FAQs
Yes. Across Canada, all plastic venting systems for gas appliances must be certified to ULC S636, as mandated by Clause 8.9.6 of the CSA B149.1 Natural Gas and Propane Installation Code. This national code is adopted in every province and territory, sometimes with local amendments, but the ULC S636 requirement applies everywhere. Provincial safety authorities (such as TSSA in Ontario, Technical Safety BC, and the Régie du bâtiment du Québec) enforce compliance.
While polypropylene may carry a slight material premium, installers typically save significant time, often up to 70% on labor, because ULC S636 polypropylene vent systems are faster and easier to install. The overall installed cost is often lower compared to alternative venting materials, particularly when factoring in long-term reliability and fewer call-backs.
InnoFlue® polypropylene Special Gas Vent Systems, tested and listed to ULC S636, have been available in Canada since 2009. Polypropylene venting has been widely used in Europe for over 25 years, establishing a proven track record of safety and performance.
ULC S636 certification ensures that:
- The entire venting system (pipe, fittings, and seals) is tested and listed as a complete assembly.
- The system meets strict performance requirements for temperature, pressure, and leakage.
- Only factory-listed components may be used; field-fabricated or mixed-material venting is not permitted.
- The vent system is safe and compliant when installed according to the listing and manufacturer’s instructions.
InnoFlue® ULC S636 venting systems are available from plumbing and HVAC wholesalers across Canada, making them easy to source for contractors and distributors nationwide.
Both standards certify venting systems for use with condensing appliances, but UL-1738 is more stringent than ULC S636. Notable differences include:
- Pressure Testing: UL-1738 tests at 250% of rated operating pressure. ULC S636 has no pressure test requirement.
- Leakage Testing: ULC S636 allows leakage of 0.3 L/h @ 100 Pa, which is at a pressure 24% lower than UL-1738 testing.
- Puncture Test: UL-1738 requires resistance to a steel plunger drop test. ULC S636 does not.
- Low Temperature Handling: UL-1738 requires a -20°C drop test with no cracks or failures. ULC S636 has no cold weather test.
- UV Testing: UL-1738 includes UV and water exposure conditioning before testing. ULC S636 has no UV test.
- High Temperature Testing: UL-1738 requires testing at 38.8°C (70°F) above rated temperature. ULC S636 does not.