In one- and two-family dwellings, exhaust air from a dwelling unit shall
not be circulated to another dwelling unit. Ducts shall be securely fastened
in place and appropriately fire-stopped.
The following provisions shall apply to air-conditioning and mechanical
ventilation systems in multifamily dwellings:
A. Refrigerants.
(1) Refrigerants that are highly flammable shall not be used
in multifamily dwellings.
(2) Direct systems using refrigerants that are flammable
or toxic shall not be used for air-conditioning purposes.
B. Ventilating systems.
(1) Ventilating systems shall be installed and maintained
so that the rapid spread of heat, flame or smoke through the system will be
prevented and so that under conditions of use the temperature of any combustible
material adjacent thereto or in contact therewith will not exceed a safe temperature.
(2) Stairways, passageways, exits, shafts, hoistways or attics
shall not be used as plenum chambers.
(3) Ducts shall be securely fastened in place and appropriately
fire-stopped.
(4) Ducts and other air-handling equipment shall be of noncombustible
material.
(5) Filters shall be installed and maintained so as not to
constitute a fire or smoke hazard.
(6) Ducts passing through or located within combustible construction
shall be separated from such construction by a clearance of at least one-half
( 1/2) inch or by a noncombustible insulating material of at least one-fourth
( 1/4) inch thick.
(7) Air required for ventilation shall be taken from the
exterior or shall be quality controlled.
(8) Exhaust air from a dwelling unit or a space whose contents
may edit odors, fumes or vapors shall not be circulated to other occupied
spaces within the building.
C. Air-intake and exhaust openings.
(1) Air-intake and exhaust openings shall be installed, located
and maintained so as not to constitute a hazard or nuisance and so as to prevent
the possibility of fire, smoke, fumes or foreign matter being drawn into the
system.
(2) Ventilating systems shall be provided with adequate openings
for incoming and outgoing air to obtain the required circulation. Intake openings
shall provide air from an uncontaminated source.
(3) Where openings for mechanical exhaust are located in
spaces that also contain fuel-burning equipment, there shall be provided fixed
intake openings from the exterior to supply sufficient air so that the fuel-burning
equipment is not adversely affected.
(4) Exhaust openings shall be located so that the exhaust
air will not create a nuisance.
D. Ventilation requirements.
(1) Enclosures or spaces where heat, gases, vapors or odors
may accumulate and become a potential source of hazard or nuisance shall be
provided with adequate means of ventilation to remove such excess.
(2) Public spaces shall be provided with means for obtaining
air supply for the maximum number of persons for which such spaces are designed.
E. Safety controls.
(1) Manually operated controls shall be provided to stop
the operation of all central fan equipment. Such controls shall be conspicuously
identified and in readily accessible locations outside the fan room.
(2) Every system using recirculated air and serving an assembly
space or more than one (1) fire area or more than one (1) story of a building
shall be provided with controls arranged so that, under abnormal rise in temperature
of the air in the system, the fans causing normal circulation shall stop and
require manual restart.
(3) Every system for ventilating an assembly space shall
be provided with an emergency switch conveniently located and with a durable
sign giving instructions for shutting down the system in case of fire.