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KTW testing or opproval or certificate

TZW Karlsruhe
Prüfstelle Wasser TZW
Information for KTW-testing
By means of the testing according to KTW Guideline, Coatings Guideline, Lubricant Guideline, and
KTW recommendation (1.3.13 rubber materials) it is determined if substances from the tested nonmetallic
product were released into the drinking water and therefore non tolerable changes of the
drinking water could occur.
Recipe (chemical formulation)
By recipe is meant the detailed chemical composition of the material that is used to manufacture
the product. The recipe in dependence of the material type has to be in accordance in each case to
the applicable positive list of KTW-Recommendations (1.3.13 rubber materials), KTW Guideline or
Coatings Guideline or Lubricant Guideline.
Hence we need the complete disclosure of the recipe for assessment. At this all used substances
and additives have to be listed. This list has to contain the chemical name of the compound
inclusive the CAS registry number, trade name, the percentaged addition of the particular
substance and the function of the substance. Please use the attached form.
For the disclosure of the recipe a secrecy agreement can be concluded. For this we refer to our
template which is also attached to this writing.
Test samples
Test samples that are required for the testing depend on the product group. Following cases have
to be differentiated:
1. Pipes
In dependence of the pipe diameter for each material type and each place of manufacture following
number of pipes is required:
- dimensions till Ø 32 mm: 25 pipe pieces à 1 m or 1 x 25 m roll for PE-X
10 pipe pieces à 1 m for PE-HD/PP-R
- dimensions Ø 32 till 50 mm: 6 pipe pieces à 1 m, machined endings
- dimensions Ø 50 mm and higher: 6 pipe pieces à 0,5 m, machined endings
Technologiezentrum Wasser (TZW)
Prüfstelle Wasser TZW
2. Finished products
For the testing of your product for example an injection molding part, we need for each material,
each manufacturing method and place of manufacture as many original test pieces that a total
surface area of 4.000 cm2 is given. For small parts like o-rings an appropriate number of parts has
to be delivered.
In case of geometrically complicated constructed devices we kindly ask you to inform us about the
total surface area (inside and outside) and attach a section drawing if possible.
3. Lubrication grease
For the testing of lubrication grease we need 500 g of each grease.
4. Material
If the test should not be performed at the product, what could be reasonable for a material
manufacturer to qualify his material, following test specimens in dependence of the application
area should be delivered:
Pipes 7 plates à 200 x 200 mm
Tanks and equipment 5 plates à 200 x 200 mm, 1 plate à 200 x 50 mm,
1 plate à 100 x 65 mm
Sealings 5 plates à 200 x 200 mm, 1 plate à 50 x 30 mm,
1 plate à 30 x 25 mm
Regardless of the application area for the warm and hot water tests following additional test plates
are required:
12 plates à 120 x 50 mm
In all cases the plate thickness should be about 3 mm. Special samples have to be agreed with us
in advance.
We ask you to attach no labeling by marking or pasting on the test samples. Also we ask you to
pay attention that storing, packaging and transportation have no influence on the surface of the test
samples for example by contaminating with organic substances.
Technologiezentrum Wasser (TZW)
Prüfstelle Wasser TZW
Validity of KTW test certificates
The KTW test certificates are strictly valid only for the manufacturer of the “finished
product”. Therefore the test certificates of materials that have been tested as plates are not valid
for the products that are manufactured of those materials. Also a transferability of the certificates is
neither from a pre-supplier of the base material to the manufacturer nor to different manufacturing
plants of the same company or different manufacturing methods possible.
The validity period of the test certificate conforms to regulations that are constituted elsewhere.
The validity period expires at the latest 5 years after date. Accordingly under certain conditions the
validity period can be extended for other 5 years. The test certificate automatically loses its validity
if the specifications changes or if changes in the recipe or in producing take place.
The test certificate covers the declared range of use and all subjacent ranges of use for which
lower standards are valid. The range of use depends on the test results.
If you have any further questions or if you need additional information please do not hesitate to
contact us.


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