(1)
Except as provided in Sentences (4) and (6), an enclosed storage garage for five or more motor vehicles shall have a mechanical ventilation system designed to
(a)
limit the concentration of carbon monoxide to not more than 100 parts per million parts of air,
(b)
limit the concentration of nitrogen dioxide to not more than 3 parts per million parts of air, where the majority of the vehicles stored are powered by diesel-fuelled engines, or
(c)
provide, during operating hours, a continuous supply of outdoor air at a rate of not less than 3.9 L/s for each square metre of floor area (see Article 3.3.1.21.). (See Note A-6.3.1.3.(1)) (See also Sentence 3.3.5.4.(4))
(2)
Mechanical ventilation systems provided in accordance with Clause (1)(a) shall be controlled automatically by carbon monoxide monitoring devices, and systems provided in accordance with Clause (1)(b) shall be controlled by nitrogen dioxide or other acceptable monitoring devices. (See Note A-6.3.1.3.(2))
(3)
Mechanical ventilation systems provided in accordance with Sentence (1) shall be designed such that the pressure in the storage garage is less than the pressure in adjoining buildings of other occupancy, or in adjacent portions of the same building having a different occupancy.
(4)
In storage garages subject to the requirements of Sentence (1), where motor vehicles are parked by mechanical means, the ventilation requirements may be reduced by one half.
(5)
Except as provided in Sentence (6), ticket and attendant booths o f storage garages shall be pressurized with a supply of uncontaminated air.
(6)
The requirements of Sentences (1) to (5) shall not apply to open-air storeys in a storage garage.
(7)
A repair garage shall have a mechanical ventilation system designed to limit the exposure of workers to,
(a)
carbon monoxide to below the time weighted average concentration of 25 parts per million for a normal 8 hour workday or 40 hour work week, and
(b)
nitrogen dioxide from diesel powered vehicles to below 0.72 parts per million for a normal 8 hour workday or 40 hour work week.
(8)
In a repair garage, when a repair bay is not immediately adjacent to an outside garage door opening, a system capable of providing continuous general ventilation of not less than 700 L/s per internal bay shall be provided.
(9)
The general ventilation system described in Sentence (8) shall be designed to,
(a)
operate continuously, or
(b)
be controlled automatically by carbon monoxide monitoring devices, located so as to provide full protection throughout the repair garage.
(10)
The general ventilation system described in Sentence (8) is not required when tail pipes of vehicles are directly connected to local mechanical exhaust systems that terminate outdoors.