Clause (8.9.5) - Venting systems, or total vent run if less than 3 ft (900mm), that employ plastic vents shall be installed such that the first 3 ft (900mm), from the appliance flue outlet is readily accessible for visual inspection except for direct vent appliances such as fireplaces that are intended to have short vent lengths to be concealed for decorative purposes.
Clause (8.9.6) -
(a) Until July 1, 2008, vents constructed using plastic piping shall be certified to ULC S636 except for special fittings (non standard vent sizes and components) which may include:
a. entire vent systems supplied with the appliance that are not comprised of standard vent sizes and components;
b. transitions with or without condensing lines; and
c. termination kits.
(b) After July 1, 2008, vents constructed using plastic piping shall be certified to ULC S636.