ASHRAE+62.1-2022+(1) - Page 012
Extracted Content
Table 5-1 Air Intake Minimum Separation Distance
Object Minimum Distance, ft (m)
Class 2 air exhaust/relief outlet 10 (3)
Class 3 air exhaust/relief outlet 15 (5)
Class 4 air exhaust/relief outlet 30 (10)
Evaporative heat-rejection equipment exhaust 25 (7.5)
Evaporative heat-rejection equipment intake or basin 15 (5)
Driveway, street, or parking place 5 (1.5)
Garage entry, automobile loading area, or drive-in queue 15 (5)
Garbage storage/pick-up area, dumpsters 15 (5)
Plumbing vents terminating at least 3 ft (1 m) above the level of the outdoor air intake 3 (1)
Plumbing vents terminating less than 3 ft (1 m) above the level of the outdoor air intake 10 (3)
Roof, landscaped grade, or other surface directly below intake 1 (0.30)
Thoroughfare with high traffic volume 25 (7.5)
Truck loading area or dock, bus parking/idling area 25 (7.5)
Vents, chimneys, and flues from combustion appliances and equipment 15 (5)
5.4.1.3 Roof, Landscaped Grade, or Another Surface Directly Below Intake. Where snow accumulation is expected, the surface of the snow at the expected average snow depth shall be considered to be a surface directly below an intake.
Exception to 5.4.1.3: The minimum separation distance in Table 5-1 shall not apply where outdoor sur faces below the air intake are sloped more than 45 degrees from horizontal or where such surfaces are less than 1 in. (30 mm) in width.
5.4.1.4 Laboratory Exhaust. Separation criteria for fume hood exhaust shall be in compliance with ANSI/AIHA Z9.5.
5.4.2 Rain Entrainment. Outdoor air intakes that are part of the mechanical ventilation system shall be designed to manage rain entrainment in accordance with one or more of the following:
a. Limit water penetration through the intake to 0.07 oz/ft [2] ·h (21.5 g/m [2] ·h) of inlet area when tested using
the rain test apparatus described in UL 1995, Section 58. b. Select louvers that limit water penetration to a maximum of 0.01 oz/ft [2] (3 g/m [2] ) of louver free area at the
maximum intake velocity. This water penetration rate shall be determined for a minimum 15 minute test duration when subjected to a water flow rate of 0.25 gal/min (16 mL/s) as described under the water penetration test in AMCA 500-L or equivalent. Manage the water that penetrates the louver by providing a drainage area or moisture removal devices. c. Select louvers that restrict wind-driven rain penetration to less than 2.36 oz/ft [2] ·h (721 g/m [2] ·h) when sub jected to a simulated rainfall of 3 in. (75 mm) per hour and a 29 mph (13 m/s) wind velocity at the design outdoor air intake rate with the air velocity calculated based on the louver face area. ( Informative Note: This performance corresponds to Class A (99% effectiveness) when rated according to AMCA 511 and tested per AMCA 500-L.) d. Use rain hoods sized for no more than 500 fpm (2.5 m/s) face velocity with a downward-facing intake
such that all intake air passes upward through a horizontal plane that intersects the solid surfaces of the hood before entering the system. e. Manage the water that penetrates the intake opening by providing a drainage area or moisture removal
devices.
5.4.3 Rain Intrusion. Air-handling and distribution equipment mounted outdoors shall be designed to prevent rain intrusion into the airstream when tested at design airflow and with no airflow, using the rain test apparatus described in UL 1995, Section 58.
5.4.4 Snow Entrainment. Where climate dictates, outdoor air intakes that are part of the mechanical ventilation system shall be designed as follows to manage water from snow that is blown or drawn into the system:
10 ANSI/ASHRAE Standard 62.1-2022