2. Passive Fire Protection (PFP) is an integral component of the three components
of structural fire protection and fire safety in a building.
PFP includes compartmentalization of the overall building through the use
of fire-resistance rated walls and floors. Organization into smaller fire
compartments, consisting of one or more rooms or floors, prevents or slows the
spread of fire from the room of fire origin to other building spaces, limiting
building damage and providing more time to the building occupants
for emergency evacuation or to reach an area of refuge.
Fire prevention includes minimizing ignition sources, as well as educating the
occupants and operators of the facility, ship or structure concerning operation
and maintenance of fire-related systems for correct function, and emergency
procedures including notification for fire service response and emergency
evacuation.
3. The aim for PFP systems is typically demonstrated in fire testing the ability to
maintain the item or the side to be protected at or below either 140 °C (for walls,
floors and electrical circuits required to have a fire-resistance rating) or ca. 550
°C, which is considered the critical temperature for structural steel, above which
it is in danger of losing its strength, leading to collapse.
PFP measures are intended to contain a fire in the fire compartment of origin,
thus limiting the spread of fire and smoke for a limited period of time.
PPF measures such as fire stops, fire walls and fire doors are tested to
determine the fire resistance rating of the final assembly usually expressed in
terms of hours of fire resistance (e.g., ⅓, ¾, 1, 1½, 2, 3, 4 hour)etc.
PFP attempts to contain fires or slow the spread, through use of fire resistant
walls, floors, and doors (amongst other examples).
4. As the name suggests Passive Fire Protection (PFP) remains inactive in the
coating system until a fire occurs.
There are mainly two types of PFP: Intumescent fire protection and
vermiculite fire protection.
Ser. Intumescent fire protection Vermiculite fire protection
1 It is a layer of paint which is applied along with the
coating system on the structural steel members.
The thickness of this intumescent coating is
dependent on the steel section used.
Structural steel members are covered with
vermiculite materials, mostly a very thick layer. This
is a cheaper option as compared to an intumescent
one, but is very crude and aesthetically unpleasant.
2 Intumescent coatings are applied as an
intermediate coat in a coating system (primer,
intermediate, and top/finish coat). Because of the
relatively low thickness of this intumescent coating
(usually in the 350- to 700-micrometer range), nice
finish and anti-corrosive nature. Intumescent
coatings are preferred on the basis of aesthetics
If the environment is corrosive in nature, then the
vermiculite option is not advisable, as there is the
possibility of water seeping into it (because of the
porous nature of vermiculite), and there it is difficult
to monitor for corrosion.
5. It should be noted that in the possibility of a fire, the steel structure will
eventually collapse once the steel attains the critical core temperature
(around 550 degrees Celsius or 850 degrees Fahrenheit).
PFP system will only delay this by creating a layer of char between the steel
and fire. Depending upon the requirement, PFP systems can provide fire
ratings in excess of 120 minutes. PFP systems are highly recommended in
infrastructure projects as they can save lives and property.
Such protection is either provided by the materials from which the building
is constructed, or is added to the construction materials to enhance their fire
resistance. It is vital that these protection measures are correctly designed,
specified and installed if the building is to behave as expected should fire
break out.
6. PFP is vital to the stability and integrity of a building or structure in case of
fire. These are designed to restrict the growth and spread of fire allowing
the occupants to escape or the fire fighters to do their job.
By their nature they are ‘passive’ until there is a fire and only then will their
fire performance be demonstrated. The occupants of a building will attend
to their daily business, visitors will shop, be entertained, or enjoy recreation
without any knowledge of the PFP measures that will protect them in fire.
However, it is essential that these measure will work if an emergency
occurs.
7. PFP includes:
Cavity barriers
Ceiling systems
Compartment walls
Fire doors and furniture (e.g. self-closing devices, latches etc.)
Fire fighting shafts and stairwells
Fire-resisting air transfer grilles (mechanical or intumescent)
Fire-resisting dampers (mechanical or intumescent) used in horizontal or
vertical air distribution ducts
Fire-resisting ductwork
Fire-resisting glazing
Fire-resisting service ducts and shafts
8. Fire-resisting walls and partitions
Hinged or pivoted fire door sets (timber or steel)
Industrial fire shutters (rolling or folding)
Linear gap seals
Penetration seals for pipes, cables and other services
Structural frame fire protection
Suspended ceilings
Membrane ceilings (horizontal partitions)
The building envelope, e.g. fire-resisting external walls, curtain walls etc.
Other elements of the building may also have a role in PFP.
9. Air transfer grille: A device which allows the passage of ventilation air in
normal conditions through a fire door, wall or partition but closes automatically
to prevent the passage of fire in a fire condition for stipulated time period.
Automatic fire and smoke damper: A device which allows the passage of
ventilation air in normal conditions through a duct, fire wall or partition but closes
automatically to prevent the passage of smoke and fire in a fire condition for a
stipulated period of time. Response to smoke is typically achieved by linking to
the automatic fire detection system.
Building hardware: Fittings designed for incorporation in a fire-resisting door
set and which contribute to ensure that the fire-resisting door (when closed)
resists the passage of fire and/or gaseous products of combustion. Such fittings
include hinges, pivots, door closing devices, latches, locks, and door furniture
(lever handles, knobs).
10. Cavity barrier: A construction provided to close a concealed space against
the penetration of smoke and flame or to restrict the movement of smoke or
flame within such a space for a stipulated time period.
Combustibility: This assesses whether a material will burn and add to a
fire when subjected to an existing fire. Spread of flame this assesses
whether the fire will spread over the surface of the material (especially wall
linings).
Compartment(fire): A building or part of a building, comprising one or more
rooms, spaces or floors constructed to prevent the spread of fire to or from
another part of the same building, or an adjoining building. The basis is to
provide adequate means of escape, and to provide fire separation for
adjoining buildings.
11. Fire door(assembly): A door or shutter provided for the passage of
persons, air or objects which together with its frame and furniture as
installed in a building is intended when closed, to resist the passage of fire
and/or gaseous products of combustion and is capable of meeting
specified performance criteria to those ends.
Fire-resisting door set: A complete installed door assembly comprising
door frame, door leaves, building hardware, seals and any glazing that,
when closed, is intended to resist the passage of fire and smoke in
accordance with specified performance criteria.
Fire-resisting glazed screen: Glazed structure or window incorporating
fire-resisting glass and designed to resist the spread of fire and the
gaseous products of combustion for a stipulated period of time.
12. Fire-resisting glass: A glass that demonstrates its ability to meet the
defined heating and pressure conditions specified in Fire resistance Test (or
any other National or International fire resistance test method). Typically,
the glass will be clear, textured, toughened, laminated or wired and may
incorporate special features such as coatings or laminations that enable the
glass to achieve a particular fire performance in terms of integrity and
insulation.
Fire-resisting ductwork: Ventilation or extraction ductwork designed to
contain fire and the products of combustion in a manner that does not allow
passage to other parts of the building from the compartment of origin for a
stipulated time period.
13. Fire-resisting partition: An internal non load bearing vertical dividing
structure designed to resist the spread of fire, heat, and the products of
combustion for a stipulated period of time. Such a partition can include a
glazed section or a fire door.
Fire-resisting suspended ceiling: A suspended ceiling designed to
contribute to the overall fire resistance of a floor assembly or to prevent the
collapse of steel beams supporting a floor or roof, for a stipulated period of
time. It may also provide fire resistance as a membrane in the same way as
a partition.
14. Fire-stopping: Sealing products that take up imperfections of fit or design
tolerance between the fire resisting fixed elements of a building to restrict
the passage of fire and smoke. They continue to take up the imperfections
of fit at all times and have the same fire rating as the fixed elements of
which they form a part. In reaction to a fire condition they swell, spread or
deform to achieve their performance.
Fire-resisting luminaire: Lighting structure or fitting for suspended ceilings
designed to resist the spread of fire and the products of combustion for a
stipulated period of time. It is required to be tested for integrity when fitted
to an individual manufacturer’s suspended ceiling.
.