[Code of Federal Regulations]
[Title 30, Volume 1]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 30CFR18.28]

[Page 95]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 18--ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES--Table of Contents
 
             Subpart B--Construction and Design Requirements
 
Sec. 18.28  Devices for pressure relief, ventilation, or drainage.

    (a) Devices for installation on explosion-proof enclosures to 
relieve pressure, ventilate, or drain will be acceptable provided the 
length of the flame-arresting path and the clearances or size of holes 
in perforated metal will prevent discharge of flame in explosion tests.
    (b) Devices for pressure relief, ventilation, or drainage shall be 
constructed of materials that resist corrosion and distortion, and be so 
designed that they can be cleaned readily. Provision shall be made for 
secure attachment of such devices.
    (c) Devices for pressure relief, ventilation, or drainage will be 
acceptable for application only on enclosures with which they are 
explosion tested.