B.
Low-temperature chimneys.
(1)
Chimneys constructed to convey products of combustion
having a temperature of 600° F. or less at the point of entrance
shall be classified as low-temperature chimneys.
(2)
The following heat-producing devices shall be included
among those requiring low-temperature chimneys: bakers' ovens, boiling
vats, candy furnaces, coffee-roasting ovens, cooking ranges, core
ovens, cruller furnaces, drying furnaces for spent materials, feed-drying
furnaces, fertilizer-drying ovens, forge furnaces, gas producers,
hardening furnaces (below dark red), hot-air engine furnaces, hot-air
heating furnaces, hot-water and lows-pressure steam-heating boilers,
japanning ovens, metal-drying furnaces, lead-melting furnaces, nickel-plate
furnaces, paraffin furnaces, rendering furnaces, rosin-melting furnaces,
sterotype furnaces, sulfur furnaces, typefoundry furnaces, wood-drying
furnaces and wood-impregnating furnaces.
C.
Medium-temperature chimneys.
(1)
Chimneys constructed to convey products of combustion
having a temperature of between 600° F. and 1,200° F. at the
point of entrance shall be classified as medium-temperature chimneys.
(2)
The following heat-producing devices shall be included
among those requiring medium-temperature chimneys: charcoal furnaces;
direct fire-heated feed driers; direct fire-heated fertilizer driers;
direct fire-heated pulp driers; galvanizing furnaces; hardening furnaces
(cherry to pale red); porcelain biscuit kilns; smokehouses; steam
boilers, other than low-pressure heating boilers; water-glass kilns;
wood-distilling furnaces; and wood-gas retorts.
D.
High-temperature chimneys.
(1)
Chimneys constructed to convey products of combustion
having a temperature of over 1,200° F. at the point of entrance
shall be classified as high-temperature chimneys.
(2)
The following heat-producing devices shall be included
among those requiring high-temperature chimneys: annealing furnaces;
blast furnaces; bone-calcining furnaces; brass furnaces; carbon-point
furnaces; cement, brick and tile kilns; coal and water-gas retorts,
cupolas; earthenware kilns; gas blow furnaces; glass-smelting furnaces;
glass kilns; open-hearth furnaces; ore-roasting furnaces; porcelain
baking and glazing kilns; regenerative furnaces; reverberatory furnaces;
stacks, carburetor or superheating furnaces in water-gas works; welding
furnaces; and wood-carbonizing furnaces.
E.
Unclassified heat-producing devices. In doubtful cases,
the Superintendent of Buildings shall decide the grade of any heat-producing
device, being governed in his decision by the degree and amount of
heat transmitted at the point of entrance to the chimney.
A.
Construction of chimneys.
(1)
Except as in this article otherwise provided, every
chimney hereafter erected shall be brick or stone, laid in cement
mortar, or of reinforced concrete extending two feet above the highest
point of the roof and at least four feet above the highest point of
contact with the roof. Every chimney shall be properly capped with
terra cotta, stone, cast iron or other approved incombustible weatherproof
material, except that on structures 40 feet or less in height, the
top courses of a brick chimney may be finished off by being carefully
bonded and anchored together to serve as coping.
(2)
Where smoke pipes enter flues, the brickwork shall
be corbeled out to the face of the studs. The part thus corbeled out
shall be not less than 16 inches by 16 inches, but in no case shall
such corbeling exceed the thickness of the wall.
B.
Supports for chimneys.
(1)
Such chimneys shall be wholly supported by self-supporting
fireproof construction. No chimneys shall rest or be built upon wood
or other combustible construction.
(2)
No such chimney shall be corbeled out or constructed
to overhang in any direction more than 1/3 the thickness of the masonry
below the corbel or overhang.
C.
Flues for low-temperature devices. The smoke flues
of stoves, cooking ranges, hot-air, hot-water and low-pressure steam-heating
furnaces and all other low-temperature heat-producing devices shall
be encased in brickwork or concrete not less than eight inches thick,
except that for smoke flues exclusively used for ordinary stoves,
ranges or open fireplaces, when no combustible studding, furring or
sheathing is placed within four inches of the face of the chimney,
such brickwork or concrete may be reduced to not less than four inches.
In chimneys of stone, the stone work of such flues shall be four inches
thicker than required for brick. Every flue shall be of well-burnt
terra cotta pipe from the bottom of the entire height of the chimney.
Such lining pipes shall be built in as the flues are carried up and
laid end to end in cement mortar so as to make a smooth flue. Where
two or more smoke flues are contained in the same chimney, the withes
shall be either brick not less than four inches thick or concrete
or grout not less than one inch thick; provided, however, that every
third withe shall consist of brick.
D.
Flues for medium-temperature devices. The smoke flues
of high-pressure steam boilers, smokehouses and all other medium-temperature
heat-producing devices shall be encased in brickwork or concrete not
less than eight inches thick or stonework not less than 12 inches
thick and, in addition, shall be lined with not less than four inches
of firebrick, laid in fireclay mortar, for a distance of at least
25 feet from the point where the smoke connection of the device enters
the flue.
E.
Flues for high-temperature devices. The smoke flues
of cupolas, brass furnaces, porcelain baking kilns and all other high-temperature
heat-producing devices shall be built with doable walls, each not
less than eight inches in thickness and with an airspace of not less
than two inches between them. The inside of the interior walls shall
be of firebrick not less than four inches in thickness.
F.
Chimneys for incinerators.
(1)
For non-fuel-fired incinerators in which the grate
area of the combustion chamber is nine square feet or less, the chimney
walls shall be at least 3 3/4 inches thick and shall be lined
with fireclay flue lining, provided that not more than three service
openings are installed in such a chimney and that such chimneys are
used in structures three stories or less in height.
(2)
For non-fuel-fired incinerators in which the grate
of the combustion chamber exceeds nine square feet in area, the chimney
walls shall be at least 3 3/4 inches thick and shall be lined
for a distance of at least 30 feet above the roof of the combustion
chamber with 4 1/2 inches of firebrick and; above this point,
the chimney wall shall be constructed with at least eight inches of
brickwork.
(3)
For fuel-fired incinerators in residence structures,
institutional structures, churches, schools and restaurants, the chimney
walls shall be encased as required for non-fuel-fired incinerators
with grates exceeding nine square feet in area, but the firebrick
lining shall extend at least 40 feet above the roof of the combustion
chamber.
(4)
For rubbish and waste material incinerators. the chimney
walls shall be encased in brickwork at least eight inches thick with
a lining of firebrick at least 4 1/2 inches thick laid in fireclay
mortar for the full height of the chimney.
(5)
The connection of a fuel-fired incinerator or rubbish
and waste material incinerator to a boiler stack or chimney for a
high-temperature heating device shall be permitted by means of an
approved breeching, provided that the cross-sectional area of such
stack or chimney is at least four times that of the incinerator breeching.
(6)
Chimneys for incinerators shall extend at least 10
feet above the roof and terminate in substantially constructed spark
arresters.
G.
Cupola chimneys. Chimneys of cupola furnaces, blast
furnaces and similar devices shall extend at least 20 feet above the
highest point of any roof within a radius of 50 feet thereof and be
covered on the top with wire netting or other approved spark arrester.
No woodwork shall be within three feet of any part of such device
or its chimney.
H.
Flues required.
(1)
Every heating apparatus or heat-producing appliance
in which fluid or solid fuel is used shall be connected with a flue,
chimney or smokestack, conforming to the provisions of this article,
to carry off the products of combustion. Such connection shall be
as direct and as short as possible.
(2)
The effective cross-sectional areas of smoke flues
shall be proportioned to temperatures produced to secure adequate
draft conditions. Such areas shall not be less than 28 square inches
for small stoves and heaters; 40 square inches for stoves, ranges
and room heaters; 50 square inches for fireplaces but not less than
1/12 of the fireplace opening; and 70 square inches for warm-air furnaces
and hot-water and steam boilers.
(3)
In every structure hereafter erected exceeding 40
feet in height where one or more smoke flues start from the cellar
or lowest story, at least one such flue shall have an internal cross-sectional
area of not less than 96 square inches and shall start not less than
three feet below the ceiling. No flue hereafter erected shall have
smoke-pipe connections in more than one story of a structure.
I.
Cleaning of flues and safety of chimneys. Upon the
completion of any new structure or an alteration in any flues of an
existing structure, the flues shall be properly cleaned and left smooth
on the inside. Any chimney which may be dangerous in any manner whatsoever
shall be repaired and made safe or taken down.
J.
Unlawful use of fires. It shall be unlawful to use
as a smoke flue any flue hereafter erected or placed in any structure
or any flue not existing and not already used as a smoke flue unless
it conforms to the requirements of this section. Nothing in this article,
however, shall prevent the use of approved metal flue linings for
the repair or alteration of flues in residence structures.
K.
Raising adjoining chimneys.
(1)
Whenever a building, wall or structure is hereafter
erected, altered, enlarged or raised so that any of the walls, whether
independent or partly along a property line or within three feet thereof,
extend above the top of any chimney, smoke flue or smokestack or an
adjoining structure, the owner of the building, wall or structure
so erected, altered, enlarged or raised shall, at his own expense,
carry up, either independently or in his own building wall or structure,
all chimneys, smoke flues and smokestacks of such adjoining structure
within 10 feet of any portion of said wall extending above such chimney,
flue or stack. The construction of such chimneys, flues or stacks
shall conform to the requirements of this article applying thereto,
but in no case shall the interior area of any flue or stack as raised
be less than that of the existing flue or stack. All such chimneys,
flues or stacks shall be carried above the walls in question to the
heights prescribed and shall, furthermore, be so constructed, supported
and braced as to be safe at all times.
(2)
It shall be the duty of the owner of the building,
wall or structure to be erected, altered, enlarged or raised to notify,
in writing, at least 10 days before such work is begun, the owner
of the chimney, flues or stacks affected of his intention to carry
up such chimneys, flues or stacks as herein provided and, unless released
in writing, he shall carry up such chimneys, flues or stacks simultaneously
with the wall.
L.
Underground smoke flues. Underground smoke flues shall
be covered with at least 12 inches of solid masonry or an approved
equivalent insulation. If clean-cut openings are installed, they shall
be provided with approved double iron doors or covers, of which the
two parts are 12 inches apart, with the intervening space filled with
insulating material. No combustible flooring shall be laid over any
such flues.
A.
Back walls for fireplaces. The firebacks of all fireplaces
hereafter erected shall be not less than eight inches in thickness
of solid masonry. A lining of firebrick or other approved material
at least two inches thick shall be provided unless the fireback is
12 inches in thickness.
B.
Trimmer arches. All fireplaces and chimney breasts
shall have trimmer arches of fireproof construction supporting hearths.
The arches and hearths shall be at least 20 inches in width measured
from the face of the chimney breast. Trimmer arches shall be of brick,
stone, terra cotta or reinforced concrete. The length of the trimmer
arch and the hearth shall not be less than the width of the chimney
breast. The hearths shall be of brick, stone, tile or other approved
fireproof material. The combined thickness of trimmer arch and hearth
shall at no point be less than six inches. Wood centers under trimmer
arches shall be removed.
C.
Wood mantels. No wood mantel or other woodwork shall
be hereafter placed within eight inches on either side nor within
12 inches of the top of any open fireplace. No combustible summer
piece or fireboard shall be used in connection with any open fireplace.
All spaces in back of combustible mantels shall be solidly filled
in with incombustible material.
D.
False fireplaces and heaters.
A.
Construction of metal smokestacks. Metal smokestacks
must be so constructed that they will be securely supported and that
the materials entering into their construction or serving as support
shall not be stressed beyond the working stresses fixed by this code.
The metalwork must be riveted and of adequate thickness but not less
than No. 16 United States gauge when the cross-sectional area is 154
square inches or less, not less than No. 14 United States gauge when
the cross-sectional area is more than 154 square inches, not less
than No. 12 United States gauge when the cross-sectional area is more
than 201 square inches but not more than 254 square inches and not
less than No. 10 United States gauge when the cross-sectional area
is more than 254 square inches. All metalwork shall be painted and
galvanized metal shall not be used. Clean-out openings shall be provided
at the base of every such stack.
B.
Extension of metal smokestacks above roof. Metal smokestacks
serving high-temperature heat-producing devices shall extend to a
height of not less than 10 feet above the highest point of any roof
within 25 feet.
C.
Foundations for independent metal smokestacks. Metal smokestacks hereafter erected outside and independent of any structure shall be supported on substantial masonry foundations so designed that the maximum pressure on the soil shall not exceed 2/3 of that prescribed in § 86-54, Soil-bearing capacity.
D.
Exterior metal smokestacks. Metal smokestacks or any
part thereof hereafter erected on the immediate exterior of the structure
it serves shall be braced to such structure at least every 20 feet.
It shall have a clearance of not less than four inches from the walls
of a fireproof or nonfireproof structure and not less than 24 inches
from the walls of a frame structure, and it shall have a clearance
of not less than 24 inches in any direction from any wall opening,
fire escape or other facility unless such stack is insulated in some
approved manner, in which case the clearances herein provided may
be reduced in an amount fixed by the Superintendent of Buildings when
approving the insulation.
E.
Interior metal smokestacks. Any metal smokestack or
part thereof hereafter erected within any nonfireproof structure shall
be enclosed in walls of solid masonry at least eight inches thick
or, if in a fireproof structure, such chimney or part thereof shall
be enclosed in walls of approved masonry at least eight inches thick
or at least four inches of solid masonry, provided that the stack
is covered with at least two inches of approved incombustible insulating
material. Where such chimney is less than 24 inches in its smallest
internal dimension, it shall have a space left between the chimney
and the enclosing walls sufficient to render the entire chimney accessible
for examination and repair. The enclosing walls shall, in all cases,
be without openings above the story at which they start. In any case,
the enclosing wall shall be at least four inches away.
F.
Clearances for smokestack and breeching.
(1)
The minimum distance between any smoke pipe or breeching
and any combustible material or construction shall be 18 inches in
the case of low-temperature heating devices and 36 inches for medium-
or high-temperature heating devices, except that when such combustible
material is protected with at least two inches of asbestos or in some
other approved manner, such clearance may be reduced by 1/2.
(2)
No smoke pipe shall pass through any floor.
G.
Smoke pipes passing through partitions. Smoke pipes
from low-temperature heating devices passing through combustible partitions
shall be guarded by a double metal ventilation thimble 12 inches larger
in diameter than the pipe or by a metal tube built in brickwork or
other approved fire-resistive materials at least eight inches thick
on all sides of the tube.
A.
Ducts for warm-air furnaces. Intake and delivery ducts
for warm-air furnaces shall be of metal or other approved fire-resistive
material.
B.
Horizontal warm-air ducts. Warm-air ducts placed under
ceilings shall be at least six inches below wood floor beams, wood
lath plaster ceilings or other combustible materials unless such combustible
construction is protected by metal lath and plaster or plasterboards
of one-half-inch asbestos, in which case the distance shall be a minimum
of three inches.
C.
Warm-air ducts through partitions and floors. Warm-air
ducts or flues placed to pass through combustible partitions or floors
shall be constructed double with a one-and-one-half-inch airspace
open at one end or shall be covered with approved incombustible insulation
at least one inch thick.
D.
Warm-air ducts in partitions. Warm-air ducts or flues
placed in combustible partitions shall be covered with one-half-inch
asbestos air-cell covering or shall be constructed double with a one-half-inch
airspace. The asbestos covering or the outside pipe shall be at least
1 1/2 inches away from the woodwork. In lieu of the above protection,
four inches of brickwork or concrete may be placed between the duct
and woodwork.
E.
Warm-air ducts in floors. Warm-air ducts hereafter
placed between the flooring and ceiling of nonfireproof floors shall
be constructed double with a one-inch airspace. The outside pipe shall
be at least two inches from any woodwork unless such woodwork shall
be covered with metal.
F.
Warm-air ducts in closets. Warm-air ducts or flues
hereafter placed in closets or similar locations shall be constructed
double with a one-and-one-half-inch airspace or shall be covered with
an approved incombustible insulation at least one inch thick. When
constructed double, the outside pipe shall be at least No. 18 United
States gauge and at least one inch from any woodwork.
G.
Warm-air ducts adjacent to woodwork. No casing, furring
or wood lath shall be placed against or cover a warm-air duct of any
kind, but this shall not prevent the placing of woodwork on a covering
of such ducts of metal lath and plaster, plasterboard and 1/2 inch
of plaster or asbestos, provided that the thickness of the cover is
at least 7/8 inch.
H.
Warm-air registers. Warm-air registers placed in any
woodwork or combustible floor shall rest upon stone or iron borders
firmly set in plaster of paris or gauged mortar. Register boxes used
in any such heating system shall be made of tinplate or galvanized
iron with a flange to fit the rabbet in the border. The register box
shall be enclosed in a tin or galvanized iron casing, turned under
the border and placed at least two inches from the sides of the box.
Such casings shall extend from the border to and through the partition
in the cellar ceiling below in the case of a first floor register
and through the partition in the case of a wall register. When a register
box is placed in the floor over a portable furnace, the space on all
sides between the casing and the register box shall be at least four
inches. Every warm-air furnace shall have at least one register without
a shutoff of any description.
I.
Cold-air ducts. The cold-air ducts of any heating
system shall be of metal or other approved fireproof material.
A.
Construction of vent flues. Flues hereafter erected for the removal of foul air or the transmission of heated air shall be encased in masonry not less than four inches thick and shall be lined with terra cotta or other approved incombustible material. Not more than one gas-burning device shall be direct-connected with any flue nor shall any device be connected to any flue used as a smoke flue. Any flue to which a gas-burning device is direct-connected shall be constructed as required in § 86-80 for a smoke flue.
B.
Vent flues for gas appliances. Every gas appliance
shall be connected to a vent flue having a cross-sectional area equal
to the aggregate area of the vent collars of such appliances as follows:
(1)
Every appliance used for domestic purposes using in
excess of 100 cubic feet of gas per hour.
(2)
Automatically controlled appliances using more than
10 cubic feet of gas per hour.
(3)
Automatically controlled appliances using less than
10 cubic feet of gas per hour, which are not equipped with an effective
device and which, in the event that the constantly burning flame or
pilot flame is extinguished, will automatically shut off the gas supply
to the main burner or burners.
(4)
Appliances installed in the same room which in the
aggregate use, at normal rating, 6/100 of a cubic foot of gas per
hour for each cubic foot of room space.
(5)
Water heaters in bathrooms, bedrooms or occupied rooms
normally kept closed.
A.
Ranges, candy kettles, cruller furnaces and appliances
for the frying of bakery or confectionery products, except ranges
in dwellings, shall be provided with ventilating hoods and pipes to
take off the smoke, gases and vapors unless such appliances are enclosed
and vented in an approved manner.
B.
Such hoods shall be within 6 1/2 feet above the
floor. The width and breadth shall be at least those of the appliance
served thereby.
C.
Such hoods and their pipes shall be constructed of
incombustible materials. The pipes shall be connected with independent
masonry flues and constructed as required for smoke flues for low-temperature
heating devices, provided that in structures heretofore erected, when
such masonry flues are unavailable, they may be connected with independent
metal chimneys outside the structure. In any case, such flues or stacks
shall be used only for the ventilation of such hoods. All the hoods
in a single room or kitchen may be connected to a single flue.
D.
Such hoods shall be installed with the clearances
required for smoke pipes. When the pipe from such a hood passes through
a partition, it shall be protected as required for smoke pipes.
Contact between steam or hot-water pipes and
any woodwork or other combustible material is forbidden. Steam or
hot-water pipes shall have a minimum clearance from any combustible
material of 1/2 inch. Where steam or hot-water pipes are located within
one inch of any combustible material, such material shall be protected
by a metal casing or lining and where passing through stock shelving,
such material shall be covered with at least 1/2 inch of insulating
material. Steam and hot-water pipe coverings shall be of fire-retarding
material.
A.
Grate areas of three square feet or more. Furnaces
or boilers having grate or burner areas of three square feet or more
shall be set upon masonry foundations, which shall rest upon incombustible
construction or assemblies. Any such boiler operating at 15 pounds
of pressure or more shall be enclosed in a room whose walls have a
fire-resistive rating of at least three hours and whose ceiling has
a fire-resistive rating of at least one hour.
B.
Grate areas of less than three square feet. Furnaces
or boilers using solid or gas fuel and having grate or burner areas
less than three square feet may be set on wood floors, provided that
they rest upon foundations consisting of at least two inches of solid
brick and four inches of hollow tile or the equivalent of these two
materials set on sheet metal plates at least as thick as No. 14 United
States gauge and at least 24 inches larger in all directions than
the base of the boiler or furnace if solid fuel is used and six inches
larger in all directions if gas fuel is used. The tile shall be laid
with open ends in contact when solid fuel is used, and an ash plate
or ashpan of metal at least as thick as No. 10 United States gauge
shall be provided above the foundation.
C.
Spaces around furnaces and boilers.
(1)
A clear working space of at least 18 inches on the
sides and 24 inches on the top shall be provided around all furnaces
and boilers. Such separation shall be maintained with respect to walls
as well as pumps and other apparatus used in connection with the heating
plant.
(2)
Combustible material shall be at least six feet away
from the front, four feet away from the top and three feet away from
the sides of furnaces or boilers, including enclosures. These separations
may be reduced by 1/2 when at least 1 1/2 inches of asbestos
insulating material or its equivalent is applied to the furnace or
combustible material.
(3)
In rooms where fuel-oil-burning equipment is installed,
the ceiling shall be insulated with material or assemblies having
a fire-resistive rating of at least one hour and extending at least
four feet on the sides and rear and eight feet in front of the furnace,
except that in private dwellings, No. 16 United States gauge sheet
metal over sheet asbestos not less than 1/16 inch may be substituted
for one-hour fire-resistive rating protection. If the ceiling is constructed
throughout so as to have a fire-resistive rating of at least one hour,
the insulation may be omitted.
D.
Safety valves on steam boilers. Every boiler generating
steam shall be equipped with a safety valve. Safety valves shall be
adjusted and set to open under a lesser pressure than the maximum
working pressure for which the boiler was designed.
E.
Relief valves, hot-water systems. Every closed hot-water
heating system shall be equipped with an approved pressure relief
valve. Such pressure relief valves shall be adjusted and set to open
at a pressure slightly higher than the normal operating pressure of
the hot-water heating system.
F.
Boiler or furnace room air supply. Rooms in which
boilers or furnaces are located shall have adequate means for fresh
air supply to ensure proper combustion. Direct connection of air inlets
to the ashpits or combustion chambers of boilers or furnaces is forbidden,
except where forced draft is employed.
A.
Cooking, laundry and heating stoves and combination
coal and gas ranges installed in dwellings shall be set on hearths
supported by masonry trimmer arches extending at least six inches
on all sides beyond such appliances, except that such appliances,
when supported on legs furnishing an open airspace of at least four
inches below the bottom of the appliance, may be set on sheet metal
of at least No. 24 United States gauge or other approved incombustible
material.
B.
The placing of such appliances within 24 inches of
wood-stud partitions, wood-furred walls or combustible material is
forbidden unless they are protected by a shield of metal or other
approved incombustible material so attached as to preserve an open
airspace behind it and to extend from the floor to two feet above
and 12 inches beyond the sides of such appliances, in which case the
appliance shall be placed at least six inches away from a wood-stud
partition, wood-furred wall or combustible material.
C.
Domestic gas ranges in which the clearance between
the base frame and the floor is two inches or less shall be set in
a base of hollow clay tile four inches thick or its equivalent and
extending at least two inches beyond the range on all sides. When
such clearance is more than two inches but less than six inches, such
ranges shall be set on a base of asbestos board 3/16 inch thick, held
between two sheets of metal at least No. 24 United States gauge and
extending at least two inches beyond the range on all sides. When
such clearance is more than six inches or the lower burners of the
range are 12 inches or more above the floor, measured from the burner
ports, no protection shall be required. When such ranges are set so
that the oven back or side of the cooking top is less than six inches
from combustible material, the combustible material shall be protected
by asbestos board 3/16 inch in thickness and by sheet metal of at
least No. 24 United States gauge or its equivalent as approved by
the Superintendent of Buildings.
D.
Stoves and ranges using solid fuel shall be connected
by a smoke pipe to a regulation chimney.
E.
Any woodwork or other combustible material less than
three feet above the range shall be covered on the underside with
sheet metal at least as thick as No. 29 United States gauge and backed
with asbestos millboard at least 3/16 inch thick, but, in any case,
the clearance shall be at least two feet.
A.
Non-fuel-fired incinerators.
(1)
Incinerators in which no fuel, other than normal refuse,
is used for combustion, except as gas flame or similar means to accomplish
ignition, and in which the chute and smoke flue are identical, when
installed in dwellings, public buildings and restaurants not over
three stories in height, shall have the enclosing walls of the combustion
chamber constructed of brickwork at least 3 3/4 inches thick
when there is a horizontal grate area of nine square feet or less
and at least eight inches thick when there is a horizontal grate area
exceeding nine square feet and, in each case, a lining of firebrick
at least 4 1/2 inches thick shall be provided. In the case of
a thicker wall, an airspace between the brick and the firebrick, sufficient
to provide for expansion and contraction, shall be provided.
(2)
The combined chute and flue in structures over three stories in height shall be constructed as prescribed for smoke flues in § 86-82D, Flues for medium-temperature devices. Such chute and flue shall be constructed straight and plumb and finished smooth on the inside.
(3)
Service openings into the chute shall be equipped
with approved self-closing hoppers so constructed that the chute or
flue is closed off while the hopper is being charged and that no part
will project into the chute or flue. The area of the service opening
shall not exceed 1/3 of the areas of the chute or flue.
(4)
Incinerator openings shall not open directly on a
required means of egress unless they are cut off from such means of
egress by a self-closing protective assembly having a fire-resistive
rating of at least one hour.
B.
Fuel-fired incinerators.
(1)
Fuel-fired incinerators, whether the fuel is specially
supplied or consists of refuse or waste material, shall have the enclosing
walls of the combustion chamber constructed of brick at least eight
inches thick with a lining of firebrick at least 4 1/2 inches
thick when the grate area is nine square feet or less and with a lining
of firebrick at least nine inches thick when the grate area exceeds
nine square feet, all strongly braced and stayed with structural steel
shapes, provided that the outer four inches of clay or shale brickwork
may be replaced by a steel plate casing 3/16 inch in thickness, and
provided that the firebrick lining is laid in fireclay mortar.
(2)
The combustion chamber shall be located in a separate
room or compartment used for no other purpose or in a room devoted
exclusively to boilers and heating plant. In either case, such room
shall be separated from the rest of the structure by floors, walls
and ceilings having a fire-resistive rating of at least three hours.
Openings to such rooms shall be protected with protective assemblies
having a fire-resistive rating of at least 1 1/2 hours.
(3)
The flue connections or breechings from the combustion
chamber shall be constructed of No. 16 United States gauge metal when
12 inches or less in diameter or greatest dimension and of No. 12
United States gauge metal when they exceed 12 inches in diameter or
greatest dimension. In addition, they shall be lined with firebrick,
laid in fireclay mortar, at least 2 1/2 inches thick when between
12 and 18 inches in diameter or greater dimension and at least 4 1/2
inches thick when they are larger. If they lead into and combine with
flue connections or breechings from other appliances, such other connections
or breechings shall also be lined as required for direct flue connections
unless the cross-sectional area of the connection into which they
lead is at least four times their required cross-sectional area.
(4)
The clearance to woodwork or other combustible materials
or construction on all sides of flue connections or breechings from
the combustion chamber shall be at least 36 inches, provided that
when such woodwork or combustible construction is guarded by a metal
shield and backed with asbestos 3/16 inch thick, such clearance may
be reduced to 18 inches.
(5)
Refuse chutes, except when used exclusively for garbage
disposal in dwellings, public buildings and restaurants, shall not
feed directly to the combustion chamber but shall discharge into a
room or bin enclosed and separated from the incinerator room by floors,
ceilings and walls of equal fire resistance to those required to enclose
the incinerator room. The opening through which material is transferred
from such room or bin to the incinerator room shall be equipped with
a protective assembly having a fire-resistive rating of at least 1 1/2
hours.
(6)
Refuse chutes shall rest on substantial incombusible
foundations. The enclosing walls of such chutes shall consist of brickwork
at least eight inches thick or of reinforced concrete at least six
inches thick. Such chutes shall extend at least four feet above the
roof and shall be covered by a metal skylight glazed with thin plain
glass.
(7)
Service openings for chutes shall be located in separate
rooms or compartments and enclosed in walls or partitions, floors
and ceilings having a fire-resistive rating of at least one hour.
Such openings shall be equipped with approved fire doors or other
approved devices.
Drying rooms or dry kilns constructed as an integral part of a structure shall be constructed entirely of incombustible materials. When the heating pipes are not placed overhead, they shall be so shielded as to preserve a clear space of not less than two inches between them and the contents at all times, All such drying rooms shall be ventilated directly to the outer air by vent flues or ducts installed as specified in § 86-84, Metal smokestacks.
All smokehouses hereafter erected as part of
any structure shall be of fireproof construction with walls of brick
or reinforced concrete. All openings shall be provided with fire doors.
The interior framing, racks, hangers and other interior fittings shall
be incombustible materials.
