30 CFR § 56.13010 Reciprocating-type air compressors.
(a) Reciprocating-type air compressors rated over 10 horsepower shall
be equipped with automatic temperature-actuated shutoff mechanisms which
shall be set or adjusted to the compressor when the normal operating
temperature is exceeded by more than 25 percent.
(b) However, this standard does not apply to reciprocating-type air
compressors rated over 10 horsepower if equipped with fusible plugs that were
installed in the compressor discharge lines before November 15, 1979, and
designed to melt at temperatures at least 50 degrees below the flash point of
the compressors' lubricating oil.