BS ISO 29903‑1:2020 Comparison of toxic gas data from different tests Part 1: Guidance and requirements.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5725-1. ISO 13943. and the following apply.
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small-scale fire test bench-scale test
fire test performed on a test specimen of small dimensions
Note 1 to entry: In these tests, the typical maximum length of a linear test specimen is less than 1 m. The typical maximum dimensions of a rectangular specimen are approximately 0,1 m.
[SOURCE: ISO 13943:2017, definition 3.346, modified — Note 1 to entry has been redrafted and the term “bench-scale test” has been added as a preferred term because of its use in this document.]
medium-scale fire test
fire test performed on a test specimen of small-medium size dimensions
Note ito entry: A fire test performed on a test specimen of which the maximum dimension is between 0,5 m and 1,0 m is here called a medium-scale fire test.
intermediate-scale fire test
fire test performed on a test specimen of medium dimensions
Note 1 to entry: A fire test performed on a test specimen for which the maximum dimension is between 1 m and 3 m is usually called an intermediate-scale fire test.
[SOURCE: ISO 13943:2017, definition 3.233, modified — Notes 2 and 3 to entry have been removed]
large-scale fire test
fire test, that cannot be carried out in a typical laboratory chamber, performed on a test specimen of large dimensions
Note ito entry: A fire test performed on a test specimen of which the maximum dimension is greater than 3 m Is usually called a large-scale fire test.
[SOURCE: ISO 13943:2017, definition 3.239]
4 Combustion conditions
4.1 General The yields and nature of the fire effluent component from a fire test of any scale are determined by the involved fuels and the prevalent thermal and oxidative conditions in the current stage of the fire. These conditions also determine the burning rate of the products/materials and thus the rate of effluent generation. See ISO 16312-1. During a fire test of a finished product, the combustion conditions are likely to change. These changes include the chemistry of the combustible item and the sufficiency of the ventilation. Whether decomposition is flaming or non-flaming is a dominant factor in the production of toxic gases. The combustion conditions under which toxic gas data are developed shall be as close to equivalent as possible between the physical fire models or test scales compared (see Clause 6). NOTE 1 A large change in the rate of combustion can affect the degree of oxidation of the emitted effluent. Smaller changes in combustion rate can have no significant effect. NOTE2 Fire stages and the corresponding combustion conditions are described in ISO 19706.BS ISO 29903‑1 pdf download.