Mineral wool insulation is manufactured through a process which involves the fusion of the constituent minerals at high temperatures (1,100–1,500°C). The result is a vitreous melt, which is spun or pulled into fibres. Immediately following their formation, the fibres are compressed to a predetermined density, bonded together with a binding agent and cured to form rigid boards, slabs or roll products of mineral wool insulation which can achieve ‘Class A1’ according to EN 13501-1. Mineral wool insulation roofing boards are available as either mono-density or dual density products. Mineral wool insulation dual density products have increased compression resistance. Mineral wool insulation boards should comply with BS EN 13162 Therma insulation products for buildings – factory made mineral wool (MW) products.