|
V. A. Voitovich, Nizhny Novgorod State Architectural and Construction University (NNGASU)
Journal "Industrial Painting", 3 / 2004 June In the chronicle of incidents in recent years, fire starts to take an increasingly prominent place. At the international symposium in Zurich had been noted that fires becoming one of the main dangers of mankind. Currently, the annual number of victims of fires around the world comes to tens of thousands, the number of injured – to hundreds of thousands of people, and billions of dollars of material losses.
Every hour on the planet about six fires erupts, every sixth of them is accompanied by destruction and for each the one who died, there are on average, 30 people injured and burned. In Russia in recent years there have been about 50 fires per day. For 9 months of 2003 in our country 121,432 fires had been recorded. They killed 13,378 people, including 562 children, and injured 10,421 people. Direct material damage amounted to 3,115 million rubles. It should be noted, that not every fire had been recorded.
The increasing frequency and intensity of fires, the increasing of material damage caused by them, the death and injury to people forced to seek new ways to prevent this disaster. One of them - the use of fire retardant paints. World experience shows that presently on a combination of factors the most effective means of protection from fire is usage of coatings that can distend (foam, intumescent) under the action of fire or heat stroke and increase in volume tenfold. Foam, forming at the same time, should be nonflammable, have low thermal conductivity, and held on the substrate during a given time. Coatings that meet these requirements are called intumescingpaint, although the swelling is the property of the coating, rather than paint. The main elements of buildings, ensuring their performance, include:
- Supporting and enclosing structures
- Glazing
- Electrical
- Water and gas
- Air ducts and air-conditioning systems
These elements differ primarily in the materials of which they are made, in the behavior prompt by fire or heat shock and several other features. Hence, from the same intumescing paint one cannot expect fitness for fire protection of all elements of the building. Therefore it is necessary to develop the intumescing paint for structural steel, designs of reinforced concrete, structures made of wood, glass, electrical, plumbing, pipeline, ventilation systems. Of course, some intumescing paints are suitable for fire resistance of several building elements, such as mentioned above.
Below we consider the specific types of intumescing paint noting in advance that some understatement in describing recipes of intumescing paint and properties of covers is not associated with the negligence of the author, but with the refusal of manufacturers to provide the necessary data because of the notorious trade secrets, which are often the open secrets. Intumescing paint for fire protection of structural steel building structures. General requirements for fire-retardant materials intended for structural steel building structures are described in standards for fire safety (Fire 236-97), "Flame Retardants for steel structures. Method for determining the fire-resistance rating”. In accordance with the coating of steel constructions there are six groups of fire-resistance rating determined by time from the beginning of the high temperature to achieving by surface of temperature of 500 ° C. For the first group performance, this interval is 150, the second - 120, third - 90, fourth - 60, fifth - 45, sixth - 30 min. At the present time for protection of the steel constructions is recommended to use two types of flame retardant materials.
One of them is a composition based on mineral binders; usually they are portland cement, gypsum plaster, phosphate, sodium silicate, filled with asbestos, expanded perlite or vermiculite with sand. These compositions are applied to the steel structure layer, the thickness of which is determined by the required time of fire retardant efficiency. The thicker the layer, the longer the time of steel constructions is protected from heating to 500 ° C. However, these materials much weight the construction.
The second type of flame retardant materials is swell paints. Despite the fact that their range is extremely limited in recent years materials of this type are preferred.
Paint "Ecran-M» is one of the first swelling paints, developed in the USSR. It is outworked to impart steel construction a fire resistance of 50 min. Covers based on it can be operated only in the indoor relative humidity below 80%. Comes in two packages. One package contains sodium silicate, in the other is a mixture of urea resins with dicyandiamide, zinc oxide, expanded perlite sand. The contents of both packages are mixing immediately before application."Ecran-M" is applied to the clean steel surface or surfaces treated with primer rust converter WA-BA-01 GISI. Apparently, the material can be applied also after treatment with other rust converters, but the official recommendations include only this primer. At the rate of 5 kg/m2 paint provides the thickness of coating 3,0 - 3,5 mm.
Mastic VPM-2 is a two packages system designed to endow the steal construction with a fire resistance equal to 45 minutes. In one package is a mixture of urea resin with melem, sodium salt carboxymethyl cellulose, dicyandiamide, in another is a mixture of coarse homopolymer polyvinyl acetate dispersion with ammonium polyphosphate, chrysotile asbestos and chopped fiberglass. The contents of packages are mixing before use.
Production of VPM-2 stopped due to the fact that the earthquake in Armenia (1988) destroyed the manufacture of Melem, and after the collapse of Soviet Union, the producers of coarse homopolymer polyvinyl acetate dispersion practically disappeared on the territory of Russia. Currently coarse homopolymer polyvinyl acetate dispersion in Russia is produced in quantities to meet any needs, and instead of Melem (its production in Russia is still available) the graphite bisulfate can be successfully used [3]. Along with this, instead of coarse homopolymer polyvinyl acetate dispersion in the composition of the intumescensent paints is permissible to use copolymer ones, covering of which can be operated in atmospheric conditions. Using these two facts, it should be necessary to restore the production of mastic VMP-2, being well-established earlier.
Water-dispersion paste Ograks-B-SC is designed to impart steel constructions a fire resistance equal to 30 minutes at a thickness of cover 0.6 mm, and 1.0 mm for 45 minutes. For the formation of porous silicon such thickness of ink should be 1.1 and 1.86 kg/m2, respectively. Operating of cover can be performed only indoors. Manufacturer of material - SPE “Unihimtek”.
Fire-retardant paste "Terma" (TU 2332-003-47935838-99) is designed to impart fire resistance of steel constructions for 30 minutes at a thickness of cover 2.6 mm. Consumption of pasta, ensuring receipt of cover of such thickness is 4 kg/m2. Paste is applied with a spatula at ambient temperature and temperature of the substrate not less than 5 ° C and the relative humidity of 80%. Covers can be operated in atmospheric conditions. Approximate duration of fire resistance is 5 years. Pasta is related to the 4th class of hazard. Manufacturer - SIC S and PB.
Fire retardant paint HPR-2 is designed to impart fire resistance in 60 minutes at a thickness of covering 1.0 mm, at a thickness of 1.1 mm -70 minutes. To obtain the cover of such thickness 1.8 and 2 kg / m 2 must be applied, respectively. The paint can be applied only to steel products, primed with UHRA-1503, GF-021 or similar. It is allowed to dilute paint to the desired viscosity of tap water. Paint HPR-2 is applied by brush, trowel, airless spray equipment “Wagner-7000" Ultrimaks 1095. Coloring can be done only at a temperature above 5 ° C, drying time of cover at 20 ° C is no more than 6 hours, Manufacturer - LLC Neohim.
Paint VD-AK-511 forms a cover with thickness of 1,8 - 2,0 mm, providing fire resistance to 0,75 pm. The paint is applied in 5 - 6 layers with a total consumption of 2.9 - 3.0 kg/m2. Manufacturer - CC "SPE Yarli”.
Intumescing paint for fire protection of concrete and reinforced concrete structures During a fire, the brittle fracture of concrete is possible. It starts, usually within 5-20 min from the beginning of fire exposure and comes out as a spalling from the heated surface area of hearth plugs with space to 1 m2 and a thickness of 5 cm. Brittle fracture is accompanied by a bang, with the possible spreading chunks of concrete weighing up to several kilograms to the distance up to 20 m [4].
There are few causes of brittle fracture of concrete. When the temperature reaches 250 ° C, dehydration of minerals forming the cement matrix begins, which leads to a decrease in strength. With increasing of temperature to 600 ° C the dissociation of oxide minerals starts, which further softens the cement stone. When heated, the amorphous part of the cement shrinks, while the crystalline formations and non hydrated cement grains increase in volume. Finally, when heated, the stresses appear caused by differences in thermal expansion coefficients of cement matrix and aggregates.
To protect reinforced concrete the same paints fit as for steel concrete, in particular, as described above. Intumescing paint for fire protection of load-bearing structures of wood Although wood is a combustible material, flammable and quickly spreading fire, wooden structures, particularly of large cross section, can maintain the carrying capacity for a longer time than steel or concrete. This is explained by the fact that on the surface of wood combustion, a layer of coal appears, wich is a kind of expanded cover, inhibiting burning.
To improve the fire resistance of wooden structures is possible, in particular, with the help of the above-described fire retardant cover. But there are covers recommended for staining only the wood. In addition, wood products are painted with special varnishes, preserving the wood texture and form on a substrate a transparent cover, protecting the wood from burning and flame propagation.
Currently, timber is being protected from burning mostly by fire retardants, with aqueous solutions of which semi-finished wood (logs, boards) are impregnated at a certain depth. However, this article deals only with covers, designed specifically for staining wood.
Requirements for materials intended for fire protection of wood are presented in standards for fire safety (Fire 251-98) "flame retardants and agentss for wood based materials. General requirements. Test methods. "
Intumescing fire-resistant coating VPD. It was, apparently, the first intumescing paint for wood in the Soviet Union. Film binder it is a melamine-urea resin MMF-50 in a mixture with sodium carboxymethyl cellulose [5]. Now, this intumescing paint is not produced.
Fire-resistant coating "OVPF-1 (TU-2311-005-47935838-99 as amended, № 1) was designed to protect wooden structures being operated indoors. Provides fire retardant efficiency of the Group 1, the estimated lifetime is 10 years. Covers along with fire retardant possess biocidal properties, and refers to the 4th class of hazard of human exposure. Material is supplied in two packages (base and hardener), being mixed immediately before use at a ratio of 100:3. The temperature during mixing and curing should be at least 5 ° C, relative humidity - less than 80%. To ensure the 1st fire retardant efficiency, thickness of cover must be 2 mm. Apply the paint with a trowel or spray gun. Manufacturer - SIC C, and SDS.
Fire retardant paint "Terma" provides the 1st fire retardant efficiency. After drying, white cover with good decorative properties forms. It can also be used for fire protection of steel concrete constructions. Manufacturer - SIC C IBT - other data on this paint are not published.
Fire-retardant paint OZK-45D (TU 2316-019-17297211-01) is designed to protect wood products, being operated both indoors and in weather conditions, but under a canopy. Paint UGC-45D in the packaging is fire and explosion proof and nontoxic. Provides the 1st fire retardant efficiency of received covers. Approximate life of the cover is at least 5 years. Apply of the paint should be in two coats by brush, roller or spray, and the second layer is applied to the first no earlier than on next day, provided that the temperature during this time is a room temperature. Permissible the dilution of paint with water. Maximum swelling of cover, forming by this paint, is at 800 ° C, and the coefficient of swelling in this case reaches 15. Producer - "Research and Production Laboratory 38080”.
Fire-retardant white paint VUP-2D (TU 2316-004-48357289-2002), is intended to protect wood products being operated indoors. Provides cover of the 1st fire retardant efficiency. Covers based on it have high adhesion, impact resistance, elasticity. Allowed to wet cleaning. Paint consumption for a given fire retardant efficiency is 0,25 kg/m2. Time of drying at (20 ± 2) ° C is no more than 4 hours. Manufacturer - NGO Neohim.
Varnish OZP-D at the rate of 1.6 kg/m2 forms a transparent gloss cover 1,5 mm thick, of the 1st fire retardant efficiency. Manufacturer - LTD TIM-SPHERE.
Fire retardant varnish SF (TU 2311-007-47935838-2000) is designed for wood. Provides cover of the 1st fire retardant efficiency with the approximate life of up to 5 years. Varnish is a two packages system consisting of a liquid foundation and powder hardener. Before using the curing agent is being dissolved in water at a ratio of 15:85 and the resulting solution is mixed with a basis in the ratio 2:10. Varnish applied by brush, roller or spray on the wood, primed with the special primer that comes in set. Primer consumption is 40 g/m2, lacquer consumption is 300 g/m2. Intumescing paints for fire protection of cables Electrical harness, especially power cables, is often the cause of fires due to overloads and short circuits. Therefore, they are also stained with the intumescing paints in accordance with the NPB 238-97 "Fire-proof cable coatings. General technical requirements and test methods" (as amended. № 1,2000). Below is information on the specific intumescing paints for cables.
Water-based fire retardant paint VUP-2K (TU 2316-003-48357289-2002) is intended to provide a protective covers to the cable lines formed by the power and control cables and communication cables. Cover is elastic, exhibits the high adhesion to a variety of cables, except for oil-filled, water-resistant (allowed to wet cleaning). Limit the spread of burning is no more than 1,5 m, the thickness of the cover must be not less than 0,6 mm, which provides the consumption of paint 1.2 kg/m2. Paint can be applied at temperatures over 10oC, drying time at the temperature (20 ± 2) ° C for no more than 6 hours. Cover color is determined by the order. Manufacturer - NGO Neohim.
Flame retardant "PC-Term" (TU 2332-013-47935838-2000) is designed to handle cables, wire and cable lines, cable bulkheads. There are produced types A for cable bulkheads and B - for other purposes specified above. Approximate duration of fire protection - up to 15 years. The composition is supplied in two packages system: in one package is the powder, the liquid in the other. The contents of packages are mixed immediately before use at a ratio of 40:60 to 50:50 type A and type B. Finished product is applied with a spatula or a mechanized way with a minimum air temperature 5oC and relative humidity not above than 80%. The thickness of the cover must be no less than 1.2 mm at a flow rate of 2.5 kg/m2.
Flame retardant PK (TU 2329-009-47935838-2000) is designed to handle cables, wire and cable lines, and cable barriers. Validity of fire protection is up to 5 years. Two packaged composition consists of the dry component and the film-forming. Before use, they are being mixed in a ratio of 44:56. The composition is applied by brush, spatula or mechanized methods with a minimum air temperature 5oC and relative humidity no more than 80%, in two layers at a rate of 2.5 kg/m2 Manufacturer - NITsSiPB.
Fire-retardant paint TC-1 – is a water-borne paint, the cover on which base with thickness 0,8 mm provides requirements NPB 238-97 and can be operated in high humidity conditions for unlimited time without loss of flame retardant properties.
Proterm CE is designed for cable communications. With a thickness of cover only 0.5 mm, the reduction factor of long current load is equal to 1. By the expert opinion of RAO UES of Russia, this VC is recommended for use in power plants. Manufacturer - PTC "A +".
Flame retardant TOZ-B1 (TU 5767-001-51954575-01) is designed for painting indoors. Producer is OOO Neohim.
The composition Endotherm XT-I50 consists of two packages, one of them contains a solution of chlorosulfonated polyethylene in the solvent, and another - sloughing graphite, flame retardants and mineral fillers. Pot life of solution is about 48 hours. Cover forming by this paint has high elasticity (elongation at break is 12 mm) and adhesion in polyvinyl fluoride, polyethylene, rubber, ie, the materials of construction for cable sheathing. Recommended consumption - 2,2-2,5 l / m 2, cover is forming the thickness of (1,5 ± 0,5) mm, providing flame retardance, corresponding to category A in accordance with GOST 12176-89 (IEC 332.4.3). Staining by this paint can be executedat a temperature of -10 to 50oC. Drying time at 20 ° C. is no more than 18 hours.
Endotherm HT-150 can be used for fire protection of steel concrete structures, providing the fire resistance of cover 1 hr for wooden, concrete structures, ventilation ducts, cables, plastic products.
Paste Ograks-B1 (TU 57-28-002-13267785-2001) is designed to protect from fire cables located on the premises. It is applied by brush, roller or airless spray in an amount of 0.96 kg/m2, which ensures formation of porous silicon thickness of 0.5 mm. Paste does not contain organic solvents, which allows to use it in unventilated spaces. After heating up to 230-250oC cover swells and its thickness increases tenfold. Cover has good adhesion and flexibility.
Ograks-V (W 5728-005-13267785-2002) is similar to the Ograks-B1, but the recommended thickness of cover is 0,8 mm.
Ograks-BB (TU 5728-026-13267785-2003) is made for protection of cable from fire in the open air and in wet areas. Properties of cover formed by this paint are like emerging from the paste Ograks-B.
One of the elements of the building is drifting through the walls. They must be designed so that cable can be freely passing through them under the normal conditions. During a fire, they must tightly shut fire way. To ensure such requirements, mastics PPV and PP-VN are proposed, which swell during the fire.
Producer - "Research and Production Laboratory 38080”.
Intumescing paints for fire protection, air ducts and air conditioning systems Flame retardant Firex-300 is applied together with a reinforcing layer of special fabrics. Provides fire resistance to 1, 5 h. The composition is based on the inorganic film-formers. Cover, which is formed out of it, is intended for use indoors. Swells under the temperature 120oC. Producer - "The Association Krilak”.
Fire retardant coating OFP-NV («KRAT») increases the fire resistance up to 2.5 hours Manufacturer – “Association Krilak”.
Intumescing paint intended for fire protection of roofs Roofing covers on most of the industrial and residential buildings are made of combustible bituminous materials. Such roofs are usually being protected against fire by the application of intumescing paints to the entire area, or only on their parts - so-called fire-zones, cutting the moving flame.
The entire roof is being painted with fireproof paint composition HT-8000. It raises fireproofing and as well waterproofing properties. When using it, the need for gravel packing material of the roof and applying reflective layer eliminates. The cover of this compound combines high flame-retarding properties (flammability class G-1, the spread of flame - Class RP 1) with water-and weather resistance (longevity in the U-1 over 20 years), good adhesion to various materials. Therefore, it is recommended for fire protection of steel, concrete and wooden structures.
Getting into the zone of fire, cover of this composition at 400oC increases in volume by 20 times.
It is recommended to prime bituminous roofing covers with the composition of HT-7000, before staining by HT-8000. Formulations of HT-7000 and HT-8000 are both supplied in two packages. The contents of packages are being mixed immediately before use. Consumption of both formulations - to 20 kg/m2. Manufacturer - ZAO “Soyuzspets-isolation"
Fire retardant roofing mastic OMC (TU 5775-002-47935838-99) of gray color is intended to fulfill the fire zones. It is applied in 2-3 layers, so that the total amount of paint was not less than 5.6 kg/m2.
At the same time cover is forming with thickness of 3 -4 mm. Application of the paste is recommended only at temperatures above 5oC and relative humidity of not more than 85%. According to the degree of human exposure related to 3-hazard class. Intumescing paint for fire protection of window openings Silicate glass is currently the main material for filling window openings, non-flammable. However, it is unstable to the fire and heat strokes. In case of fire glass is the most rapidly destructive of fencing elements. It is therefore surprising that almost nobody pays attention to increasing of fire resistance of glass fences. Among domestic paints there is no one designed for glass. There are no fire safety regulations for fire retardant materials that element fence. Abroad paints for fire protection of silicate glasses are already being produced. REFERENCES 1. Fire safety. 2003. № 3. P. 73.
2. Strakhov V. L. Fire protection of building structures, Ed. Y. A. Koshmarova. M.: Information and Publishing Center "Timra”, 2000. 443 p.
3. Romanenkov I. G. , Lewites F. A. Fire protection of building structures. M: Stroiizdat 1991.320 p.
4. Recommendations for the protection of concrete and reinforced concrete structures from brittle fracture at a fire / Institute of concrete and reinforced concrete. MM: Stroyizdat, 1979. 21 p.
5. Ways and means of fire protection of timber (the Guidelines). M.: Izd-Union Scientific Research Institute of Fire Defense, 1985. 57 p.
6. Saint-Petersburg constructive market. 2004. № 1-2. P. 46. |
|
