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// CODE SNIPPET

Section 503 Venting of Equipment

NYC Fuel Gas Code 2008 > 5 Chimneys and Vents > 503 Venting of Equipment
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503.1 General

This section recognizes that the choice of venting materials and the methods of installation of venting systems are dependent on the operating characteristics of the equipment being vented. The operating characteristics of vented equipment can be categorized with respect to (1) positive or negative pressure within the venting system; and (2) whether or not the equipment generates flue or vent gases that might condense in the venting system. See Section 202 for the definition of these vented appliance categories.

503.2 Venting Systems Required

Except as permitted in Sections 503.2.1 through 503.2.3 and 501.8, all equipment shall be connected to venting systems.

503.2.1 Ventilating Hoods

Ventilating hoods and exhaust systems shall be permitted to be used to vent equipment installed in commercial applications (see Section 503.3.4) and to vent industrial equipment, such as where the process itself requires fume disposal.

503.2.2 Direct-Vent Equipment

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Listed direct-vent equipment shall be considered properly vented where installed in accordance with the terms of its listing, the manufacturer's instructions, and Section 503.8.

503.2.3 Equipment With Integral Vents

Equipment incorporating integral venting means shall be considered properly vented when installed in accordance with its listing, the manufacturer's instructions, and Section 503.8.

503.3 Design and Construction

A venting system shall be designed and constructed so as to develop a positive flow adequate to convey flue or vent gases to the outdoor atmosphere.

503.3.1 Equipment Draft Requirements

A venting system shall satisfy the draft requirements of the equipment in accordance with the manufacturer's instructions.

503.3.2 Design and Construction

Gas utilization equipment required to be vented shall be connected to a venting system designed and installed in accordance with the provisions of Sections 503.4 through 503.15.

503.3.3 Mechanical Draft Systems

Mechanical draft systems shall comply with the following:
  1. Mechanical draft systems shall be listed and shall be installed in accordance with the terms of their listing and both the appliance and the mechanical draft system manufacturer's instructions.
  2. Equipment, except incinerators, requiring venting shall be permitted to be vented by means of mechanical draft systems of either forced or induced draft design.
  3. Forced draft systems and all portions of induced draft systems under positive pressure during operation shall be designed and installed so as to prevent leakage of flue or vent gases into a building.
  4. Vent connectors serving equipment vented by natural draft shall not be connected into any portion of mechanical draft systems operating under positive pressure.
  5. When a mechanical draft system is employed, provision shall be made to prevent the flow of gas to the main burners when the draft system is not performing so as to satisfy the operating requirements of the equipment for safe performance.
  6. The exit terminals of mechanical draft systems shall be in compliance with Section 503.8.

503.3.4 Ventilating Hoods and Exhaust Systems

Ventilating hoods and exhaust systems shall be permitted to be used to vent gas utilization equipment installed in commercial applications. Where automatically operated equipment is vented through a ventilating hood or exhaust system equipped with a damper or with a power means of exhaust, provisions shall be made to allow the flow of gas to the main burners only when the damper is open to a position to properly vent the equipment and when the power means of exhaust is in operation.

503.3.5 Circulating Air Ducts and Furnace Plenums

No portion of a venting system shall extend into or pass through any circulating air duct or furnace plenum.

503.4 Type of Venting System to Be Used

The type of venting system to be used shall be in accordance with Table 503.4.

503.4.1 Plastic Piping

Plastic piping used for venting equipment listed for use with such venting materials shall be permitted when approved by the commissioner.

503.4.2 Special Gas Vent

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Special gas vent shall be listed and installed in accordance with the terms of the special gas vent listing and the manufacturers' instructions.

503.5 Masonry, Metal, and Factory-Built Chimneys

Masonry, metal and factory-built chimneys shall comply with Sections 503.5.1 through 503.5.10.

503.5.1 Factory-Built Chimneys

Factory-built chimneys shall be installed in accordance with their listing and the manufacturers' instructions. Factory-built chimneys used to vent appliances that operate at positive vent pressure shall be listed for such application.

503.5.2 Metal Chimneys

Metal chimneys shall be built and installed in accordance with NFPA 211.

503.5.3 Masonry Chimneys

Masonry chimneys shall be built and installed in accordance with Chapter 21 of the New York City Building Code and NFPA 211, and shall be lined with approved clay flue lining, a listed chimney lining system, or other approved material that will resist corrosion, erosion, softening, or cracking from vent gases at temperatures up to 1800°F (982°C).
  Exception: Masonry chimney flues serving listed gas appliances with draft hoods, Category I appliances and other gas appliances listed for use with Type B vent shall be permitted to be lined with a chimney lining system specifically listed for use only with such appliances. The liner shall be installed in accordance with the liner manufacturer's instructions and the terms of the listing. A permanent identifying label shall be attached at the point where the connection is to be made to the liner. The label shall read: "This chimney liner is for appliances that burn gas only. Do not connect to solid or liquid fuel-burning appliances or incinerators."
  For information on installation of gas vents in existing masonry chimneys, see Section 503.6.5.

503.5.4 Chimney Termination

Chimneys serving gas fired equipment shall comply with the appliance listing, the manufacturer's instructions and the following requirements:
  1. Chimneys serving appliances less than 600°F (316°C) shall extend at least 3 feet (914 mm) above the highest construction, such as a roof ridge, parapet wall, or penthouse, within 10 feet (3048 mm) of the chimney outlet, whether the construction is on the same building as the chimney or on another building. However, such constructions do not include other chimneys, vents, or open structural framing. Any chimney located beyond 10 feet (3048 mm) from such construction, but not more than the distance determined by Equation 5-1 shall be at least as high as the construction.
  2. Chimneys serving appliances between 600°F (316°C) and 1000°F (538°C) shall extend at least 10 feet (3048 mm) above the highest construction, such as a roof ridge, or parapet wall or penthouse within 20 feet (6096 mm) of the chimney outlet, whether the construction is on the same building as the chimney or on another building. However, such constructions do not include other chimneys, and vents or open structural framing. Any chimney located beyond 20 feet (6096 mm) from such construction, but not more than the distance determined by Equation 5-1 shall be at least as high as the construction.
  3. Chimneys serving appliances greater than 1000°F shall extend at least 20 feet (6096 mm) above the highest construction, such as roof ridge, parapet wall, penthouse, or other obstruction within 50 feet (15 240 mm) of the chimney outlet, whether the construction is on the same building as the chimney or in another building. However, such constructions do not include other chimneys, vents, or open structural framing. Any chimney located beyond 50 feet (15 240 mm) from such construction but not more than the distance determined by Equation 5-1 shall be at least as high as the construction.
  4. Termination caps shall not be permitted and a 3 inch (76 mm) minimum drain installed to receive collected water shall be required. A positive means shall be provided to prevent water from entering the appliance.
  Exception: Termination caps shall be permitted on listed factory built chimneys,
  5. Decorative shrouds shall not be installed at the termination of factory-built chimneys except where such shrouds are listed and labeled for use with the specific factory-built chimney system and are installed in accordance with the manufacturers' installation instructions.
  6. The following equation shall be used for determining the distances referred to in Items 1, 2 and 3 of this section.


D = F X √A (Equation 5-1)

where:
D = Distance, in feet, measured from the center of the chimney outlet to the nearest edge of the construction.
F = Value determined from table below.
A = Free area, in square inches, of chimney flue space

"F" FACTOR FOR DETERMINING CHIMNEY DISTANCES
Type of Fuel "F" Factor
600°F (316°C )
and less
600°F (°C ) to
1000°F (538°C)
Greater than
1000°F (538°C)
Gas 2 2 3

503.5.5 Size of Chimneys

The effective area of a chimney venting system serving listed appliances with draft hoods, Category I appliances, and other appliances listed for use with Type B vents shall be determined in accordance with one of the following methods:
  1. The provisions of Section 504.
  2. For sizing an individual chimney venting system for a single appliance with a draft hood, the effective areas of the vent connector and chimney flue shall be not less than the area of the appliance flue collar or draft hood outlet, nor greater than seven times the draft hood outlet area.
  3. For sizing a chimney venting system connected to two appliances with draft hoods, the effective area of the chimney flue shall be not less than the area of the larger draft hood outlet plus 50 percent of the area of the smaller draft hood outlet, nor greater than seven times the smallest draft hood outlet area.
  4. Chimney venting systems using mechanical draft shall be sized in accordance with approved engineering methods.
  5. Other approved engineering methods.

503.5.5.1 Incinerator Venting

Where an incinerator is vented by a chimney serving other gas utilization equipment, the gas input to the incinerator shall not be included in calculating chimney size, provided the chimney flue diameter is not less than 1 inch (25 mm) larger in equivalent diameter than the diameter of the incinerator flue outlet.

503.5.6 Inspection of Chimneys

Before replacing an existing appliance or connecting a vent connector to a chimney, the chimney passageway shall be examined to ascertain that it is clear and free of obstructions and it shall be cleaned if previously used for venting solid or liquid fuel-burning appliances or fireplaces.

503.5.6.1 Chimney Lining

Chimneys shall be lined in accordance with NFPA 211.
  Exception: Existing chimneys shall be permitted to have their use continued when an appliance is replaced by an appliance of similar type, input rating, and efficiency.

503.5.6.2 Cleanouts

Cleanouts shall be examined to determine if they will remain tightly closed when not in use.

503.5.6.3 Unsafe Chimneys

Where inspection reveals that an existing chimney is not safe for the intended application, it shall be repaired, rebuilt, lined, relined, or replaced with a vent or chimney to conform to NFPA 211 and it shall be suitable for the equipment to be vented.

503.5.6.4 Test Run

All new chimneys shall be test run by the design professional engineer responsible for the testing under operating conditions to demonstrate fire safety and the complete exhausting of smoke and the products of combustion to the outer air. The results of such test run shall be certified as correct by the design professional engineer responsible for the test and shall be submitted in writing to the department.

503.5.6.5 Requirement of a Smoke Test

A smoke test shall be made as outlined below. Any faults or leaks found shall be corrected. Such smoke test shall be witnessed by a representative of the commissioner. In lieu thereof, the commissioner may accept the test report of the design professional engineer responsible for the test which shall be submitted in writing to the department.

503.5.6.5.1 Smoke Test

To determine the tightness of chimney construction, a smoke test shall be made in accordance with the following conditions and requirements:
  1. The equipment, materials, power and labor necessary for such test shall be furnished by, and at the expense of, the owner or holder of the work permit.
  2. If the test shows any evidence of leakage or other defects, such defects shall be corrected in accordance with the requirement of this chapter and the test shall be repeated until the results are satisfactory.
  3. Method of test. The chimney shall be filled with a thick penetrating smoke produced by one or more smoke machines, or smoke bombs, or other equivalent method. As the smoke appears at the stack opening on the roof, such opening shall be tightly closed and a pressure equivalent to one-half inch (12.7 mm) column of water measured at the base of the stack, shall be applied. The test shall be applied for a length of time sufficient to permit the inspection of the chimney.

503.5.7 Chimneys Serving Equipment Burning Other Fuels

Chimneys serving equipment burning other fuels shall comply with Sections 503.5.7.1 through 503.5.7.4.

503.5.7.1 Solid Fuel-Burning Appliances

Gas utilization equipment shall not be connected to a chimney flue serving a separate appliance designed to burn solid fuel.

503.5.7.2 Liquid Fuel-Burning Appliances

Where one chimney flue serves gas utilization equipment and equipment burning liquid fuel, the equipment shall be connected through separate openings or shall be connected through a single opening where joined by a suitable fitting located as close as practical to the chimney. Where two or more openings are provided into one chimney flue, they shall be at different levels. Where the gas utilization equipment is automatically controlled, it shall be equipped with a safety shutoff device.

503.5.7.3 Combination Gas and Solid Fuel-Burning Appliances

A combination gas- and solid fuel-burning appliance shall be permitted to be connected to a single chimney flue where equipped with a manual reset device to shut off gas to the main burner in the event of sustained back draft or flue gas spillage. The chimney flue shall be sized to properly vent the appliance.

503.5.7.4 Combination Gas- And Oil Fuel-Burning Appliances

A listed combination gas- and oil fuel-burning appliance shall be permitted to be connected to a single chimney flue. The chimney flue shall be sized to properly vent the appliance.
SEE MORE

Related Code Sections


Section 503 Chimneys and Vents, Venting of Equipment
characteristics of the equipment being vented. The operating characteristics of vented equipment can be categorized with respect to (1) positive or negative ...
NYC Fuel Gas Code 2008 > 5 Chimneys and Vents > 503 Venting of Equipment
503.11 Chimneys and Vents, Vent Connectors for Category II, III, and IV Appliances
Vent connectors for Category II, III and IV appliances shall be as specified for the venting systems in accordance with Section 503.4 ...
NYC Fuel Gas Code 2008 > 5 Chimneys and Vents > 503 Venting of Equipment > 503.11 Vent Connectors for Category II, III, and IV Appliances
503.13 Chimneys and Vents, Manually Operated Dampers
A manually operated damper shall not be placed in the vent connector for any equipment. Fixed baffles shall not be classified as manually operated ...
NYC Fuel Gas Code 2008 > 5 Chimneys and Vents > 503 Venting of Equipment > 503.13 Manually Operated Dampers
503.14 Chimneys and Vents, Automatically Operated Vent Dampers
An automatically operated vent damper shall be of a listed type complete with safety controls to prove open position of the damper before equipment ...
NYC Fuel Gas Code 2008 > 5 Chimneys and Vents > 503 Venting of Equipment > 503.14 Automatically Operated Vent Dampers
503.15 Chimneys and Vents, Obstructions
of their listing.   4. Approved economizers, heat reclaimers, and recuperators installed in venting systems of equipment not required ...
NYC Fuel Gas Code 2008 > 5 Chimneys and Vents > 503 Venting of Equipment > 503.15 Obstructions
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