1314.5 Vacuum Source Exhausts. The medical-surgical

vacuum pumps shall exhaust in a manner and location that minimizes the hazards of noise and contamination to the facility and its environment. [NFPA 99:5.1.3.7.6.1]

(3) They shall have a relief pressure setting not higher than

the maximum allowable working pressure (MAWP) of the component with the lowest working pressure rating in the portion of the system being protected. (4) They shall be vented to the outside of the building,

except that relief valves for compressed air systems hav

(5) They shall have a vent discharge line that is not smaller

than the size of the relief valve outlet. (6) Where two or more relief valves discharge into a com mon vent line, its internal cross-sectional area shall be

1314.5.1 Location. The exhaust shall be located as follows: (1) Outdoors. (2) At least 25 feet (7620 mm) from any door, window,

air intake, or other openings in buildings or places of

(4) They shall be vented to the outside of the building,

except that relief valves for compressed air systems having less than 3000 cubic feet (84 950 L) at STP shall be permitted to be diffused locally by means that will not restrict the flow. (5) They shall have a vent discharge line that is not smaller

than the size of the relief valve outlet.

(2) At least 25 feet (7620 mm) from any door, window,

air intake, or other openings in buildings or places of public assembly. (3) At a level different from air intakes. (4) Where prevailing winds, adjacent buildings, topog raphy, or other influences will not divert the exhaust

(6) Where two or more relief valves discharge into a com mon vent line, its internal cross-sectional area shall be not less than the aggregate cross-sectional area of all relief valve vent discharge lines served. (7) They shall not discharge into locations creating potential

hazards.

(8) They shall have the discharge terminal turned down and

screened to prevent the entry of rain, snow, or vermin. (9) They shall be designed in accordance with ASME B31.3.

[NFPA 99:5.1.3.5.6.1]

(4) Where prevailing winds, adjacent buildings, topog raphy, or other influences will not divert the exhaust into occupied areas or prevent dispersion of the exhaust. [NFPA 99:5.1.3.7.6.2] 1314.5.2 Screening. The end of the exhaust shall be turned down and screened or otherwise be protected against the entry of vermin, debris, or precipitation by screening fabricated or composed of a noncorroding material. [NFPA 99:5.1.3.7.6.3] 1314.5.3 Dips and Loops. The exhaust shall be free of dips and loops that might trap condensate or oil or provided with a drip leg and valved drain at the bottom of the low point. [NFPA 99:5.1.3.7.6.4] 1314.5.4 Multiple Pumps. Vacuum exhausts from multiple pumps shall be permitted to be joined together to one common exhaust where the following conditions are met:

(7) They shall not discharge into locations creating potential

hazards. (8) They shall have the discharge terminal turned down and

screened to prevent the entry of rain, snow, or vermin.

(9) They shall be designed in accordance with ASME B31.3.

[NFPA 99:5.1.3.5.6.1] 1315.2.1 Category 3 Dental Air Pressure ReliefValve Discharge. Pressure relief valves for dental air systems having less than 3000 cubic feet (84 950 L) at STP shall be permitted to discharge locally indoors in a safe manner that will not restrict the flow. [NFPA 99:5.3.3.6.1.4] 1315.2.2 Isolation. A pressure-relief valve shall not be isolated from its intended use by a valve.