صفحه 1:
oP Wydorwboo Our بم۱۳۳) اسو0
Learning from a recent incident
This presentation consist of 6 view graphs (plus this header)
Action required:
1) To be distributed to relevant staff and to be discussed HSE
meetings in the context of your own operations
2) To verify that you have a control system in place to prevent
incidents from hydrocarbon leaks
صفحه 2:
oP Wydorwboo Our بم۱۳۳) اسو0
The incident:
- A Natural Gas Condensate leak in one of the legs of an
offshore production platform resulted in exposure to
hydrocarbon vapours, causing the death of two operators
Background:
- The narcotic hazard of natural gas condensate had been
identified in the Health Hazard Register and the Material
Safety Data Sheet (MSDS)
- The HEMP analysis had identified leaks as an exposure
threat, but indicated that normal plant integrity procedures
should identify and control/repair leaks when they occur
- The HRA process and Leg Entry Procedures had identified
the required control measures and emergency procedures
- Nevertheless, it appears that the hazard was poorly
understood in the line and appropriate procedures and
control measures were not implemented
)یگ
صفحه 3:
oP Wydorwboo Our بم۱۳۳) اسو0
The hazards:
- The narcotic effect of a hydrocarbon mixture depends
on the dose and the concentrations of the various
hydrocarbons in the mixture
Narcotic effects occur very quickly - within 2-3 breaths.
This can result in confusion and inability to take rational
decisions, and finally to unconsciousness and death
~ Narcotic effects from hydrocarbon vapours can occur at
normal oxygen concentration in air, so the oxygen
depletion alarm does not protect from narcotic effects
- Alarm levels of portable and fixed monitors are set as a
percentage of the Lower Explosion Limit (LEL) - alarm
should trigger appropriate action, i.e. respiratory
protection and immediate evacuation
6 )ی
صفحه 4:
oP Wydorwboo Our بم۱۳۳) اسو0
Narcotic Effect vs Portable Monitor
Readin'
Corresponds to approx
50% general anaesthetic
dose required for surgical
operations
Alarm setting for monitor
% Lower Flammable
Limit
100 #
1%
80
%
is an example. Actual effects
end on the nature of the
hydrocarbon vapour
صفحه 5:
oP Wydorwboo Our بم۱۳۳) اسو0
Learning and Actions - Toxic Substances in
Confined Spaces
- Leaks of toxic substances in confined spaces can quickly result
in hazardous concentrations in breathing air
- As well as direct health risks, these can result in confusion and
inability to react properly
- Competence Assurance Systems should verify that the
appropriate personnel and supervisors are fully familiar with
the understanding of the hazards of toxic substances and
confined space entry procedures
- Substances heavier than air, such as butane, can collect in low
points, resulting in toxic or flammable pools which may not be
detected by fixed gas heads or portable monitors as normally
positioned
- Further guidance is provided in the Group Guide Confined
Space Entry,which be issued in April 2004
صفحه 6:
oP Wydorwboo Our بم۱۳۳) اسو0
Learning and Actions - HEMP for Confined Spaces
- The Hazard and Effects Management Process (HEMP) should
be applied for confined space activities
- The HEMP should contain the following -
* Identification of the hazards
+ Assessment of the risks using the Risk Assessment Matrix (RAM)
* Analysis of the hazards, e.g. by Job Hazard Analysis (JHA) and HRA
as indicated by the RAM
۰ Necessary controls and recovery measures
* Demonstration that controls and recovery measures are effective
- The HEMP should demonstrate that alternatives to entering
the confined space have been considered, and all reasonably
practicable steps taken to eliminate hazards to health
- Confined space entry should be authorised and controlled by
Permit to Work
صفحه 7:
oP Wydorwboo Our بم۱۳۳) اسو0
Learning and Actions - HEMP for Confined Spaces
- The HEMP and JHA should also cover hazards which may be
released into the confined space for reasons not directly
connected with the activity, for example a leak from
pipework
- Findings of the HEMP and HRA should be incorporated into
operating procedures, tool-box talks, training etc. Cross-
checks should be made against the HRA to ensure all health
risks are being managed
- The HEMP, JHA and HRA should clearly specify the
monitoring and escape procedures to be adopted. This
should include the monitoring devices to be used, alarm
levels, and escape and rescue procedures (including the use
of breathing apparatus) if the alarm sounds
6 )ی