Central Plastics Company — Pipeline Safety Interpretation

Page 1October 18, 1977 Mr. Bob Pourchot Product Engineer Central Plastics Company P.O. Box 762 Shawnee, OK 74801 Dear Mr. Pourchot: Your letter to Mr. Paul Cory requests that we review the design of the anodeless service riser manufactured by Central Plastics Company and determine if it violates the requirements of the Federal gas pipeline safety regulations, 49 CFR Part 192. The Office of Pipeline Safety Operations (OPSO) does not approve, endorse, or make the requested determination on proprietary items. We can, however, discuss the design and indicate the requirements that would be applicable. You previously supplied Mr. Cory with drawings of the service riser in question that show the transition from plastic to metal pipe occurring belowground. This transition is enclosed in a metallic casing that extends belowground over the plastic pipe and upward over the steel gas pipe to a point below the threaded upper end of the service riser. The steel gas pipe and the transition fitting are insulated from the casing by a combination of polyethylene tubing and epoxy materials. These plastic materials fill the void between the steel gas carrying pipe and the casing and since the plastic is not carrying gas, it is not subject to the temperature limits of Section 192.123. Also, according to the design provided to OPSO, the steel gas carrying pipe that extends from belowground to the head of the service riser is enclosed in a covering of plastic material which in turn is covered by the steel casing. Plastic material fills the void between the casing and carrier pipes and is intended to insulate the carrier pipe from the casing. If it can be shown under Section 192.455(b) that the steel gas pipe is in a location where a corrosive environment does not exist, then cathodic protection would not be required. dal\192\455\77-10-18 1#

Page 2Thank you for your interest in pipeline safety. If you have additional questions, please advise. Sincerely, \signed\ Cesar DeLeon Acting Director Office of Pipeline Safety Operations dal\192\455\77-10-18 2#

Page 3CENTRAL PLASTICS COMPANY September 12, 1977 D.O.T., Office of Pipeline Safety Attn: Paul Cory Trans Point Bldg. 2100 Second Street, S.W. Washington, D.C. 20590 Dear Paul, We certainly appreciate your efforts to answer P.G.& E.'s questions concerning our anodeless service riser. We are sorry for the mix-up. As I was not entirely sure that Tom Timen was the engineer at P.G.& E. who originally inquired, I feel it necessary to go and talk with them again. In order to prevent any further embarrassment, I was hoping you could send me a letter. If you would review our design again and merely say if it violates the code or not, we would be most grateful. We would then clear up the matter with P.G.& E. and P & F ourselves. Thanks again for your concern. Regards, \signed\ Bob Pourchot Product Engineer dal\192\455\77-10-18 3#

Page 4February 2, 1974 Mr. Richard B. Bender Richard B. Bender Corrosion Associates P.O. Box 11302 Fort Worth, TX 76110 Dear Mr. Bender: In your letter of January 17, 1974, you asked about corrosion control requirements for steel risers on plastic service lines. Steel risers on plastic services must be coated and cathodically protected as required by Section 192.455 of Subpart I of the Federal regulations. So as to facilitate cathodic protection, each service riser must be electrically insulated from other house piping such as at the regulator, shut- off valve or meter as required by Section 192.467(b). The level of protection must meet one or more of the criteria contained in Section 192.463. Also, the frequency for monitoring the cathodic protection applied to service risers is covered by Section 192.465. We trust this clarifies the requirements for corrosion control measures applicable to steel risers on plastic services. If you desire any further information, please advise. Sincerely, \signed\ Joseph C. Caldwell Director Office of Pipeline Safety dal\192\455\77-10-18 4#