R 325.50255 Blast-cleaning enclosures.

Rule 5. (1) An employer shall ensure that blast-cleaning enclosures are exhaust ventilated so that a continuous inward flow of air will be maintained at all openings in the enclosure during the blasting operation. (2) An employer shall ensure that all air inlets and access openings are baffled or arranged so that, by combining inward air flow and baffling, the escape of abrasive or dust particles into an adjacent work area will be minimized and visible spurts of dust will not be observed. (3) The rate of exhaust shall be sufficient to provide prompt clearance of dust-laden air within the enclosure after the cessation of blasting. (4) Before the enclosure is opened, the blast shall be turned off and the system shall be run for a sufficient period of time to remove the dusty air within the enclosure. (5) Where hard deep-cutting abrasives are used, an employer shall ensure that safety glass protected by screening is used in observation windows. (6) Slit abrasive-resistant baffles shall be installed in multiple sets of all small access openings where dust might escape and shall be inspected regularly and replaced when needed. (7) Doors on blast-cleaning enclosures shall be flanged and tight when closed. (8) An employer shall ensure that doors on blast-cleaning rooms are operable from both inside and outside, except that where there is a small operator access door, the large work access door may be closed or opened from the outside only.