Village of New Haven, MI Article VIII Gas-Fired Space Heating Equipment

§ 293-93 Inspection, testing and approval.

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.

§ 293-94 Interference with combustion prohibited.

No devices or attachment shall be installed on any gas burner which may in any way impair the combustion of the gas.

§ 293-95 Electrical considerations.

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.)

B. All electrical work and equipment of the system shall be in accordance with the requirements of the Electrical Code of the Village of New Haven, Michigan.[1]

[1] Editor's Note: See Ch. 230, Electrical Standards.

§ 293-96 Installation requirements.

A. Gas burners shall be rigidly installed and so connected to the piping as not to exert undue strain on connections.

B. No gas burner shall be installed in a room in which the facilities for ventilation do not permit the proper combustion of gas.

§ 293-97 Gas cocks and shutoffs.

A. The gas cock or shutoff for a gas burner shall be easily accessible.

B. On conversion burner installations, the gas supply cock shall be located approximately five feet above the floor and approximately two feet to the rear of the face of the furnace where practicable.

§ 293-98 Use of air or oxygen.

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.).

§ 293-99 Location and installation.

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.

§ 293-100 Floor furnaces.

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.

§ 293-101 Safety considerations and controls.

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.

§ 293-102 Chimney flues and flue pipes.

A. Chimney flues and flue pipes shall freely conduct the flue gases to the outside atmosphere.

(1) Before making a vent connection, the chimney or flue shall be examined to assure that it is properly constructed in accordance with the requirements of the Official Building Code of the Village of New Haven, Michigan.[1]

[1] Editor's Note: See Ch. 160, Building Construction.

(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.

§ 293-103 Clearances.

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.

§ 293-104 Vent pipes and connections.

A. Location.

(1) The vent pipe shall enter the chimney or flue lining to its inner face but not beyond and shall be so cemented to the chimney wall.

(2) In entering the chimney or flue, the connection shall be made at least six inches above the extreme bottom.

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.

§ 293-105 Operating instructions.

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.