Why discuss breaking containment ? Breaking containment is a hazardous activity in the oil and gas business. Fatal accidents continue to happen, showing that a work permit, by itself, does not make work safe Workplace safety depends on people factors ! • Briefings and discussions like this are essential: • To maintain awareness of the risks involved, the importance of full application of the controls, and the penalties of failure • To learn the lessons from past accidents • To add local knowledge to the Company’s procedures
Breaking into pressurised systems designed to contain hazardous materials What is breaking containment ? • Opening pipeworkby breaking flanges • Opening ofprocess machinery • Opening of vessels and other process equipment
What are the risks ? • Poorly designed facilities • Failure of isolation • Exposure to hazardous substances and process conditions • Risks associated with preparation of equipment • Risks associated with purging of equipment • Environmental risks eg. spillage leading to pollution • Failure to distinguish between ‘live’ systems and those to be worked on
Managing the risks • Plan and think through the work in advance, involving all the relevant people including specialists • Identify and assess the risks in accordance with site risk assessment procedure • Apply the appropriate controls to the extent warranted by the risks – can a safer method be used ? – apply procedural controls – train and brief those involved including contractors NOTE: The controls described in this Safety Talk are generic and may not cover the precise risks and circumstances at your site
Decommissioning/valve isolation • Review provisions for isolation, draining and venting, including access • Arrange for temporary facilities if required • Mark-off / barricade worksite • Shut down equipment • Valve isolate; extent of isolation should match the risk associated with it failing (see next slide) • Reinforce by padlocking
Risk assessment for isolation needed High risk if any of the following apply: • Pressure > 20 bar g (300 psig) • Temperature > 200°C (400°F) • Dirty, corrosive or erosive duty • Toxic material present Valving required; Double block valve and bleeder Medium risk ifnoneof the above apply: Valving required; Single block valve and bleeder
Depressuring and venting • Depressure to fuel gas system, then to flare, and finally (if impractical to purge) vent to atmosphere • Test and confirm effectiveness of valve isolation • Allow to cool, drain and pump out Wherever possible two methods for confirming that equipment is depressured and drained should be used before breaking containment
Displacement of contents • Equipment contents should be displaced to a closed drain / vent system wherever possible • PPE must be provided againstcontact with line contents • Preferred methods of displacement should be selected eg: – steam or inert gas for hot oil (care about condensate) – water or air for caustic soda
Risks of draining • Fire hazard – drains overloaded can spread hydrocarbon – hot oil above its auto-ignition temperature – volatile materials can flash to form a flammable mixture • Physical harm – hot material – toxic material – if ‘blocked’ drain clears unexpectedly • Product loss • Environmental hazard
Precautions when draining • Hot oil should be allowed to cool • Drain through permanently installed drain points • If necessary use temporary piping to drain to closed system – may need to improvise to contain and collect • Minimise quantities of oil drained to the sewer • Valves should be opened slowly, and if blocked should be shut again and the situation reviewed • Proprietary equipment is available for clearing blocked drains – welding rods and bits of wire must NOT be used • The open end of a drain line should be visible to the operator, and in a safe location DRAINING SHOULD NEVER BE LEFT UNATTENDED
Use a cold work permit • Breaking of containment requires a cold work permit • Authority and accountability for all aspects of the work • Description of the work to be carried out, the exact equipment and location, and time period • Steps required to isolate equipment and prepare worksite • Test results confirming work area free from unacceptable risks • Description of remaining hazards and required precautions including monitoring • Completion, acceptance of work and withdrawal of permit
‘Routine’ breaking of containment • Breaking of containment is sometimes regarded as ‘routine’ – cleaning or changing filters – disconnecting hoses – winging ‘Hamer’ blinds – launching and receiving pigs • Area Operating Authorities must list types of work classified as low risk which do not require a Work Permit • There must be no confusion about – who is responsible for carrying out work eg. operators or maintenance/contractors – whether a work permit is required
Preparation • Adequate support on either side of the joint • Isolation of the section of equipment • Confirm release of pressure – where possible, two methods should be used before breaking containment • Assume line is full / underpressure. Also considerthe fire hazard • Area demarcation andaccess / exit
General precautions • Specify tools, equipment and methods to be used eg. hand tools only • Safe location of equipment • Precautions for interactions with other work • MSDS sheets for hazardous substances, available / attached to permit • If toxic gas might be present, suitable breathing apparatus must be worn • PPE to be worn – use gloves and a face shield over safety goggles in addition to boots, hat, overalls etc • Removal of equipment from worksite on completion
Specific risks and precautions Risk identification, assessment and control are needed for specific hazards like: • Hydrogen sulphide, lead, caustic, acid etc • Pyrophoric material • Equipment which normally operates under a vacuum • Electrically traced lines • Cathodically protected equipment • Machinery Note: Details of precautions needed will be found in the handout and in refinery procedures and guidelines
Breaking a joint • Replace corroded bolts one at a time with new ones • Loosen bolts so they can be retightened if necessary • Start with the bolt farthest away and at the bottom • Keep nearest bolt tight until wedge inserted and contents drained • Care with blocked or choked pipes • Blank off open ends • Clean dismantled parts beforeremoving from site
Completion of work • If joints have not been remade, blank off open ends • Drains and vents should be capped, blanked or plugged • Blanking provides protection against inadvertent opening of a valve, as well as it passing • There have been many incidents when they were used as ‘unofficial’ sample points with disastrous results • Cold work permit must be – signed off by Performing Authority – withdrawn by Operating Authority after inspecting and accepting work
Wrong equipment The permit must clearly describe the specific work to be carried out. To avoid confusion draw a diagram and tag the equipment Contractors were opening up a live foul gas line containing H2S, thinking it was a steam line. They were stopped by a maintenance foreman who happened to be passing. This lucky coincidence almost certainly prevented a fatality.
‘Exploding’ shell • The pressure build up caused by a restriction in the path of the steam flow to the vents • Be aware of the potential force of steam, nitrogenor air used as a maintenance aid,and not allow buildup of pressure to occur A maintenance crew was unable to remove the shell cover of a heat exchanger, so an operator heated it by introducing steam. The shell cover blew off and killed the operator.
Ejected plug A plug was removed to replace a thermal relief valve whilst the vessel was under pressure (7 contractors injured, 2 seriously). The vessel had been shut down when the relief valve was removed but had since been recommissioned *.
Draining blind Vessel relief valves were beingprepared for on-line testing. To prove isolation integrity, a hose was fitted to a drain point.The drain point was 50 feet above the ground, and was led away to a drain at ground level. Valving errors led to the vessel discharging liquid to drain. Because the end of the hose was not visible this was not detected. A pool (of crude) formed and flashed from an adjacent furnace.
Release during spading A pair of heat exchangers, taken out of service to repairan internal leak, were being prepared for maintenance. During spading, naphtha was released and ignited on hot exchangers below, injuring 3 contractors.
Gas tester overcome A gas tester was overcome by gas (mainly nitrogen) which flowed from an open flare line he was testing. He was not wearing respiratory protection despite being told to do so. Ironically the gas test was required to permit flash photography of an incident which had occurred earlierin the day !
Fire during blind removal No proper risk assessment was carried out ! During the removal of a24 inch blind from a crude oiltransfer line, an explosion and fireoccurred injuring 7 people and killing 1 contractor. The job followed an unscheduled partial shutdown, and it was not possible to isolate the transfer line without total shutdown.
‘Blocked’ drain • Drains are designed for shut down / start up operations, under low pressure • Drains and vents should be plugged / blanked off during normal operations • Stand-in personnel eg. for absence must be formally accredited as competent in the job they will perform A stand-in operator opened a drain valve on a reformate debutaniserwhich was still under pressure. Debrisinitially blocked the flow, but then suddenly cleared. The senior operator tried to shut the drain valve and was soaked in reformate.A vapour cloud formed and flashed off a nearby heater. The senior operator’soveralls caught fire andhe was killed.
‘The door flew open . . .’ Experienced operators have been killed opening up equipment with quick-release devices such as pig receivers. Suggest modifications to improve inherent safety at your site Through the proper channels of course !
Optional Quiz 1. Name 4 general hazards of breaking containment 2. Managing risk involves (4 steps) 3. What criteria are used to decide the valve isolation required ? (4) 4. What are the risks associated with draining ? (4) 5. What precautions should be taken when draining ? (4) 6. Is a cold work permit needed for breaking containment ? (2) 7. What specific precautions should be taken when breaking into a line that has contained hydrogen sulphide ? 8. What controls can be used to avoid confusion over which equipment is to be worked on ? (4) 9. Give 5 examples from this Safety Talk of incidents involving breaking of containment 10. Give 2 more examples from your experience
Quiz Certification 1. Apakah resiko yang berhubungan dengan DRAINING (4)? 2. Apakah tindakan pencegahan yang diambil saat draining dilakukan (4) ? 3. Apakah sebuah Cold work permit diperlukan saat breaking containment ? Apa berikan (2) alasannya. 4. Berikan tindakan pencegahan yang specifik saat breaking containment dilakukan yang mana line tersebut mengandung solvent? 5. Tolong siapkan untuk PM 0-P-625B Yang akan dikerjakan nanti Sore Jam 17.00. PM termasuk internal inspection di W/shop. 6. Mohon disiapkan permit untuk PM Baby Past equipment yang akan dikerjakan jam 15.00, termasuk heater nya akan di bawa ke W/shop.