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Design of High Pressure Gas Supply Main

Middletown, Connecticut

Services: Structural, Mechanical, Electrical
Clients Served: Industrial

Loureiro was retained to provide the design of a new high pressure natural gas main to serve the updated test cell, X960, at their Middletown facility as well as related upgrades to the test cell.

The existing test cell was to be supplied with high pressure natural gas for a new test program. The test cell was to be upgraded to accommodate the use of natural gas as a test medium. The new high pressure gas main consisted of 700 feet of 4 inch schedule 80 stainless steel welded piping with an operating design pressure of 750 psig. All welds were radiographed.

The new pipe route included design of concrete pier supports, building hangers and a pipe bridge to span an access road. Safety items designed in the new gas main included an excess flow shutoff valve and a fusible link firesafe valve. Additional items for venting, purging, metering and overpressure relief were also designed into the system.

The test cell was upgraded with new power wiring to serve the new Class I Division II unit heaters. A new ventilation system was designed to meet FM, NFPA and State of Connecticut Building Code requirements. A new gas monitoring system was designed to continuously monitor the test area and adjacent spaces for any buildup of natural gas during testing.


  • Design of the new natural gas supply system included coordination with Yankee Gas for the new supply header as well as Test Systems Engineering for final connections to the test facility.
  • The piping design provided a substantial cost savings over the quoted design provided by Yankee gas.
  • The design included consideration of normal purging and venting operations as well as emergency relief conditions which resulted in the design of a free standing 30 foot tall structural support for the emergency relief valve exhaust piping.