Page 61 - Critical Control flipbook_Neat

Liquid Fuel Fire

1 What is the name of the 2 What are its specific objectives related to the Priority Unwanted
Event (PUE)?
critical control for Liquid
Fuel Fire?
Alarm, Interlock and Trip Early detection of loss of containment/leakages, and prevent the formation of an
explosive atmosphere that could potentially lead to an explosion

3 What are the critical 4 What are the activities 5 What can be sampled from
control performance
within the management
the set of activities for
requirements to meet the systems that support verification, providing a
objectives? having the critical control clear image of the critical
able to do what is required? control status?
Fuel leak detectors/sensors (vapour and Low flash point fuels are identified Check SDS for flashpoint
liquid) should: Safe operating limits and alarm setpoints Check SOP for defined Alarm and Trip
a. Activate an alarm are included in SOP limits with operator response
b. Trip all pumps
c. Close all the actuated valves (interlock) FDS (Functional Design Specification) has Check layout drawings for hydrocarbon
at a predefined set threshold value alarm and trip specified detectors and verify the location/
d. Be placed/positioned within the Layout drawing showing the position of proximity in the field
predicted leak contour (e.g. leak detector hydrocarbon detectors
inside the bund closer to the bund floor)
*only applicable to fuel with flashpoint <60°C
Fuel distribution pipeworks have process P&ID (Process & Instrumentation Loss of pressure interlock is in place in
interlock on the loss of downstream Diagrams) showing pressure tansmitters Human Machine Interface (HMI)
pressure or fire detection system that will and isolation valves
isolate the fuel supply by either slam shut- FDS has the pressure interlock specified
ting the isolation valve or actuated valve

Overfill protection system has both level P&ID showing level gauge/transmitter, Level gauge/transmitter, and level switch
gauge and level switch level switch, pumps and actuated valves on storage vessel
a. At high tank level (gauge) - ALARM Safe operating limits and alarm/trip Defined SOP and trip set points are in
b. At high-high tank level (level switch) - setpoints are included in SOP SOP and HMI
TRIP pump, slam shut actuated valves FDS has high level alarm and high-high
Siphoning protection (e.g. Non-return level trip/interlock
valves in feed pipe)

If it is possible to route the fuel to incorrect P&ID showing fuel routing and manifolds Check the P&ID for fuel routes and
tank (due to common manifold or common with diverter valves potential for misdirected flow
unloading points), a process interlock in FDS has interlocks on diverter valve Defined interlock on diverter valve
place on the diverter valve position positions position in SOP and HMI

All interlocks and trips tested (end-to- Report deviation/failure as near miss on Completion rate of trip testing
end) periodically (min once a year), and iCare Number of failed Trips upon testing
maintained Scheduled preventative maintenance and
calibration in CMMS as per manufacturer’s
requirements/ Corporate CEM guidance.
Classified as highest priority and critical
equipment in CMMS.

6 What is the target performance for critical 7 What is the critical control performance
control?
trigger for shutdown, critical control review or
investigation?
All the inspection, maintenance and testings are carried out Failed Trip
100% without any deferments. All the trips are fully effective Unauthorised deferment without Plant Manager’s written
during trip/interlock tests. Critical limits known by operators. authorisation
Control system elements visually identifiable If any trip system is overridden or disabled

Creation date: 01/2021 • The latest and only controlled version of this document is available on the HSE intranet.
© 2021 Holcim - For internal use only