Page 59 - 2018_IMC

EXHAUST SYSTEMS

provisions for exterior wall opening protectives in accor- [F] 502.4 Stationary storage battery systems. Stationary
dance with the International Building Code. storage battery systems, as required by Section 1206.2.11.3
501.4 Pressure equalization. Mechanical exhaust systems of the International Fire Code, shall be provided with venti-
shall be sized to remove the quantity of air required by this lation in accordance with this chapter and Section 502.4.1 or
chapter to be exhausted. The system shall operate when air is 502.4.2.
required to be exhausted. Where mechanical exhaust is The exhaust system shall be designed to provide air move-
required in a room or space in other than occupancies in ment across all parts of the floor for gases having a vapor
Group R-3 and dwelling units in Group R-2, such space shall density greater than air and across all parts of the vault ceiling
be maintained with a neutral or negative pressure. If a greater for gases having a vapor density less than air.
quantity of air is supplied by a mechanical ventilating supply [F] 502.4.1 Flammability limit in rooms. The ventilation
system than is removed by a mechanical exhaust for a room, system shall be designed to limit the maximum concentra-
adequate means shall be provided for the natural or mechani- tion of flammable gas to 25 percent of the lower flamma-
cal exhaust of the excess air supplied. If only a mechanical bility limit or, for hydrogen, limit the maximum
exhaust system is installed for a room or if a greater quantity concentration to 1.0 percent of the total volume of the
of air is removed by a mechanical exhaust system than is sup- room.
plied by a mechanical ventilating supply system for a room, [F] 502.4.2 Ventilation rate in rooms. Continuous venti-
adequate makeup air shall be provided to satisfy the defi-
ciency. lation shall be provided at a rate of not less than 1 cubic foot
2
3
2
per minute per square foot (cfm/ft ) [0.00508 m /(s • m )] of
501.5 Ducts. Where exhaust duct construction is not speci- floor area of the room and not less than 150 cfm (4.25 m /
3
fied in this chapter, such construction shall comply with min).
Chapter 6.
[F] 502.4.3 Supervision. Mechanical ventilation systems
required by Section 502.4 shall be supervised by an
SECTION 502 approved central, proprietary or remote station service or
REQUIRED SYSTEMS shall initiate an audible and visual signal at a constantly
attended on-site location.
502.1 General. An exhaust system shall be provided, main-
tained and operated as specifically required by this section [F] 502.5 Ventilation of battery systems in cabinets. Sta-
and for all occupied areas where machines, vats, tanks, fur- tionary storage battery systems installed in cabinets, as regu-
naces, forges, salamanders and other appliances, equipment lated by Section 1206.2.11.3.1 of the International Fire
and processes in such areas produce or throw off dust or par- Code, shall be provided with ventilation in accordance with
ticles sufficiently light to float in the air, or emit heat, odors, Section 502.4.
fumes, spray, gas or smoke in such quantities so as to be irri- [F] 502.6 Dry cleaning plants. Ventilation in dry cleaning
tating or injurious to health or safety. plants shall be adequate to protect employees and the public
502.1.1 Exhaust location. The inlet to an exhaust system in accordance with this section and DOL 29 CFR Part
shall be located in the area of heaviest concentration of 1910.1000, where applicable.
contaminants. [F] 502.6.1 Type II systems. Type II dry cleaning systems
[F] 502.1.2 Fuel-dispensing areas. The bottom of an air shall be provided with a mechanical ventilation system
inlet or exhaust opening in fuel-dispensing areas shall be that is designed to exhaust 1 cubic foot of air per minute
2
3
located not more than 18 inches (457 mm) above the floor. for each square foot of floor area (1 cfm/ft ) [0.00508 m /
2
502.1.3 Equipment, appliance and service rooms. (s • m )] in dry cleaning rooms and in drying rooms. The
Equipment, appliance and system service rooms that ventilation system shall operate automatically when the
house sources of odors, fumes, noxious gases, smoke, dry cleaning equipment is in operation and shall have man-
steam, dust, spray or other contaminants shall be designed ual controls at an approved location.
and constructed so as to prevent spreading of such contam- [F] 502.6.2 Type IV and V systems. Type IV and V dry
inants to other occupied parts of the building. cleaning systems shall be provided with an automatically
activated exhaust ventilation system to maintain an air
[F] 502.1.4 Hazardous exhaust. The mechanical exhaust
of high concentrations of dust or hazardous vapors shall velocity of not less than 100 feet per minute (0.51 m/s)
conform to the requirements of Section 510. through the loading door when the door is opened.
Exception: Dry cleaning units are not required to be
[F] 502.2 Aircraft fueling and defueling. Compartments
housing piping, pumps, air eliminators, water separators, provided with exhaust ventilation where an exhaust
hose reels and similar equipment used in aircraft fueling and hood is installed immediately outside of and above the
defueling operations shall be adequately ventilated at floor loading door and operates at an airflow rate as follows:
level or within the floor itself. Q = 100 × A LD (Equation 5-1)
[F] 502.3 Battery-charging areas for powered industrial where:
trucks and equipment. Ventilation shall be provided in an
approved manner in battery-charging areas for powered Q = Flow rate exhausted through the hood, cubic feet
industrial trucks and equipment to prevent a dangerous accu- per minute.
mulation of flammable gases. A = Area of the loading door, square feet.
LD

42 2018 INTERNATIONAL MECHANICAL CODE 
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