U.S. Environmental Protection Agency
Office of Mobile Sources

June 1999 (posted to web 7/22/99)

"Evaluation of Two Prototype Purge Flow Test Instruments"

EPA Report Number EPA420-R-99-017 (draft was EPA420-P-99-022)

Abstract:

This report presents the results of an evaluation of two
prototype purge test devices conducted at Automotive Testing
Laboratories, Inc. in January 1999.  The evaluation was performed
under contract for EPA.  One prototype device was submitted by
Sensors Inc., and a second device by EPA's Office of Mobile
Sources Engine Programs and Compliance Division.  Each device was
evaluated on approximately 90 test vehicles recruited from the
Mesa, Arizona emission inspection station.  Each method was
compared to a reference method as a check on the prototype
method's accuracy.  Due principally to problems with
intrusiveness (the need for slave purge lines or the need to
create a small hole in the purge line by inserting a needle),
lack of timeliness of the methods, and high false failure rates,
EPA determined neither method merits further development effort.

Copies of Appendices 2-5 are available only in hard copy form, by
request.

Questions about this report may be submitted electronically to
Martin Reineman at: reineman.martin@epa.gov or by Fax at: 
734-214-4052, or by mail at: U.S. EPA, attn Martin Reineman, 
2000 Traverwood Dr., Ann Arbor, MI 48105.