Temporary equipment offshore

SPC/TECH/OSD/25

Version No:

4

OG Status:

Fully Open

Author Section:

OSD 3.1

Issue Date:

18 July 2008

Review Date:

18 July 2011

Target Audience:

All OSD Inspectors

Purpose

This document provides topic guidance on the management of risks associated with the use of temporary equipment used on offshore installations.

Background

1  This SPC provides guidance to inspectors in support of OSD's Inspection Manual and HSE's Assessment Principles for Offshore Safety Cases (APOSC). It provides a topic overview of issues arising from the use of temporary equipment on offshore installations.

[Whilst written as guidance to offshore inspectors, many of the principles in this guidance will also apply to onshore operations involving temporary equipment.]

Introduction

2  Temporary equipment used on offshore installations can present new hazards to the installation for the duration of its installation, use and removal. Potential hazards need to be identified and assessed. Temporarily revised management and control arrangements for safe operation and maintenance may need to be in place. Annex 1 contains summary tables of example considerations relevant to the use of temporary equipment. The tables provide prompts, as applicable, to assist inspectors carrying out safety case assessments, inspections, etc. Annex 2 contains some example case histories to demonstrate some of the principles contained in this SPC.

What is temporary equipment?

3  Temporary Equipment (TE) comprises equipment that is not a permanent part of the installation and which it is intended should be removed after a finite period of time. TE offshore can range from small items such as portable welding sets to large skid mounted packages such as temporary generators, proprietary well testing equipment, temporary process or utility equipment, temporary diagnostic/measurement equipment etc. Whilst there are potential hazards associated with the introduction of all types of TE (including small portable equipment), the emphasis in this guidance is placed upon larger temporary packaged equipment requiring hook-up to an operating system. Consideration is also given to other temporary operating arrangements applied to the permanent system involving temporary hook-up, supply or operating procedure.

4  Some TE will have been envisaged as part of the original design for the installation (eg well test equipment). The original hazard assessment process should have considered the use of such equipment as part of normal platform operations. Indeed, some permanent facilities may have been incorporated to facilitate the TE installation (eg permanent piping to drains or vent systems, etc.).

5  As the life of the installation progresses, it may be necessary to introduce further TE that was not considered during the original design (eg temporary power generation skids, temporary process skids and additional services). The introduction of such equipment involves the management of change process for modifications. In this respect, the management system should assess the associated hazards. However, due to its temporary nature, the potential exists for engineering solutions to be undertaken that are less well considered or inherently secure than might be the case for permanent solutions. An example is the use of flexible hose assemblies to make connections rather than inherently more robust hard piped connections.

6  Some TE initially intended for short-term use may, for operational or other reasons, remain in use for extended periods. Equipment used in this way might better be considered as permanent, for which a more robust permanent engineering solution would be better suited. Prolonged use of TE in this way could be regarded as an abuse of the temporary principle and a cheap opt-out from a properly engineered arrangement covered by formal engineering change procedures and subject to rigorous hazard assessment. Arrangements should be in place to periodically review the continuing status of equipment as temporary.

Standards and procedures for controlling risks

7  Procedures should exist detailing the management of the installation and use of TE. They should address the definition of TE and how such equipment is obtained, identified, installed, removed, tested and maintained. The means whereby hazards associated with the TE are identified, assessed and controlled should be outlined. There should be a clear statement of responsibilities of the process for installing TE and interfaces with contractors and verification bodies should be explained.

Safety critical temporary equipment

8  Any temporary equipment being introduced to the installation must be assessed to determine whether it will be safety critical or impacts upon safety critical equipment. If the assessment finds that the temporary equipment is safety critical (or impacts upon safety critical equipment) the ICP must be consulted prior to its deployment in order that the verification scheme can be reviewed or revised and appropriate verification activities defined. The purpose of these verification activities is for the ICP to advise the duty holder whether the equipment will be suitable when it is put into use. Further guidance can be found in the safety case regulations guidance.

Hazard considerations

9  TE brought onto an installation (more specifically, packaged TE integrated into the operating system) that is a non-routine piece of equipment may not have been considered in hazard assessments conducted during original design. In such cases, it is effectively a modification which, for a defined period of operation, becomes an integral part of the installation with the potential to present new hazards.

10  It is common for TE to be installed under the installation's Permit to Work (PTW) system. The PTW system will usually address the control of hazards associated with installation and removal of the equipment, eg safe isolations, purging, personal protective equipment, temporary fire protection arrangements, etc. However there is a risk that the assessment process may not fully address further hazards arising from the integration of the equipment into the existing operating system. Examples of how additional hazards might arise include system impacts arising from the introduction of additional isolations, temporary changes to operating conditions, temporary bypassing of equipment, changed safety or relief requirements, etc.

11  As with any permanent modification, consideration should be given to properly conducted formal hazard identification and assessment processes to reduce any new risks to ALARP. Where there are temporarily run services to equipment, it may be appropriate for a review to be conducted on-site to fully appreciate local factors, such as temporary routings, access considerations, etc.

12  Layout is an important area for consideration. Packaged TE units have the potential to affect existing defined hazardous area zones, established escape / transfer routes, restriction of explosion vent paths, maintenance access restrictions, operating envelopes (eg cranes), etc. TE having the potential to produce missiles or dropped objects following serious failure, or due to inadequate fixing to the installation structure, could present new hazards to permanent equipment. Where this is the case, it should be established that potentially affected equipment is not safety critical.

13  Examples of how TE can introduce risks include (but are not limited to):

• Temporary flexible or fixed piping systems and revised routings
• Temporary tie-ins to permanent systems
• Temporary isolations - piping/mechanical/electrical/control/ESD
• Temporary revised or new operating procedures
• Temporary hazardous zones
• Temporary space and /or load restrictions, lifting and laydown restrictions
• Temporary revised maintenance and inspection requirements
• Temporary amendment to process design
• Temporary revised or new human interfaces
• Contract staff
• Temporary new dependencies
• PTW requirements
• Possible EER impacts
• Additional management responsibilities
• Additional sources of hazard from failure of equipment (missiles, loss of containment, ignition sources, etc.)
• Temporary layout considerations (including effects on explosion venting, maintenance or other access requirements, natural venting impacts, effectiveness of fire and gas detection arrangements, etc.)

Control of change

14 Integration of permanent modifications is normally implemented through company Engineering Change Procedures. These include procedures for updating relevant documentation and operating procedures as part of the modification.

15  In the case of temporary facilities there may be short term amendments to be made to drawings, specifications, operating and maintenance practices, etc. The introduction of new hazards may also temporarily affect the basis of previous risk assessments. Procedures should exist defining how such temporary impacts are managed. There should be a system for controlled temporary amendment of drawing and documents, including arrangements for distribution and storage on and off-shore as appropriate. There should be a defined process for withdrawal or return of temporarily amended documentation to reflect the permanent operational state as necessary, following removal of the temporary facilities. Examples of documentation that may be required or could be affected by introduction of TE may include (but are not limited to):

• Equipment identification lists
• As-built drawings
• Operating and maintenance procedures
• Verification schemes
• Pressure, calibration or load certificates
• Data sheets
• Hazard identification, risk assessments, task hazard analyses
• Lifting arrangements
• Hook-up / deconstruct instructions
• Design calculations
• Etc.

Isolation and reinstatement

16 Installation of TE may require temporary isolation of facilities (piping, controls, ESD, power, etc.). An important part of the process is the controlled reinstatement to normal operating conditions following removal of the temporary facilities. This is particularly important if temporary amendment or isolation of safety related functions such as ESD is involved. It is important that procedures document details, not only of how installation is to be safely achieved, but also how reinstatement is to be achieved following removal of the TE.

Competence and training

17  Temporary training requirements need to be identified, recorded and implemented.

18  Where different training arrangements exist for permanent and contract personnel, the means whereby they are integrated and managed within the dutyholder's normal arrangements should be identified.

Control of contractors

19  TE may be introduced to an installation by the dutyholder or by contractors. Different procedures may be employed for TE used or installed by contractors, or operating company own procedures may be applied. There needs to be clear understanding of any integration of procedures and an assurance that control and management of documentation, hazard analysis, control of spares, maintenance interfaces, training, competencies, etc. are properly managed.

Further information

Further information can be obtained from: Head of Section OSD 3.1 (Process Integrity), Redgrave Court, Bootle.

Annex 1 - Summary Table of Considerations Relevant to the Use of Temporary Equipment

The following table identifies some considerations which may be relevant to the introduction of Temporary Equipment (TE) to installations. The list should not be regarded as exhaustive nor relevant to all types of TE, but should be used as an aide-memoire.

Annex 2 - Sample case histories

1 A high pressure armoured flexible hose assembly was used to supply injection water to wells. Pumped injection water supplies were permanently connected to some other wells via a manifold. An additional pump had been installed in an adjacent module and was piped to the existing injection water manifold from which a temporary connection to the hose assembly was made.

The hose was used to supply water to a selected well for periods of time varying from weeks to months. The hose was supported by temporary chain blocks and nylon lifting strops from convenient attachment points to provide a basic control on hose curvature when in use. The strops were replaced every 6 months as part of routine maintenance. However the trailing hose presented a tripping hazard and over time was vulnerable to damage, presenting a potential hazard from high pressure leaks. Documentation covering the temporary hook-up and supply arrangements were found to be out of date.

[Issues: Long term use of temporary facilities with no temporary status review; layout considerations (tripping hazards); poor document control]

2  A temporary air hose to a piece of temporary equipment was routed such that it was subject to a significant vertical drop. Although the hose was tied back vertically, the stress on the hose due to the imposed hung weight was sufficient to lead to a failure of the hose at its connection ferrule. Inadequate support led to minimum bending radius criteria for the hose being compromised.

[Issues: Layout considerations - inadequate consideration to required supports and poor awareness of manufacturer hose installation criteria]

3  Poorly routed discharge piping from a pressure relief valve on a temporary stock tank was found to have been routed such as to create a long undrained low point section of piping. There was a potential for hydrocarbon or other condensed liquids to collect in the low point section with consequential potential for blockage or dismantling hazards.

Although the stock tank was a standard piece of contractor supplied equipment, installed by the contractor, incomplete routing drawings had been prepared for this installation. The case illustrates that where piping is to be site run (as may often apply to temporary facilities), it is important that those responsible for routing the piping are aware of associated hazards. Familiarisation with the equipment needs to be accompanied by an equal understanding of the total system of which it is to become a part.

[Issues: Poor routing of temporary piping; inadequate identification and assessment of hazards; inadequate consideration of removal requirements]

4  A temporary flexible flowline and choke manifold suffered failure of the hose due to sand erosion. The temporary line had been routed through an open door to an adjacent module allowing flammable gases to migrate outside of the working module following hose failure. A HAZOP had been conducted but failed to note the presence of flow straightening vanes (thought to have been a contributor to the failure) which were not shown on the relevant drawings used onshore for the HAZOP.

[Issues: Documentation not maintained to current status; impairment of barriers to gas migration (open door); questionable representation on the onshore HAZOP team - would local site knowledge of, or visit to, installed facilities have identified the presence of flow straightening vanes?]

5  A temporary hose was fitted to a deaerator vent and routed into another module to allow continued local operations during a shutdown. When the deaerator inlet valve was cracked open, blanket gas was displaced through the hose leading to a gas alarm. Plant operating manuals were subsequently amended to reflect a different procedure for purging.

[Issues: Inadequate assessment of hazards for temporary plant hook-up and operating condition applied to the permanent system to allow short term shutdown of part of the facilities]

6  A temporary hose split causing a leak of oily water to sea. The leak was caused by a pump pulsating, causing the hose to rub against the deck gratings. Oil was being transported from a crude oil storage tank putting the hose under a pressure of approximately 7 barg.

[Issues: Inadequate support of temporary hose; inadequate identification of hazards (abrasion hazard)]