NTSB Safety Recommendation P-98-020

NTSB safety recommendation P-98-020.

THE NTSB RECOMMENDS THAT THE MUELLER COMPANY: 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: 2002-09-13

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: Mueller Company

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 2002-09-13

Addressee Organization Type: P-Private Industry

Communication Date: 2002-07-26

Communication Type: Official Correspondence

Communication Contents: Letter Mail Controlled 08/05/2002 2:24:06 PM MC# 2020752 As described in earlier correspondence, Mueller Co. has decided to proceed with reference to ASTM D2774-01 Standard Practice for Underground Installation of Thermoplastic Pressure Piping and the AGA Plastic Pipe Manual, Seventh Edition, 2001 on tags that are included with our products that provide connection between steel gas mains and plastic service piping. Included with this is a copy of our Form 10766 which shows this addition. These new tags are being used with all of our appropriate products. We hope this will bring this matter to a closure as an acceptable response. We have great concern for the safety of any gas installation and will continue our efforts to provide safe and reliable products for the industry.

Addressee Organization Type: P-Private Industry

Communication Date: 1998-05-22

Communication Type: Official Correspondence

Communication Contents: (Letter Mail Controlled 5/26/98 4:06:33 PM MC# 980673) THIS LETTER WILL ACKNOWLEDGE RECEIPT OF MUELLER CO. IN RESPONSE, WE PLAN TO OBTAIN A COPY OF THE ACCIDENT REPORT (ACCIDENT NO. DCA95P0001, WATERLOO, IA) & STUDY ITS CONTENTS. THIS WILL BE COMBINED WITH EXISTING GUIDE MATERIAL AVAILABLE FROM TECHNICAL PUBLICATIONS TO DETERMINE WHAT IS NEEDED IN ADDITION TO THE INSTRUCTIONS & RECOMMENDATIONS WE NOW SUPPLY WITH THESE PRODUCTS. THEN, WE WILL ALTER OUR INSTRUCTIONS & RECOMMENDATIONS ACCORDINGLY.

Addressee Organization Type: P-Private Industry

Communication Date: 1998-08-21

Communication Type: Official Correspondence

Communication Contents: (Letter Mail Controlled 8/24/98 3:56:00 PM MC# 981048) WE HAVE STUDIED NTSB/SIR-98/01 "BRITTLE-LIKE CRACKING IN PLASTIC PIPE FOR GAS SERVICE" & RECOMMENDATION P-98-20 AS WELL AS DISCUSSING THIS TOPIC WITH OTHERS IN THE INDUSTRY. WE THINK THAT DETAILS OF HOW BEST TO PROTECT PLASTIC SERVICE LINES FROM DAMAGE AT THE TRANSITION POINT TO A STEEL TEE IS PART OF THE DESIGN TO THE SYSTEM & NOT SOMETHING A MANUFACTURER WOULD NORMALLY COVER IN INSTALLATION INSTRUCTIONS. IT IS OUR BELIEF THAT THE PROPER PLACE TO DEVELOP THIS INFO IS IN THE TECHNICAL COMMITTEE OF THE GAS INDUSTRY, TO WHOM YOU HAVE ALSO SENT RECOMMENDATIONS, AS THEY HAVE THE EXPERTISE. MUELLER CO. PLANS TO PARTICIPATE IN AT LEAST TWO OF THESE GROUPS WITH THE INTENTION OF SUGGESTING LANGUAGE ACCEPTABLE TO THE INDUSTRY TO BE PLACED ON AN INFORMATIONAL TAG TO GO WITH THE PRODUCT THAT WILL DIRECT THE USER TO THE APPROPRIATE REFERENCE DOCUMENTS SUCH AS THE ANSI/GPTC Z380 GUIDE FOR TRANSMISSION & DISTRIBUTION PIPING SYSTEMS, AGA PLASTIC PIPE MANUAL & ASTM D2774. WE SHARE YOUR CONCERN FOR THE SAFETY OF ANY GAS INSTALLATION & WILL CONTINUE OUR EFFORTS TO PROVIDE SAFE & RELIABLE PRODUCTS FOR THIS INDUSTRY.

Addressee Organization Type: P-Private Industry

Communication Date: 2001-11-05

Communication Type: Official Correspondence

Communication Contents: Letter Mail Controlled 12/27/2001 6:18:17 PM MC# 2010978 Work has proceeded through industry committees as described in my letter of August 21, 1998. I represent Mueller Co. as a member of ASTM F17 and the Gas Piping Technology Committee. ASTM Committee F17 has produced additional language in ASTM D2774-01 which has recently published. The Gas Piping Technology Committee continues working on a response to be added to ANSI/GPTC Z380 Guide for Transmission and Distribution Piping Systems. New language had been added to the AGA Plastic Pipe Manual and we have been told it will publish in the very near future. Our plan is to use these reference documents that contain language acceptable to the industry on tags and/or other information supplied with our products. One document is now available with a second to follow shortly. It is uncertain when the third will be available. It has been our hope to include all three but if the GTPC does not produce something in the near future, we may need to proceed without their input. We have great concern for the safety of any gas installation and will continue our efforts to provide safe and reliable products for the industry.

Addressee Organization Type: P-Private Industry

Communication Date: 2002-03-25

Communication Type: Official Correspondence

Communication Contents: The Safety Board understands that the Mueller Company plans to use the above two documents, which contain language acceptable to the industry, on tags and other information supplied with Mueller Company products. The Board notes that if a second document is not published by the GPTC, the Mueller Company may need to proceed without GPTC's input. The Safety Board appreciates the effort the Mueller Company has made to implement the recommendation. Accordingly, pending receipt of further information from the Mueller Company indicating the completion of this project, Safety Recommendation P-98-20 is classified "Open--Acceptable Response."

Addressee Organization Type: P-Private Industry

Communication Date: 2002-09-13

Communication Type: Official Correspondence

Communication Contents: In 2001, Mr. Humes informed the Safety Board that the Mueller Company worked with the American Society of Technical Materials' (ASTM) Committee F17, the Gas Piping Technology Committee (GPTC), and the American Gas Association (AGA), to develop guidance to address the recommendation. Specifically, ASTM's Committee F17 produced additional language in the recently published ASTM D2774-01 regarding underground installation of thermoplastic pressure piping; the Gas Piping Technology Committee added ANSI/GPTC Z380, Guide for Transmission and Distribution Piping Systems; and new language had been added to the AGA's Plastic Pipe Manual regarding the installation of plastic piping. Mr. Humes now reports that the Muller Company now references ASTM D2774-01 Standard Practice for Underground Installation of Thermoplastic Pressure Piping and the AGA Plastic Pipe Manual, seventh edition, on tags included with the company's products that provide connection between steel gas mains and plastic service piping. Accordingly, Safety Recommendation P-98-20 is classified "Closed--Acceptable Action."

Addressee Organization Type: P-Private Industry

Communication Date: 1998-06-24

Communication Type: Official Correspondence

Communication Contents: THE BOARD UNDERSTANDS THAT THE MUELLER COMPANY INTENDS TO ALTER THE INSTRUCTIONS & RECOMMENDATIONS CURRENTLY PROVIDED WITH THIS PRODUCT, AFTER REVIEWING THE BOARD'S SPECIAL INVESTIGATION REPORT & EXISTING GUIDANCE AVAILABLE FROM TECHNICAL PUBLICATIONS. PENDING FURTHER RESPONSE FROM THE MUELLER COMPANY ON THE STATUS OF THIS INITIATIVE, P-97-20 HAS BEEN CLASSIFIED "OPEN--ACCEPTABLE RESPONSE."

Addressee Organization Type: P-Private Industry

Communication Date: 1998-10-06

Communication Type: Official Correspondence

Communication Contents: HE BOARD RECOGNIZES THAT STEEL TAPPING TEE MANUFACTURERS MAY HAVE COMPARATIVELY LESS TECHNICAL EXPERTISE THAN PLASTIC PIPING MANUFACTURERS REGARDING CERTAIN CHARACTERISTICS OF PLASTIC PIPE. NEVERTHELESS, STEEL TAPING TEE MANUFACTURERS, WHO HAVE DESIGNED THEIR RIGID STEEL TEE TO CONNECT TO FLEXIBLE GAS PIPE, HAVE A RESPONSIBILITY TO PROVIDE GUIDANCE FOR THE SAFE USE OF THEIR PRODUCTS. THE BOARD UNDERSTANDS THAT MUELLER COMPANY PLANS TO WORK WITH GAS INDUSTRY TECHNICAL COMMITTEES TO DEVELOP APPROPRIATE INSTALLATION INSTRUCTIONS TO SAFELY LIMIT SHEAR & BENDING FORCES AT PLASTIC SERVICE CONNECTIONS TO STEEL MAINS VIA STEEL TAPPING TEES. MUELLER WILL THEN INCLUDE THIS INFO ON A TAG TO GO WITH ITS SHIPPED PRODUCT. PENDING FURTHER RESPONSE FROM THE MUELLER COMPANY ON THE STATUS OF THIS INITIATIVE, P-98-20 WILL REMAIN CLASSIFIED "OPEN--ACCEPTABLE RESPONSE."

Addressee Organization Type: P-Private Industry

Communication Date: 2001-09-28

Communication Type: Official Correspondence

Communication Contents: To date, the Safety Board has not received any further response from the Mueller Company and would appreciate being informed about the efforts that have been made or are being made to implement this safety recommendation. Enclosed are copies of our correspondence concerning this recommendation. Please address your response to Ms. Marion C. Blakey, Chairman, National Transportation Safety Board, and refer to the recommendation by number.