Ref. No.: Rev. No.:
**CLARIFICATION NOTICE FOR
Subject: **Clarification notice for the Variance Conditions for Continued Use of Existing
Uncertified Plastic Vent
**Sent to: **Posted on Web-Site, Code Adoption RRG
The Technical Standards and Safety Authority (TSSA) adopted the 2007 supplement to the
national Natural Gas and Propane Installation Code (B149.1S1-07) on August 1, 2007. A major
change to the code supplement is that all plastic venting will have to be certified to ULC S636.
TSSA understands that there are possible difficulties relating to replacement appliance
installations, where it is deemed that the replacement of the entire vent with certified ULC S636
plastic venting is not possible or is impractical due to specifics of that particular installation. To
address these installations, TSSA released the Advisory FS-101-07 to indicate the variance
conditions for the continued use of existing uncertified plastic vents.
To facilitate the review process and ensure timely response for this variance, ensure that the
application is submitted with:
• Fee of $560 per condominium/multi-family dwellings or $150 for single family
• Summary of why it is not possible or practical to replace the entire vent;
• Evidence of a satisfactory reasonable visual inspection by a certificate holder; and
• Satisfactory results of the pressure test performed by a certificate holder on the existing
venting outlined under condition 5 of Advisory FS-101-07.
The approval of the variance is also subject to the condition that every five years, the vent shall
be visually inspected and pressure tested by an appropriate certificate holder in accordance to the
terms outlined in the advisory.
Variances approved under Advisory FS-101-07 may be subjected to safety audits by TSSA.
Further information may be obtained by contacting: Director – Fuels Safety Division, Technical Standards and Safety Authority,
14th Floor – Centre Tower, 3300 Bloor St. West, Etobicoke ON., M8X 2X4 Ph:416 734 3300 Fx:416 231 7525
Ref. No.: Rev. No.: **Fuels
Safety Program **FS – 101-07
**ADVISORY **April 16, 2007
**Subject: **Variance Conditions for Continued Use of Existing Uncertified Plastic Vent
**Sent to: **Posted on Web-Site and Distributed to 149.1 Code Adoption RRG, Natural Gas Council,
The Technical Standards and Safety Authority (TSSA) will adopt the 2007 supplement to the national Natural gas
and propane installation code (B149.1S1-07), on August 1, 2007. A major change in the code supplement is that all
plastic piping will have to be certified to ULC S636 “Standard for Type BH Gas Venting Systems”.
This requirement has been put in place due to the investigated failures in a number of existing plastic gas vents,
predominantly ABS plastic pipe and fittings. Noted failures have included stress cracking and melting. This may
result in a carbon monoxide (CO) safety hazard in homes and may possibly cause personal injury.
This code change will affect all new appliance installations and replacement installations. For example, if an
existing water heater is replaced with a new water heater, the existing plastic venting must be completely replaced
with a certified ULC S636 plastic venting system.
Existing appliances and their plastic venting systems will not require action until replacement of the appliance is
required as this code change is not retroactive.
There may be situations where the replacement of the entire vent is not possible or is impractical due to specifics of
that particular installation. For those situations, TSSA will consider a variance to allow the continued use of the
existing vent provided that the following conditions are met:
- Completed application form with either the required deposit or purchase order number;
- Summary of why it is not possible or practical to replace the entire vent;
- The 1st 5 feet immediately downstream of the appliance is replaced with vent suitable for the appliance that
is certified to ULC S636;
- The existing vent is visually inspected and found in good working order;
- The existing vent is pressure tested as follows:
• Use air or an inert gas;
• A minimum test pressure of positive or negative 7 inches water column shall be applied to the
entire length of the existing plastic vent but shall not exceed a pressure of 2 psig. at any time;
• The minimum test pressure of +/- 7 inches water column shall be measured by either a pressure
gauge or equivalent device and, if a gauge is used, the minimum diameter shall be 3 in (75 mm)
and the maximum range shall exceed the test pressure by at least 15% but not more than 300%. The
pressure gauge or equivalent device shall be calibrated to read in increments of not more than 2%
of the maximum dial reading of the pressure gauge,
• The minimum test pressure shall be applied for at least 5 minutes and at least 75% of the test
pressure shall be retained.
- Conditions 4 and 5 shall be repeated every 5 years to demonstrate that the existing vent remains in good
If any of the above conditions are not met, the entire venting system shall be replaced with vent suitable for the
appliance that is certified to ULC S636.
Note: Buildings housing multiple units will be treated as a single variance