Installation Guide

4
Definitions:
AL 29-4C - A superferritic stainless steel alloy designed by Allegheny Ludlum
for extreme resistance to chloride ion pitting, crevice corrosion and stress
corrosion cracking. Equivalent material made by other manufacturers may be
identified by the UNS designator S44735.
Category I Appliance - An appliance which operates with a non-positive vent
static pressure and with a vent gas temperature that avoids excessive
condensate production in the appliance.
Category II Appliance - An appliance which operates with a nonpositive vent
static pressure and with a vent gas temperature that may cause excessive
condensate production in the appliance.
Category III Appliance - An appliance that operates with a positive vent static
pressure and with a vent gas temperature that avoids excessive condensate
production in the appliance.
Category IV Appliance - An appliance that operates with a positive vent static
pressure and with a vent gas temperature that may cause excessive condensate
production in the appliance.
Combustible Material - Any material made of or surfaced with wood,
compressed paper, plant fibers, or other materials that are capable of being
ignited or burned. Such material shall be considered combustible even though
it is flame-proofed, fire-retardant treated, or plastered. (Source: NFPA54/
ANSI Z223.1-1999.)
Condensate - The liquid that separates from the vent gases due to a reduction
in temperature or increase in pressure.
Condensing Type Appliance - Any Category II or IV appliance. During start-
up, some Category III appliances may also produce condensate in the vent.
Non-Combustible Material - Any material that is not capable of being ignited
and burned, such material consisting entirely of, or of a combination of, steel,
iron, brick, tile, concrete, slate, asbestos, glass, and plaster. (Source: NFPA54/
ANSI Z223.1-1999).
Special Gas Vent - Gas vents for venting listed Category II, III, and IV, gas-
burning appliances.
Type L Vent - Vent systems for use with gas and oil fired appliances Listed as
suitable for venting with Type L venting systems.
UL 1738 - A standard issued by Underwriters Laboratories that covers the
requirements for venting systems intended for use on Category II, III, or IV
gas- burning appliances.
Vent Connector - The vent or pipe which connects a fuel-gas burning appliance
to a vent or chimney.