Evaluation of the fire performance of thermal pipe insulations is required by all mechanical codes in the United States. This paper describes a recently developed test to evaluate flame spread, heat release, and smoke generation when pipe insulation systems are exposed in a vertical pipe chase apparatus. This apparatus allows the testing of composite pipe insulation systems, including the core insulation, adhesives, jacketing materials, sealants, tapes, and all other components that are used to field apply these insulation systems.
The method simulates a small, growing fire which escalates into a fully involved fire that may be anticipated when combustible materials burn within a vertical chase or a confined ceiling cavity or plenum. The initial fire exposure is 20kW for three minutes followed by a 70kW exposure for seven minutes. The specimen is comprised of three 2-inch NPS pipes insulated with thermal insulation and accessories. The pipe chase is made up of a 4-foot (1.22 m) horizontal pipe run connected to a 6.5-foot (1.98 m) vertical run. A square gas burner is located 14 inches (0.35 mm) from the vertical rise to ensure that flames will propagate from the horizontal to the vertical pipe section. The fire performance of the insulation system is evaluated by the following: vertical flame spread, heat release determined by oxygen consumption calorimetry, and smoke measurement in the exhaust duct. The vertical configuration ensures that the specimen will remain in the flame exposure area for the duration of the test.