Fire performance indexes

Note FPI, fire performance index (m2 s/kW) RHR, rate of heat release (kW/m2) SEA, smoke extinction area (m2/kg) SP, smoke parameter (MW/kg) TTI, time to ignition (s). 

ASTM E 84 Steiner tunnel test, thus generating more useful results. Figure 21.13 shows a room-comer test layout. The cone calorimeter fire-performance index (with tests conducted at 50kW/m2)179 was shown to be a good predictor of time to flashover in FAA full aircraft fires170 180 and in the ISO 9705 room-corner test.181 In addition, the same cone calorimeter tests, but using only heat release criteria, have been shown to have almost perfect predictability of ISO 9705 room-comer test rankings.181... 

Propensity of flashover The ratio of ignition time to peak rate of heat release. It is the same as fire performance index iirs/kW... 

Heat transmission rate, peak of heat transmission rate, propensity of flashover (or fire performance index) are the parameters which characterize heat generation during a fire. These parameters are affected by g]]ei-s/ o> 4,i5,23.. ,5,29 12.4 pg. 

Fire performance index (FPI) is the ratio of TTI to Peak RHR. It has been suggested that it relates to the time to flashover (or time available for escape) in a full-scale fire situation. 

Figure 13.13 Reduction in PHRR, time to ignition (/ign), fire performance indexes (FPI), and fire growth rate (FIGRA) of different PMMA, d ZnAl, and melamine compositions (P=PMMA M=melamine LDH=Zn3Al undecenoate). FPI = /,gn/PHRR and FIGRA = PHRR/time to PHRR. Reproduced with permission from Ref. [85].

Elame-spread and smoke-density values, and the less often reported fuel-contributed semiquantitive results of the ASTM E84 test and the limited oxygen index (LOI) laboratory test, are more often used to compare fire performance of ceUular plastics. AH building codes requite that ceUular plastics be protected by inner or outer sheathings or be housed in systems aH with a specified minimum total fire resistance. Absolute incombustibHity cannot be attained in practice and often is not requited. The system approach to protecting the more combustible materials affords adequate safety in the buildings by aHowing the occupant sufficient time to evacuate before combustion of the protected ceUular plastic. 

Several micron-sized layered silicates, such as talcs, can improve the fire retarding behavior of EVA by partial substitution of metal hydroxides. Clerc et al.63 have shown that better fire performance was achieved using higher values of the lamellarity index and specific surface area for four different types of talcs in MH/EVA blends. Expanded mineral and charred layers were formed, similar to intumescent compositions with APP, proving the barrier effect on mass transfer, even at the micron scale for the mineral filler. 

This chapter explains the meaning of the above statements. It describes flammability and smoke/toxic gases evolntion at burning of wood compared to wood-plastic composite (WPC) materials and products of different compositions and profiles. It also explains flammability and fire ratings and indexes as quantitative measures for fire hazard and fire safety, and fire performance characteristics in general of wood and composites. 

The fire propagation index (overall performance) of the material (/) is calculated from the individual results of each tests as follows ... 

This, in ultrafine grades with surface areas from 10 to 1 5 m g and thermally stable up to 29()°C, functions mainly in the condensed phase, promoting the formation of a char, which can be enhanced by the finer particle size. Grades are also suitable for use in translucent halogenated polyester resin systems, to improve fire performance while retaining clarity, and/or with a refractive index of 1,5 9 (similar to that of glass and many polyester resins). 

Methods for performing hazard analysis and risk assessment include safety review, checkhsts, Dow Fire and Explosion Index, what-if analysis, hazard and operabihty analysis (HAZOP), failure modes and effects analysis (FMEA), fault tree analysis, and event tree analysis. Other methods are also available, but those given are used most often. 

Design practices stem from standard fire test procedures in which the temperature history of the test furnace is regarded as an index of the destructive potential of a fire. Thus, the practice of describing the expected effects and damage mechanism is based on temperature histories. This standard design practice is convenient but lacks accuracy in terms of structural performance. The severity of a fire should address the expected intensity of the heat flux that will impact the structure and the duration of heat penetration. A simple analysis of the expect nature of an unwanted fire can be based on the heats of combustion and pyrolysis of the principal contents in the facility. The heat of combustion will identify the destructive nature of the fire, while the heat of pyrolysis will identify the severity of the fire within the compartment itself and will also identify the destructive potential of the fire in adjacent spaces. 

Polyetherimides are inherently fire resistant, with oxygen indices superior to 47 and a UL94 VO rating. Compounding can improve these performances and certain grades reach an oxygen index of 50. In the event of fire, smoke emissions are low. 

The principle uses of the zinc borate Zn[B304(0H)3] are as a polymer additive and preservative for wood composites, such as oriented strand board (OSB). As a polymer additive it functions as a fire retardant synergist and modifier of electrical and optical properties. Its function as a fire retardant additive is discussed further below. A substantial amount of Zn[B304(0H)3] is used to improve the tracking index, which is an important performance criterion for polymers, such as polyamides (nylon) and polybutyl teraphtha-lates (PBT), used in electrical applications. 

Equivalent Weight and Volume an d Their Precision Indexes for Comparison of Explosives in Air. Data for mean peak pressures and positive impulses determine figures of merit which express performances of expls fired in air. Equivalent Weight (EW) Equivalent Volume (EV) are easily interpretable by ordnance designers. The EW of a new expl is the ratio of wt of a known expl to the wt of a new expl which gives. equiv power as measured by peak pressure or positive impulse. The EV is similarly defined... 

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