Gas burners and devices, attachments or accessories
to gas burners, which can in any way affect combustion or safety,
shall not be installed until they have been inspected, tested and
approved by the Inspector.
A.
This inspection and test shall cover arrangement of
parts, suitability of material, strength of parts, electrical control,
thermostatic arrangement, reliability of automatic features and positiveness
of ignition.
B.
Any combination of gas burners, attachments or devices
used together in any manner shall meet the requirements which apply
to individual pieces of equipment.
C.
All gas burners, devices, attachments and accessories,
covered by this section, shall bear the manufacturer's identification
marking.
No devices or attachment shall be installed
on any gas burner which may in any way impair the combustion of the
gas.
No devices employing or depending upon an electrical
current shall be used if of such character that failure of the electrical
current could result in the escape of unburned gas or in failure to
reduce the supply of gas under conditions which would normally result
in its reduction unless other means are provided to prevent the development
of dangerous temperatures, pressures or the escape of gas. Only approved
devices and controls may be used.
A.
Electrically operated safety devices shall not depend
upon the closing of a circuit to shut off the main gas supply. (This
requirement shall not be construed as prohibiting the use of electrical
regulating devices, provided the required safety devices are also
installed.)
A.
When air or oxygen under pressure is used in connection
with any gas supply, effective means shall be provided to prevent
the air or oxygen from going back into the gas piping.
B.
Power burners (gas-air mixture furnished by a power
blower) shall be equipped with an air interlock control that will
shut off the gas supply to the burner in the event of failure of the
air supply to the burner (Controls actuated by failure of power supply
to the blower motor do not meet this requirement.).
All gas burners shall be located so that they
will be readily accessible for operation, repair and adjustment and
for maximum safety.
A.
Gas burners shall be installed so that their continued
operation shall not raise the temperature of surrounding combustible
materials or construction more than 90° F. above normal room temperature.
B.
Equipment with closed bases, in which no provision
is made for the circulation of air below the burner boxes or combustion
chambers, shall be properly insulated from combustible floors.
C.
Clearances.
(1)
The minimum clearance of gas-fired heating units from
combustible partitions and materials shall be as set forth in Table
No. 4,[1] except in the case of equipment especially designed for
burning gas and tested and listed for lesser clearances by a nationally
recognized testing laboratory.
[1]
Editor's Note: Table No. 4 is included at the end of this chapter.
(2)
The clearance to combustible construction may be reduced
as specified in Table No. 2,[2] where the combustible construction is protected in accordance
with this table.
[2]
Editor's Note: Table No. 2 is included at the end of this chapter.
Gas-fired floor furnaces shall be specifically
approved by the Inspector for services in direct contact with combustible
floors in which they may be installed.
A.
Manual main shutoff valve. A separate manual main
shutoff valve shall be provided ahead of all controls and a union
connection shall be provided downstream from this valve to permit
removal of the controls or the floor furnace.
B.
Combustion air. Fixed ventilation by means of a duct
or grille arranged to supply air from a permanently ventilated attic
or underfloor space shall be provided to any confined space which
encloses the floor furnace. The duct or grille shall be screened and
have a free area at least twice the free area of the vent collar of
the floor furnace or one square inch per 1,000 BTUs per hour of gas
input, whichever is the greater, and shall be installed in such a
manner as to ensure proper combustion.
C.
Placement. The following are requirements that will
serve in properly placing the furnace or furnaces to serve one story.
(1)
No floor furnace shall be installed in the floor
of any aisle or passageway of any auditorium, public hall, or place
of assembly, or in an exitway from any such room or space.
(2)
Walls and corners. With the exception of wall-register
models, a floor furnace shall not be placed closer than six inches
to the nearest wall, and wall-register models shall not be placed
closer than six inches to a corner.
(3)
Draperies. The furnace shall be so placed that
a door, drapery, or similar object cannot be nearer than 12 inches
to any portion of the register of the furnace.
(4)
Central location. Generally speaking, the more
central the location the better, favoring slightly the sides exposed
to the prevailing winter winds.
D.
Bracing. The floor around the furnace shall be braced
and headed with a framework of material not lighter than the joists.
E.
Support. Means shall be provided to support the furnace
when the floor grille is removed.
F.
Clearance. The lowest portion of the floor furnace
shall have at least a six-inch clearance from the general ground level,
except that where the lower six-inch portion of the floor furnace
is sealed by the manufacturer to prevent entrance of water, the clearance
may be reduced to not less than two inches. When these clearances
are not present, the ground below and to the sides shall be excavated
to form a "basin-like" pit under the furnace so that the required
clearance is provided beneath the lowest portion of the furnace. A
twelve-inch clearance shall be provided on all sides except the control
side, which shall have an eighteen-inch clearance.
G.
Access. Provisions shall be made for an access door
to the floor furnace by means of an opening in the foundation wall
of at least 18 inches by 24 inches and a trap door of at least 24
inches by 24 inches, located at some convenient point, and a clear
and unobstructed passageway to the floor furnace of at least 18 inches
high by 24 inches wide.
H.
Seepage pan. Whenever the excavation exceeds 12 inches
or water seepage is likely, a pit made of concrete, waterproof, not
less than 3 3/4 inches thick and extending four inches above
the grade level shall be used. The pit shall be not less than six
feet by six feet inside dimension, with at least 2 1/2 feet of
clearance on the control side and clearance on all other sides of
not less than six inches.
I.
Wind protection. Floor furnaces shall be protected,
where necessary, against severe wind conditions.
J.
Upper floor installations. Listed gas floor furnaces may be installed in an upper floor, provided the furnace assembly projects below into a utility room, closet, garage, or similar nonhabitable space. In such installations, the floor furnace shall be enclosed completely (entirely separated from the nonhabitable space) with means for air intake to meet the provision of Subsection B, with access facilities for servicing on the control side, with minimum furnace clearances of six inches to all sides and bottom, and with the enclosure constructed of portland cement plaster on metal lath or material of equal fire resistance.
No gas-fired boilers, furnaces or other devices
for space heating a building or buildings shall be installed and no
boiler or furnace designed for other fuels shall be converted to the
use of gas unless the following regulations are complied with:
A.
Either an automatic safety pilot, so constructed and
adjusted that no gas can flow through the main burner unless the pilot
is burning, or some other approved type of safety device serving this
same shall be installed and employed.
(1)
Pilot burners shall be supported in such manner
that their position relative to the main burner or burners shall be
fixed.
(2)
Pilot burners shall be so positioned as to be
safely lighted and readily accessible for inspection, cleaning or
replacement.
(3)
Automatic safety pilots of gas burners having
a hourly input of less than 400,000 BTUs shall be so adjusted that
the main gas supply will be shut off within three minutes after a
pilot flame has been extinguished. Gas burners having an hourly input
of 400,000 BTUs or more shall be provided with a flame rod or other
approved instantaneous type safety pilot which will shut off the main
gas supply within 10 seconds of pilot flame failure; except that gas-designed
sectional cast-iron boilers will be accepted when provided with an
approved type safety pilot which shuts off the main gas supply within
75 seconds of pilot flame failure.
(4)
Pilot flames shall be so adjusted as to effectively
ignite the gas in the main burner or burners, shall be adequately
protected from drafts and shall not become extinguished when the main
burner or burners are turned on or off in a normal manner.
(5)
All pilots shall be so adjusted as to prevent
carbon deposits.
B.
All warm air furnaces shall be equipped with an approved
high temperature limit device and set not to exceed 300° for gravity
air systems and not to exceed 200° F. for mechanical air distribution.
All hot water boilers shall be equipped with an approved high water
temperature limiting device and the steam boilers shall be equipped
with approved pressure limiting devices and approved low water cut
off. Limiting devices on water and steam boilers shall be set so as
to not exceed the limitations as specified by the regulations of the
American Society of Engineers. These limiting devices shall be in
addition to operating controls.
C.
An approved gas pressure regulator of sufficient size
shall be installed in the gas line leading to the gas burner. An additional
approved adjustable gas pressure regulator shall be installed in the
gas pilot supply line.
(1)
All gas pressure regulators or diaphragm control
valves, used with space heating equipment, shall be vented to a constant
burning pilot so that any gas leaking to the atmospheric side of the
regulator or control valves will be carried to and ignited by the
pilot or an approved venting device shall be used.
(2)
On burners where no constant burning pilot is
provided, the gas pressure regulator or diaphragm control valve shall
be vented to the smoke pipe on the chimney side of the draft diverter
or directly to the outside atmosphere.
D.
An approved manual main shut-off valve shall be provided
ahead of all controls and a union connection shall be provided downstream
from this valve to permit removal of the controls or equipment.
(1)
A pilot gas supply line shall be installed on
the supply side of an approved main burner shut-off device through
an approved fitting and shall be equipped with a shut-off valve and
an adjustable pilot gas pressure regulator.
(2)
Drilling and tapping the fuel line for the purpose
of connecting a pilot gas supply line is prohibited.
E.
All gas burners shall consist of factory-assembled
and -tested units.
(1)
Gas burner units shall be so installed or attached
as to prevent twisting, sliding or dropping out of the intended correct
position.
(2)
Burners shall be so installed as to be readily
accessible for inspection and cleaning, and no part of the flames
shall impinge so as to cause incomplete combustion. No baffles shall
be applied which will interfere with proper combustion.
(3)
Air shutters shall be adjusted to produce a
good flame at the prevailing gas pressure.
(4)
Secondary air openings shall provide sufficient
area to supply an adequate amount of air for complete combustion and,
if automatically controlled, the construction shall be such that,
in case the control fails in any way, either the gas will be shut
off or the secondary air door will remain open.
(5)
The flames from constant burning pilots and
burners shall freely ignite the gas from adjacent burners when operating
at prevailing gas pressure and when the main control valve is regulated
to deliver about 1/3 the full gas rate.
(6)
Burners shall not expel gas through air openings
in mixer faces when operating at prevailing pressures.
F.
The combustion chamber and all its passages shall
be gastight.
G.
Pressure relief; venting.
(1)
The fuel door of a converted appliance shall
be arranged to relieve pressure due to puffs or backfire caused by
delaying ignition or other causes and shall be provided with an approved
self-closing device.
(2)
Every gas-fired boiler, furnace or other space
heating device shall be effectively vented to the outside atmosphere.
H.
Where dampers are an integral part of the equipment,
they shall be removed or permanently secured in the wide-open position,
except such dampers as may be used to alter the passage of flue gases
through the equipment, which will be locked in such a position as
not to interfere with the safe operation of the burner.
(1)
Every gas-fired boiler, furnace or other nonportable
space heating device shall be connected to a flue.
(2)
In case of conversion burners, the section of
the vent pipe between the outlet of the equipment and the chimney
shall be full size as the flue collar of the appliance and in no case
less than one square inch per 6,500 BTUs' hourly input. Where the
outlet from the equipment is larger than the above indicated size,
an orifice plate or other approved restricted section may be inserted.
(3)
No adjustable dampers in the flue pipe shall
be permitted.
(4)
A draft hood or diverter of approved design
or its approved equivalent shall be placed in and made a part of the
flue pipe from the equipment, or in the equipment itself. Such device
shall be designed to (1) ensure the ready escape of the products of
combustion in the event of no draft, backdraft or stoppage beyond
the equipment, (2) prevent a backdraft from entering the equipment
and (3) neutralize the effect of stack action of the flue upon the
operation of the burner and shall otherwise comply with the requirements
hereinafter specified for such devices and their installation.
(5)
The draft hood or diverter shall be located
at a point not lower than the top of the highest flue passage.
(6)
The draft hood or diverter shall be located
at least one foot higher than the top of the highest flue passage
for equipment of the revertible (down draft furnace) flue type, and
all boilers or furnaces of this type not specifically designed for
the use of gas fuel shall be so altered or equipped as to prevent
accumulation of gas in any part thereof.
(a)
Part 3, Section 5c from ASA Z-21.8 1948.
A.
Chimney flues and flue pipes shall freely conduct
the flue gases to the outside atmosphere.
(2)
Whenever the type of fuel for heating equipment
is changed, the flue shall be cleaned from the base of the chimney
to the point the vent enters the chimney, and the remainder of the
flue shall be clear so as to properly conduct the products of combustion
to the outside atmosphere. Cleanouts or other approved devices shall
be provided at the base of all chimneys to enable the flues to be
maintained clean.
B.
Type A flues (lined chimneys of masonry or reinforced
concrete or metal smoke stack) are required for (1) all space heating
equipment which may be converted to the use of solid or liquid fuel;
(2) all boilers and furnaces. The above provisions shall apply except
where special approval is granted by the Inspector for the use of
Type B vent piping.
C.
Chimneys or flues installed for the use of gas-fired
space heating equipment but which are not suitable for solid or liquid
fuels must be plainly and permanently marked: "This flue is for the
use of gas-burning appliances only." Such marking or label shall be
placed at a point near where the vent pipe enters the chimney or,
with Type B vent piping used in places of a chimney, where the Type
B vent piping enters the wall, floor or ceiling.
D.
Type B flues shall be used only with approved gas-fired
equipment which is not required to be vented to Type A flues, and
which produces flue gas temperatures not in excess of 550° F.
at the outlet of the draft hood when burning gas at the maximum permissible
manufacturer's input rating. Type B flues shall be constructed in
accordance with one of the following specifications:
(1)
A Type B flue may be an Underwriter's Laboratory
Inc. listed for gas appliances or an equivalent flue tested in a like
manner by other nationally recognized testing laboratories.
(2)
A Type B flue may be of double construction
with at least one-inch clearance at all points between the inner lining
and the outer casing. The inner lining shall be made of standard iron
or steel pipe with threaded joints; or transite pipe with cemented
joints; or U.S. twenty-gauge galvanized metal or U.S. twenty-four-gauge
copper with gas-tight joints, secured with at least two metal screws
in each joint. The inner lining shall be sealed at the bottom and
fitted with a suitable condensate trap. The outer casing shall be
made of iron or steel pipe, cast iron, transite pipe, or of galvanized
sheet metal not less than U.S. twenty-four-gauge, or of sheet copper
not less than U.S. twenty-four-gauge. The required clearance between
the lining and casing shall be maintained by means of suitable permanent
metal spacers which will not materially restrict the circulation of
air. A flue so constructed shall extend at least two inches between
the finished ceiling line and sufficiently high to provide adequate
venting (at least three feet above the finished roof line) and shall
be equipped with a suitable weather cap or an approved exhauster.
The cross-sectional area of the inner lining of such flues shall be
at least 20 square inches with no dimension less than five inches
except where special approval is given by the Village of New Haven.
A minimum clearance of one inch shall be maintained by the outer casing
of such flue and any combustible material. (Note: See Detail A.[2])
[2]
Editor's Note: Detail A is included at the end of this chapter.
(3)
A Type B flue may be of double construction
with at least two inches clearance at all points between the inner
lining and the outer casing. The inner lining shall be made of galvanized
sheet metal of not less than U.S. twenty-gauge or of copper of not
less than U.S. twenty-four-gauge with tight-fitting joints secured
with a least two metal screws in each joint. Joints in the inner lining
shall be fabricated with the crimped portion extending downward inside
the next lower section. The outer casing shall be made of galvanized
sheet metal or copper of not less than U.S. twenty-four-gauge with
tight-fitting joints secured with at least two metal screws in each
joint. Joints in the outer casing shall be fabricated with the crimped
portion extending upward inside the next higher section. The annular
space between the lining and the casing shall be filled with mineral
wool or other noncombustible insulating material, and the ends of
the space shall be sealed with tight-fitting metal washers or collars
of the same material as used to construct the inner lining.
(a)
The washer or collar on the weather end shall
be so fitted as to effectively prevent water or moisture from entering
the insulated filled space.
(b)
A flue so constructed shall extend at least
two inches below the finished ceiling line and sufficiently high to
provide adequate venting (at least three feet above the finished roof
line), shall be equipped with a suitable weather cap or approved exhauster,
and sealed at the bottom and fitted with a suitable condensate trap.
The cross-sectional area of the inner lining of such flues shall be
at least 20 square inches with no dimension less than five inches,
except where special approval is given by the Department. A minimum
clearance of one inch shall be maintained between the outer casing
and such flue and any combustible material (Note: See Detail B.[3])
[3]
Editor's Note: Detail B is included at the end of this chapter.
(4)
The vent piping may be of double construction
with at least two inches of clearance at all points between the inner
lining and the outer casing. The inner lining shall be made of galvanized
sheet iron of not less than U.S. twenty-gauge or of copper of not
less than U.S. twenty-four-gauge with tight-fitting joints secured
with at least two metal screws in each joint. Joints in the inner
lining shall be fabricated with the crimped portion extending downward
inside the outer portion. The outer casing shall be made of galvanized
sheet iron or copper of not less than U.S. twenty-four-gauge with
tight-fitting joints secured with at least two metal screws in each
joint. Joints in the outer casing shall be fabricated with the crimped
portion extending upward inside the outer portion. The annular space
between lining and casing shall be filled with mineral wool or other
noncombustible insulating material, and the ends of this space shall
be sealed with tight-fitting metal washers or collars of the same
material as used to construct the inner lining. The washer or collar
on the weather end shall be so fitted as to effectively prevent water
or moisture from entering the insulation-filled space. A vent flue
so constructed shall extend at least two inches below the finished
ceiling line and sufficiently high to provide adequate venting (at
least three feet above the finished roof line), shall be equipped
with a suitable weather cap and shall be sealed at the bottom and
fitted with a suitable condensate trap. The cross-sectional area of
the inner lining of such vent flues shall be at least 20 square inches
with no dimension less than five inches, except where special approval
is given by the Department. (Note: See Detail B.[4])
[4]
Editor's Note: Detail B is included at the end of this chapter.
E.
Other patented prefabricated flues may be used, provided
such flues have been specifically approved by the Inspector for such
use. Such approved vent flues must bear the trademark of the manufacturer
and must be installed in strict compliance with the manufacturer's
specifications.
F.
Type B or other patented prefabricated flues shall
not be terminated on an exterior wall, except upon special approval
of the Board of Examiners.
Clearance from combustible material to gas-fired
space heating unit vent piping shall be such that continued operation
of the equipment will not raise the temperatures of surrounding combustible
materials or construction more than 90° F. above normal room temperatures.
B.
The vent connection shall not be smaller than the
size indicated by the vent collar on the space heating unit.
C.
The horizontal vent connection shall not be longer
than 1/2 the effective height of the chimney.
(1)
The vent pipe shall maintain a pitch or rise
of 1/4 inch per foot of the horizontal run from the equipment to the
flue or chimney.
(2)
The exposed connection between a gas-fired appliance
and flue or chimney shall be made with sheet metal of at least U.S.
twenty-four-gauge or other approved durable incombustible material.
In the case of floor furnaces, such vent shall be constructed of asbestos
cement pipe with cemented joints or material of equal insulating value.
Such vent pipe shall not pass into or through any floor, ceiling,
roof or exterior wall but may pass through interior partitions if
properly protected by a metal thimble with a one-inch air space on
all sides.
(3)
Clearances from vent pipes to combustible material
shall be in accordance with Table No. 3.[1] The clearances from metal flue or vent connectors to combustible
construction may be reduced as specified in Table No. 2,[2] where the combustible construction is protected in accordance
with this table.
[1]
Editor's Note: Table No. 3 is included at the end of this chapter.
[2]
Editor's Note: Table No. 2 is included at the end of this chapter.
D.
The vent pipe shall be so installed as to avoid sharp
turns or other constrictive features which would create excess resistance
to flow of the gaseous products.
E.
Interconnections.
(1)
Vent pipes from one or more gas-fired space
heating appliances may be interconnected, provided that the cross-sectional
area of the manifold shall be equal to the sum of the cross-sectional
areas of the vent collar connections of the appliances.
(2)
No vent from a gas-fired heating appliance shall
be interconnected with a vent pipe from an appliance burning other
fuels or designed for other uses except with the specific approval
of the Department.
F.
A vent pipe from a gas-fired heating appliance and
vent pipes from other appliances, burning the same or other fuels,
may be connected into the same chimney through separate openings located
at different levels, provided that the operation of any of the equipment
is not adversely affected.
G.
The material used for vent pipes shall be new and
shall be such as to resist the corrosive action of flue gases and
condensate. The vent pipe shall be rigidly and securely installed.
The customer shall be thoroughly instructed
by the vendor or his agent as to proper and safe operations of the
gas burner before it is placed in continuous service, and suitable
printed instructions shall be supplied by the vendor or his agent
and prominently displayed near the gas burner.