Westpac Utilities — Pipeline Safety Interpretation

Page 1August 24, 1993 Ms. Anne Radomski Westpac Utilities P.O. Box 30028 Reno, Nevada 89520-3028 Dear Ms. Radomski: Your letter of July 20, 1993, requests our interpretation of 49 CFR §§ 192.355(b) (2) and 192.357(d) regarding venting of customer regulators. In your first question, you ask if a meter with a relieving regulator in an enclosed space is properly vented if an outside door to the space has slats at the top and air space clearance at the bottom. Since the regulator has an internal relief valve, it must be vented directly to the outside atmosphere through piping. Slats and air space are not acceptable. Your second question asks if venting to the outside atmosphere is necessary for a confined space that contains a working regulator and a monitor regulator. Neither regulator has external relief. In the absence of state or local requirements to the contrary, direct venting is not necessary if the regulator is in a confined space, and has no internal relief valve. Accordingly, venting is not required. The third question regards a confined space that contains a regulator with an internal relief valve. As in the first question, the relief valve must be vented directly to the outside atmosphere through piping. Sincerely, Cesar De Leon Director, Regulatory Programs Office of Pipeline Safety dal\192.355\93-08-24#