brent bravo utility leg fatality – jan 2005 report findings from the shell investigation team

Brent Brent BravoBravo Utility Leg Fatality – Jan 2005 Utility Leg Fatality – Jan 2005

Report Findings from the Shell Investigation Team


Agenda

•Brent Bravo

•Summary of what happened on the 1st January 2005

•Results of the Investigation

•Findings and Actions


• Situated 116 miles north-east of Shetland

• Concrete Platform

• Exports gas from the rest of the Brent Field into the FLAGS pipeline system

• Three legs – one accessible (utility shaft), 2 flooded.


• The circumstances of this incident and the incident of September 11th, 2003 are completely different

• At no time during the incident was there a hydrocarbon gas atmosphere in the leg

• Both men followed the correct alarm response procedures in evacuating the leg

• The platform personnel did an excellent job responding to the incident

Key Observations


• Normal platform operations prior to incident

• Two Electrical Technicians, on night shift, were in the leg at the 76 metre level installing services for a planned inspection of pipework below the 76 metre level.

• At around 02:20 hours both men smelled H2S and at the same time 1 of 4 portable gas monitors at the worksite alarmed at 5 ppm H2S

• None of the fixed toxic gas monitors nor any of the hydrocarbon gas monitors went into alarm.

• Both men donned their Draeger Rebreather sets and, in accordance with procedures, started to evacuate the leg by climbing the internal stairs.

• At the 81 metre level one of the men stopped and activated the platform GPA and then continued to climb the stairs.

What happened


• At a stair landing just below the 124 metre level one of the men (Graeme Burns) stopped climbing and sat down on the stair landing

• The other man continued to climb the stairs out of the leg believing Graeme was taking a rest and would soon follow.

• The second man reached the top of the leg at 02:33 hours and informed the leg sentry that Graeme was following behind him.

• Several tannoy messages were given by the OIM to tell Graeme that the leg was gas free.

• A two man rescue party was sent into the leg and found Graeme laying on the stair landing where he originally stopped – just below 124 metre level.

• Graeme was given CPR by the rescue team and the medic was called to the scene.

• The rescue party were unable to resuscitate Graeme.

---- EL124 m

What happened (con’t)


• The Death Certificate indicates Graeme died as a result of a heart attack caused by a coronary artery thrombosis.

• We have no further information about the cause of death, but what we do know is:

– Graeme had a valid UKOAA offshore medical certificate

– The gas monitor that alarmed reached a maximum H2S value of 6.7 ppm (the other portable showed zero, and neither personal meter alarmed during the event). The 6.7 ppm is well below the Theshold Limit Value - Short-Term Exposure Limit of 10 ppm

– All of the gas detectors were independently tested and found to be operating correctly

– The rebreather set was also independently tested and found to be operating correctly

Cause of Death

Brent Brent BravoBravo Utility Leg Fatality – Jan 2005 Utility Leg Fatality – Jan 2005Investigation Findings

H2S in the LegBackground• By design the bottom of the leg contains seawater to a depth of approximately 35

metres. • A consequence of this seawater is that H2S gas is produced by naturally occurring

Sulphate Reducing Bacteria (SRB)• The H2S is managed by continuous sparging with air and diluting with fresh

seawater and when required chemical treatment.• The Threshold Limit Value – Short Term Exposure Limit for H2S exposure is10 ppm

(meaning the value to which nearly all workers can be exposed to for up to four, 15 minute intervals per day without adverse health effects).

Findings • The seawater had been treated with a chemical scavenger a week before the

incident• At the 76 metre level, the reading was 0 ppm in the days prior to the event• The gas monitor that alarmed reached a maximum H2S value of 6.7 ppm.• Laboratory examination of the portable gas monitors indicated they were working

correctly at the time of the incident and giving accurate readings.

Brent Brent BravoBravo Utility Leg Fatality – Jan 2005 Utility Leg Fatality – Jan 2005Investigation Findings

Gas MetersBackground• The men had in their possession 4 forms of gas detection (2 Crowcon

Tetra Portables and 2 personal gas detectors).• There were 11 fixed detectors at, above, and below the 76 metre level

where the men were working. • Only one of the detectors gave an indication of H2S (one of the

Crowcons)

Findings

• The Crowcon that alarmed reached a maximum H2S value of 6.7 ppm.

• It had not been reset at any time during the incident or after• Laboratory examination of the portable gas monitors indicated they

were functioning normally and giving accurate readings


Investigation FindingsDraeger Rebreathers

Background• Introduced in 2003 on all Shell UK platforms to

replace existing rebreathers following trials at RGIT Montrose.

• The sets are widely used in the military, nuclear, mining, and oil and gas industries

Findings• Both men had been trained in the use of the

Draeger sets and had been assessed as leg competent

• Based on the video evidence, both men had not donned the units in strict accordance with the manufacturers recommendations

• Laboratory examination of the unit worn by Graeme confirmed it was functioning normally

• Andy reported the unit worn by him was also functioning


Investigation FindingsMedical Fitness of Personnel Working Offshore

Background• The medical fitness requirement for personnel working offshore in the

UK is the UKOOA Offshore Medical.

• The UKOOA medical examination does not require a test of aerobic fitness such as the Chester Step Test. Although this is still part of the Shell Medical examination for offshore staff.

Findings• Graeme had a valid UKOOA Offshore Medical Certificate


Investigation FindingsOther Issues

Leg Entry Control• The procedure for the monitoring of personnel movements into and

out of the leg was not being strictly followed in accordance with the OCOP

Leg Competency Training• The Leg Competency training in the use of portable gas monitors

only requires personnel to understand the meaning of the alarms – not how to reset and retest for harmful atmospheres

Radio Communications• There was cross-channel interference during radio communications

First Aid Response Time• The time taken to get First Aid support to casualties in the lower

half of the leg, when using the stairs as access, is longer than the Shell standard of 4 minutes


Immediate Follow-Up Actions (Underway)

1. Emergency Escape Rebreather Training• Immediately re-train all platform personnel in the use of the Draeger

rebreathers (where applicable)– Show the instruction DVD– Have an appropriate person (medic, etc.) physically

demonstrate the use of the equipment– Encourage people to use the “buddy system” to check each

others deployment in the event they are ever needed – Re-emphasise the advantages of the Draeger system– Carry out practical exercise by donning training sets (when

available)

2. Leg Entry Control • For the concrete leg platforms, immediately test the application of

the appropriate leg entry Operating Code of Practice (OCOP) to ensure the effectiveness of leg registers

• Carry out regular “spot checks” to identify all personnel in the leg at a point in time and then validate against the Leg Register detail.


Follow-Up Actions (Planned)3. Medical Fitness • Review medical fitness requirements for personnel in the legs of

concrete gravity base structures in consideration of the unique requirements for ingress and egress

4. Enhanced Training• As already agreed with the HSE previously, enhance rebreather

training.• Review the requirements for Leg Competency and if necessary

include requirement for training in the use of portable gas monitors

5. Radio Communications• Carry out planned work to upgrade radios to avoid cross channel

interference immediately.

6. First Aid Response Time• Review First Aid response time for casualties in concrete legs and

ensure the risks are ALARP7. Concrete Leg Working Environment• Form a joint Shell/Sigma 3 team to evaluate additional improvement

opportunities specific to the unique environment of concrete legs

Brent Brent BravoBravo Utility Leg Fatality – Jan 2005 Utility Leg Fatality – Jan 2005Summary

• The circumstances of this incident and the one on September 11th are very different

• At no time during the incident was there a hydrocarbon gas atmosphere in the leg

• Both men followed the correct alarm response procedures in evacuating the leg

• The platform personnel did an excellent job responding to the incident

• The Death Certificate indicates Graeme died as a result of a heart attack caused by a coronary artery thrombosis.

• Graeme had a valid UKOAA offshore medical certificate• The gas monitor that alarmed reached a maximum H2S value of 6.7

ppm (the other portable showed zero, and neither personal meter alarmed during the event). The 6.7 ppm is well below the Theshold Limit Value - Short-Term Exposure Limit of 10 ppm

• All of the gas detectors were independently tested and found to be operating correctly

• The rebreather set was also independently tested and found to be operating correctly

• There were other improvement opportunities discovered that are being actioned


Complete The Ones I already made to you on January 7th• Immediately re-train all platform personnel in the use of the Draeger rebreathers

(where applicable), as per my instruction on January 5th– For installations using other types of rebreathers, do the same with your

existing training package• For the concrete leg platforms, continue to test your application of the appropriate

leg entry Operating Code of Practice (OCOP) to ensure the effectiveness of leg registers

New Requests• Use elements of this slide pack to communicate to all platform personnel ASAP• Re-educate all platform personnel in the dangers of hydrocarbon vapour (next

slide)• Confirm to your Ops Manager and Asset Leader via email when you have

completed these requests• Ensure these same requests are handed over to your back-to-back

Requests of You


Additional Observations Not Connected with the Incident

A key finding from the September 2003 incident was a lack of awareness of the risks associated with the ‘Narcotic Effect of Hydrocarbon Gas’

There is evidence that these risks are still not understood by the workforce.

Please re-communicate the dangers of breathing hydrocarbon vapour to all members of the workforce.

20%

40%

60%

80%

100%

% L

ow

er

Exp

losi

ve L

imit

10%

Hyper-excitation, loss of ability to

take rational decisions

Failure to respond to verbal

commands

No impairment of functionality

Likely there is no impairment of functionality

brent bravo utility leg fatality – jan 2005 report findings from the shell investigation team

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