Drinking-water seals for the future

Using seals today with the legal requirements of tomorrow: Angst+Pfister has designed an elastomer that anticipates future drinking water regulations. In addition to the classic O-rings, the new material has made more complex seal shapes possible - and they carry the familiar superior mechanical properties. 

Angst+Pfister is launching a new elastomer for drinking water seals that already meets all the major approvals requirements from February 2025 and beyond. HITEC® DW EPDM is as innovative as it is safe and reliable. 

"Due to the increasing number of regulations applying to drinking water applications and food applications, in the future it will no longer be possible to use the same material in both industries," explains Reto Mueller, Product Leader in Sealing Technology at Angst+Pfister. For drinking water, the focus is on mechanical properties, whereas for food, the purity of materials has priority. Consequently, Angst+Pfister pushed forwards with the development process in both directions. "Due to our closeness to and participation in pertinent experts panels and associations, we recognize regulatory developments at an early stage." Thanks to their exceptional materials knowledge, the Angst+Pfister engineers can then respond rapidly. 

Poised for the dynamic markets
The "assessment basis for plastics and other organic materials that have contact with drinking water" (KTW-BWGL) will come into force in Germany on 1st March 2025 and also be legally binding for elastomers. Angst+Pfister is expecting the KTW-BWGL to also determine the hygiene regulations of the others of the "4 member states" - that is in France, the Netherlands and the United Kingdom. This means that fewer additives are going to be allowed in the elastomer compounds, and this will encompass peroxides. The carbon black used must be purer. The permitted migration values will be significantly tightened, as will be the microbiological requirements. "This makes the manufacture of reliable elastomers with good mechanical properties even more of a challenge," says Reto Müller. 

Angst+Pfister developed HITEC® DW EPDM on its own and owns the formula for it. As an independent proprietor, Angst+Pfister is able to control every development and lessen the risks for its customers - such as those regarding deliverability. The material with its new additives goes above and beyond compliancy with the stricter standards. Its mechanical properties at minus 57 to 150 degrees Celsius are comparable to those of the current elastomers for drinking water applications: Angst+Pfister has already extensively tested its latest high-performance elastomers. In low temperatures, it is even better than the previous one. 

Increased processability 
Initially, the engineers concentrated on O-rings. However, the material's processability for geometrically complex molded seals has meanwhile become downright impressive. "O-rings and shaped-seals for equipment or systems can be made from the same compound, thereby increasing safety and reliability," explains Reto Müller. The material shows very good results in long-term compression deformation tests. It is suitable for both static and dynamic applications. In addition it is degradation resistant to copper and brass - from which many pipes and faucets for drinking water applications are made. The same goes for silicone grease. The black EPDM compound meets the PAK Class 1 specification (in accordance with AfPS GS 2019:01). 


HITEC® DW EPDM meets numerous food standards in addition to the major global regulations for water: 

•  Drinking water: NSF 61, AS/NZS 4020, ACS, D.M. n°174, DVGW EN 681, DVGW W534, ÖNORM, KIWA, UBA (KTW-BWGL), WRAS
•  Food and beverages: 3-A Sanitary, FDA, NSF 51, BfR XXI, D.M. n° 1973, EC 1934/2004, LFGB, SR 817.023.21, GB 4806.11-2016
•  Additionally: USP Class VI, DVGW CERT ZP 5101:2021


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published: Mar 13, 2023, 3:06:00 PM  by: Angst+Pfister Group