What is Lambda 90/90?
Lambda 90/90 is the method of thermal declaration which most accurately reflects the long term performance of insulation products; comparison with alternative products may not be appropriate unless the same procedures have been followed. With the introduction of Harmonized European Standard BS EN 13165, (Thermal insulation products for buildings – Factory made rigid polyurelic foam (PF) – Specification), a new method of measurement and declaration of thermal conductivity and thermal resistance was implementedthane foam (PUR) products – Specification) and BS EN 13166, (Thermal insulation products for buildings – Factory made products of pheno to create a level playing field for insulation materials where permanent blowing agents are used. This approach towards thermal performance declaration takes account of ageing either by a fixed increment procedure or an accelerated ageing method. Both methods apply statistical factors which are designed to ensure that 90% of the test results obtain
