Fisher Controls Company — Pipeline Safety Interpretation

Page 1PI-72-0100 January 21, 1972 Mr. Frank St. Amand Assistant Sales Manager Fisher Controls Company Marshalltown, Iowa 50158 Dear Mr. St. Amand: In response to your letter of December 20, 1971, requesting an interpretation of Section 192.195 Protection Against Accidental Overpressuring, we offer the following: Question: (Paraphrased) Is there any intent in 192.195 to limit the use of some types of overpressure protective devices that were previously permitted under certain conditions under the interim standards (B31.8) such as relief, monitoring, rupture discs, shut-off and series regulation? Answer: Except as specifically provided for in Section 192.195, there is no intent to limit the type of overpressure protection device that an operator may use. The operator is free to choose the device, including those referenced by you, that will best suit his situation so long as it complies with applicable requirements of Part 192. If you have further question, please advise. Sincerely, Original signed by: Joseph C. Caldwell Acting Director Office of Pipeline Safety#

Page 2Fisher Controls Company Marshalltown, Iowa 50158 December 20, 1971 Secretary of Transportation 400 Sixth St. S.W. Washington, D. C. Attention: Mr. Joseph C. Caldwell Acting Director Office of Pipeline Safety Dear Mr. Caldwell: The general requirement in the Minimum Federal Standards under 192.195, Protection Again Accidental Overpressuring, is a performance standard. The previous guideline for gas industry engineers was Section 845 of the B31.8 Code, specifically, Paragraphs 845.212, 845.222, and 845.23. With certain qualifications, these areas allowed overpressure protection by relief, monitoring, rupture discs, shut-off and series regulation. The question which we have received from some of our customers and which we would like to ask you is, "Is there any intent in 192.195 to limit the use of any of these types of overpressure protection, or are they all still acceptable, as long as they meet the performance as required under the minimum Federal Standards?" Very truly yours FISHER CONTROLS COMPANY Frank St. Amand Assistant Sales Manager#