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:
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.
Stairways, passageways, exits, shafts, hoistways or attics shall not be used as plenum chambers.
Ducts shall be securely fastened in place and appropriately fire-stopped.
Ducts and other air-handling equipment shall be of noncombustible material.
Filters shall be installed and maintained so as not to constitute a fire or smoke hazard.
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.
Air required for ventilation shall be taken from the exterior or shall be quality controlled.
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.
Air-intake and exhaust openings.
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.
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.
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.
Exhaust openings shall be located so that the exhaust air will not create a nuisance.
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.
Public spaces shall be provided with means for obtaining air supply for the maximum number of persons for which such spaces are designed.
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.
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.
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.