Equiviscous Temperature (EVT) Application Range

The recommended bitumen application temperature range. The range is approximately 25° F (14° C) above or below the EVT, thus giving a range of approximately 50° F (28° C). The EVT range temperature is measured in the mop cart or mechanical spreader just prior to application of the bitumen to the substrate.

For Asphalt

• Mop Application: the temperature at which the asphalt’s apparent viscosity is 125 centipoise (0.125 Pa·s).
• Mechanical Spreader Application: the temperature at which the asphalt’s apparent viscosity is 75 centipoise (0.075 Pa·s).

Note: In order 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.

For Coal Tar

• the recommended EVT for roofing coal tar (ASTM D 450, Type I or III) is the temperature at which the coal tar’s apparent viscosity is 25 centipoise (0.025 Pa·s).