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§^1559.10
<br />DWELLING HOUSE CODE
<br />1559.10 Type C gas vents.
<br />(a) Type C gas vents shall be constructed
<br />of approved noncombustible, corrosion-re-
<br />sistant material. Copper gas vents shall be
<br />not less than 24 U. S. gage and galvanized
<br />iron vents not less than 20 U. S. gage.
<br />(b) Type C gas vents may be used from
<br />rooms and spaces in which agas-fired heat
<br />appliance is 'located, extending directly
<br />through the roof. Such Type C gas vent shall
<br />not pass through any attic or concealed
<br />space nor through any floor. This shall not
<br />be construed as;prohibiting use of such gas
<br />vent to vent attic furnaces installed in ac-
<br />cordance with the provisions of this Dwell-
<br />ing House Code.
<br />(c) Unless stated in the conditions of ap-
<br />proval, installation with reference to clear-
<br />ance from combustible material and passage
<br />through wall or roof shall comply with the
<br />provisions of Section 1559.16.
<br />1559.11 Y,abeling gas flues.
<br />Chimneys or flues installed for the use of
<br />gas heat appliances, but which are not suit-
<br />able for solid or liquid fuels, shall be plainly
<br />and permanently labeled, This Flue is f or the
<br />Use of Gas-Burning Appliances Only. This
<br />label shall be attached at a point near where
<br />the gas vent connector enters the chimney,
<br />or where a Type B gas vent is used in place
<br />of a chimney, at a place where the Type B
<br />gas vent enters the wall, floor or ceiling.
<br />1559.12 Termination of Types B and C gas
<br />vents.
<br />When Type B or C gas vents project
<br />through the roof, they shall terminate in an
<br />"A" hood or other type of vent cowl ap-
<br />proved by the Building Official. The clear-
<br />ance of the base of the vent cowl above the
<br />highest point where the vent passes through
<br />the roof shall be determined by the Building
<br />Official, but in no event shall it be less than
<br />12 inches.
<br />1559.13 Condition upon completion.
<br />Upon the completion of a building or the
<br />alteration of existing flues, all flues and vents
<br />shall be cleaned and -left smooth on the in-
<br />side: The Bnildfng Official may require an
<br />inspection to .be made to assure safe condi-
<br />tion of the flue before permitting its use.
<br />1559.14 Smoke pipes and gas vent connec-
<br />tors.
<br />(a) Requirement of installation. All heat
<br />appliances requiring flues shall be connected
<br />by means of smoke pipes or gas vent con-
<br />nectors.
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<br />(b) Gas tight. All smoke pipes and gas
<br />vent connectors shall be gas tight and con-
<br />nected to the flue by means of a tight joint.
<br />(c) Required area. The cross-sectional
<br />area of a smoke pipe or a gas vent connector
<br />shall be sufficient to serve the heat appliance
<br />connected thereto, Unless otherwise au-
<br />thorized by the Building Official, a smoke
<br />pipe shall not be smaller than the size of the
<br />smoke outlet or flue collar of the heat ap-
<br />pliance it serves. A gas vent connector shall
<br />not be smaller than the flue collar or the
<br />outlet of the draft hood supplied by the
<br />manufacturer of the gas-fired heat appli-
<br />ance.
<br />(d) Area on conversion. When a heat
<br />appliance, originally designed for other fuel,
<br />is converted to gas fuel, the gas vent con-
<br />nector may have a. cross-sectional area
<br />smaller than the smoke outlet of the heat ap-
<br />pliance but the area shall not be less than 1
<br />square inch for each 6500 Btuh input rating.
<br />(e) General construction. Smoke ,pipes
<br />and gas vent connectors shall enter masonry
<br />chimneys through afire-clay or noncorro-
<br />sive metal thimble or a flue ring of masonry.
<br />Neither the intake pipe nor the thimble shall
<br />project through the flue. All smoke pipes
<br />and gas vent connectors shall be as short and
<br />direct as possible and, unless specifically ap-
<br />proved by the Building Official for mechani-
<br />cally induced draft, all smoke pipes and gas
<br />vent connectors shall pitch upward not less
<br />than 1/z inch for each linear foot of length.
<br />Metal or other approved supports shall be
<br />provided at intervals not exceeding 5 feet.
<br />Sections shall be fastened together with
<br />screws or by a method approved as equiva-
<br />lent by the Building Official.
<br />(f) Serving separate living units. Smoke
<br />pipes or gas vent connectors from heat ap=
<br />pliances, which serve separate dwelling units
<br />or parts of a building occupied by independ-
<br />ent tenants, may. be connected to the same
<br />flue or gas vent only when the net area and
<br />the height and location of that flue or gas
<br />vent are such as to serve adequately all such
<br />heat appliances under all probable conditions
<br />of operation.
<br />;g) Tw;, or „yore smoke pipes info a single
<br />flue. Except as provided in paragraph (f}
<br />of this section, two or more smoke pipes may
<br />be joined for, a single flue connection or into
<br />a single flue, provided that the smoke pipes
<br />and flue are,, in the opinion of. the Building
<br />Official, of .sufficient size to serve the heat
<br />appliances thus connected., ,
<br />(h} Gas vent connector and ,smoke, pipe
<br />into a single.. flue.. Except •as provided in
<br />
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<br />C~
<br />f
<br />
<br />
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<br />Chimneys, Flues, and Gas Vents
<br />paragraph (f) of this section, when the gas
<br />heat appliance served by a gas vent con-
<br />nector is equipped with an automatic pilot
<br />device to prevent the escape of unburned gas
<br />at the burners, the gas vent connector may
<br />connect into the same flue as the smoke pipe,
<br />provided the connection is above the smoke
<br />pipe. For liquid petroleum gas systems, the
<br />automatic pilot device shall prevent the es-
<br />cape of any unburned gas at the burner and
<br />also at the pilot light.
<br />(i) Materials. Smoke pipes and gas vent
<br />connectors shall be constructed of approved
<br />durable materials. Metal pipe shall be not
<br />lighter than No. 26 U. S. gage up to 6"
<br />diameter, not lighter than No. 24 U. S. gage
<br />for over 6" and up to 12" diameter, and not
<br />lighter than No. 20 U. S. gage when larger
<br />than 12" diameter.
<br />(j) Draft regulator. An automatic draft
<br />regulator, barometric or equivalent, ap-
<br />proved by the Building Official, shall be in-
<br />stalled in each smoke pipe or breeching serv-
<br />ing aliquid or solid fuel-fired heat appliance.
<br />It shall be permanently set for the proper op-
<br />eration of the heat appliance.
<br />(k) Connections to incinerator flue. No
<br />gas vent connector or smoke pipe from any
<br />other heat appliances shall be connected into
<br />the flue of an incinerator in which the rub-
<br />bish chute is identical with the smoke flue:
<br />1559.15 Clearances for chimneys and type
<br />A flues.
<br />(a) Combustible construction around
<br />chimneys. No combustible beam, joist rafter
<br />or header shall be placed within 2" of the
<br />outside face of a chimney. No combustible
<br />studding, lathing, furring or plugging shall
<br />be placed against any chimney nor in the
<br />joints thereof. Such combustible construc-
<br />tion shall be set at least 1/a" away from the
<br />chimney, or the plastering shall be directly
<br />on the chimney or on metal lath and furring
<br />or on other noncombustible lathing and
<br />furring materials. Combustible furring
<br />strips placed around chimneys to support
<br />base or other trim shall be maintained not
<br />less than 1/z" clear from the masonry by use
<br />of nonrnm~i,igtilwle ;*IasherS CT Other non-
<br />combustible spacers. Metal wall plugs or
<br />other noncombustible nail-holding devices
<br />attached to the wall surface shall be used for
<br />nailing. Finished flooring shall be placed no
<br />closer than i/z" to a chimney, except at the
<br />corners as may be necessary for lateral sup-
<br />port of the chimney, where the finished wood
<br />flooring may be in contact with the chimney
<br />for not more than 3" each way at the cor-
<br />ners.
<br />§ 1559.17
<br />(b) Construction around Type A flues.
<br />Lateral support and clearances for Type A
<br />flues shall be provided as stipulated in the
<br />conditions of approval or listing by the
<br />Underwriters' Laboratories, Inc, or other ac-
<br />credited agency. Such lateral supports shall
<br />be of noncombustible material.
<br />(c) Space filled only f or firestopping. The
<br />space between a chimney and a wood floor, a
<br />wood floor framing or a roof framing shall
<br />not be filled except as needed for firestopping
<br />around the chimney.
<br />1559.16 Clearances for gas vents.
<br />(a) Type B gas vents. Except as may be
<br />otherwise specified in the conditions of ap-
<br />proval or listing by the Underwriters' Labo-
<br />ratories, Inc. or other accredited agency,
<br />Type B gas vents shall be installed with a
<br />clearance from combustible material or con-
<br />struction, whether plastered or unplastered,
<br />of not less than 1", and gas vents from floor
<br />furnaces shall be not less than 3" from such
<br />construction for a distance of not less than
<br />3'-0" from the outlet of the draft hood, meas-
<br />ured along the center line of the gas vent
<br />piping.
<br />(b) Type C gas vents. Type C gas vents,
<br />where they pass through a combustible ex-
<br />terior wall or roof shall be guarded at the
<br />point of passage by either:
<br />i. double metal ventilated thimbles not
<br />less than 6" larger in diameter than the di-
<br />ameter of the gas vent, or
<br />ii. double metal thimbles not less than 4"
<br />larger in diameter than the diameter of the
<br />gas vent with the annular space filled with
<br />mineral wool or other approved noncombus-
<br />tible insulating material, and installed with
<br />not less than 1/z" clearance between the
<br />metal thimble and combustible material; or
<br />in lieu of such protection, all combustible
<br />material in the wall or partition shall be cut
<br />away from the vent pipe a distance of not
<br />less than 6" for flue gas temperatures of 550
<br />F and less, and not less than 9" for rated
<br />flue gas temperatures over 550, F. Where
<br />such combustible material or construction is
<br />protected in the manner specified in sub-
<br />section 1559.17 (c), such c-learances may be
<br />not less than 3"for flue gas temperatures up
<br />to 550 F and not less than 6" for rated flue
<br />gas temperatures over 550 F.
<br />1559.17 Clearances for smoke pipes.
<br />(a) At floors or ceilings. No smoke pipe
<br />shall pass through a floor or ceiling of com-
<br />bustible material: A smoke pipe may pass
<br />through a floor or ceiling of noncombustible
<br />material only when such passage and loca-
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