ISSUE DATE: 4/28/2011

PROGRAM INFORMATION BULLETIN NO. P11-31

FROM: KEVIN G. STRICKLIN

 Administrator for 

 Coal Mine Safety and Health

 NEAL H. MERRIFIELD

 Administrator for

 Metal and Nonmetal Mine Safety and Health

 LINDA F. ZEILER

 Acting Director of Technical Support

SUBJECT: Reissue of P07-17 - Test Procedure for Evaluating

 Maximum Total Exhaust System Backpressure on an

 Underground Diesel-Powered Machine

Who needs this information?

This Program Information Bulletin (PIB) is intended for underground coal mine and 

metal and nonmetal mine operators using diesel-powered equipment, manufacturers of 

diesel-powered underground mining equipment (including manufacturers of exhaust 

after-treatment control devices and systems), diesel engine manufacturers, miners’ 

representatives, and Mine Safety and Health Administration (MSHA) personnel.

Why is MSHA issuing this PIB?

This PIB describes how MSHA evaluates the maximum total exhaust system

backpressure on engines for compliance purposes. MSHA provides a list of approved 

engines that specifies each engine’s respective maximum total exhaust system 

backpressure limit at Technical Support’s “Approval and Certification Center’s (A&CC)

List of Approved Products.” This list can be found on the internet at: 

https://lakegovprod2.msha.gov/ReportView.aspx?ReportCategory=EngineAppNumb

ers .
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For engines used in metal and nonmetal mines that are not MSHA approved, the engine 

manufacturer provides a specification for the maximum total exhaust system 

backpressure limit for each engine. 

How will MSHA check the maximum total exhaust system backpressure on an 

underground diesel-powered machine? 

Engine manufacturers specify a maximum total exhaust system backpressure limit. 

MSHA evaluates an engine’s maximum total exhaust system backpressure for 

compliance with the engine manufacturer’s specification using the following test 

procedures:

1) The maximum total exhaust system backpressure is measured at a port in the 

exhaust pipe located near the outlet of the exhaust manifold or turbocharger. The 

measurement location must be upstream of exhaust devices such as a catalytic 

converter, muffler, or diesel particulate matter (dpm) filter. For permissible equipment, 

the procedure in the Power System Checklist is followed.

2) A pressure measurement device is used to measure the maximum total exhaust

system backpressure. 

3) For a naturally aspirated engine, the engine is run at high idle, no load speed. 

4) For turbocharged engines, the engine is run at torque converter stall or hydrostatic 

transmission load. This operating procedure is the same as that established by the coal 

mine operator to conduct the undiluted exhaust emissions weekly test required under 

Title 30 Code of Federal Regulations (30 C.F.R.) § 75.1914(g). For turbocharged engines 

that are installed in equipment that has a clutch, the engine is run at high idle, no load 

speed. 

5) The test is run until the total exhaust backpressure reading is reasonably stable.

6) The identification of the machine being tested, the engine’s serial number, and the 

maximum total exhaust system backpressure reading is recorded.

MSHA may also evaluate data collected from an on-board exhaust backpressure 

monitoring device that continuously measures and records the exhaust backpressure 

during normal operating conditions.

Where can I find more information?

More information on engine backpressure effects or measurements can be obtained by 

contacting A&CC at the number below or engine manufacturers or distributors. As 
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stated above, MSHA provides a list of approved engines which specifies their 

respective maximum total exhaust system backpressure limits. For engines that are 

not MSHA approved, their specifications are available from the engine manufacturer or 

distributor.

What is the background for this PIB?

Diesel engine manufacturers specify a maximum total exhaust system backpressure 

limit in their specifications for each engine model. Monitoring the exhaust 

backpressure will ensure that the exhaust system has not been compromised by a 

clogged dpm filter, catalytic converter, or any other device that is installed. MSHA’s 

standards found in 30 C.F.R. Part 7 Subpart E, 30 C.F.R. § 75.1914, and 30 C.F.R.

§57.5066 require that diesel engines be maintained in approved condition or to

manufacturer’s specifications. This test procedure is used to determine compliance

with these requirements.

Who are the contact persons for this PIB?

Coal Mine Safety and Health, Health Division

Robert Thaxton, (202) 693-9515

E-mail: thaxton.robert@dol.gov

Metal and Nonmetal Mine Safety and Health

Reginald J. Richards, (202) 693-9600

E-mail: richards.reginald@dol.gov 

Technical Support, Approval and Certification Center

Jeffrey Moninger, (304) 547-2324

E-mail: moninger.jeffrey@dol.gov

What is the authority for this PIB?

The Federal Mine Safety and Health Act of 1977, as amended, 30 U.S.C. § 801 et seq.; 

30 C.F.R. part 7 subpart E, 30 C.F.R. part 75 subpart T, and 30 C.F.R. § 57. 5066.

Who will receive this PIB?

Program Policy Manual Holders

Miners' Representatives

Underground Coal Mine Operators

Special Interest Groups

Engine Manufacturers