CIBA - GEIGY Pipe Systems — Pipeline Safety Interpretation

Page 1April 11, 1983 Mr. Philip K. Gilbert CIBA - GEIGY Pipe Systems Suite 190 7676 Hillmont Houston, TX 77040 Dear Mr. Gilbert: A formal interpretation of 49 CFR §192.281, Plastic pipe, paragraph (a) as requested by your letter of March 23, 1983, is enclosed. Sincerely, Richard L. Beam Associate Director for Pipeline Safety Regulation Materials Transportation Bureau Enclosure dal\192\281\83-04-11 1#

Page 2No. 83-3 Date: April 11, 1983 DEPARTMENT OF TRANSPORTATION RESEARCH AND SPECIAL PROGRAMS ADMINISTRATION MATERIALS TRANSPORTATION BUREAU ______________________________________________________________________________ PIPELINES SAFETY REGULATORY INTERPRETATION ______________________________________________________________________________ Note: This pipeline safety regulatory interpretation applies a particular rule to a particular set of facts and circumstances, and as such, is binding only on the operator to whom the interpretation is specifically addresses. SECTION: 192.281 SUBJECT: FACTS: None. Joining plastic pipe with a plastic mechanical fitting that is threaded to provide gasket pressure. QUESTION: Would DOT consider the CIBA-GEIGY Pronto-Lock, Pronto-Lock II, and Pronto-Lock III mechanical coupling systems as threaded joints or as mechanical joints? INTERPRETATION: The Pronto-Lock, Pronto-Lock II, and Pronto-Lock III mechanical coupling systems are "mechanical joints" and would not be considered as "threaded joints" which are prohibited under §192.281(a). The threaded portions of these joints are used to apply compressive stress to a gasket or O-ring seal similar to many other joint systems now used in gas piping systems. Threads are designed to minimize stresses and are not used as a gas seal. Richard L. Beam Associate Director for Pipeline Safety Regulation Materials Transportation Bureau dal\192\281\83-04-11 2#

Page 3March 23, 1983 Mr. Richard L. Beam Assoc. Director for Pipeline Safety Regulations Material Transportation Bureau Department of Transportation Washington, D.C. 20590 Ref: Title 49 Of The Code Of Federal Regulations Interpretation Of Part 192, Section 192.281 Dear Mr. Beam: This letter is a formal request for written interpretation of the referenced section. The question has been raised whether the D.O.T. would classify our Pronto-Lock®, Pronto Lock II, or Pronto- Lock III mechanical coupling systems (see enclosed literature) as a "threaded joint" or a "mechanical joint". In recent telephone conversations with Mr. Paul Cory of your department, he indicated that since the seal was effected by an "O"-ring instead of the threads, the coupling systems would be considered mechanical coupling systems. We did not discuss the Pronto-Lock III coupling system but it seals by a lip seal gasket and not by thread interference. If you have any questions, or would like to see actual joint samples, I would be pleased to help in any way I can. Thank you for handling this matter and I look forward to hearing from you soon. Sincerely, Philip K. Gilbert Engineer dal\192\281\83-04-11 3#