The agency has provided a list of approved engines as well as each respective unit’s limit as defined by MSHA’s technical support team. The document, entitled Approval and Certification Center’s (A&CC) List of Approved Products, is available for viewing at https://lakegovprod1.msha.gov/ReportView.aspx?ReportCategory=EngineAppNumbers.
For those unapproved engines, it added, users can refer to the manufacturers’ guidelines for the backpressure limit.
MSHA said that its method of checking backpressure on diesel machines is sixfold, and the agency said that their thresholds are in compliance with manufacturer specifications.
Included in their check methods:
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 filter);
A pressure measurement device is used to measure the maximum total exhaust system backpressure;
For a naturally aspirated engine, the engine is run at high idle, no load speed;
For turbocharged engines, the engine is run at torque converter stall or hydrostatic transmission load (see weekly tests procedures under Title 30 Code of Federal Regulations (30 C.F.R.), 75.1914(g), for more information);
The test is run until the total exhaust backpressure reading is reasonably stable; and
The identification of the machine being tested, the engine's serial number and the maximum total exhaust system backpressure reading is recorded.
MSHA added that it can also collect the needed data from onboard exhaust backpressure monitoring units.
“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,” the agency said in a statement.
“MSHA's standards found in 30 CFR Part 7 Subpart E, 30 CFR 75.1914 and 30 CFR 57.5066 require that diesel engines be maintained in approved condition or to manufacturers’ specifications.”
