Backgrounders

Background and Fact Sheet for the Pipeline Investigation Report No. P00H0061

Compressor Station Occurrence, East Hereford, Quebec
28 December 2000

The sole mission of the Transportation Safety Board of Canada (TSB) is to advance safety through the investigation of accidents or incidents in the marine, pipeline, rail and air modes of transportation. As a result of the detailed investigation into the pipeline occurrence in East Hereford, Quebec, significant safety actions have already been taken to make the system safer. These actions include:

  • 29 May 2001-the National Energy Board (NEB) directs Gazoduc TQM (TQM) to take additional safety measures at both the Terrebonne and East Hereford compressor stations.
  • 24 July 2001-the TSB issues a Pipeline Safety Advisory Letter to the NEB outlining safety issues and concerns at the East Hereford station.
  • 10 September 2001-the NEB authorizes two design changes at the East Hereford station requested by TQM.
  • 21 September 2001-the TSB issues a second Pipeline Safety Advisory Letter to the NEB outlining further safety issues and concerns.
  • 30 November 2001 and 21 February 2002-the NEB authorizes additional changes to the electrical systems at the station.
  • June 2003-the Canadian Standards Association amends its standards for oil and gas pipeline systems to include quality management and control programs for all Canadian pipeline projects.
  • Summer 2004-committee struck to review deficiencies in the Canadian Electrical Code.

Additionally, as a result of the accident and the subsequent TSB investigation, the following 15 design changes were made to the compressor stations at East Hereford and Terrebonne:

  • introduction of a continuous venting feature between the compressor and the electrical and services buildings
  • changes to the station shutdown features so that the unit can be stopped, isolated and vented of gas once a critical level of pressure is reached
  • installation of a manually operated vent valve on the terminal junction box
  • installation of gas detectors in the electrical and services building
  • changes to the controls in the electrical and services building so they will stop, isolate and initiate venting in the event that gas is detected
  • additional venting to direct any gas leaks to overhead detectors
  • inspection of all fittings to conform to standard
  • changes to the control cables to prevent gas migration to the electrical and services building
  • inspection of the Passthru flange and elements
  • changes to O-rings
  • testing of relevant components to ensure required sealing
  • verification of proper functioning of the pressure transmitter in the terminal junction box
  • testing of the terminal junction box and Teck cables
  • integration of pipeline system for telecommunications and data
  • installation of a dehydrator in the unit to remove water from the gas stream

The public report, P00H0061, is also available on this site.