Following the dry looper, the felt enters the saturator, another point of POM
emissions within the asphalt roofing process. Moisture is driven out of the felt in the saturator
and the felt fibers and intervening spaces are filled with saturant asphalt. If a fiberglass mat web
is used instead of felt, the saturation step and the subsequent drying-in process are bypassed. The
saturator also contains a looper arrangement, which is almost totally submerged in a tank of
asphalt maintained at a temperature of 450 to 500(F (232 to 260(C). The absorbed asphalt
increases the sheet or web weight by about 150 percent. At some plants, the felt is sprayed on
one side with asphalt to drive out the moisture prior to dipping. This approach reportedly results
in higher POM emissions than does use of the dip process alone (U.S. EPA, 1980).