Blistering of Built-Up Roof Membranes Pressure Measurements.

摘要

Several blisters in built-up roof membranes were instrumented with pressure and temperature sensors. Internal blister pressures varied from positive during the heat of the day to negative during the cool of the night; these pressure changes cause blisters to grow. Air is drawn into the blister at night. When exposed to sunshine, the air rapidly expands before it can escape. Water is not necessary to cause growth. Blisters grow best when the days are hot and the nights are cool. Pressures apparently do not occur within the insulated space of a roof to cause blisters. Reflective coatings may help to slow blister growth. Growth can be stopped by using a miniature pressure relief valve.