Questar Gas - Good Practices for Gas Piping and Appliance ...

of all fuel-burning appliances installed in that space. Rooms
communicating directly with the space in which the appliances
are installed, through openings not furnished with doors, are
considered a part of the unconfined space.
UNIT HEATERS - A heating appliance designed for nonresidential
space heating and equipped with an integral means for circulation
of air.
UNUSUALLY TIGHT CONSTRUCTION - Construction where:
a. Walls and ceilings exposed to the outside atmosphere have a
continuous water vapor retarder with a rating of one perm or
less with any openings gasketed or sealed, and
b. Weather-stripping on openable windows and doors, and
c. Caulking or sealants are applied to areas such as joints around
window and door frames, between sole plates and floors,
between wall-ceiling joints, between wall panels and at
penetrations for plumbing, electrical and gas lines and at other
openings.
VENT - A listed factory-made vent pipe and vent fittings for
conveying flue gases to the outside atmosphere that extends in a
generally vertical direction.
VENTS -
a. Type “A” Gas Vents: See Chimney, Type “A”.
b. Type “B” Gas Vents: Factory-made gas vents listed by a
nationally recognized testing agency for use with appliances
with draft hoods and other Category I appliances. Vent requires
1" clearance from combustibles.
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