NTSB Safety Recommendation P-98-017

NTSB safety recommendation P-98-017.

THE NTSB RECOMMENDS THAT THE CONTINENTAL INDUSTRIES, INC.: DEVELOP & PUBLISH RECOMMENDATIONS & INSTRUCTIONS FOR LIMITING SHEAR & BENDING FORCES AT LOCATIONS WHERE YOUR STEEL TAPPING TEES ARE USED TO CONNECT PLASTIC SERVICE PIPE TO STEEL MAINS.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 1998-04-30

Adopted Date: 1998-04-23

Overall Date Closed: 1999-07-13

Synopsis: DESPITE THE GENERAL ACCEPTANCE OF PLASTIC PIPING AS A SAFE & ECONOMICAL ALTERNATIVE TO PIPING MADE OF STEEL OR OTHER MATERIALS, THE BOARD NOTES THAT A NUMBER OF PIPELINE ACCIDENTS IT HAS INVESTIGATED HAVE INVOLVED PLASTIC PIPING THAT CRACKED IN A BRITTLE-LIKE MANNER. FOR EXAMPLE, ON 10/17/94, AN EXPLOSION & FIRE IN WATERLOO, IOWA, DESTROYED A BUILDING & DAMAGED OTHER PROPERTY. SIX PERSONS DIED & SEVEN WERE INJURED IN THE ACCIDENT. THE BOARD INVESTIGATION DETERMINED THAT NATURAL GAS HAS BEEN RELEASED FROM A PLASTIC SERVICE PIPE THAT HAD FAILED IN A BRITTLE-LIKE MANNER AT A CONNECTION TO A STEEL MAIN.

Probable Cause: None

Ntsbnumber: DCA95MP001

Report Number: SIR-98-01

Addressee Name: Continental Industries, Inc.

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 1999-07-13

Addressee Organization Type: P-Private Industry

Communication Date: 1998-06-08

Communication Type: Official Correspondence

Communication Contents: Letter Mail Controlled 6/11/98 11:19:38 AM MC# 980751) WITH RESPECT TO THE FIRST "SAFETY RECOMMENDATION" REGARDING THE NEED TO ENSURE THAT THE USE OF PROTECTIVE SLEEVES WITH THE TAPPING TEES AT PLASTIC PIPE CONNECTIONS TO STEEL MAINS DOES NOT COMPROMISE CORROISON PROTECTION FOR THE CONNECTION, WE INTEND TO REVISE OUR PLASTIC COMPRESSION OUTLET ASSEMBLY INSTRUCTIONS TO INDICATE THAT "SUCH DEVICES SHOULD ALLOW A MINIMUM OF 1/2 INCH CLEARANCE BETWEEN THE SLEEVE & THE TEES SUFFICIENT FOR THE INSTALLATION OF CORROSION PROTECTION COATING ON THE TEE." IN ADDITION TO ABOVE, CONTINENTAL WILL INCLUDE, IN OUR PRODUCT PROFOLIO, SLEEVES WITH THE PROPER CLEARANCE FOR ALL INSTALLATIONS. SECOND "SAFETY RECOMMENDATION" REGARDING THE DEVELOPING & PUBLISHING OF RECOMMENDATIONS & INSTRUCTIONS FOR LIMITING SHEAR & BENDING FORCES AT LOCATIONS WHERE OUR STEEL TAPPING TEES ARE USED TO CONNECT PLASTIC SERVICE PIPE TO STEEL MAINS, WE WOULD LIKE TO HAVE FURTHER DISCUSSIONS WITH THE NTSB REGARDING THE IMPLEMENTATION OF THIS RECOMMENDATION. WE ARE CONCERNED THAT IT IS A PRACTICAL IMPOSSIBILITY FOR US TO PROVIDE RECOMMENDATIONS THAT CAN ADEQUATELY ADDRESS THE INFINITE NUMBER OF INSTALLATION SITUATIONS AN INSTALLER MAY ENCOUNTER IN THE FIELD. WE SUGGEST THAT THE MOST PRUDENT COURSE WOULD BE FOR CONTINENTAL TO REVISE ITS PLASTIC COMPRESSION OUTLET ASSEMBLY INSTRUCTIONS TO INCLUDE A STATEMENT THAT CONTINENTAL RECOMMENDS THAT THE INSTALLER OF THE GAS SERVICE CONSIDER ADOPTING PROCEDURES CONSISTENT WITH CURRENT AGA, ASTM & D.O.T. RECOMMENDATIONS TO LIMIT SHEAR & BENDING FORCES ON STEEL TEES WITH COMPRESSION OUTLETS BASED ON THE PARTICULAR CONDITIONS. PRESENTED AT THE INSTALLATIN SITE. CONTINENTAL WILL CONTINUE TO MAKE AVAILABLE PROTECTIVE SLEEVES FOR OUR PRODUCTS & WILL NOTIFY OUR CUSTOMERS THAT THESE CONTINUE TO BE AVAILABLE. CUSTOMERS WILL BE ENCOURAGED TO CONTACT THEIR CONTINENTAL REPRESENTATIVE FOR ADDITIONAL INFO WITH RESPECT TO THESE ITEMS. WE THEREFORE, SUGGEST A TASK FORCE, INCLUDING THE OFFICE OF PIPELINE SAFETY, THE TEE MANUFACTURERS & SELECTED REPRESENTATION FROM THE GAS DISTRIBUTION COMPANIES & PIPE MANUFACTURERS, BE COMMISSIONED TO DEVELOP A STANDARD.

Addressee Organization Type: P-Private Industry

Communication Date: 1998-10-07

Communication Type: Official Correspondence

Communication Contents: Letter Mail Controlled 10/14/98 6:10:52 PM MC# 981237 CONTINENTAL WILL ADD THE FOLLOWING NOT TO ITS INSTALLATION INSTRUCTIONS: IT IS ADVISABLE TO LIMIT SHEAR AND BENDING FORCES AT MAIN CONNECTIONS. APPROPRIATE PROCEDURES WILL BE DETERMINED BY THE PARTICULAR SITE CONDITIONS, PIPE MATERIAL AND INSTALLATION CONFIGURATION. CONSULT YOUR COMPANY POLICY AND THE FOLLOWING REFERENCE MATERIALS: ASTM 2774, STANDARD PRACTICE FOR UNDERGROUND INSTALLATION OF THERMOPLASTIC PRESSURE PIPING, PAR.7.4.4 "SERVICE CONNECTIONS" CODE OF FEDERAL REGULATIONS, TITLE 49 TRANSPORTATION PART 192, PAR, 192.321 - THE GUIDANCE MANUAL FOR OPERATORS OF SMALL GAS SYSTEMS BY THE U.S. DEPT. OF TRANSPORTATION, APPENDIX M; A.G.A. PLASTIC PIPE MANUAL FOR GAS SERVICE, FEBRUARY 1989, PAGE 46, PAR. "EXTERNAL STRESSES AND PAGE 48, PAR. "DIRECT BURIAL REQUIREMENTS WITH PLASTICS". COPIES OF THE APPROPRIATE DOCUMENTS ARE ATTACHED TO THIS LETTER. WE BELIEVE THESE ACTIONS ADDRESS THE SUBJECT RECOMMENDATIONS. CONTINENTAL INDUSTRIES REMAINS VERY CONCERNED THAT ITS PRODUCTS ARE USED IN A SAFE AND RESPONSIBLE MANNER. WE HAVE CONSTRUCTED THE ABOVE INSTRUCTIONS TO ADVISE INSTALLERS OF THE NEED TO PROVIDE SUPPORT AIMED AT LIMITING SHEAR AND BENDING FORCES IN A VARIETY OF SITE SPECIFIC SITUATIONS. WE LOOK FORWARD TO YOUR RESPONSE.

Addressee Organization Type: P-Private Industry

Communication Date: 1999-04-06

Communication Type: Official Correspondence

Communication Contents: Letter Mail Controlled 4/12/99 5:14:46 PM MC# 990393 CONTINENTAL INDUSTRIES, INC. HAS COMPLIED WITH P-98-16 AND -17. ENCLOSED YOU WILL FIND AN UPDATED CATALOG SHEET LISTING OUR PROTECTIVE SLEEVES AND AN UPDATED INSTRUCTION SHEET.

Addressee Organization Type: P-Private Industry

Communication Date: 1998-08-06

Communication Type: Official Correspondence

Communication Contents: PENDING FURTHER RESPONSE FROM RESPONSE FROM CONTINENTAL, P-98-17 HAS BEEN CLASSIFIED "OPEN--ACCEPTABLE RESPONSE." IF AFTER REVIEWING THIS LETTER & THE REFERENCED SPECIAL INVESTIGATION REPORT, CONTINENTAL WISHES TO DISCUSS THE IMPLEMENTATION P-98-17, THE BOARD IS CERTAINLY WILLING TO PARTICIPATE. P-98-16 WILL REMAIN CLASSIFIED "OPEN--AWAIT RESPONSE," PENDING INFO FROM CONTINENTAL ON WHAT ACTION IT WILL TAKE TO IMPLEMENT THE RECOMMENDED ACTION.

Addressee Organization Type: P-Private Industry

Communication Date: 1998-12-17

Communication Type: Official Correspondence

Communication Contents: THE SAFETY BOARD NOTES THAT CONTINENTAL INDUSTRIES WILL ADD A NOTE TO ITS INSTALLATION INSTRUCTIONS ADVISING CUSTOMERS ABOUT LIMITING SHEAR AND BENDING FORCES AT MAIN CONNECTIONS WHEN STEEL TAPPING TEES ARE USED TO CONNECT PLASTIC SERVICE PIPE TO STEEL MAINS. ALTHOUGH RELIANCE ON MANUFACTURERS' RECOMMENDATIONS FOR LIMITING FORCES AT PLASTIC SERVICE CONNECTIONS TO STEEL MAINS VIA STEEL TAPPING TEES IS A COMMON THEME RUNNING THROUGH MANY OF THE PUBLISHED SOURCES OF INDUSTRY GUIDANCE (SUCH AS, THE AMERICAN GAS ASSOCIATION PLASTIC PIPE MANUAL FOR GAS SERVICE AND ASTM D2774), CONTINENTAL'S PLANNED NOTE APPEARS SUFFICIENT TO ALERT PIPELINE OPERATORS TO THE NEED TO CAREFULLY LIMIT FORCES AT THESE CONNECTIONS. PENDING FURTHER REPLY FROM CONTINENTAL INDUSTRIES ON PUBLICATION OF THIS ADVISORY NOTE, P-98-17 IS CLASSIFIED "OPEN--ACCEPTABLE RESPONSE."

Addressee Organization Type: P-Private Industry

Communication Date: 1999-07-13

Communication Type: Official Correspondence

Communication Contents: THE SAFETY BOARD UNDERSTANDS THAT CONTINENTAL INDUSTRIES HAS ADDED A NOTE TO ITS INSTALLATION INSTRUCTIONS THAT ADDRESSES LIMITING SHEAR AND BENDING FORCES WHERE ITS STEEL TAPPING TEES ARE USED TO CONNECT PLASTIC SERVICE PIPE TO STEEL MAIN. THEREFORE, P-98-17 HAS BEEN CLASSIFIED "CLOSED--ACCEPTABLE ACTION."