KTW Certificate

The KTW certificate concerns plastics that come into contact with drinking water. Water is classified as drinking water when it does not contain microorganisms, parasites or other substances that may pose an indirect or direct threat to human life or health.

UBA

The German Environment Agency (Umweltbundesamt – UBA) has defined the applicable criteria for assessing materials and substances that come into contact with drinking water. All coatings used for the production or transport of drinking water must have the appropriate certificate. UBA defines, among other things: a list of permitted substances, methods of material analysis, and limit values for materials.

Materials and substances permitted for contact with water must not contribute to the development and proliferation of microorganisms or contaminants.

The criteria for assessing materials and substances clearly specify the allowable amount of substance release into drinking water. Coatings used for the production or transport of drinking water must not adversely affect water quality, organoleptic properties, clarity, color, taste or odor. Furthermore, in no way directly or indirectly may they violate the protection of human health provided for by the TrinkwV (the German Drinking Water Ordinance).

KTW certificate – what is it?

KTW stands for plastics in drinking water (Kunststoff-Trinkwasser). This certificate defines the hygienic requirements that plastics (e.g. polypropylene, polyethylene, polyester, vinyl chloride, polyamide) and silicone must meet before being permitted for use in contact with drinking water. In applications requiring sealing, it is worth considering appropriately selected silicone gaskets. The type of material alone, however, does not confirm compliance with KTW — the documentation of the specific compound and the finished product must be verified.

The KTW standard – W270 certifies that materials and substances coming into contact with water suitable for consumption have been tested by German laboratories (TZW and DVGW) based on the criteria and guidelines of the German Environment Agency (UBA).

Requirements for materials used in drinking water installations differ depending on the market. In the United Kingdom, an important reference point is also the WRAS certificate, related to requirements for products used in water installations.

During testing, laboratories are responsible for checking:

• the appearance of the water, its odor and taste

• emissions of estimated total organic carbon compounds (TOC)

• the consumption of diluted chlorine in the water

• the level of substances released into drinking water (e.g. formaldehyde, phenol)

• extraction of heavy metals (e.g. lead, zinc)

The KTW certificate additionally contains assessment criteria for tests in accordance with EN-16421. This standard defines three methods of assessing the ability of non-metallic materials to increase microbial growth. EN 16421 applies to materials intended for use under various conditions for the transport and storage of water intended for human consumption. It applies to one type of material or product that comes into contact with water. The EN-16421 criteria included in the KTW certificate aim to attest hygienic safety with regard to growth promotion. Additional criteria and guidelines for other thermoplastic elastomers and similar compounds have also been taken into account.

KTW certificate – assessment criteria

All materials and substances that come into contact with drinking water must ensure hygienic safety before being permitted to transmit water. This applies to plastics (e.g. elastomers), mineral raw materials (e.g. glass), as well as metallic materials and greases and adhesives.

Below are the criteria for specific materials:

• Assessment criteria for metallic materials – hygienic metals suitable for contact with drinking water

• Assessment criteria for enamels and ceramic materials – only the listed components should be present in them

• Assessment criteria for cementitious materials

• Assessment criteria for plastics and other organic materials in contact with drinking water – assessment criteria for plastics, organic coatings and greases

• Silicones, elastomers, thermoplastic elastomers – additional guidelines should also be taken into account

When designing installations, it is important not only to meet hygienic requirements but also to choose the right sealing material for the medium and operating conditions. More information about solutions used in water installations can be found in the article on rubber gaskets for water.

The granted KTW certification is valid for 5 years.

Do you need rubber products with a KTW Certificate?

If you have any questions or doubts, please contact our customer service at: +48 22 292 40 24 or +48 505 16 03 03, by email (power|powerrubber.com| style="background-color: rgb(255, 255, 255); color: rgb(0, 91, 171); border-bottom: 1px dotted rgb(0, 91, 171); text-align: justify;"|Power|PowerRubber.com) or via our contact form