05/04/2016
Faculty of Chemical Engineering
Universiti Teknologi MARA
Principles of fire and
explosion protection
Health, Safety and Environment -
CGE653
Dr Syed Shatir A. Syed-Hassan
Principles of fire protection
The protection of petroleum facilities
follows the same overall philosophy that
would be applied to any building or
installation.
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Basic requirements:
Personnel evacuation
Containment
Isolation
Suppression
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General Philosophy
The fire and explosion protection
engineering design philosophy can be
defined by the following objectives:
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i. Prevent the immediate exposure of
individuals to fire and explosion hazards.
No facility should be designed such that an employee or the
public could be immediately harmed if they were to be
exposed to the operation.
General Philosophy
ii. Provide inherently safe facilities.
Inherently design safety features at facilities provides for
adequate spacing, arrangement and segregation of
equipment from high hazard to low hazard.
• The least hazardous process systems should be used for
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obtaining the desired product or production objectives.
• Protective systems are provided to minimize the effects
that may occur from a catastrophic incident.
iii. Meet the prescriptive and objective
requirements of governmental laws and
regulations.
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General Philosophy
iv. Achieve a level of fire and explosion risk that
is acceptable to the employees, the general
public, the petroleum and related industries,
the local and national government, and the
company itself.
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v. Protect the economic interest of the
company for both short and long range
impacts.
vi. Comply with a corporation's policies,
standards and guidelines.
Layers of Protection
Most facilities are designed around layers of
protection commonly referred to as
Independent Layers of Protection (ILP).
A protection layer qualifies as an ILP when one
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of the following conditions are met
the protection provided reduces the risk of a serious event
by 100 times
the protective function is provided with a high degree of
availability
it has the following characteristics - specificity,
independence, dependability, and auditability
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Layers of Protection
EMERGENCY RESPONSE
• BPCS - Basic process
CONTAINMENT control
A • Alarms - draw attention
RELIEF
U • SIS - Safety interlock
SIS T system to stop/start
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O equipment (ESD)
ALARMS M
• Relief - Prevent excessive
A pressure
BPCS T
I • Containment - Prevent
O materials from reaching,
workers, community or
N environment
• Emergency Response -
evacuation, fire fighting,
health care, etc.
Layers of protection Health, Safety and Environment -
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Segregation, Separation and
Arrangement
Segregation is the grouping of similar
hydrocarbon processes into the same major
area.
The segregated high hazard areas can also be
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separated as far as necessary from other areas
of the facility and the public.
The major facility segregation categories are
process, storage, loading, flaring, utilities and
administrative.
Segregation, Separation and
Arrangement
The primary design consideration should be
the protection of employees and the general
public from the effects of an explosion or fire.
The ideal situation for offshore facility is to
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locate the accommodation on a separate
installation jacket that is spaced as far as
practical from the production processes and
the process platform oil or gas pipeline risers.
Arrangement means the orientation and
assemblage of the equipment in a facility.
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Control of Ignition Source
A common ignition source is sparks resulting
from static charge buildup and sudden
discharge.
Static charge buildup is a result of physically
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separating a poor conductor from a good
conductor or another poor conductor.
Examples of static charge build up:
Walking across a rug
Removing a sweater
Combing hair
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Control of Ignition Source
The major generators of static electricity at
hydrocarbon facilities are:
Flowing liquids or gases containing impurities or
particulates
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Sprayed liquids
Liquid mixing or blending operations
Moving machinery
Personnel
Control of Ignition Source
Static electricity can be overcome
or controlled by several basic
approaches such as bonding and
grounding.
Bonding tries to achieve a common
electrical potential on all
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equipment so that a charge does
not have the opportunity to
accumulate.
Grounding is the process of
electrically connecting one or more
conducting objects to a ground
potential.
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Control and Instrumentation
Process control maintains
variables at set points, which are
fixed at some desired values
Without adequate and reliable
process controls, an unexpected
process occurrence cannot be
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monitored, controlled and
eliminated.
Alarm has an annunciator and
visual indication. Require
analysis by a person - A plant
operator must decide.
Emergency Shutdown System
An Emergency Shutdown (ESD) system is a method to
rapidly cease the operation of the process and isolate
it from incoming or going connections or flows to
reduce the likelihood of an unwanted event from
occurring, continuing, or escalating.
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Facilities that do not have the capability to
immediately provide an emergency shutdown should
be considered high risks. Similarly, if the reliability of
an ESD system is very poor.
ESD systems are designed so that several mechanisms
can initiate a facility shutdown
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Methods of Fire Suppression
The objectives of fire suppression systems: i) to
provide cooling; ii) to control fire (prevent it from
spreading); ii) to provide extinguishment of the fire
incident.
Some methods of fire suppression
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Portable Fire Extinguishers
Sprinkler System
Water Deluge System
Water Spray System
Water Flooding
Steam Smothering
Water Curtains
Portable Fire Extinguishers
The most common method of extinguishing
hydrocarbon fires in the incipient stage.
Portable extinguishers are classified by
expected application on a specific type of fire
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(i.e., A, B, C, or D) and the expected area of
suppression.
The four types of fires are grouped according to
the type of material that is burning
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Portable Fire Extinguishers
Class A fires include those in which ordinary
combustibles such as wood, cloth, and paper
are burning.
CIass B fires are those in which flammable
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liquids, oils, and grease are burning.
Class C fires are those involving live electrical
equipment.
Class D fires involve combustible metals such as
magnesium, potassium, and sodium
Portable Fire Extinguishers
Extinguishers for Class A Fires
Class A fire extinguishers are usually water
based. Water provides a heat-absorbing
(cooling) effect on the burning material to
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extinguish the fire.
Pressurized water extinguishers use air under
pressure to expel the water.
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Portable Fire Extinguishers
Extinguishers for Class B Fires
• Class B fires are put out by excluding air, by
slowing down the release of flammable vapors,
or by interrupting the chain reaction of the
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combustion.
• Three types of extinguishing agents: carbon
dioxide, dry chemical, and foamwater.
Portable Fire Extinguishers
Extinguishers for Class C Fires
• The extinguishing agent in a class C fire extinguisher
must be electrically non-conductive.
• Both carbon dioxide and dry chemicals can be used in
electrical fires.
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Extinguishers for Class D Fires
• A heat-absorbing extinguishing medium is needed for
fires in combustible metals.
• Also, the extinguishing medium must not react with
the burning metal.
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Sprinkler Systems
Commonly provided to indoor occupancies, such as
warehouses, offices, etc.
Considered essentially 100% effective for fire
suppression if properly maintained and the hazard has
not changed since the original design.
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Activated by the heat of the fire melting a tension
loaded cap at the sprinkler head.
Cap melts or falls away releasing water from the pipe
distribution network. Thus they do not activate until a
fire condition is absolutely real.
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Water Deluge System
Should generally be activated by automatic means.
Activation by manual means defeats the objective of
installing a deluge system.
Most systems provided at petroleum facilities are
typically activated by a heat detection.
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Water Flooding
Water flooding is the principle to inject water
into the interior of a storage tank for the
purposes of preventing flammable or
combustible liquids from being released from a
leakage point or to extinguish a fire.
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The principle involves fill a vessel or tank so
that the lighter density hydrocarbon fluids float
on the water and only water is released from
the container.
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Steam Smothering
Typically limited to fires that might occur as a
result of a tube leak in a furnace or heater.
The steam is most effective in smothering fires
when they are located in relatively small
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confined areas.
Steam extinguishes fire by the exclusion of free
air and the reduction of available oxygen
content to the immediate area, similar to other
gaseous suppression agents
Summary
• Layers of protection (6 layers)
• Segregation, separation and arrangement
• Control of ignition point
• Control and instrumentation
• Alarms
• Blinking light (visual indicator)
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• Emergency shutdown system
• Fire suppression methods
• Fire extinguisher
• Sprinkler
• Water deluge system
• Water flooding
• Steam smothering
• Evacuation, fire fighting, health care etc.
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