To supply jet fuel to the airport, a 33 km x 14 in. pipeline, scheduled for completion in 2005, is being built that will hot tap from the existing multi-product white oils pipeline running from tank farms to the current international airport. Mr Buree Whanchid (Technical Leader) and Mr Nipon Lumpiganon of the JP-One Asset Co Ltd (pipeline owners) have highlighted the many challenges in construction and its critical role for the new airport’s services.
The pipeline route will take it through Central Bangkok District, necessitating street works in busy, crowded locations. With major road crossings, construction activities will need to be planned for restricted working hours. The logistics of supply of pipe, materials, equipment and manpower will be critical. Standard pipe jacking/HDD construction methods will be modified with Poor Boy Spreads to meet these challenges.
The pipeline design and construction supervision is being undertaken by Penspen Ltd of the UK, an international company specialising in design and construction activities for oil and gas pipelines and terminal facilities. Penspen have also been responsible for the design of the BAFS Pipeline Receipt and Transfer Facilities as well as the fuel depot, with variable speed hydrant pump facilities and the 24 in. airport fuel hydrant system – all of which are currently under construction.
Penspen’s Engineering Manager, Simon Kitchen, advised that the pipeline size has been optimised to utilise the existing pipeline pumping facilities and meet the projected fuel demand from the new pipeline.
The pipeline design is to ASME B 31.4 Code and based upon application of API 5L X52 linepipe. Design Pressure is 76.7 barg, and pipeline wall thickness is generally 7.14 mm. Buried crossings sections have been designed according to API RP 1102 recommendations. It will be internally epoxy lined for jet fuel service and welding specified for the joints for optimal internal cleanliness.
Penspen’s Construction Manager, Gordon J. Black, views the construction issues as challenges that have to be factored into the planning and logistics with numerous Mainline and Poor Boy crews that will work simultaneously to execute the large number of crossings and special sections.
The pipeline route will cross klongs (waterways) and in certain locations limited space will lead to pipe bridging techniques as it will not be possible to trench or directionally drill.
As the route progresses, it will also need to cross several roads including the Department of Highways’ Airport Access ROW and congested areas requiring closely controlled directional drilling, including one HDD of approx 1,200 m.
The new pipeline ROW generally follows the south side of the railway with some rail crossings. A major challenge is the restricted width of the ROW, due to the proximity of the railway and adjacent private properties.
A large number of short pipe sections will require winching operations after welding of joints, NDT and coating holiday testing before lowering into padded, prepared trenches for immediate backfill.
Pipelay will be further challenged by having to weld and blast all the joints and coat field joints in this crowded ROW. X-ray testing also presents unique challenges due to the proximity issues of the public.
Taking account the difficult construction issues, pipeline coating selection involved trials and testing which led to the selection of a Liquid Polymer Epoxy (LPE) coating (SP2888) as the mainline coating of choice over traditional FBE and Trilaminate (3LPE) coatings.
The LPE coating, SP2888, exhibited ultra hardness characteristics, better abrasion resistance, flexibility and adhesion. The same coating could then be used as the mainline coating, as well as for the HDD sections, the field joint coating, bends and repairs for any coating damage. In short a single coating could be used over the pipeline, providing one uniform pipeline coating across the entire pipeline. The selection of this coating also assisted the pipe procurement programme, with pipe procured bare ex-Japan and coated onshore in Thailand. Profound Innovations Ltd, a local Thai company with world class pipe coating facilities, won the contract to coat the pipe and “˜Blondie Robinson’ – its manager – says the new SP2888 LPE coatings have worked well and is a much easier coating to work with than traditional FBE or 3LPE coatings.