Natural Resources Engineering Company — Pipeline Safety Interpretation

Page 1PI-04-0106 U.S. Department of Transportation Research and Special Programs Administration 400 Seventh Street, S.W. Washington, D.C. 20590 April 20, 2004 Mr. Joseph Peterson GIS Specialist Natural Resources Engineering Company 69 North 28th Street, Suite 27 Superior, WI 54880 Dear Mr. Peterson: This is in response to your e-mail of March 29, 2004, in which you request an interpretation of the provisions of the Federal gas pipeline safety regulations at 49 CFR 192.5, Class locations, as it relates to the concept of clusters. The original edition of the gas pipeline safety regulations at 49 CFR Part 192 (35 FR 13251; August 19, 1970) sought to address the problem that the class location scheme could create a two-mile stretch of higher class location solely to protect a small cluster of buildings at a crossroads or road crossing. To avoid this situation a new paragraph was added to allow adjustment of class location unit boundaries to address isolated clusters of buildings intended for human occupancy. In the regulations the term, "cluster," is used in its ordinary dictionary sense, and has not been a significant source of misunderstanding. The dictionary meaning is: a number of similar things together, a bunch, a group. The history of § 192.5 shows that the cluster exception applies only when all buildings in a one-mile class location unit are in a single cluster. If a class location unit contains buildings outside a cluster or more than one cluster of buildings, all buildings in the unit must be counted to determine the class location of the unit. If you have any further questions about the pipeline safety regulations, please contact Sincerely, Richard D. Huriaux, P.E. Manager, Regulations Office of Pipeline Safety#