BS ISO 17749:2018 pdf download – Thermal insulation products — Sheep wool mat and board — Specification 5 Requirements 5 .1 General Product properties shall be determined in accordance with Clause 6. The test methods to be used for determination of each property are given in Table 4, which also shows the required test specimen dimensions and the minimum number of test specimens required to give one test result. One test result for a product property is the average of the measured values on the number of test specimens given in Table 4. NOTE For FPC, see Annex B. 5.2 Material properties 5.2.1 Thermal resistance and thermal conductivity For thermal conductivity testing, the specimen shall be conditioned according to the following: (80 ± 2) °C to constant mass. Thermal resistance and thermal conductivity shall be based upon measurements carried out in accordance with ISO 8302 or ISO 8301 for thick products. The thermal resistance and thermal conductivity shall be determined in accordance with the procedures given in Annex A and declared by the manufacturer according to the following. — The reference mean temperature shall be 10 °C and/or 23 °C. — The measured values shall be expressed with three significant figures. — For products of uniform thickness, the thermal resistance, R D , shall always be declared. The thermal conductivity, λ D , shall be declared where possible. Where appropriate, for products of non-uniform thickness (i.e. for sloped and tapered products), only the thermal conductivity, λ D , shall be declared. — The declared thermal resistance, R D , and the declared thermal conductivity, λ D , shall be given as limit values representing at least 90 % of the production, determined with a confidence level of 90 %. — The value of the thermal conductivity, λ D 90/90 , shall be rounded up to the nearest 0,001 W/(m·K) and declared as λ D in levels with steps of 0,001 W/(m·K). — The declared thermal resistance, R D , shall be calculated from the nominal thickness, d N , and the corresponding thermal conductivity, λ 90/90 · — The value of the thermal resistance, R 90/90 (when calculated from the nominal thickness, d N , and the corresponding thermal conductivity, λ D90/90 ), shall be rounded down to the nearest 0,05 m 2 ·K/W and declared as R D in levels with steps of 0,05 m 2 ·K/W. — The...
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