Experimental Evaluation of the Fire Performance of Pipe Insulation Materials Under ISO 20632 Actual Fire Test Conditions

Continuous organic pipe insulation can promote flame spread during fires and is therefore an important fire safety factor. However, Korean regulations separately control the flame-retardant performance of pipe insulation under the Building Act and Fire Services Act, mainly through small-scale material tests that may not reflect actual piping installation conditions. This study conducted the ISO 20632 actual fire test using five pipe insulation materials widely used in Korea: polyurethane, expanded polyethylene, foamed rubber, glass wool, and multilayer composite insulation. The tests applied 100 kW for 10 min, followed by 300 kW for 10 min, under simulated installation conditions. PHRR, SPR, FIGRA, SMOGRA, zone-based temperature histories and temporal temperature rise rates were compared. Polyurethane (PHRR 2857 kW) and expanded polyethylene (1469 kW) showed high heat release, rapid fire growth, and flashover, while glass wool (384 kW) and multilayer composite insulation (801 kW) did not reach flashover. Multilayer composite insulation showed the lowest FIGRA and SMOGRA, while glass wool exhibited relatively favorable thermal stability. These results indicate that material-based standards may not adequately reflect actual fire behavior, supporting the need for ISO 20632 actual fire tests.