This document specifies the requirements for factory-made flexible microporous insulation (FMI), which is used for the thermal insulation of industrial applications. It specifies requirements for insulation that exhibits thermal insulating performance through nano-sized pore composite material comprising a blend of inorganic powder, fibres and opacifiers. The products are delivered as a flexible microporous type. This document describes product characteristics and includes procedures for testing, evaluation of conformity, marking and labelling. It does not specify the required level of a given property to be achieved by a product to demonstrate fitness for purpose in a particular application. The levels required for a given application can be found in regulations or non-conflicting standards.