(1)
Except as permitted by Sentence (2), vibration isolation connectors in air duct systems shall be noncombustible.
(2)
Combustible fabric vibration isolation connectors are permitted provided they
(a)
are not more than 250 mm long,
(b)
comply with the flame-resistance requirements of CAN/ULC-S109, “Standard Method for Flame Tests of Flame-Resistant Fabrics and Films,” and
(c)
are not used in a location where they are exposed to heated air or radiation from heat sources that could cause the exposed surface temperature to be more than 120°C.