American Standard VAPORSHIELD Residential 30 Operating, Installation And Service Manual page 11

AIR
SUPPLY
Important air for combustion and ventilation must not come from
a corrosive atmosphere.Any failure due to corrosive elements in
The following types of installation
and may reduce but not eliminate the presence of corrosive
chemicals in the air.
• Beauty shops.
• Photo processing labs.
• Buildings with indoor pools.
• Water heaters installed in laundry, lobby, or craft rooms.
• Water heaters installed in chemical storage areas.
12" MAX
Combustion air must be free of acid-forming chemicals such as
sprays, detergents, bleaches, cleaning solvents, air fresheners, paint
and varnish removers, refrigerants, and many other commercial or
household products. When burned, vapors from these products
form highly corrosive acid compounds. These products should not
be stored or used near the water heater or air inlet.
Combustion and ventilation air requirements are determined by
the location of the water heater. The water heater may be located
in either an open
areas with less than 50 sq.ft.
FIGURE 5
One opening shall be within 12 inches of
the top and one within 12 inches of the
bottom of the enclosure.
CHIMNEY OF GASVENT
Furnace
Water
Heater
(not limited to the following)
MIN
100 sq in
AIR DUCT
12" MAX
100 sq in MIN
ALL AIR
FROM
BUILDING
THE
be provided with two
permanent openings
communicating directly with
an additional room(s) of
the combined volume of all
spaces meets the criteria for
be considered in making this
determination. Each opening
shall have a minimum free
area of I square inch per
1,000 BTU per hour
of the total input rating of all
gas utilization equipment in
less than 100 square
ALL AIR
two permanent openings, one commencing
within 12 inches of the top and one
commencing within 12 inches of the
will bottom of the enclosure.The openings shall
communicate directly, or by ducts, with the
outdoors or spaces (crawl or attic) that freely
communicate with the outdoors.
When directly communicating with the
outdoors, each opening shall have a minimum
free area of I square inch per 4,000 BTU per
hour of total input rating of all equipment in
the enclosure. (Figure 6)
Chimney
of Gas Vent
Alternate
Air Inlet
When communicating with the outdoors
through vertical ducts, each opening shall
have a minimum free area of I square inch per
4,000 BTU per hour of total input rating of all
equipment in the enclosure.
INSIDE
1. When communicating with the outdoors through
horizontal ducts, each duct opening shall have a
minimum free area of I square inch per 2,000 BTU
per hour of total input rating of all equipment in the
enclosure. (Figure 8).
When ducts are used, they shall be of the same
cross-sectional area as the free area of the openings
to which they connect. The minimum dimension of
inches.
rectangular air ducts shall not be less than 3 inches.
For other combustion and ventilation air openings,
refer to the National Fuel Gas Code ANSI Z223.I.*
OUTDOORS
FROM
Ventilation Louvers
(Each end of attic)
Outler
Air
Furnace Water
Heater
Inlet
Air
(Figure 7).
Chimney of Gas Vent
Ventilation Louvers
(Each end of attic)
Outlet Air
Outlet Air
Furnace Water
Heater Inlet Air Duct
(ends. If above floor)
6
FIGURE 6
Equipment located
in confined spaces;
all air from
outdoors-inlet
air from ventilated
crawl space and
outlet air to
ventilated attic
FIGURE 7
Equipment Located
in Confined Spaces;
All Air From
Outdoors Through
Ventilated Attic