Spread of flames

Edwards, K. L. and Norris, M. J. 1999. Materials and Constructions Used m Devices to Prevent the Spread of Flames m Pipelines and Vessels. Materials and Design, 20(5), 245-252. 

Fire safety Class P not easily ignitable to BS 476 Part 5. Can achieve Class 1 surface spread of flame to BS 476 Part 7 when faced with aluminum foil. 

Traps should also be installed in plant ditches to prevent the spread of flame. These are normally liquid U-legs, which block the spread of flammable liquid along ditches. 

A description is given of the initiatives carried out within the European Community for the harmonization of fire testing. The technical and economic reasons are explained for such initiatives, which are taken in order to remove barriers to trade from the European internal market. Of the various fire aspects, only fire reaction testing is taken into consideration here, because it appears as a major technical obstacle to the free circulation of construction materials. All possible approaches are considered for the attainment of such a harmonization and one, the so called interim solution, is fully described. The proposed interim solution, is based on the adoption of three fundamental test methods, i.e. the British "Surface Spread of Flame", the French "Epiradiateur" and the German "Brandschacht", and on the use of a rather complicated "transposition document", which should allow to derive most of the national classifications from the three test package. 

British "Surface Spread of Flame" BS 476 Part. 7 (Figure 3)... 

The number of small scale test methods, used for classification purposes, should be limited and based on ISO tests, presumably the Cone Calorimeter /10/ (see Fig. 8) and possibly the ISO Surface Spread of Flame test /11/. 

In addition the room-corridor scenario will also be investigated in full scale and attempts made to seek correlations with the Cone Calorimeter and the ISO spread of flame test. 

Surface spread of flame test. The 13 materials listed in Table I were tested in the IMO and ISO surface spread of flame tests. 

Table I. Results from the Surface Spread of Flame Test and the Cone Calorimeter... 

Figure 1. Surface spread of flame test for particle board.

Tested According to ISO and IMO Spread of Flame Tests", SP-RAPP 1984 36, Swedish National Testing Institute, Boris, 1984. 

Fire Retardent Paints. Fire retardant paints are based on chlorinated rubber and chlorinated plasticizers with added SbO. These reduce the rate of spread of flames. Addn of NH4H2PO4, PE, or dicyandiamide produces an intumescent or swelling paint that forms a thick insulating layer over the surface to which it is applied when exposed to flames Fire retardant paints do not control fires and are no substitute for an automatic sprinkler system. They are best used where the only hazard is exposed, combustible, interior finish materials or in isolated buildings where sprinklers will not be installed. The paint must be applied at the rate specified on the container if spread thinner the proper... 

Test samples are preconditioned in a specified atmosphere before exposure, and the test flame exposure is continued for 10 minutes unless the sample is completely consumed before that time. Observations of the spread of flame are made at 15-second intervals during the test. If the flame spread reaches only part of the distance between the end of the test flame and the end of the sample, the percentage of the distance traveled establishes the classification. If the flame spread reaches the end of the tunnel, the percentage of the time required against the time for the red oak... 

This is rather bulky test setup, but it seems to be a realistic approach to the problem of observing what happens to exposed materials when a fire starts somewhere in the room. The extent of spread of flame beyond the test flame area is observed, and the thermocouple readings indicate the potential life hazard from breathing in the atmosphere in the test room. Perhaps the dimensions of the test room could be reduced and thus bring about the installation of this type of equipment at other laboratories. 

At this point a differentiation should be made between a nonflammable and a fire-retardant film. On the one hand, the coating is designed to be applied on a nonflammable substrate and, in this case, the film itself should be as near nonflammable as possible. On the other hand, a fire-retardant film is designed to retard the spread of flame through a flammable substrate. Most commercial paints are fire-retardant to a degree an unpainted wood or wall board surface will burn much more freely if unpainted than if coated with an ordinary flat wall paint such as TT-P-47. There has been a widespread misconception that the dried paint film is a fire hazard, when actually a wood or cellulosic wallboard surface is considerably more readily combustible uncoated than when coated with the average wali paint. 

Filler, inert Flame retardant A filler having no reinforcing effect. An added substance that inhibits the initiation and/or spread of flame and/or amount of smoke generated during combustion. 

Critical flux is defined as the radiant flux at which the flame extinguishes or the radiant flux after a test period of 30 min, whichever is the lower (i.e., the flux corresponding with the furthest extent of spread of flame). 

Melamine-formaldehyde resins are inherently flame-retardant and normally, when bonded to chipboard, to plywood, or MDF, HGS and VGS laminates will achieve Class 2 in the spread of flame test (BS 476 Part 76). 

BS 476 Part 7 1987 Fire tests on building materials and structures Method for classification of the surface spread of flame of products. 

Imprecise concepts are also helpful for describing the spread of flames in the gas phase, through condensed-phase fuels. A general approach, applicable in complex configurations, is first to identify a surface of fuel involvement that encloses the fuel. This surface, which flames approach at some... 

In contrast to downward spread, upward spread of flames along vertical fuel surfaces usually is acceleratory. Rates of heat transfer to the fuel by radiation and conduction from the luminous flames of height /, that bathe the surface are so great that, in comparison, transfer elsewhere can be neglected in the first approximation. If q is the average normal energy flux from these flames to the surface, then from geometric considerations, q — (l/L)q for the q in equation (67), where L is the thickness of the fuel... 

Additional physical phenomena influence rates of horizontal spread of flames over surfaces of liquid fuels [111]-[120]. If the equilibrium vapor pressure of the liquid fuel at its initial temperature is high enough for the fuel concentration in the gas mixture at the liquid surface to lie above the lower flammability limit, then premixed flame propagation occurs in the gas above the liquid, and flame spread is rapid. If the liquid is cold and... 

Boron compounds can be added in combination with other chemicals such as nitrogen and phosphorus. A solution containing sodium tripolyphosphate, boric acid, and ammonia provides a ready-to-use treatment on cellulose products such as plywood, fiberboard, and cardboard (87). The resulting products passed the British Standard 476, Section 6 (Fire Propagation test) Class 0 and Class I requirements of the British Standard Section 7 (Surface Spread of Flame). 

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