energy isolation grace - process

GRACEGroup Risk Assessment Conversation & Experience transfer

Identify hazards within your own working areas…!!

Isolation of pressurized system: 1of 3Installation of flow line

Identify Potential Hazards!

1/3

Isolation of pressurized system: 2 of 3

Activity Installation of flow linePreparations Work PermitPersonnel Operation and maintenance teamCircumstances Work was being carried out to install new flowline The new flowline had been positively isolated from the

production manifold by a blind A hot work permit had also been issued for cutting with an open

flame, the work site was adjacent to the flowline workAction The new flowline was only isolated from the production manifold

by a single remotely actuated isolation valve which was not locked

2/3

Isolation of pressurized system: 3 of 3

Actual / potential consequence Gas leakage / multiple fatalitiesWhat happened The remotely actuated isolation valve on the new flowline was

opened by a mistake and a gas release triggered two gas detectors, shutting down the installation

The gas release was identified to have come from the incompletely made up flowline connector

The work with the welding had stopped before the leak occuredDirect causes5-7 Inadequate isolation of process or equipmentSystem causes11-1 Inadequate work planning13-1 Inadequate assessment of needs and risks (tools &

equipment)

3/3

Working on pressurized system: 1 of 3Replacement of choke

1/3


Working on pressurized system: 2 of 3

2/3

Activity Replacement of chokePreparations Work permit, isolation certificatePersonnel One technicianCircumstances Replacement of choke on flowline On removal of the choke it was found that the upstream flange

face was in need of repair Both exposed faces of the flowline were capped with

Teklok/Graylock type hubcaps until repairs could be effected Action The following day the technician started to remove the hubcap

again


3/3

Actual / potential consequence Minor injury (DAFWC) / serious injuryWhat happened As the technician was loosening the hub clamp the hubcap blew

off with force, hitting him on the shoulder and propelling him backwards off an access platform onto the floor grating below

Pressurized nitrogen had migrated into the flowlineDirect causes1-10 Shortcuts3-1 Lack of knowledge of hazards present5-7 Inadequate isolation of process or equipmentSystem causes5-4 Inadequate reinforcement of critical safe behavior11-1 Inadequate work planning13-1 Inadequate assessment of needs and risks (tools &

equipment)

Blinding of processing plant: 1 of 3Installation of blinds

1/3


Blinding of processing plant: 2 of 3

2/3

Activity Installation of blinds in preparation for planned shutdownPreparations Planned program for blinding Work permit, isolation certificatePersonnel Four mechanicCircumstances The blinding team were under pressure to complete the work

prior to the scheduled start of the maintenance work The blind list and drawings had been prepared by a contractor

rather than by the operations team There was only one last blind to install on a flare line adjacent to

a valveAction An operations representative was at the worksite along with the

3 man contractor crew as the work was started on the final blind

Blinding of processing plant: 3 of 3

3/3

Actual / potential consequence Four fatalities / multiple fatalitiesWhat happened Hydrocarbon gas was released as the flange by the valve was

wedged open because the flange was split on the wrong side of the valve on the live flare line

The gas was immediately ignited by the nearby crane causing a flash fire that killed all four people

Direct causes1-2 Violation by group7-4 Energized systems, other than electrical System causes8-2 Inadequate leadership11-1 Inadequate work planning13-1 Inadequate assessment of needs and risks (tools &

equipment)

Work on El-system: 1 of 3Control of 440 V El-system

1/3


Work on El-system: 2 of 3

2/3

Activity Control of 440 V El-systemPreparations NonePersonnel One electricianCircumstances An electrician had been working with a 440 El-system The following day he detected a strange smell from the same

system Action The electrician proceeded to investigate without informing the

CCR, applying for a work permit or seeking assistance The electrician was not wearing safety glasses or gloves despite

this being required in this area

Work on El-system: 3 of 3

3/3

Actual / potential consequence Serious injury (DAFWC) / fatalityWhat happened A flash over occurred and the electrician was burned on the face

and hands, hospitalized for 12 days The immediate cause of the incident was the introduction of a

foreign body which caused the sudden short-circuit, rather than the escalation of a long-standing fault

Direct causes1-1 Violation by individual4-1 Improper decision making or lack of judgment5-3 Inadequate personal protective equipment7-3 Energized electrical systemsSystem causes5-4 Inadequate reinforcement of critical safe behaviors11-1 Inadequate work planning13-1 Inadequate assessment of needs and risks14-4 Inadequate enforcement of PSP

Depressurization: 1 of 3Commissioning of a gas lift system

1/3


Depressurization: 2 of 3

2/3

Activity Commissioning of a gas lift systemPreparations Work PermitPersonnel OperatorCircumstances Lift gas at 85 bar was supplied to a wellhead platform by a 4”

pipeline The pipeline ESDV on arrival at the wellhead platform was stuck

in an open position and required to be repaired In preparation for this it was decided to depressurized the

flowline to the host platform cold ventAction An operator opened a control valve to route high pressure (HP)

lift gas from the pipeline to vent Operator suspects no flow due to noise and no indication of

flaring

Depressurization: 3 of 3

3/3

Actual / potential consequence Near missWhat happened There was no flow in the line and the operator identified that the

line was blocked by the closed valve and the section had been over pressurized

The operator followed the depressurization line and found the tie-in valve to the cold flare closed

Central control room was alarmed and the exposed area roped off

Direct causes3-1 Lack of knowledge of hazards present4-1 Improper decision making or lack of judgment5-1 Inadequate guards or protective devicesSystem causes7-3 Inadequate training effort10-1 Inadequate technical design11-1 Inadequate work planning14-1 Lack of PSP for the task15-5 Inadequate communication between work groups

Work on FPSO deck: 1 of 3Replacement of passing butterfly valve

1/3Identify Potential Hazards!

Work on FPSO deck: 2 of 3

2/3

Activity Replacement of passing butterfly valvePreparations Work permit, Toolbox talk meeting, no risk assessmentPersonnel Two deck operators and crane driverCircumstances During a maintenance shutdown it was planned to change out a

passing butterfly valve on the tank vent line The tanks had been hydrocarbon gas freed, cleaned, inspected

then inerted with a nitrogen/CO2 mixture The butterfly valve was in closed positionAction The bolts between the valve and the tank were removed in order

to replace the butterfly valve

Work on FPSO deck: 3 of 3

3/3

Actual / potential consequence Unconsciousness (DAFWC) / multiple fatalitiesWhat happened One of the operators collapsed and the supervisor although groggy

managed to radio for help and drag his unconscious colleague into a safe position

The crane driver observed the incident and also radioed for assistance

The butterfly valve was in the closed position before the bolts were removed. This prevented free venting of the system immediately prior to valve removal

Direct causes3-1 Lack of knowledge of hazards present4-1 Improper decision making or lack of judgment5-5 Inadequate warning systemSystem causes6-1 Inadequate assessment of required skills7-4 No training provided11-1 Inadequate work planning13-1 Inadequate assessment of needs and risks

Process Isolation: 1 of 3Replacement of a bursting disc

1/3


Process Isolation: 2 of 3

2/3

Activity Replacement of a bursting discPreparations Work permit but no isolation certificatePersonnel One mechanicCircumstances Trouble with the compressor seal system Replacing bursting discs was a common occurrence. The

mechanic was used to getting cooling water spilling out of the piping when replacing the discs

Action The mechanic started to slacken the bolts on the bursting disc

holder

Process Isolation: 3 of 3

3/3

Actual / potential consequence HC gas leakage / escalation (fire, explosion)What happened As the mechanic slackened the bolts he heard a valve operate in

the flare system and gas started to emit from loose bolted flange

The bursting disc had not been isolated and there was no valid mechanical isolation certificate

Direct causes1-2 Violation by groups4-8 Routine activity without thought5-7 Inadequate isolation of process or equipmentSystem causes7-3 Inadequate training effort11-1 Inadequate work planning13-1 Inadequate assessment of needs and risks15-4 Inadequate communication between work groups

Working on valves: 1 of 3Working in the well bay area

1/3


Working on valves: 2 of 3

2/3

Activity Working in the well bay areaPreparations Considered as a routine workPersonnel OperatorCircumstances A number of body plugs had been replaced The valves were of exotic material and some of the plugs that

had been installed were of carbon steel Action Ongoing work in the well bay area

Working on valves: 3 of 3

3/3

Actual / potential consequence HC gas leakage / fatalityWhat happened A CS plug blew out of a valve body, narrowly missing the

operator and causing a minor hydrocarbon leak The direct cause was related to galvanic corrosion as a

consequence of different materials in valve and body plugsDirect causes3-1 Lack of knowledge of hazards presentSystem causes11-3 Inadequate repair11-6 Inadequate inspection13-1 Inadequate assessment of needs and risks14-4 Inadequate enforcement of PSP

Isolation of export pipeline: 1 of 3Boundary isolation against a pressurized gas export

1/3


Isolation of export pipeline: 2 of 3

2/3

Activity Boundary isolation against a pressurized gas exportPreparations Maintenance shutdown, working plan and isolation planPersonnel Maintenance teamCircumstances The 24” pipeline was not fitted with a subsea checkvalve. The

pressure in the pipeline was 180 barg The isolation comprised a double block and bleed comprised of two

hydraulically operated 24” sealine valves and a 2” bleed left open to atmosphere between them

Action Towards the end of the shutdown the hydraulic actuator on the

outboard valve was to be fitted with a spring return actuator instead and thus the control facilities for the valve had been dismantled

Work was being carried out locally on the hydraulic supply to the outboard valve, the system was disconnected from the platform shutdown and safety systems

Isolation of export pipeline: 3 of 3

3/3

Actual / potential consequence HC gas leakage / multiple fatalitiesWhat happened The outboard valve was opened resulting in a 2” full bore flow of

gas at 180 barg at the platform cellar deck level The area was immediately evacuated but the gas leak continued

unstopped. The leak was only brought under controlwhen an operator approached the open 2” valve with breathing apparatus on and manually closed the valve

Direct causes1-3 Violation by supervisor4-1 Improper decision making or lack of judgment5-7 Inadequate isolation of process or equipmentSystem causes6-1 Inadequate assessment of required skills11-1 Inadequate work planning13-1 Inadequate assessment of needs and risks14-1 Lack of PSP for the task

Working on pressurized system: 1 of 3Replacement of grease nipple

1/3



2/3

Activity Replacement of grease nipplePreparations Work PermitPersonnel One mechanicCircumstances Plan for nipple replacement established The mechanic were in the process of performing corrective

maintenance on the valve Action Mechanic started to unscrew the cap He ensured that no leak occurred After a while he continued to unscrew the cap completely


3/3

Actual / potential consequence HC gas leakage / escalation (fire or explosion)What happened A gas leakage occurred after the cap was fully removed Attempt to screw cap back on failed and the gas leakage

increased The leak was detected by gas detector Manual blow downDirect causes3-1 Lack of knowledge of hazards present5-7 Inadequate isolation of process or equipment6-1 Defective equipment6-3 Defective toolsSystem causes10-3 Inadequate assessment of potential failure11-2 Inadequate preventive maintenance13-3 Inadequate standards or specifications13-7 Inadequate removal / replacement of unsuitable items14-2 Inadequate development of PSP

energy isolation grace - process

Documents