# State of Minnesota Department of Public Safety — Pipeline Safety Interpretation - **operation:** document - **citation:** PI-91-037 - **title:** State of Minnesota Department of Public Safety — Pipeline Safety Interpretation - **source type:** guidance - **agency:** Pipeline and Hazardous Materials Safety Administration - **status:** guidance - **official:** true - **published on:** 1991-12-24 - **effective on:** Not available - **summary:** PI-91-037 response to State of Minnesota Department of Public Safety concerning 192.375. - **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-91-037.json - **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-91-037.md - **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-91-037 - **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1991/PI91037.pdf **body:** <<>> Mr. Walter T. Kelly Director, Office of Pipeline Safety State of Minnesota Department of Public Safety 175 Aurora Avenue St. Paul, MN 55013-2356 Dear Mr. Kelly: This responds to your letter of August 25, requesting our opinion whether .049 square inches of exposed polyethylene pipe are acceptable under 49 CFR §192.375(a). You said the ,049 square inches of exposed polyethylene pipe are exposed to ultraviolet rays through a vent hole on a service riser. Section 192.375(a) requires that all plastic service lines transporting gas above ground, outside a building, be protected against deterioration and external damage. Ultraviolet rays are known to deteriorate polyethylene pipe; so no exposure of polyethylene pipe to ultraviolet rays is permitted under §192.375(a). We trust this adequately responds to your inquiry. Sincerely, Cesar DeLeon Director for Pipeline Safety Regulatory Programs DB C:\WP51]INTERPRT\192\375\91-12-24 1 - **truncated:** false - **body characters:** 948