The ASTM 610 specification covers molded expanded perlite block, fittings, and thermal pipe insulation intended for use on surfaces with temperatures between 80 to 1200°F (27 to 649°C). It specifies that certain test methods shall be performed in order to determine the properties of the block, fitting, and pipe insulations: density, apparent thermal conductivity, linear shrinkage after heat soaking, flexural strength, compressive strength, weight loss by tumbling, moisture content, water absorption after heat aging, surface bearing characteristics, hot-surface performance, and stress corrosion cracking of austenitic stainless steel.
Sproule WR-1200 made by Johns Manville Industrial Insulation Group is a pre-formed, high-temperature, non-wicking pipe and block insulation that meets or exceeds the physical property requirements of ASTM C610. Sproule WR-1200 has compressive strength, low thermal conductivity and corrosion inhibiting properties that are ideal for piping that is susceptible to stress corrosion cracking at operating temperatures above 140°F (60°C). The XOX corrosion inhibitor that is implemented during the Sproule WR-1200 manufacturing process prevents corrosion where moisture and chlorides may become trapped between the insulation and stainless steel.