Clyinder Jacket Jackets Kitemarked to, and manufactured in accordance with, British Standard Number BS 5615: 1985. Tested and approved at British Standards Institute (BSI Testing Hemel Hempstead) Licence No: KM36881. 80mm nominal thickness glass fibre infill kitemarked to BS 5803: Part 1: 1985 and non combustible to BS 476: Part 4: 1970. 100 micron flame retardant cover. Heavy duty fixings of tensile strength not less than 40N. Multi Panel (4) design to meet the heat loss requirements of BS 5615: 1985 (not more than 2.5KW per 24 hour standing heat loss).