§ 111.106-15 Ventilation of hazardous locations.

(a) The ventilation design principles must comply with Clauses 8.1.3, 8.2, and 8.3 of IEC 60092-502:1999 (incorporated by reference, see § 110.10-1). Note to § 111.106-15(a): The word “mechanical,” as used in this section, is interchangeable with the word “artificial” used in IEC 60092-502:1999. (b) A ventilation system must— (1) Be positioned so as not to recycle vapors from ventilation discharges; (2) Have its operational controls outside the ventilated space, if the system is mechanical; and (3) Have a protective metal screen of not more than 13 mm (0.512 in.) square mesh on each ventilation intake and exhaust opening. (c) The mechanical ventilation of enclosed flammable or combustible liquid cargo handling or cargo pump rooms must be sufficient to effect a minimum complete 30 air changes per hour based on the volume of the pump room and associated trunks up to the deck at which access from the weather is provided. The power ventilation system must be designed to remove vapors from the bottom of the space at points where concentrations of vapors may be expected. (d) The following spaces must have a supply-type mechanical ventilation system capable of providing at least 8 air changes per hour: (1) Each space that contains electric motors for cargo handling equipment. (2) Each cargo control station.