Fireproofing is rendering something proof against fire, or incombustible; or
material for use in making anything fire-proof. It is a passive fire
protection measure. "Fireproof" or "fireproofing" can be used as a noun,
verb or adjective; it may be hyphenated. Applying a certification listed
fireproofing system to certain structures allows them to have a
fire-resistance rating. The term "fireproofing" may be used in
conjunction with standards, as reflected in common North American construction
specifications. An item classed as fireproof is resistant in specified
circumstances, and may burn or be rendered inoperable by fire exceeding
the intensity or duration that it is designed to withstand.
Markets Commercial construction
Residential construction Industrial construction
Marine Offshore construction
Aerodynamics Tunnel concrete walls and ceilings or
linings Under and above ground mining operations
Patrick Cabacungan Applications
Structural steel to keep below critical temperature ca. 540 °C
Electrical circuits to keep critical electrical circuits below 140 °C so they
stay operational Liquified petroleum gas containers to
prevent a BLEVE 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
History Asbestos was one material historically
used for fireproofing, either on its own, or together with binders such as
cement, either in sprayed form or in pressed sheets, or as additives to a
variety of materials and products, including fabrics for protective
clothing and building materials. Because the material was later proven to cause
cancer in the long run, a large removal and replacement industry has been
established. Endothermic materials have also been
used to a large extent and are still in use today, such as gypsum, concrete and
other cementitious products. More highly evolved versions of these are used in
aerodynamics, intercontinental ballistic missiles and re-entry vehicles, such as
the space shuttles. The use of these older materials has
been standardised in "old" systems, such as those listed in BS476, DIN4102 and
the National Building Code of Canada. 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 "cementitious", 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 solids, 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 combustibility rating as per DIN4102. Fibrous plasters, containing
either mineral 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 architects'
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 protection 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 reinforced 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. This method was patented in the 19th century
although the first prominent example was 89 years later.
Substandard fireproofing Money can be saved fraudulently by using
apparently suitable fireproofing that is not built to the required standard. Such
fraud can be prevented when documentation is required and checked to
ensure that all installed configurations meet the certification standards.
Possible cases include: Entraining too much air in inorganic
systems, thus reducing densities below fire-tested, saving on materials and
labour. Spraying inorganic fireproofing
materials over through-penetrations and building joints that should be
firestopped, not fireproofed. This practice negates fire-separation
integrity. Firestops must precede spray fireproofing.
Substitution of intumescent and/or endothermic fireproofing coatings by
less expensive paints of similar appearance, sometimes in the packaging
of the correct materials. 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, requiring 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. As of 2014 certification of
fireproofing and firestopping remained optional for systems installed in
nuclear power plants in Canada and the United States.
Reuse of older materials from demolished buildings, in newer buildings.
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 building
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, liquefied petroleum gas and other hydrocarbons, which are known to
cause a very rapid temperature rise and high ultimate temperatures in case of a
fire. Where hydrocarbon transports are permitted in tunnel construction 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 cannot by itself withstand severe hydrocarbon fires. In the Channel
tunnel that connects the United Kingdom and France, an intense fire broke out
and reduced the concrete lining in the undersea tunnel down to about 50 mm. 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 generates pressure high enough
to spall off the concrete, which falls in small pieces on the floor of the
tunnel. Humidity probes are inserted into all concrete slabs that undergo
fire testing to test for this, even for the less severe building elements curve.
The need for fireproofing was demonstrated, among other fire
protection measures, in the European "Eureka" Fire Tunnel Research Project,
which gave rise to in building codes for the trade to avoid the effects of such
fires upon traffic tunnels. Cementitious spray fireproofing must be certification
listed and applied in the field as per that listing, using a hydrocarbon fire
test curve such as the one used in UL1709.
Fireproof vaults Fireproof vaults to protect important
paper documents are usually built using concrete or masonry blocks as the
primary building material. In the event of a fire, the chemically-bound water
within the concrete or masonry blocks is forced into the vault chamber as steam,
which soaks the paper documents to keep them from igniting. This steam also
helps keep the temperature inside the vault chamber below the critical 176.7
°C threshold, which is the point at which information on paper documents is
destroyed. The paper can later be remediated with a freeze drying process,
if the fire is extinguished before internal temperatures exceed 176.7 °C.
An alternate less expensive and time-consuming construction method is
using dry insulating material. This vault construction method is
sufficient for paper documents, but the steam generated by concrete and masonry
structures will destroy contents that are more sensitive to heat and moisture.
For example, information on microfilm is destroyed at 65.5 °C and magnetic media
lose data above 51.7 °C. Fireproof vaults built to meet the more stringent
Class 125 requirement are called data-rated vaults.
All components of fireproof vaults must meet the fire protection rating of the
vault itself, including doors, HVAC penetrations and cable penetrations.
See also References
External links NFPA Standards
Fire Protection Materials and Methods