Fire retardant formulations

The molten salts quickly dissolve the metal oxides at high temperatures to form a clean metal surface. Other uses are as catalysts and in fire-retardant formulations (see Flame retardants). 

Another problem occurs when some fire retardant formulations ate exposed to elevated temperatures (eg, when used as roof tmsses or as roof sheathing) thermal-induced strength reductions can occur in-service. The thermo-chemical factors were discussed by LeVan and Winandy (26), and a kinetic degrade model was developed (27). The treater should be consulted to obtain appropriate in-service modifications for specific fire retardant treatments. 

Solutions of these fire retardant formulations are impregnated into wood under fliU cell pressure treatment to obtain dry chemical retentions of 65 to 95 kg/m this type of treatment greatly reduces flame-spread and afterglow. These effects are the result of changed thermal decomposition reactions that favor production of carbon dioxide and water (vapor) as opposed to more flammable components (55). Char oxidation (glowing or smoldering) is also inhibited. 

Chromium compounds are also used ia fire-retardant formulations where their function is to prevent leaching of the fire retardant from the wood and corrosion of the equipment employed. 

M. LeBras., Mineral fillers in intumescent fire retardant formulations - Criteria for the choice of a natural clay filler for the ammonium polyphosphate/pentaeythritol/polypropylene system, Fire and Materials, vol. 20, pp. 39-49,1996. 

Currently in our laboratories we are exploring the role of anion structure and packing as well as intrastructural metal ion composition of these potential components of fire retardant formulations, as well as investigating LDHs for this purpose. The focus of this report is on evaluation of the effects of a zinc/copper HDS on thermal stability and flammability of low density poly(ethylene). 

Most of the chemicals used in fire-retardant formulations have a long history of use for this purpose, and most formulations are based on empirical investigations for best overall performance. These chemicals include the phosphates, some nitrogen compounds, some borates, silicates, and more recently, amino-resins. These compounds reduce the flame spread of wood but have diverse effects on strength, hygroscopicity, durability, machinability, toxicity, gluability, and paintability (J, 12, 13). 

Smoke Production. Smoke production can be a critical problem in fire-retardant formulations. The 25-ft tunnel test uses a photoelectric cell to measure the amount of smoke evolved. The smoke density is measured continuously and is assigned a value relative to the behavior of red oak. The effect of fire retardants on smoke production varies depending on the chemical. Figure 6 demonstrates this effect as measured in the 8-ft tunnel however, smoke values measured in various tunnel tests may not agree or correlate. 

Most fire-retardant formulations are not resistant to leaching by water. Therefore, there have been increased efforts to develop leach-resistant chemicals that can be impregnated into wood products for use in exterior or high humidity applications. Some of the proposed leach-resistant systems include chemical combinations that form insoluble complexes, amino-resin systems, and monomers that polymerize in the wood. 

Formulations. Fire-retardant formulations are numerous, although most of them are based on the inorganic salts, such as diammonium phosphates. Increased emphasis on improving the related wood properties associated with fire retardants has led to many interesting and creative formulations and processes. 

Electrostatic applications and fire retarding formulations have yet to become the major focus in these apphcations. Only in the USA and Canada is a specific fire rating a requirement. In Europe, fire is still mostly prevented by the design of the electrical circuitry rather than the plastic design. Only in some applications, close to the source of possible fire ignition are some flame retarded plastics used. 

Bhatnagar, V. M. Fire Retardant Formulation Handbook, Technomic Publishing Co., Inc., Westport 1972... 

Some types of polymers are not yet available commercially as fire retardant formulations. Their fire retardant characteristics are given in Table 6.9. 

The incorporation of a reinforcing agent such as glass fibres into a non-fire retardant or a fire retardant formulation might also have an effect on polymer properties as discussed next. 

Le Bras, M. Bourbigot, S. Mineral AUcts in intumescent fire retardant formulations criteria for the choice of a natural clay, filler for the ammonium polyphos-phate/pentaerythritol. Fire Mater. 1996, 20, 39-49. 

Rubber systems normally include a processing oil which provides a variety of benefits. Among them is reduced cost. In the fire-retarded formulation, the oil is a chlorinated paraffin (40% chlorine). The oil aids in making the rubber resilient, tough, and compatible with the filler. 

Lower cost general purpose bagasse-rubber composite formulations are identical to those for the fire-retarded formulation, except that a non-chlorinated rubber processing oil (e.g., Sun-dex 790) is substituted for the chlorinated paraffin oil, no... 

An tinique sine tx>rate combining the optimum effects of zinc and boron oxides and water release for developing fire retardant formulations processable up to 290C. 

The American Wood-Preservers Association Standards specified the four types of fire-retardant formulations given below (A, B, C, D). Many newer formulations have been developed by commercial enterprises and are proprietary. 

Experience has indicated that Busan 11-Ml can replace antimony trioxide in most fire retardant formulations. Subject to the degree of halogenation and the degree of fire resistance required. Replacement can be 50 to 100%. 

---