Page 27 - Critical Control flipbook_Neat

Coal Mill Explosion

1 What is the name of the 2 What are its specific objectives related to the Priority Unwanted
critical control for Coal Mill
Event (PUE)?
Explosion?
Damper and Fan System Trip Early detection of change, and prevent the formation of an explosive atmosphere that
could potentially lead to an explosion
Detect the change in the process condition/parameters of Temperature, CO level and trip
the booster fan (suction), coal mill, and isolate baghouse by slam shutting the dampers

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?
Pre-defined safe operating limits with Safe operating limits and alarm setpoints Operators are aware of critical limits, and
high-level alarm and high-high level trip are included in SOP the ‘defined operator response’ for high
on Temperature and CO alarm scenarios

Control system elements - Temperature Scheduled preventative maintenance Percentage of PM completion rate
transmitter, CO analyser, dampers and calibration in Computerized Number of defects found during
proximity switches, and damper magnetic Maintenance Management System calibration and PMs. (This should be
release mechanism are periodically (CMMS) as per manufacturer’s documented on CMMS)
calibrated, along with a suitable requirements/ Corporate CEM guidance
preventative maintenance (PM) schedule Classified as highest priority and critical
and free of build up or any obstruction equipment in CMMS

Periodic ‘end to end’ Trip testing Scheduled end to end trip testing in CMMS Completion rate of trip testing
(min once a year) Report deviation/failure as near miss on Number of failed Trips upon testing
iCare
Coloured or tagged control system A systematic approach across the plant Number of non compliance to the
elements as “Critical Control” in the field to identify, colour or tag as “critical” (This defined systematic approach
should be visual as well as identifiable 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 tests. Critical limits known by operators. Control authorisation
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