NTSB Safety Recommendation P-84-008

NTSB safety recommendation P-84-008.

THE NTSB RECOMMENDS THAT THE BOSTON GAS COMPANY: SECURE THE BALANCE WEIGHTS ON THE DIAPHRAGM PLATE ON ALL REGULATORS THAT USE BALANCE WEIGHTS.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 1984-04-09

Adopted Date: 1984-04-03

Overall Date Closed: 1984-08-01

Synopsis: ON SEPTEMBER 23, 1983, THE BOSTON WATER AND SEWER COMMISSION RECEIVED A TELEPHONE CALL FROM THE BOSTON POLICE DEPARTMENT NOTIFYING IT OF A BROKEN WATER MAIN AND FLOODING AT THE INTERSECTION OF PORTER AND BREMEN STREETS IN EAST BOSTON, MASSACHUSETTS. GAS PRESSURE IN THE BOSTON GAS COMPANY'S (GAS COMPANY) DISTRIBUTION SYSTEM IN EAST BOSTON RAPIDLY INCREASED FROM 7 INCHES WATER COLUMN (W.C.) (ABOUT 0.25 PSIG) TO MORE THAN 16 INCHES W.C. (ABOUT 0.6 PSIG). THE BOSTON FIRE DEPARTMENT BEGAN RECEIVING TELEPHONE CALLS ABOUT GAS ODORS, HIGH PILOT LIGHTS, AND FIRES, AND MORE THAN 200 SIMILAR TELEPHONE CALLS WERE RECORDED BY THE FIRE DEPARTMENT. GAS COMPANY CREWS SEARCHING FOR THE SOURCE OF THE HIGH GAS PRESSURE FOUND THE DISTRICT REGULATOR VAULT AT BREMEN AND PORTER STREETS (ONE OF FOUR DISTRICT REGULATORS IN THE EAST BOSTON AREA) HAD BEEN SUBMERGED IN WATER. AFTER THE VAULT HAD BEEN PUMPED OUT, INSPECTION OF THE PRIMARY REGULATOR AT BREMEN AND PORTER STREETS SHOWED THAT WATER HAD ENTERED THE REGULATOR THROUGH LEAKS IN A GASKET AND THROUGH THE VENT PIPING, THAT WATER HAD FILLED THE AREA ABOVE THE REGULATOR DIAPHRAGM, AND THAT THE WEIGHT OF THIS WATER IN THE DIAPHRAGM HAD HELD THE REGULATOR VALVE OPEN, THEREBY ALLOWING THE GAS PRESSURE TO INCREASE IN THE DISTRIBUTION SYSTEM.

Probable Cause: None

Ntsbnumber: DCA83MP025

Report Number: PAR-84-05

Addressee Name: Boston Gas Company

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 1984-08-01

Addressee Organization Type: P-Private Industry

Communication Date: 1984-05-16

Communication Type: Official Correspondence

Communication Contents: BOSTON GAS LETTER: BOSTON GAS IS ACQUIRING ADDITIONAL BALANCING WEIGHTS WHICH ARE DESIGNED WITH A CENTER HOLE SO THAT THEY MAY BE POSITIONED OVER AND RESTRAINED BY THE DIAPHRAGM OPERATOR OR VALVE STEM. THESE WEIGHTS WILL REPLACE THOSE THAT WERE PREVIOUSLY POSITIONED UNSECURED ON THE DIAPHRAGM PLATE AND WILL PREVENT THE LATERAL MOVEMENTS WHICH IMPEDE PROPER VALVE OPERATION. REPLACEMENT OF THE UNSECURED WEIGHTS IS BEING UNDERTAKEN ON AN ACCELERATED BASIS AS PART OF OUR ANNUAL MAINTENANCE AND INSPECTION PROGRAM WHICH IS CURRENTLY IN PROGRESS. ALL WEIGHT-LOADED REGULATORS, WHICH REQUIRE THESE RESTRAINABLE BALANCING WEIGHTS, WILL BE SO EQUIPPED BY JUNE 1, 1984.

Addressee Organization Type: P-Private Industry

Communication Date: 1984-08-01

Communication Type: Official Correspondence