[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: 30CFR27.21]

[Page 144]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 27--METHANE-MONITORING SYSTEMS--Table of Contents
 
             Subpart B--Construction and Design Requirements
 
Sec. 27.21  Methane-monitoring system.

    (a) A methane-monitoring system shall be so designed that any 
machine or equipment, which is controlled by the system, cannot be 
operated unless the electrical components of the methane-monitoring 
system are functioning normally.
    (b) A methane-monitoring system shall be rugged in construction so 
that its operation will not be affected by vibration or physical shock, 
such as normally encountered in mining operations.
    (c) Insulating materials that give off flammable or explosive gases 
when decomposed shall not be used within enclosures where they might be 
subjected to destructive electrical action.
    (d) An enclosure shall be equipped with a lock, seal, or acceptable 
equivalent when MSHA deems such protection necessary for safety.
    (e) A component or subassembly of a methane-monitoring system shall 
be constructed as a package unit or otherwise in a manner acceptable to 
MSHA. Such components or subassemblies shall be readily replaceable or 
removable without creating an ignition hazard.
    (f) The complete system shall ``fail safe'' in a manner acceptable 
to MSHA.