Transco identified a need to increase the capacity of Henley Belle Hatch PRI to reinforce the downstream medium pressure (MP) network.
The new installation was designed to IGE/TD13, and was located on the existing Henley Belle Hatch PRI site. The new PRI required preheat, and has a remote monitoring facility, which entailed two additional housings for the preheat boiler package unit, and the instrumentation/telemetry control room. The housings had to be sited to suit hazardous areas, and requirements for maintenance access. Additional capacity was achieved by addition of a new third regulator stream to supplement the existing two regulator streams. Flow limit was installed on the existing two streams only, since the new third stream operates in standby mode only. A control system was installed to maintain constant outlet pressure, regardless of the number of working streams. Existing heat exchangers were removed from the existing two streams, and installed with revalidated filters from stock, as a common bank for all three streams. The new pressure reduction single stream module was supplied as a prefabricated unit.
GM5 pipeline was affected by proposed new landfill works which were due to commence during late summer 2004.
The work involved construction of a new landfill “cell”, part of the existing Shelford Farm landfill site, near Canterbury, Kent. GM5 runs throughout these works.
The proposed diversion route lay to the north of the existing and passed through two areas of note:
- Through a newly built slope.
- Through a utility corridor, 40 to 50metres in width, with overhead high voltage cables on either side of the pipeline of 133Kv and 432kv
The pipeline operates at a MOP of 38barg with the design pressure being 69barg. It is made of 457mm outside diameter with a wall thickness of 9.52mm in APILX52 material.
The design team had liaised with the Waste Management Consultants, Network Management & Network Construction.
The following design disciplines were covered:
- Mechanical Engineering
- Cathodic Protection
- Civil and Structural Engineering
- Technical Safety Engineering