Support / FAQ


Q. What is the difference between a Grade Ring and Finish Ring?

Grade Ring has grooves on the underside and a tongue on the upper side to form a tongue and groove joint between multiple Grade Rings and Finish Rings. A manhole frame should never be installed on a Grade Ring.  Finish Rings have grooves on the underside and are mostly flat on top with a groove located on the inside diameter which is there to accept and lock in an Angle Ring if used.

PRO-RINGs may be vacuum tested and the test should not be performed until after the adhesive has been cured for a minimum of 24 hours.  Any vacuum testing that is conducted should be done in accordance with ASTM C-1244, “Standard Test Method for Concrete Sewer Manholes by the Negative Air Pressure (Vacuum) Test Prior to Backfill.

Yes.  PRO-RINGs have been tested to meet or exceed the requirements of AASHTO M-306, HS-20 and HS-25 loading.

The recommended application temperature for the M-1 Adhesive is 32º Fahrenheit, however is kept warm until ready for use, we have applied the material down as low as 15º Fahrenheit.

There are other materials that may work, however all of our testing related to vacuum testing and exfiltration testing has been performed using the M-1 Adhesive.  Please contact us or your local representative regarding possible substitutions.

X-85 External Chimney Seal

Q. Are there any special tools required to tighten the bands on the X-85 External Chimney Seal?

A large flat blade screwdriver, 5/16” nut driver or cordless impact or drill with a 5/16” socket is all that is needed to tighten the bands on the X-85 seal.

Yes.  The EPDM rubber used to manufacture the seal is UV resistant and may be left exposed to the elements.