PuK - Process Technology & Components 2024

Components
Gaskets
The complete, worry-free package for drinking
water gaskets with KTW-BWGL conformity
Dipl.-Ing. Norbert Weimer
With the KTW-BWGL (assessment
basis for plastics and other organic
materials in contact with drinking
water), a new regulation has come
into force that has a strong influence
on the handling of gasket materials
in drinking water. The use of
established gasket materials is now
prohibited and there are few options
for new types of gaskets that
conform to the regulation.
Buyers of drinking water gaskets
need new options
The UBA (German Environment Agency)
has defined new requirements for
drinking water supply components.
The KTW-BWGL is authoritative for
organic materials used in elastomer
and compressed fibre gaskets. Products
and components made of organic
materials are evaluated with
regard to the raw materials (primary
materials) used and the transfer of
substances to drinking water.
Those raw materials that may be
used to manufacture elastomers in
contact with drinking water are included
in the UBA’s positive list. The
list for organic materials also applies
to fibre-reinforced gasket sheets
bonded with elastomers (FA – fibrebased
gasket sheets). The positive
list contains the fully evaluated substances
(monomers, fillers, plasticisers,
anti-ageing agents, processing
aids, cross-linking agents, etc.). Only a
few months remain before the end of
the transition period for gasket materials
containing raw materials that
have not been evaluated fully or at
all. Switching to new gasket materials
then becomes mandatory.
intended for drinking water applications
can no longer be used in this
field. It is painful that the established
range of applications is no longer
guaranteed due to the curtailment of
the possible ingredients.
This also affects processors in
particular, such as cutting shops and
technical distributors, who have to
readjust (storage and costing) with
regard to the utilisation of gasket
sheets in cutting as well as storage for
different applications (e. g. drinking
water, gas, temperature ranges, etc.).
Manufacturers of valves, pumps and
equipment may also encounter problems
when the assignment of various
gasket materials to different fields of
application in production is not manageable
(example: heating appliances
with gaskets for gas as well as heating
water and drinking water) and an allpurpose
gasket is no longer available.
All of this means that users and
the supply chain should look for a
well-functioning alternative in good
time. This is where the gasket material
manufacturer KLINGER comes
in with a new product. KLINGERSIL
C-4240 is a new fibre-based (FA) gasket
that is extremely well suited as a
solution to this problem.
This gasket type (FA) is commonly
used in drinking water systems, and
is affected by the new KTW-BWGL
regulation due to the binder (elastomer).
The reduction in the permitted
ingredients for the production process
is so great that the rolling and
vulcanisation process requires the
highest level of know-how in order
to be able to produce a gasket sheet
under these conditions at all. To date,
KLINGER is the only manufacturer to
have successfully developed an FA
gasket sheet in conformity with KTW-
BWGL in risk class P2. Meeting the requirements
of risk class P2 is mandatory
when the surface in contact with
drinking water is more than 1% of the
component’s total surface area.
Reliability is also important in
assembly
There are two typical fields of application
in drinking water systems.
In one of these, we have the service
technician with a mobile workshop
who makes service calls. The service
technician, a tradesperson with experience
and qualifications, replaces or
installs new components on site under
often adverse conditions.
The other field of application is
the industrial production of composite
components and equipment from
water filters to valves or pumps to
The supply chain needs to respond
– only a few months remain
For the manufacturer of FA gasket
sheets, this situation means that the
previous formulations for products
Fig. 1: The new KLINGERSIL C-4240 fibre-based gasket
102 PROCESS TECHNOLOGY & COMPONENTS 2024