TWI Accreditation for all Niplast Welders

The skills of all Niplast’s qualified welders have been recognised with The Welding Institute’s (TWI) accreditation. Simpson Thomson Filtration Ltd, manufacturers of Niplast Tanks, was approached by TWI to review how the recognised qualification could offer new business opportunities, particularly in the offshore wind industry sector.

_MG_1656Fabrication Technicians, Lee Dervan and Mark Richardson successfully completed the assessment following a two-day hot gas and extrusion welding qualification programme to BS EN 13067, for welding polypropylene and polyethylene. The team’s acknowledged skills in welding thermoplastic sheet and pipe offer customers guaranteed quality assurance and further confidence in the manufacture of Niplast Storage Tanks.


Simpson Thomson Filtration (STF) is one of the longest serving and leading plastic storage tank manufacturers. Niplast Tanks are manufactured to BS EN 12573 and to DVS 2205, to a maximum capacity of c.150,000 litres. Through their expertise in plastic fabrication, STF have developed a number of generic liquid handling products, for a variety of industry sectors, in addition to their bulk storage tanks.

During discussion with TWI, STF identified the delivery of hot gas and extrusion welding, and butt fusion and socket fusion as areas for skill consolidation and recognition, offering quality assurance of welded products manufactured. In addition, STF saw a benefit in qualifying all of their skilled fabrication technicians to BS EN 13067 ‘Approval Testing of Plastic Welders’, which could offer a lever into new market opportunities where welding certification is required, such as the oil, gas and offshore wind sectors. The accreditation was supported by the Offshore Wind Technology Transfer Project, funded by the Regional Growth Fund.

During the process, a TWI Senior Plastics Welding Instructor conducted a hot gas and extrusion welding course for Lee and Mark. Their capability was assessed and further guidance on the welding techniques provided as necessary. The course also included welding procedures, process controls, advice on how to avoid defects, inspection and health and safety.

The qualification programme consisted of theory and practical assessments. Successful completion by both fabricators resulted in a CSWIP qualification aligned to BS EN 13067.

Managing Director, Adrian Greenwood, commented, “Recognition of their welding skills is great news for Lee and Mark and our customers, who now have further confidence in our storage tanks. All our skilled fabricators are now accredited to this standard. We are committed to the professional development of our staff and hope to work with TWI to assess all Niplast trainees in the future.”

Categories: Accreditation

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