Pennsylvania Code
Title 67 - TRANSPORTATION
Part I - Department of Transportation
Subpart A - Vehicle Code Provisions
Article VII - Vehicle Characteristics
Chapter 169 - DIESEL SMOKE MEASUREMENT PROCEDURE
Section 169.2 - Scope

(a) This chapter applies to the dynamometer test procedure which can be used to assess the smoke emission characteristics of vehicular diesel engines. In particular, these procedures describe the smoke emissions test, smoke test cycle, equipment and instrumentation, instrument checks and chart reading and calculation, for evaluation of the steady-state and transient smoke emission characteristics of an engine.

(b) A full-flow smoke opacimeter as opposed to other types of smokemeters shall be required because the test is designed to monitor transient smoke. Sampling type instruments have an excessive and variable delay and do not provide an accurate measurement of the transient smoke output of the engine. Appendix A shows that the Beer-Lambert law can be used to correlate opacity measurements with different meter path lengths.

(c) Additional or modified test conditions may be requested when this chapter is cited in a request for a smoke assessment. These modified test conditions should be clearly stated whenever the results of the smoke assessments are reported. Similarly if the fuel is specified in the test request, this should be stated when the results are reported.