Section 27-752
§ 27-752 Areas requiring mechanical ventilation. Mechanical
ventilation shall be provided in all occupiable rooms or spaces where
the requirements for natural ventilation are not met; in all rooms or
spaces, which because of the nature of their use or occupancy, involve
the presence of dust, fumes, gases, vapors, or other noxious or
injurious impurities, or substances which create a fire hazard; or where
required by the provisions of article eight of this subchapter or
subchapters six through eight of this chapter.
Section 27-753
§ 27-753 Index for ventilation. The index for ventilation for any room
or space shall be computed by adding the following:
(a) The contents per occupant, in cubic feet.
(b) The floor area per occupant, times ten, in square feet.
(c) The clear, unobstructed openable area of windows, skylights, and
other sources of natural ventilation per occupant times two hundred, in
square feet. In all cases, the number of occupants used in computing the
index for ventilation shall be the maximum number who will occupy the
room or space simultaneously during any two-hour period.
Section 27-754
§ 27-754 Minimum quantity of outside air for mechanical ventilation.
The minimum quantity of outside air required for mechanical ventilation
in any occupiable room, where not otherwise prescribed, shall be
determined according to table 12-2.
Table 12-2 Required Minimum Outdoor Air Supply and Exhaust
(cfm per sq. ft.)
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Ventilated Rooms Ventilated Rooms
with Natural without Natural
Index for Ventilation Ventilation Air Conditioned
Ventilation Openings Openings Rooms
------------------------------------------------------------------------
Supply Exhaust Supply Exhaust Supply Exhaust
------------------------------------------------------------------------
0- 300... 2.5 2.0 2.5 2.0 1.5 1.5
301- 520... 2.0 1.5 2.0 1.5 1.2 1.2
521- 850... 1.5 1.25 1.5 1.25 0.9 0.9
851-1250... .. 1.0 1.0 1.0 0.6 0.6
1251-1650... .. 0.67 0.67 0.67 0.5 0.5
over 1650... .. .. 0.33 0.33 0.4 0.4
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(a) Window requirements. To be credited as ventilating openings under
the provisions of this subchapter, windows or other openings shall meet
the requirements of section 27-749 of article six of this subchapter,
and where mechanical supply ventilation is not provided, shall have a
free openable area of at least one square foot per one hundred square
feet of floor area.
(b) Air conditioning.
(1) In air conditioned rooms, the windows and other openings shall not
be credited as such in computing the index for ventilation. Air
conditioned rooms shall be considered as interior rooms.
(2) Air that has been exhausted from an air conditioned space may be
reconditioned by air conditioning apparatus and recirculated as
equivalent outdoor air, provided that the total of supply air is not
less than required for air conditioned rooms by table 12-2 and that the
amount of actual outdoor air is at least thirty-three and one-third per
cent of the required total. The actual outdoor air supply shall not,
under any circumstances, be reduced to less than five cfm per occupant,
except that these minimum requirements may be reduced by fifty per cent
as provided in section 27-755 of this article.
(c) Required exhaust. Required exhaust may be accomplished by raising
the pressure within the space with consequent leakage through doors and
windows, or by drawing the vitiated air from air conditioned spaces into
the return air duct of air conditioning apparatus or into an exhaust
duct discharging directly to the outdoor air.
(d) Make-up air. A sufficient quantity of air to make the exhaust
system effective shall be provided to the space being exhausted by one
or by any combination of the following methods:
(1) By supplying air to the space by means of a blower system.
(2) By infiltration through louvres, registers, or other permanent
openings in walls, doors, or partitions, adjoining spaces where air is
supplied by one of these methods.
(3) By infiltration through cracks around window sash and doors.
(4) By other methods acceptable to the commissioner.
(e) Prohibited use of recirculated air. Air drawn from any of the
following spaces may not be recirculated; mortuary rooms; bathrooms or
toilet rooms; or any space where an objectionable quantity of flammable
vapors, dust, odors, or noxious gases is present. Air drawn from rooms
that must be isolated to prevent the spread of infection shall not be
recirculated, except that air drawn from hospital operating rooms may be
recirculated, if in compliance with the following requirements:
(1) There shall be a minimum of twenty-five total air changes per
hour, of which five air changes per hour shall be outdoor air.
(2) All fans serving exhaust systems shall be located at the discharge
end of the system.
(3) Outdoor air intakes shall be located at least twenty-five feet
from exhaust outlets of ventilation systems and other exhaust
discharges, combustion equipment stacks, medical surgical vacuum
systems, and plumbing vent stacks, from areas which may collect
vehicular exhaust such as off-street loading bays, and from areas which
may collect other noxious fumes. The bottom of outdoor air intakes
serving central systems if installed above a roof, shall be located at
least three feet above roof level.
(4) Positive air pressure shall be maintained at all times in relation
to adjacent areas.
(5) All ventilation or air conditioning systems serving such rooms
shall be equipped with a filter bed of twenty-five per cent efficiency
upstream of the air conditioning equipment and a filter bed of ninety
per cent efficiency downstream of the supply fan, any recirculating
spray water systems and water reservoir type humidifiers. All filter
efficiencies shall be average atmospheric dust spot efficiencies tested
in accordance with ASHRAE standard 52-68.
(6) A manometer shall be installed across each filter bed.
(7) Duct linings shall not be used in ventilation and air conditioning
systems serving such rooms unless terminal filters of at least ninety
per cent efficiency are installed downstream of linings.
(8) Air supplied shall be delivered at or near the ceilings and all
exhaust air shall be removed near floor level, with at least two exhaust
outlets not less than three inches above the floor.
(f) Outdoor air intakes. For high-rise office buildings erected
pursuant to new building applications filed on or after the effective
date of this section, outdoor air intakes serving spaces above the
second story and serving spaces greater than ten thousand square feet of
floor area shall be located at least twenty feet above ground level, at
least twenty feet from exhaust outlets of ventilation systems and other
exhaust discharges, and at least twenty feet from areas that may collect
vehicular exhaust such as off-street loading bays.
Section 27-755
§ 27-755 Use of adsorption devices. In all cases where the use of
recirculated air is permitted, the required outdoor air supply may be
reduced up to fifty per cent, provided that the recirculated air is
passed through adsorption devices. The adsorption devices shall be
approved and rated. Means shall be provided for maintaining the
effectiveness of the adsorption devices.
(a) Improper maintenance. Should the adsorption devices be improperly
maintained so that their effectiveness is impaired, the commissioner may
order their removal. If the adsorption devices are removed, the air
conditioning or ventilating system shall not be operated without
supplying one hundred per cent of the outdoor air required by this
article or article eight of this subchapter.
(b) Test records. The building owner shall, at all times, maintain a
maintenance record showing the manufacturer's recommendation of the
frequency of tests, the method of making tests, and the results of all
tests of the adsorption devices. Such tests shall be made and certified
by the manufacturer or by a laboratory acceptable to the commissioner at
least twice every six months. The records of such tests shall be
maintained for a period of at least two years, and shall be available
for inspection by the commissioner.
(c) Ventilation of water closet compartments. The use of any device
that returns exhaust air from water closet compartments or from toilet
rooms after passing through adsorption devices is not permitted as a
means of providing ventilation for a water closet compartment for which
a mechanical system of ventilation is required.
Section 27-756
§ 27-756 Installation and operation of ventilating and air
conditioning systems. Where mechanical ventilation is accepted as an
alternate for, or a supplement to, natural means of ventilation, or is
required under the conditions herein prescribed, or where ventilation is
provided by means of air conditioning system, the system, equipment, and
distributing ducts shall be installed in accordance with the applicable
provisions of subchapters thirteen through fifteen of this chapter. Such
required ventilating and/or air conditioning systems shall be kept in
operation at all times when the building or space is being used in a
normal manner in accordance with the purpose for which it was intended.
To the extent possible under law, Friends of Devin Balkind for Public Advocate has waived all copyright and related or neighboring rights to New York City Administrative Code. This work is published from: United States.
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