|Equiviscous temperature (EVT)||
The temperature at which a bitumen attains the proper viscosity for built-up membrane application.
|Equiviscous temperature (EVT) application range||
The recommended bitumen application temperature range. The range is approximately 25 F below the EVT to 25 F above the EVT (50 degree Fahrenheit span). The EVT is measured in the mop cart or mechanical spreader just prior to application of the bitumen to the substrate.
|Equiviscous temperature (EVT) for asphalt||
The recommended EVT for roofing asphalt (ASTM D312, Type I, II, III or IV) is as follows:
mechanical spreader application: The temperature at which the asphalt's apparent viscosity is 75 centipoise. Note: To avoid the use of two kettles if there are simultaneous mop and mechanical spreader applications, the EVT for mechanical spreader application can be used for both application techniques.
|Equiviscous temperature (EVT) for coal tar||
The recommended EVT for roofing coal tar (ASTM D450, Type I or III) is the temperature at which the coal tar’s apparent viscosity is 25 centipoise.