Article 4 Incinerator Chimneys and Refuse Charging Chutes

Charging chutes shall be constructed in accordance with the following requirements:

(a) Directly connected. When directly connected to the combustion chamber of an incinerator, the chutes shall be gas tight with smooth linings and shall conform to the following:

(1) They shall be constructed in accordance with the requirements for medium temperature chimneys.

(2) They shall extend through the building roof and be open to the outer air. The opening shall be equal to the required chute size at the top floor.

(3) If a roof damper is used it shall be constructed to open automatically under conditions of excessive pressure or temperature. The roof damper shall be electrically interlocked with the auxiliary burners.

(4) Each charging chute shall be provided with a spark arrester of corrosion resistive, noncombustible construction in which the maximum size of mesh opening shall not exceed three-quarters of an inch. The cross-sectional free area of such arrester shall be not less than that of the inside of the chute to which it is attached. The height of the spark arrester shall be such that there will be a minimum of twenty-four square feet of total free area provided for a chute height to sixty feet; thirty-six square feet for a chute height from sixty-one feet to one hundred twenty feet; and forty-four square feet for chute heights over one hundred twenty feet. In no case, however, shall the height of the spark arrester be less than one foot.

(5) Provisions shall be made for sterilizing the charging chute by heating or purging at a temperature of at least four hundred degrees Fahrenheit but not higher than one thousand degrees Fahrenheit.

(b) Not directly connected. When not directly connected to a building service incinerator, the chutes shall be gas tight with smooth linings and shall conform to the following:

(1) They shall be constructed in accordance with the applicable requirements for shafts in table 3-5 and subchapter five of this chapter.

(2) They shall extend through the building roof and be open to the air. The opening shall be equal to at least one square foot.

(3) If a roof damper is used it shall be constructed to open automatically under conditions of excessive pressure or temperature.

(4) Provisions shall be made for sterilizing the chute by spraying, washing, or other equivalent means.

(5) Bins, containers, or rooms for receiving rubbish shall be constructed as required by section 27-837 of article eighteen of subchapter fourteen of this chapter and sprinklers shall be provided as required by the construction provisions of subchapter seventeen of this chapter.

(c) Sizes.

(1) The sizes of chutes directly connected to the incinerators in buildings shall conform to table 15-9.

(2) Charging chutes not directly connected to the incinerator shall have a cross-sectional free area adequate for the service intended.

(d) Charging doors. Charging doors, service openings, or hopper doors for chutes may be located in separate rooms or compartments enclosed in non-combustible walls or partitions, floors, and ceilings having a fire resistance rating of at least one hour and a self-closing fire door with a three-quarter-hour fire-protection rating. Service openings shall, in no case, have a free area of more than one-third of the cross-sectional free area of the chute to which they give access. All such openings shall be substantially constructed of steel or the equivalent metal of sufficient thickness to prevent distortion or other damage in normal usage. The door shall be provided with counterweights, door checks, or other equivalent means for automatically closing after use and where the chute is connected directly to the combustion chamber of an incinerator, the door shall be so constructed that the chute is closed off while the hopper is being loaded. No part of the door shall project into the chute at any time. The minimum height of charging door openings shall be eleven inches, and the minimum width shall be thirteen inches.

(e) When charging chutes are located in multiple dwellings, in addition to the requirements of this subchapter, the chutes shall be constructed in accordance with the requirements for noise control of chutes in subchapter twelve of this chapter.

TABLE 15-9
MINIMUM SIZE OF CHARGING CHUTES

Building Height	Location	If Square	If Round
7 stories or less	All 7 stories	22 1/2" x 22 1/2"	24" dia.
8 to 30 stories	Top 7 stories	22 1/2" x 22 1/2"	24" dia.
	8th to 30th from the top	27" x 27"	30" dia.
31 stories and over	Top 7 stories	22 1/2" x 22 1/2"	24" dia.
	8th to 30th from the top	27" x 27"	30" dia.
	Remaining lower	32" x 32"	36" dia.

Chimneys for building service incinerators shall be constructed in accordance with the requirements of this subchapter for high or medium temperature chimneys, based upon the temperature of the flue gases leaving the equipment, except that no reduction of flue gas temperature shall be recognized if such reduction is the result of using water scrubbers or barometric dampers. In addition, such chimneys shall comply with the following:

(a) Chimneys shall extend through the roof and be open to the air.

(b) Chimneys shall be provided with a spark arrester as required in paragraph four of subdivision (a) of section 27-875 of this article.

(c) Incinerators may discharge into chimneys serving other equipment provided such combined chimney is of adequate size for both uses, conforms to construction required for the highest temperature, and adequate draft control equipment is provided for each device connected to the combined chimney.

Chimneys for central incinerator plants shall be constructed in accordance with the requirements for:

(a) Medium temperature chimneys if the incinerator is provided with a heat recovery unit or other means to assure a flue gas temperature not in excess of one thousand degrees Fahrenheit at the base of the stack.

(b) High temperature chimneys if the incinerator has no heat recovery unit or other means to assure a flue gas temperature less than one thousand degrees Fahrenheit.

(a) The chimney connector from the combustion chamber of an auxiliary fuel-fired incinerator shall be constructed of metal at least as heavy as no. 16 manufacturers standard gauge when twelve inches or less in diameter or greater dimension, and of metal at least as heavy as no. 12 manufacturers standard gauge when they exceed twelve inches in diameter or greater dimension.

(b) Chimney connectors from auxiliary fuel-fired incinerators shall be lined with firebrick, laid in fire clay mortar, at least two and one-half inches thick when they are between twelve inches and eighteen inches in diameter or greater dimension and at least four and one-half inches thick when they are larger; where no flue gas temperature reduction is effected the chimney connectors shall be equipped with a guillotine or horizontal sliding damper or butterfly damper interlocked with the fuel firing controls so that operation of the incinerator occurs when the damper is open. If chimney connectors from auxiliary fuel-fired incinerators lead into and combine with chimney connectors from other equipment, the connectors from the other equipment shall also be lined as required for direct flue connections unless the cross-sectional area of the connector into which they lead is at least four times their required cross-sectional area.

(c) Chimney connectors for an auxiliary fuel-fired incinerator to a boiler stack or chimney for a high temperature heating equipment shall be permitted when the cross-sectional area of such stack or chimney is at least four times that of the incinerator chimney connector.

(d) The clearance of incinerator chimney connectors from combustible material or construction shall be at least thirty-six inches. This clearance may be reduced as outlined in table 15-8 in accordance with the type of protection applied to the combustible material or construction.