Test Methods
FM Loss Prevention Data Sheet 1-52 (FM 1-52), “Field Uplift Tests,” provides for two methods of testing wind uplift resistance: the negative pressure test and the bonded uplift test. The negative pressure test utilizes a five foot by five foot dome that is placed over the roofing membrane surface. Negative pressure is then applied to the dome starting at an initial pressure of 15 pounds per square foot (psf). The pressure is increased in increments of 7.5 psf with each increment held for one minute until 1.5 times the design test pressure is reached or failure occurs. A deflection bar positioned in the center of the chamber measures upward deflection of the roof membrane. This test is sometimes referred to as the “bubble test.” In years past, the test was often conducted using a durable skylight dome. In recent years, test pressures have been increased substantially requiring the use of negative pressure domes constructed of stronger materials.