4.208. Thermal insulation materials should not compromise any safety functions in the event of their deterioration. They should be installed and affixed to prevent loosening and the possible clogging of sieves and valves as a consequence.

4.209. In particular, materials used to insulate pipes and tanks inside the containment should be selected and designed to achieve the following:

(a) To minimize the production of debris that can accumulate on containment floors and clog sumps or damage recirculation pumps,

(b) To ensure easy decontamination if the need arises,

(c) To avoid giving rise to fire hazards,

(d) To minimize the release of toxic gases during their heating at startup.

4.210. Ageing mechanisms that affect thermal insulation materials should be assessed and appropriate replacement intervals should be established (para. 4.39).