Reaction to fire tests Ignitabilityofbuilding products subiect to direct impingement of flame Part 1 Guidance on ignitability (BS ISO TR 11925-1:1999 which has been produced by the British Standards FSH 21/2 Sub-Committee
It is very important to examine the ignitability of materials for two reasons. First, at the initiation of a fire some object or local area of material is ignited. Therefore the likelihood of ignition commencing is of great importance. Secondly, during the growth of a fire ignitability is the essential factor in the spread of fire to other parts of the room or compartment. A range of flame sources of different sizes has been studied by ISOITC92ISC1, which are discussed in detail in the recently published guidance standard (BS ISO TR 11925-1). In this document two main types of ignition source are discussed, namely Radiative and Flame. Radiative ignition sources may be either electrical or gas while flame sources may be diffusion flames or premixed flames.
Dealing first with Electrical Radiative Sources
The test methods which utilise this type of ignition source are based on truncated cone heaters. These are found in the instrumentation for the following tests, namely ISO 5657 and ISO 5660- the cone calorimeter, in which one of the parameters measured is the time to ignition.
Gas Radiative Sources
These are involved with instruments for testing according to the following standards: ISO 5658-2 and -3 (the so-called LIFT apparatus [Lateral Ignition and Flame Spread Test] and ISO 9239-1, the radiant panel flooring test.
Diffusion Flame Sources
The scenario to which many tests are referred to is the room corner test (ISO 9705). This uses a sand box through which propane percolates and once ignited burns as a diffusion flame above the sand box surface. ISO 11925-3 uses a variety of diffusion flames which are supposed to equate to flames from real sources.
Premixed Flame Sources
These are relevant to ISO 11925-2 & -3. This equipment is part of the clutch of tests which are part of the requirements for the Euroclass system of classification.
FIRE can supply any or all of the instruments mentioned in this brief. Refer to the appropriate pages on the website for more details.
The standard goes on to examine the various theoretical treatments of ignition and then in the final section looks at comparisons of experimental methods.
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