ARLINGTON, Va. - The Gas Appliance Manufacturers Association (GAMA) continues to identify problems with the new provision in the 2007 supplements to the Canadian Standards Association (CSA) B149.1, Natural Gas and Propane Installation Code, requiring plastic piping used for gas appliance vents to be certified to ULC S636.

GAMA recently sent a letter to Sandra Cooke, Ontario Technical Standards and Safety Authority (TSSA), raising two issues. The first issue involves the temperature subcategories in the scope of ULC S636 and how those ratings relate to the Z21/CSA standard requirements for certifying appliances for use with non-metallic vent materials. The letter asked TSSA to acknowledge that any ULC S636 listed plastic vent pipe can be used on an appliance as long as it is the type of plastic material specified by the appliance manufacturer, regardless of the ULC S636 temperature subcategory.

The second issue involves the requirement that the first three feet of the plastic vent from the flue outlet must be readily accessible for visual inspection. The letter asks TSSA to confirm that this requirement does not apply to wall-mounted direct-vent appliances or clarify how this requirement could be applied to those appliances.

GAMA received a letter from the Interprovincial Gas Advisory Council (IGAC), which Cooke chairs, responding to GAMA’s concerns. This response noted that work is underway at the standards level to resolve the differences between the ULC S636 and the Z21 appliance standards, and that the IGAC is considering modifications to address the issue concerning wall-mounted direct-vent appliances. Based on this response, GAMA has contacted Underwriters Laboratories Canada to become involved in the ULC activities to resolve the standards issue. GAMA will also continue to pursue this matter with TSSA. For more information, contact Frank Stanonik, GAMA chief technical advisor, at 703-525-7060 ext. 221, or e-mail

Publication date:04/30/2007