[Code of Federal Regulations]

[Title 30, Volume 1]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 30CFR36.23]



[Page 181-182]

 

                       TITLE 30--MINERAL RESOURCES

 

  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR

 

PART 36_APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED 

TRANSPORTATION EQUIPMENT--Table of Contents

 

             Subpart B_Construction and Design Requirements

 

Sec.  36.23  Engine intake system.



    (a) Construction. The intake system (exclusive of the air cleaner) 

shall be designed to withstand an internal pressure equal to 4 times the 

maximum pressure observed in explosion tests, which are described in 

Sec.  36.46, or a pressure of 125 pounds per square inch, whichever is 

the lesser. Joints in the intake system shall be formed by metal flanges 

fitted with metal or metal-clad gaskets, positively positioned by 

through bolts or other suitable means for secure assembly, or shall meet 

the requirements for flanged metal-to-metal flame-proof joints as 

required in Sec.  36.20(b). Either type of joint shall withstand 

repeated explosions within the intake system without permanent 

deformation and shall prevent the propagation of flame through the joint 

into a surrounding flammable mixture.

    (b) Intake flame arrester. (1) The intake system shall include a 

flame arrester that will prevent an explosion within the system from 

propagating to a surrounding flammable mixture. This flame arrester 

shall be between the air cleaner and the intake manifold and shall be 

attached so that it may be removed for inspecting, cleaning, or 

repairing. Its construction shall be such that it may be cleaned 

readily. The flame arrester shall be of rugged construction to withstand 

the effects of repeated explosions within the intake



[[Page 182]]



system, and the material of construction shall resist deterioration in 

service. It shall be so mounted in the equipment assembly that it is 

protected from accidental external damage.

    (2) The parts of any flame arrester shall be positively positioned 

to produce a flame path that will arrest the propagation of an explosion 

and shall be so designed that improper assembly is impossible. In flame 

arresters of the spaced-plate type, the thickness of the plates shall be 

at least 0.125 inch; spacing between the plates shall not exceed 0.018 

inch; and the plates forming the flame path shall be at least 1 inch 

wide. The unsupported length of the plates shall be short enough that 

deformation during the explosion tests shall not exceed 0.002 inch. 

Corrosion-resistant metal shall be used to construct flame arresters.

    (c) Air shutoff valve. The intake system shall include a valve, 

operable from the operator's compartment, to shut off the air supply to 

the engine. This valve shall be constructed to permit its operation only 

after the fuel supply to the engine is shut off. In reverse operation 

the valve must open fully before fuel can be supplied to the engine.

    (d) Air cleaner. An air cleaner shall be included in the engine 

intake system and so arranged that only clean air will enter the flame 

arrester. The resistance to airflow shall not increase rapidly in dusty 

atmospheres. Filters of the self-cleansing (oil-bath) type will be 

considered satisfactory for this application. Provision, satisfactory to 

MSHA, shall be made to prevent overfilling the oil-bath air cleaner.

    (e) Vacuum-gage connection. A connection shall be provided in the 

intake system for temporary attachment of a vacuum gage to indicate the 

pressure drop under flow conditions. This opening shall be closed by a 

plug or other suitable device that is sealed or locked in place except 

when a gage is attached.