BS 13859-2:2010 pdf download – Flexible sheets for waterproofing — Definitions and characteristics of underlays Part 2: Underlays for walls
18.104.22.168 Class W3 If the product fails the test indicated in 22.214.171.124, e.g. the measured mean volume passing the specimens exceeds 100 ml, it shall be classified as resistant to water penetration Class W3. Untested products shall also be classified as resistant to water penetration Class W3.
4.3.3 Water vapour transmission properties The product shall be tested in accordance with 5.2.5 and the results shall lie within the declared tolerance of the manufacturer’s declared value. Other measuring methods shall also be allowed if the correlation with 5.2.5 is proved and recorded. If the water vapour diffusion-equivalent air layer thickness s d is above or equal to 0,2 m the product shall be tested in accordance with 126.96.36.199. If the s d value is below 0,2 m the product shall be tested in accordance with 188.8.131.52. If the s d value is below 0,1 m the standard deviation s shall also be recorded in the test report.
4.3.4 Resistance to penetration of air The product shall be tested in accordance with 5.2.6. The test result shall be given as air permeability, expressed in m 3 air per m 2 , hour at 50 Pascals pressure difference (m 3 /(m 2 × h × 50 Pa)). The value of air permeability shall be equal to or lower than the manufacturer’s limiting value.
4.3.5 Tensile properties The product shall be tested in accordance with 5.2.7 and the results shall lie within the declared tolerance of the manufacturer’s declared values for tensile strength and the maximum and/or minimum values for elongation for both longitudinal and transverse directions.
4.3.6 Resistance to tearing The resistance to tearing of underlays shall be tested in accordance with 5.2.8 and the results shall lie within the declared tolerance of the manufacturer’s declared value in both (longitudinal and transverse) directions.
4.3.7 Dimensional stability The dimensional stability shall be determined in accordance with 5.2.9. The shrinkage or lengthening shall be equal to or less than the manufacturer’s limiting value.
4.3.8 Flexibility at low temperature (pliability) Where appropriate, the flexibility at low temperature (pliability) determined in accordance with 5.2.10 shall be equal to or less than the manufacturer’s limiting value.
4.3.9 Artificial ageing behaviour The product shall be tested in accordance with 5.2.11. The mean values of tensile strength and elongation of the test specimens before and after artificial ageing shall be declared on the product data sheet by the manufacturer. The resistance to water penetration of artificially aged materials shall pass the same class declared by the manufacturer as defined in 4.3.2. For walls which do not exclude UV exposure, e.g. with open joints, the artificial ageing by UV shall be extended over a period of 5 000 h. NOTE “UV-exposed“ means that there are designed open joints in the wall covering which allow the penetration of daylight to reach the product.
4.4 Dangerous substances For products placed on the market within the European Economic Area see ZA.1. Outside the EEA products shall conform to any applicable provisions related to dangerous substances valid in the place of use. Underlays covered by this document shall not contain asbestos or coal tar constituents. The manufacturer shall disclose on the product wrapper and in the health and safety data sheets the use of any additive or constituent considered hazardous. NOTE See also  and .
5.1 Sampling Samples shall be taken in accordance with EN 13416.
5.2 Test methods
5.2.1 Determination of dimensions, straightness and mass per unit area The length, width, straightness and mass per unit area of underlays shall be determined in accordance with EN 1848-1 and EN 1849-1 for bitumen sheets and in accordance with EN 1848-2 and EN 1849-2 for all other sheets.
5.2.2 Determination of reaction to fire Where required, the product shall be tested and classified in accordance with EN 13501-1:2007, Table 1. When tested according to EN ISO 11925-2, the products shall be tested under conditions of surface flame attack (surface exposure).
NOTE 1 It is currently considered that the Euroclasses Classification system at Classes D and above requires investigation to determine its appropriateness to the products covered by this document (the SBI test (EN 13823:2002) may be inappropriate for products covered by the standard). Pending results of such an investigation and discussions in the Fire Regulators Group, products covered by this document are tested to EN ISO 11925-2. If and when a new fire test scenario and test method are developed for the products, this document will be amended to refer to them.