The benefits to CIPP contractors of using a CIPP vacuum pump is compliance and ensuring the air in the liner material is completely replaced by resin.
Compliance
CIPP lateral sewer lining is governed by ASTM F-1216 (inverting) or ASTM F-1743 (pulling in place) (ASTM F-1743), which detail how to prepare and install CIPP liners in an existing pipe.
7.2 Resin Impregnation—The tube should be vacuum impregnated with resin (wet-out) under controlled conditions. The volume of resin used should be sufficient to fill all voids in the tube material at nominal thickness and diameter. The volume should be adjusted by adding 5 to 10 % excess resin for the change in resin volume due to polymerization and to allow for any migration of resin into the cracks and joints in the original pipe.
Ensuring the pipe is lined right! Vacuuming during impregnation ensures all the air in the liner material is replaced by resin. If the void left is not impregnated with resin, roots can grow through the liner over time. In addition, wet-out will take considerably longer adding labor costs to your liner installations.