FIRE ENGINEERING: ANS

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FIRE ENGINEERING: ANS

1.Fire protection engineering

Fire Protection Engineering

(also known as
fire engineering

or
fire safety engineering
) is the
application of science and engineering principles to protect people and their environments
from the destructive effects of
fire

and smoke.

The discipline of fire protection engineering in
cludes, but is not exclusive to:



Active fire protection

-

fire suppression systems, and fire alarm.



Passive fire protection

-

fire and smoke barriers, space separation



Smoke control and management



Escape facilities
-

Emergency exits, Fire li
fts etc.



Building design, layout, and space planning



Fire prevention programs



Fire dynamics

and
fire modeling



Human behavior during fire events



Risk analysis
, including economic factors



Wildfire Management

Fire protection engineers identify risks and design safeguards that aid in preventing, controlling,
and mitigating the effe
cts of fires. Fire protection engineers assist
architects
, building owners
and developers in evaluating buildings' life safety and property protection goals. FPEs are also
employed as
fire investigators, including such very large
-
scale cases as the analysis of the
collapse of the World Trade Centers.
NASA

uses fire protection engineers in its space program
to help improve safet
y.
[1]

Fire protection engineers are also employed to provide 3rd party
review for performance based fire engineering solutions submitted in support of local building
regulation
applications

2.
Alternative fireproofing methods

Among the conventional materials, purpose
-
designed spray fireproofing
plasters

have become
abundantly available the world over. The
inorganic

methods include
:



Gypsum

plasters



Cementitious plasters



Fibrous plasters

The industry considers
gypsum
-
based plasters to be "cem
entitious", even though these contain
no
Portland
, or
calcium aluminate

cements. Cementitious plasters that contain Portland cement
have been traditionally lightened by the use of inorganic lightweight
aggregates
, such as
vermiculite

and
perlite
.

Gypsum plasters have been lightened by using chemical additives to create bubbles that
displace solid
s, thus reducing the bulk density. Also, lightweight
polystyrene

beads have been
mixed into the plasters at the factory in an effort to reduce the density, which generally results
in

a more effective insulation at a lower cost. The resulting plaster has qualified to the
A2
[
clarification needed
]

combustibility rating as per DIN4102.
[
full citation needed
]

Fibrous plasters,
containing either
mine
ral wool
, or
ceramic

fibres tend to simply entrain more air, thus
displacing the heavy fibres. On
-
site cost reduction efforts, at times purposely contravening the
requirements of the
certification listing
, can further enhance such displacement of solids. This
has resulted in
archit
ects
' specifying the use of on
-
site testing of proper densities to ensure the
products installed meet the certification listings employed for each installed configuration,
because excessively light inorganic fireproofing does not provide adequate protectio
n and are
thus in violation of the listings..

Proprietary boards and sheets
, made of
gypsum
,
calcium
silicate
,
vermiculite
,
perlite
,
mechanically bonded composite boards made of punched sheet
-
metal and cellulose reinf
orced
concrete have all been used to clad items for increased fire
-
resistance.

An alternative method to keep building steel below its softening temperature is to use
liquid
convection cooling

in hollow structural members.
[1]

This method was patented in the 19th
century although the first prominent example was 89 years later.
[2

3.Active fire protection

Active fire protection (AFP)

is an integral part of
fire protection
. AFP is characterised by items
and/or
syst
ems
, which require a certain amount of motion and response in order to work,
contrary to
passive fire protection
.

Categories of Active Fire Protection

Fire su
ppression

Fire can be controlled or extinguished, either manually (firefighting) or automatically. Manual
includes the use of a
fire extinguisher

or a Standpipe system. A
utomatic means can include a
fire
sprinkler

system, a gaseous clean agent, or fire fighting foam system. Automatic
suppression systems would usually be found in l
arge commercial kitchens or other high
-
risk
area.

Sprinkler systems

Fire sprinkler

systems are installed in all types of buildings, commercial and residential. They
are usually

located at ceiling level and are connected to a reliable water source, most
commonly city water. A typical sprinkler system operates when heat at the site of a fire causes
a glass component in the sprinkler head to fail, thereby releasing the water from t
he sprinkler
head. This means that only the sprinkler head at the fire location operates
-

not all the
sprinklers on a floor or in a building. (This is a common misconception which stems from action
movie scenes). Sprinkler systems help to reduce the growt
h of a fire, thereby increasing life
safety and limiting structural damage.

Fire detection

The fire is detected either by locating the
smoke
,
flame

or
heat
, and an alarm is sounded to
enable
emergency evacuation

as well as to dispatch the local
fire department
. An introducti
on
to fire detection and suppression can be found
here
. Where a detection system is activated, it
can be programmed to carry out other actions. These i
nclude de
-
energising magnetic hold open
devices on
Fire doors

and opening servo
-
actuated vents in stairways.

Hypoxic air fire prevention

Fire can be prevented by hypoxic air.
Hypoxic air fire prevention systems
, also known as oxygen
reduction systems are new automatic fire prevention systems that reduce permanently the
o
xygen concentration inside the protected volumes so that ignition or fire spreading cannot
occur. Unlike traditional fire suppression systems that usually extinguish fire after it is detected,
hypoxic air is able to prevent fires.

Construction and maintena
nce

All AFP systems are required to be installed and maintained in accordance with strict guidelines
in order to maintain compliance with the local
building code

and the fire cod
e. An example
treatise on code compliance in Miami Dade County can be seen
here
. Code authorities can
encourage compliance through open communications, such as an
invitation for code questions

or an
invitation to participate or an explanation of
the code development process

AFP works alongside
modern architectural designs and construction materials

and fire safety
education to prevent, retard, and sup
press structural fires.

20 MARKS:

1. Fire protection

Fire protection

is the study and practice of mitigating the unwanted effects of potentially
destructive fires
.
[1]

It involves the study of the behaviour,
compartmentalisation
, suppression
and invest
igation of
fire

and its related emergencies, as well as the research and development,
production, testing and application of mitigating
systems
. In structures, be they land
-
based,
offshore or even ships, the owners and operators are responsible to maintain their facilities in
accordance with a design
-
basis that is rooted in laws, including the local
building code

and fire
code, which are enforced by the
Authority Having Jurisdiction
. Buildings must be
constructed in
accordance with the version of the building code that is in effect when an application for a
building permit is made. Building inspectors check on compliance of a building under
construction

with the building code. Once
construction

is complete, a building must be
maintained in accordance with the current fire code, which is enforced by the fi
re prevention
officers of a local fire department. In the event of fire emergencies,
Firefighters
, fire
investigators, and other fire prevention personnel called to mitigate, investi
gate and learn from
the
damage of a fire
. Lessons learned from fires are applied to the authoring of both building
codes and fire codes.

Goals

Fire protection has three major goals:



Continuity of operations

-

on a public scale, this is intended to prevent the interruption
of critical services necessary for the public welfare (e.g., a 911 emergency call center).



Property protection

-

on a public scale, this is intended to prevent area
wide
conflagrations. At an individual building level, this is typically an
insurance

consideration
(e.g., a requirement for financing), or a regulatory requirement.



Life safety

-

the min
imum standard used in fire and building codes

Components

Structural fire protection (in land
-
based
buildings
,
offshore construction

or onboard
ships
) is
typically achieved via three means:



Pas
sive fire protection

(use of integral, fire
-
resistance rated wall and floor assemblies
that are used to form fire compartments intended to limit the spread of
fire
, or
occupancy separations, or
firewalls
, to keep fires, high temperatures and
flue gases

within the fire compartme
nt of origin, thus enabling firefighting and evacuation)



Active fire protection

(manual and automatic detection and suppression of fires, as in
using and instal
ling a
fire sprinkler

system or finding the fire (
fire alarm
) and/or
extinguishing it)



Education

(ensuring that building owners and operators have copies and a working
understanding of the applicable building and fire codes, having a purpose
-
designed
fire
safety plan

and ensuring that building occupants, operators and emergency personnel
know the
building
, its means of
Active fire protection

and
Passive fire protection
, its
weak spots and strengths to
ensure the highest possible level of safety)

Balanced Approach

Passive fire protection (PFP) in the form of compartmentalisation was developed prior to the
invention of or widespread use of active fire protection (AFP), mainly in the form of automatic
fire

sprinkler systems. During this time, PFP was the dominant mode of protection provided in
facility designs. With the widespread installation of fire sprinklers in the past 50 years, the
reliance on PFP as the only approach was reduced. Lobby groups are typ
ically divided into two
camps favouring active or
passive fire protection
. Each camp tries to garner more business for
itself through its influence in establishing or changing local and national building and fire codes.
At present, the camp favouring AFP appears to be leading, because of the factors mentioned
above.

Building Operation in conformance with Design

The buildin
g is designed in compliance with the local
building code

and
fire code

by the
architect and other consultant
s. A building permit is issued after review by the
Authority Having
Jurisdiction (AHJ)
.

Deviations from that original plan should be made known to

the AHJ to make sure that the
change is still in compliance with the law to prevent any unsafe conditions that may violate the
law and put people at risk. For example, if the
firestop

sys
tems in a structure were inoperable, a
significant part of the fire safety plan would not work in the event of a fire because the walls
and floors that contain the firestops are intended to have a
fire
-
resistance rating
, which has
been achieved through passing a
fire test

and, often,
product certification

of the components
involved in the construction of those walls and floors. Likewise, if the
sprinkler system

or fire
alarm

system is inoperable for lack of knowledgeable maintenance, or if the
building

occupants
prop open a
fire door

and th
en run a
carpet

through, the likelihood of damage and casualties is
increased. It is vital for everyone to realise that
fire protection

within a structure is a
system

that relies on all of its components.

2. Fireproofing

Fireproofing
, a
passive fire protection

measure, refers to the act of making
materials

or
structures

more resistant to
fire
, or to those materials themselves, or the act of applying such
materials. Applying a
certification listed

fireproofing system to certain
structures allows these
to have a
fire
-
resistance rating
. The term fireproof does not necessarily mean that an item
cannot ever burn: It relates to measured per
formance under specific conditions of testing and
evaluation. Fireproofing does not allow treated items to be entirely unaffected by any fire, as
conventional materials are not immune to the effects of fire at a sufficient intensity and/or
duration.

Market
s



Commercial
construction



Residential construction



Industrial construction



Marine (
ships
)



Offshore construction



Aerodynamics



Tunnel

concrete

walls and ceilings or linings



Under and above ground mining operations

Applications



Structural steel

to keep below critical temperature ca. 540 °C



Electrical circuits to
keep critical electrical c
ircuits below 140 °C

so they stay operational



Liquified petroleum gas

containers to prevent a
BL
EVE

(boiling liquid expanding vapour
explosion)



Vessel skirts and pipe bridges in an
oil refinery

or
chemical plant

to keep the
structural
steel

below critical temperature ca. 540°



Concrete

linings of traffic tunnels

Fraud

The following examples of fraud are preventable when documentation is required and checked
to ensure that all installed configurations fall within the tolerances of active certification
listings.



Entraining too much air in

inorganic systems, thus reducing densities, saves on materials
and labour.



Spraying inorganic spray fireproofing materials over through
-
penetrations and building
joints that should be
fir
estopped
, not
fireproofed
. This practice negates fire
-
separation
integrity. Firestops must precede spray fireproofing..



Substitution of
intumescent

and/or
endothermic

fireproofing coatings with less
expensive paints that physically resemble the
passive fire protecti
on

products,
sometimes involving re
-
use of packaging and de
-
canting of contents.



The American and Canadian nuclear industries have, historically, not insisted on
listing
and approval use and compliance
, on the basis of the use of accredited certification
laboratories. This has allowed the use of Thermo
-
Lag 330
-
1, for which the basis of
testing has been proven to be faulty,
[
citation needed
]

resulting in millions of dollars of
remedial work. The Thermo
-
Lag scandal came to light as a result of disclosures by
American

whistleblower

Gerald W. Brown
, who reported the
deficiencies

in
fire testing

to the
Nuclear Regulatory Commission
. Presently,
product certification

of fireproofing
and
firestopping

remains optional for systems installed in
nuclear power plants

both in
Canada

and the
United States
.

Work staging

Spray fireproofing products have not been qualified to the thousands of firestop

configurations,
so they cannot be installed in conformance of a certification listing. Therefore, firestopping
must precede fireproofing. Both need one another. If the structural steel is left without
fireproofing, it can damage fire barriers and a buildi
ng can collapse. If the barriers are not
firestopped properly, fire and smoke can spread from one compartment to another.

Traffic tunnel fireproofing

Traffic tunnels may be traversed by vehicles carrying flammable goods, such as petrol,
liquified
petroleum gas

and other
hydrocarbons
, which are known to cause a very rapid temperature
rise
and high ultimate temperatures in case of a fire (see the hydrocarbon curves in
fire
-
resistance rating
). Where hydrocarbon transports are permitted in tunnel co
nstruction and
operations, accidental fires may occur, resulting in the need for fireproofing of traffic tunnels
with concrete linings. Traffic tunnels are not ordinarily equipped with fire suppression means,
such as
fire sprinkler systems
. It is very difficult to control hydrocarbon fires by
active fire
protection

means
, and it is expensive to equip an entire tunnel along its whole length for the
eventuality of a hydrocarbon fire or a
BLEVE
.

Concrete exposed to hydrocarbon fires

Concrete
, by itself, cannot withstand hydrocarbon fires. In the
Channel tunnel

that connects
United Kingdom

and
France
, an intense fire broke out and reduced the concrete lining in the
undersea tunnel down to about 50

mm.
[
citation needed
]

In ordinary building fires, concrete typically
achieves excellent fire
-
resistance ratings, unless it is too wet, which can cause it to crack and
explode. For unprotected concrete, the sudden
endothermic

reaction of the
hydrates

and
unbound humidity inside the concrete causes such pressure as to spall off the concrete, which
then winds up in small pieces on the floor of

the tunnel. This is the reason why laboratories
insert humidity probes into all concrete slabs that undergo fire testing even in accordance with
the less severe building elements curve (DIN4102, ASTM E119, BS476, or ULC
-
S101). The need
for fireproofing wa
s demonstrated, among other
fire protection

measures, in the European
"Eureka" Fire Tunnel Research Project, which resulted in building codes for the trade to avoid
the effec
ts of such fires upon traffic tunnels. Cementitious spray fireproofing must be
certification listed
and applied in the field a
s per that listing
, using a hydrocarbon fire test curve
such as the one that is also used in UL1709.
[3]

Fireproof Vaults

The traditional method for constructing fireproof vaults to protect important paper documents
has been to use concrete or masonry blocks as the primary building material
[
citation needed
]
. In the
event of a fire, the chemically bound water within the concrete or masonry blocks will be
forced into the vault chamber as steam. The steam will soak the paper documents to keep
them from burning
[
citation needed
]
. This steam will also help keep the temperature inside the vault
chamber below the critical 350
-
degree Fahrenheit (176.7
-
degrees Celsius)

threshold, which is
the point at which information on paper documents is destroyed
[
citation needed
]
. The paper can
later be remediated with a freeze dryi
ng process, if the fire is extinguished before internal
temperatures exceed 350
-
degrees F
[
citation needed
]
. An alternate less expensive and time
-
consuming

process is using dry insulating material
[
citation needed
]
.

3.Automatic fire suppression

Automatic fire suppression

systems control and extinguish fires w
ithout human intervention. It
was not until Feb. 10, 1863 that the first
fire extinguisher

patent was issued to Alanson Crane of
Virginia. The first
fire sprinkler system

was patented by H.W. Pratt in 1872. But the first
practical automatic sprinkler system was invented in 1874 by
Henry S. Parmalee

of New Haven,
CT. He installed the system in a piano factory he owned

Types of automatic systems

Today there are numerous types of Automatic Fire Suppression Systems. Systems are as d
iverse
as the many applications. In general, however, Automatic Fire Suppression Systems fall into two
categories:
engineered

and
pre
-
engineered

systems.

Engineered Fire Suppression Systems

are design specific. Engineered systems are usually for
larger ins
tallations where the system is designed for the particular application. Examples
include marine and land vehicle applications, computer clean rooms, public and private
buildings, industrial paint lines, dip tanks and electrical switch rooms. Engineered sys
tems use a
number of gaseous or solid agents. Many are specifically formulated. Some, such as 3M Novec
1230
Fire Protection Fluid
, are stored as a liquid and disc
harged as a gas.

Pre
-
Engineered Fire Suppression Systems

use pre
-
designed elements to eliminate the need for
engineering work beyond the original product design. Typical industrial solutions use a simple
wet or dry chemical agent, such as
potassium carbonate

or
monoammonium phosphate

(MAP),
to protect spaces such as paint ro
oms and booths, storage areas and commercial kitchens. In
Europe, a small number of residential designs have also emerged. These units often employ
water mist with or without a
surfact
ant

additive, and target retrofit applications where the risk
of fire or fire injury is high but where a conventional
fire sprinkler system

would be
unacceptably expensive.

Components

By definition, an automatic fire suppression system can operate without human intervention.
To do so it must possess a means of detection, actuation and delivery.

In many systems, detection is accomplished by me
chanical or electrical means. Mechanical
detection uses fusible
-
link or thermo
-
bulb detectors. These detectors are designed to separate
at a specific temperature and release tension on a release mechanism. Electrical detection uses
heat detectors equipped
with self
-
restoring, normally
-
open contacts which close when a
predetermined temperature is reached. Remote and local manual operation is also possible.

Actuation usually involves either a pressurised fluid and a release valve, or in some cases an
electric

pump.

Delivery is accomplished by means of piping and nozzles. Nozzle design is specific to the agent
used and coverage desired.

Health and environmental concerns
.

Modern systems

Since the early 1990s manufacturers have successfully developed safe and eff
ective Halon
alternatives. These include DuPont FM
-
200, American Pacific’s Halotron and 3M Novec 1230
Fire Protection Fluid. Generally, the Halon replacement agents available today fall into two
broad categories, in
-
kind (gaseous extinguishing agents) or n
ot in
-
kind (alternative
technologies). In
-
kind
gaseous agents generally fall into two further categories, Halocarbons
and Inert Gases. Not in
-
kind alternatives include such options as water mist or the use of early
warning smoke detection systems.


4.Gaseo
us fire suppression

Gaseous fire suppression

is a term to describe the use of
inert gases

and chemical agents to
extinguish a
fire
. Also called Clean Agent Fire Suppression. These Agents are governed by the
NFPA Standard for Clean Agent Fire Extinguishing Systems
-

NFPA 2001 in the USA, with
different standards and regulations in other parts of the world. The system typically con
sists of
the agent, agent storage containers, agent release valves,
fire detectors
, fire detection system
(wiring control panel, actuation signaling), agent delivery piping, and
agent dispersion nozzles.
Less typically, the agent may be delivered by means of
solid propellant

gas generators

that
produce either inert or chemically active gas.

Theory

There are four means used by the agents to extinguish a fire. They act on the "
fire
tetrahedro
n
":



Reduction or isolation of fuel

No agents currently use this as the primary means of fire suppression.



Reduction of heat

Representative agents:
HFC
-
227ea

(MH227, FM
-
200),
Novec 1230
,
HFC
-
125

(ECARO
-
25),
FS 49 C2

.



Reduction or isolation of oxygen

Representative agents:
Ar
gonite

/ IG
-
55 (ProInert), CO
2

carbon dioxide
, IG
-
541
Inergen
,
and IG
-
100 (NN100).



Inhibiting the chain reacti
on of the above components

Representative agents:
FE
-
13
,
FE
-
227
,
FE
-
25
,
MH227, FM
-
200
,
Halons
,
Halon 1301
,
Freon 13T1
, NAF P
-
IV, NAF S
-
III, and Triodide (
Trifluoroiodomethane
).

Application

Broadly speaking, there are two methods for applying an extinguishing agent: total flooding and
local application.

Systems working on a
total flooding

principle apply an extinguishing agent to a three
dimensional enclosed space in order to achieve a concentration of the agent (volume percent
of the agent in air) adequate to extinguish the fire. These types of systems m
ay be operated
automatically by detection and related controls or manually by the operation of a system
actuator..

Safety precautions

Suffocation

Systems using certain agents, such as
carbon dioxide
, in enclosed spaces present a risk of
suffocation. Numerous incidents have occurred where individuals in these spaces have been
killed by carbon dioxide agent release. To prevent such occurrences, additional life safety
systems are t
ypically installed with a warning alarm that precedes the agent release. The
warning, usually an audible and visible alert, advises the immediate evacuation of the enclosed
space. After a preset time, the agent starts to discharge. Accidents have also occu
rred during
maintenance of these systems, so proper safety precautions must be taken beforehand.
[1]

Barotrauma

The positive pressure caused by extinguishant release
of the Inert agents in this group (IG
-
541,
IG
-
55, IG
-
100) may be sufficient to break windows and walls. Humans and structures must be
adequately protected.
[1]