(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.
