Fire Retardant and Resistant Paint and Coatings
- 18 June 2018
- Posted by: Stm Coatech
- Category: Educational Articles
Günümüzde çoğu bina ve yapıların bir dereceye kadar yangın koruması vardır. Yaşamları korumak, tahliyeye olanak tanıyan olası yapısal çöküşü geciktirmek, alanları sağlamak Yangın durumunda geçici sığınak, ve kaçış yolları bütünlüğünü sağlamak Bir yangının tırmanmasını önleme veya geciktirme ve yüksek değerli varlıkları koruma.
FIRE PROTECTION KINDS
Today most buildings and structures have some degree of fire protection in order to protect lives, delay possible structural collapse allowing for evacuation, provide areas of temporary refuge in the case of fire, and ensure the integrity of escape routes by preventing or delaying the escalation of a fire and protect high-value assets.
There are two basic types of fire protection: active and passive.
Active fire protection includes alarms and detection systems, sprinklers and water deluge systems, firefighting equipment and foam and powder extinguishers. Passive fire protection involves components of structural methods and materials such as concrete, mineral fiber boards, vermiculite cements and intumescent coatings.
A BRIEF HISTORY OF FIREPROOFING STEEL
Different techniques for fireproofing steel have come and gone. Dense concrete was the method of choice for most processing facilities built prior to World War II. Heavy concrete was applied to structural steel (which had to be over-specified to accommodate the additional weight) because concrete was known to be inexpensive and to withstand extremely high temperatures well.
Eventually, lightweight cementitious coatings were developed to address the problem of weight. These fireproofing materials are also inexpensive, but they also share many issues with the original dense concrete method. Cement-based coatings have a tendency to crack during cooling. So when cementitious coatings are exposed to a fire event, they tend to lose significant strength and stability in the aftermath. These fireproofing methods are also extremely labor intensive. After a certain point, cost savings from inexpensive materials were canceled out by rising labor costs, so other options had to be developed.
Intumescent coatings are now the preferred method for fireproofing steel. Known as reactive fireproofing coatings, these work by foaming up, or intumescing, when exposed to extreme heat. This expansion forms a high-volume, low-density barrier against the transfer of heat to the substrate. The result is a drastic increase in the amount of time it takes for the fire to compromise the integrity of the structural steel.
Intumescent coatings work by charring and expanding in the presence of extreme heat. The increase in volume and subsequent decrease in density slows the heating of the substrate, increasing the time before the steel itself begins to melt. Intumescents typically swell to 25 times their original thickness when engulfed in flames. This expansion allows them to provide a barrier between the flames and the steel that is exponentially larger than a coating that does not swell.
Adding thickness to an intumescent coating application increases the amount of swelling that will occur in the case of a fire incident. For example, if a 350 mil coating of a given intumescent has been determined to have a fire rating of 1.5 hours, 700 mils would theoretically be necessary to achieve a fire rating of 3 hours. In reality, though, added thickness is sometimes specified in certain areas such as curves and crevices, so something like a thickness of 750 mils may be required in order to achieve a 3-hour rating.
When intumescent coatings come in single-component formulas, they are much simpler to apply than dense concrete and lightweight cementitious coatings and are therefore accompanied by far lower labor costs.
Additionally, since they are applied directly to steel, no gap is created in which moisture can sit and incite corrosion. Intumescent coatings fight corrosion in much the same way as traditional protective coatings, the difference being their ability to swell and the much greater thicknesses at which they are initially applied. With all of the benefits of intumescent coatings combined, it’s our recommended method of fireproofing steel.
General composition of an intumescent coating:
1) Carbon source
2) Acid donor
3) Blowing agent
Benefits of Intumescent Fireproof Coatings:
- Fire Ratings up to 2 hours
- Meets ASTM, NFPA, and UL testing standards
- Perfect for structural steel, tanks, drywall…even wood!
- Flat white in color
- Can be top coated with paint to match surroundings
- Strong adhesion and durability
- Fast drying time
Application is quick and easy. It can be top-coated with a water-based flat or semi-gloss paint to achieve a seamless finish in any color. For existing structures which are being upgraded or repurposed, intumescent fireproofing offers a method of achieving a fire-rated assembly with minimal disruption to the existing operations.
And because the coating can be applied directly onto original surfaces, it is the perfect choice for protecting and preserving historical structures against fire damage
The image above shows typical crack formation in the fireproofing material. Cracks in the dark blue topcoat often followed cracks in the underlying fireproofing.
The project specification for the building addition required that fireproofing materials be field applied to structural steel framing members (i.e., steel columns and floor beams) that were critical to the support of the building in the event of fire.
One component, multiple coats
There are primarily two generic coating types that comprise intumescent coatings—one component acrylic/vinyl/polyvinyl acetate coatings or high-build epoxy coatings. The single component acrylic based coatings are applied in multiple coats, with the number of coats dependent on the thickness necessary for the coating to provide the required fire rating.
Since multiple coats are required, the time frame for a complete application may span several days based on the recoat time between coats. After application is completed, additional time may be needed to allow for sufficient curing of the intumescent coating layers before application of any required exterior finish coat. Finish coats may be required since the intumescent coating alone may not be suitable for prolonged exterior exposure.
Generally, the consistency of the fireproofing layer was hard and brittle, comparable to that of a thick layer of dried plaster. However, there were isolated areas where the fireproofing layer was found to be soft and pliable. In these areas the fireproofing layer could be indented with only light to moderate thumb pressure.
STM Coatech, SSPC PCI (International Coating Enspektörlüg), and Corroder (MPA Group England), Turkey, Romania, Ukraine, Georgia, Russia, Azerbaijan, Turkmenistan, Kazakhstan, Iraq, Qatar, Kuwait, Oman, the Sudan and Algeria official licensors.
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