The EJOT Group collaboration, led by EJOT Asia, has provided a complete building envelope fastening solution for the construction of the US $1bn factory at the Vietnam Singapore Industrial Park III in Binh Duong near Ho Chi Minh City.
The project involved EJOT UK manufacturing and supplying more than 750,000 EJOT HTK 2G 50 tube-washers for use in combination with EJOT TKR fasteners for the roofing, with EJOT Austria also supplying 120,000 stainless steel fasteners for the facades. Roofing and cladding contractor HTF Holdings was tasked with the installation using fasteners supplied by EJOT’s Vietnamese distribution partner, HHK Asia.
EJOT UK’s tube-washer and fastener combination was selected primarily because it enabled important sustainability and cost-saving goals to be realised compared with other fixing approaches for the flat roof design.
This envelope features a Mapei TPO (Thermoplastic Polyolefin) membrane and a 150mm layer of Rockwool insulation to meet the demanding local environmental conditions, where high temperatures average between 30°C (86°F) and 32°C (89°F) throughout the year, with added humidity and rainfall during the wet season.
The fastener specification had to be resistant to corrosion in this climate and to minimise thermal transfer through the roof structure. After the initial fastening proposal for the flat roof membrane was reviewed, a process which would have involved using metal stress plates and unusually long fasteners to fix through the full depth of insulation, plus embedment into the substrate, EJOT Asia was approached for an alternative.
Its technical consultants, and EJOT Group’s Business Development Director for the Asia Pacific region, Ben Gallant, proposed EJOT HTK 2G telescopic tube-washers featuring a 50mm diameter stress plate in combination with EJOT TKR fasteners. This would enable a secure attachment to be provided for the roof deck at the deepest point and deliver a host of additional benefits.
Ben says: “This fastening approach was adopted due to the multiple benefits it offers over the original recommendation, most notably in terms of meeting the building performance objectives and delivering notable cost savings in the construction phase.
“Importantly, the EJOT solution provided the design team with independent certification in respect of its performance. The HTK 2G 50mm washer is FM Approved when used in combination with either the EJOT TKE or TKR fastener, and both of these fasteners have respective European Technical Assessments (ETAs) to confirm their performance.”
As the EJOT HTK tube-washer is manufactured from engineering-grade PE (polyethylene), it offers a significant reduction in thermal conductivity compared to using metal stress plates. This means reduced heat transfer through the building envelope from outside to in, and vice versa, helping to maintain a more stable internal climate.
EJOT’s tube-washer and fastener combination also provides an advantage over metal stress plates and fasteners in respect of load-bearing capacity, and it provided significant cost and material savings given that it requires shorter fasteners. Long-term durability is also guaranteed with the HTK tube-washer’s nylon composition as well as the high quality EJOT carbon steel fasteners specified.
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