KTW approval for sensor liners

KROHNE's OPTIFLUX is the only electromagnetic flowmeter with liners that meet KTW and DVGW specifications. Drinking water supply companies demand without exception KTW-approved sensor liners to protect their water from chemical impurities. "KTW" stands for the German Federal Health Ministry's health-related evaluation of plastics used in potable water systems. KTW came into effect in 2003 and is therefore mandatory.

A new requirement is that the suppliers also be in compliance with DVGW's (German Association for Gas and Water) Code of Practice W 270, ?The spread of microorganisms on nonmetallic materials". This standard deals with the protection of potable water from biological impurities by specifying sensor liners that are certified to be safe. The W 270 specifications are now also legally binding. 

After initial hesitation because no appropriate equipment was available on the market, suppliers are now implementing the requirements for applying biologically safe materials as strictly as they implemented the chemical compatibility specifications. For example, GELSENWASSER, Germany's largest drinking water supply company, specifies: "Plastics shall comply with KTW recommendations and test criteria specified by the DVGW W 270 Code of Practice".

The municipal water works in Göttingen and Duisburg issue similar specifications. OPTIFLUX is available with either a polypropylene or hardrubber liner. Both materials have received KTW approval, and the hard rubber liner is also certified to W 270. KROHNE therefore makes the only electromagnetic flowmeter that meets the statutory requirements.
Bacterial contamination can occur in potable water reservoirs, piping, plastic valves or plastic-lined EMFs used in potable water networks.

Low molecular weight organic compounds are formed between the liner and the water, or a microbacterial growth (slime) that becomes a breeding ground for bacteria, amebae and fungi builds up. The equipment and systems may require cleaning using pressure washers, chlorine bleach solutions or pigging. It would be much better to prevent or limit such contamination in the first place. This can be achieved by choosing a suitable synthetic liner in an appropriate meter such as OPTIFLUX.

Further information: KROHNE Messtechnik GmbH & Co. KG, Thomas Zimmerling,
e-mail: TZimmerling@krohne.de

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