3] with and report any violations to the control room / |

| |area authority |

| |Provide rescue cover if required |

| |Maintain all safety equipment while works in progress |

Safe Working on the Roof of a Floating Roof Tank

1 Precautions for Safe Working on Floating Roof Tanks

1 General

The roof drain valve must either be removed or Locked fully open and a positive check made to ensure that the drain system on the roof deck is free from debris and operating satisfactorily. Roof water drainage systems should be opened and flushed with water to ensure that oil has not leaked into and been retained in them. Roof supports should be checked and flushed with water. Floating-roof supports should be checked for thinning, notching, pin-holes, or buckling and plumb, and for adequate clearance.

IMPORTANT NOTE: Whenever work is to be carried out on the roof of a floating roof tank, the roof will be raised to within 1.5m of the tank rim to ensure good ventilation and reduce the risk of gas pockets developing.

If the work on the tank roof dictates, the tank will be drained of hydrocarbons, then isolated and prepared for opening in accordance with PR-1076 – Isolation of Process Equipment and PR-1079 - Gas Freeing and Purging of Tanks Procedure.

NOTE: During the gas freeing operation, if weather conditions develop which might cause lightning, all tank openings should be closed. If very still air conditions develop the tank opening may have to be closed to prevent a gas / air mixture from flowing into a non-restricted area. If continuous supervision is not available the tank side opening should be closed.

2 Safety

A Job HSE Plan and Health Risk Assessment (HRA) shall be developed which should include an ‘emergency response scenario’.

Personal Protection Equipment (coveralls) MUST be made from materials which does not generate or influence static electricity

In all cases where the roof is 1.5 metres or more below the rim level, the Permit Applicant shall raise a Confined Space Entry Certificate and stipulate on the PTW that appropriate gas tests are undertaken depending on the content of the tank. Gas testing will be carried out before any work is commenced on the tank roof. The following tests will be carried out:

• oxygen test

• toxic gas test (H2S)

• test for explosive mixture.

WARNING: UNDER NO CIRCUMSTANCES WILL HOT WORK BE PERMITTED ON THE ROOF OF A TANK THAT CONTAINS FLAMMABLE INVENTORY.

All gas tests on site shall be performed by an authorised gas tester approved and calibrated gas test equipment. The Area Authority shall arrange for gas tests and accompany the authorised gas tester on to the tank roof and verify the gas test results. Self contained breathing sets will be worn on all sites designated ‘sour’.

The atmosphere shall be deemed to be a breathable atmosphere if the oxygen content exceeds 20% providing that hydrogen sulphide is measured at less than 10ppm. A result of 10 ppm or more of H2S requires that personnel shall use breathing apparatus while below the tank rim.

Breaking of containment i.e. removing manway covers etc, will be performed wearing SCBA and gas tests will be carried out to verify the area safe before personnel are allowed to approach the area without breathing equipment.

Continuous multi-gas monitoring shall be in place during the course of the work on the tank roof.

The Tank Sentry shall be present at the tank rim during this activity. If the oxygen level is less than 20%, the tank roof must be immediately vacated and the supervisor contacted. If the oxygen measurement is satisfactory, measurement of toxic gas and flammability tests may proceed.

Self Contained Breathing Apparatus (SCBA) will be provided for Rescue Teams and Escape Sets will be carried by all personnel working in confined spaces or area where hydrocarbon fumes may accumulate.

The Production Operator shall ensure that appropriate protective equipment is carried or worn, and that the job watcher is positioned, aware of his responsibilities and the activities of personnel involved, and in good radio contact with the Area Authority and / or CCR.

2 Process for Safe Working on the Roof of a Floating Roof Tank

Preparation and execution of work on the roof of a Floating Tank Roof will be in accordance with the following process.

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|1. |Work on Floating Roof Tanks will either be authorised to enable planned maintenance, repairs or inspection to be carried |

| |out. In these instances the tank may be emptied and purged or it could be ‘live’ and contain hydrocarbons. PR-1172 – |

| |Permit to Work System – Section 3 will provide details of the type of permit Class A or Class B, required to undertake |

| |the work. |

| |A Job HSE Plan will be prepared for the work activity to be undertaken. PR-1172 – Permit to Work System – Section 11.2 |

| |for details. |

| |Complete a Confined Space Entry Certificate if the work activity involves work in areas defined as Confined Spaces in |

| |accordance with PR-1148 – Entry into a Confined Space. |

| |NOTE: Where possible the floating tank roof should be raised to approximately 1.5 metres below the tank rim, this shall |

| |allow for natural ventilation of the tank top. In cases where this is not possible then a Confined Space Entry |

| |Certificate shall be required. |

|2. |Carryout and inspection of the work site and identify / agree on all hazards. Agree the best means of evacuation in the |

| |event of an emergency and mark on site plan. |

| |NOTE: If mobile cranes or lifting equipment is to be used ensure a ‘Lifting Plan’ is developed and approved and positions|

| |of cranes are clearly identified on the site plan. |

| |Obtain authorisation of the PTW from the Responsible Supervisor. |

|3. |The Permit Holder will take the authorised PTW to the Area Authority for validation at the start of the work. The PTW |

| |will require to be re-validated each time the work is restarted. |

|4. |The Permit Holder will conduct a TRIC discussion using the completed TRIC. See PR-1172 - Permit to Work System – Section|

| |11.3 for details. |

| |The Permit Holder will appoint the tank top sentry and ensure that their role is fully understood. |

| |Prior to commencing work a gas test will be completed and recorded. Gas testing will be in accordance with PR-1154 – Gas |

| |Testing Procedure. |

| |NOTE: Toxics such as H2S if suspected or identified will be tested for using approved testing equipment. |

|5. |The work activity will be undertaken in accordance with any approved procedures or the Job HSE Plan. |

| |Personnel working in the vicinity of tank sides or rims shall wear safety harnesses at all times. |

| |The sentry will maintain a log of all personnel and record when anyone leaves or comes onto the tank roof. |

| |Scaffolding will be erected in accordance with SP-1257 - HSE Specification - Scaffolding, Working at Heights or Over |

| |Water, Lifting Operations and Earthworks and Earthworks and GU-363 - Guideline for the use of Scaffolding. |

| |Periodic gas testing shall be as detailed on the PTW and will be carried out by an authorised gas tester. |

|6. |At the end of each shift (if applicable) the work site will be inspected by the Permit Holder and the Area Authority and |

| |any additional hazards not included on the original Job HSE Plan shall be recorded. |

| |On completion of the work the Permit Holder and the Area Authority will inspect the work site before close out of the |

| |PTW. |

Appendix 1 – Abbreviations

The following abbreviations are used in this procedure.

|JSP |Job Safety Plan |

|PDO |Petroleum Development Oman LLC |

|PR |Procedure |

|CCR |Central Control Room |

|HRA |Health Risk Assessment |

|HSE |Health Safety & Environment |

|PTW |Permit to Work |

|SCBABA |Self Contained Breathing ApparatusBreathing Apparatus |

|TRIC |Toolbox Talk Risk Identification Card |

Appendix 2 – Reference Material

PDO Specifications

SP-1257 - HSE Specification - Scaffolding, Working at Heights or Over Water, Lifting Operations and Earthworks

PDO Procedures

PR-1001e – Operations Procedure Temporary Variance

PR-1076 – Isolation of Process Equipment

PR-1078 - Hydrogen Sulphide Management Procedure

PR-1079 - Gas Freeing and Purging of Tanks Procedure

PR-1148 – Entry in to a Confined Space

PR-1154 – Gas Testing Procedure

PR-1172 – Permit to Work System

PDO Guidelines

GU-363 - Guideline for the use of Scaffolding

Appendix 3 - User Feedback Page

|[pic] |PR-1083 – Safe Working on the Roof of a Floating Roof Tank |

| |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 | |Date: | |

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|Page Ref: |Brief Description of Change Required and Reasons |

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|To: |UOP6 |

| |Custodian of Document |Date: | |

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[1] Including the licensing of PTW holders, applicants, responsible supervisors and area authorities.

[2] For major tank work it is suggested that a specific audit of the PTW system for that job be carried out by the Responsible Supervisor and Production Coordinator.

[3] Intrinsically safe radio to be provided for communication with CCR.

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