Seals for Drinking Water Applications
GMORS offers o-rings and seals for
drinking water applications with compliance
to WRAS Standards and NSF 61 (National
Sanitation Foundation). Our R&D team of
engineers formulate at least 20 compounds
suitable for drinking water applications
complying with the above standards.
NSF Standards 61: The guidelines
which regulate the requirements of system
components and chemicals that is exposed to
drinking water during treatment is NSF
Standards 61. The standards ensure that
chemicals and substances that are toxic do
not end up in drinking water systems,
causing adverse effects on health.
WRAS: Water Regulations Advisory
The approval scheme in the United Kingdom
that regulates the use of components and
materials to ensure non-contamination of
water supply system sis the WRAS.
For many years, the potable water industry
makes use of chlorine as a disinfectant
against bacteria. However, the use of
chlorine in drinking water systems gives
rise to DBP (disinfectant-by-products) which
at higher concentration, has been shown to
be carcinogenic. The EPA (Environment
Protection Agency) set limits on the level
of disinfectant-by-product to be found in
potable drinking systems.
The new regulatory limits set by the
Environment Protection Agency resulted in
chloramine been used as a substitute for
chlorine as municipalities, water processing
and distribution facilities find ways to
reduce disinfectant-by-products caused by
chlorine usage. Although chloramine produces
less DBP, it has a damaging effect on
elastomeric seals, giving rise to a loss of
resilience and excessive swelling. A higher
incidence of failure of elastomeric seals
and gaskets occurs with the use of
chloramine as disinfectant, with
sulfur-cured elastomers performing less
satisfactory than peroxide-cured elastomers.
It has been tested and shown that chloramine
has a more damaging effect on certain
GMORS Solution: Chloramine-Resistant
Sealing systems formulated to be chloramine
resistant are offered by GMORS, with a
selection of elastomeric compounds
Ethylene propylene diene monomer (EPDM)
has excellent resistance to chlorine
found in drinking water, and is extensively
used in drinking water systems. At higher
concentrations of chlorine or chloramine
however, additional resistance testing is
formulations of EPDM has a higher level of
saturated ethylene and a lower level of
Silicone (VMQ) performs better
against chloramine attack as compared to
other elastomers. However, silicone has a
lower abrasion resistance and lower tensile
and tear strength. The lesser mechanical
properties of silicone has to be taken into
account while considering the benefits of
its resistance to chloramine attack.
Contact us for a cost efficient
recommendation of a chloramine-resistant
Rubber Industrial Co., Ltd.
No. 15, Kung Yeh East 4th Rd., Lukang, Chang Hua 505, Taiwan, R.O.C.
Mao Rubber Industrial Co., Ltd. All rights reserved.