Appendix

The following information is based on the report of ‘ACCEPTANCE OF METALLIC MATERIALS USED FOR PRODUCTS IN CONTACT WITH DRINKING WATER. Common Approach. Part A – Procedure for the acceptance and Part B – Common Composition List’ accessible via http://www.umweltbundesamt.de/wasser-e/themen/trinkwasser/4ms-initiative.htm.

Excerpt 1 of the ‘ACCEPTANCE OF METALLIC MATERIALS USED FOR PRODUCTS IN CONTACT WITH DRINKING WATER. Common Approach. Part A. Procedure for the acceptance’ presented in chapter 2.

1.    Acceptance of metallic materials onto the Composition List

Metallic materials used for PDW must be listed on the Composition List.

1.1.    Procedure for the addition of materials to the Composition List

The primary responsibility for assessment of materials will remain at the national level making use of established processes and the expert resources available there. However, the interpretation of test results and the application of acceptance criteria described below is complex. For this reason a Committee of Experts should advice in the decision-making process.

The Committee of Experts should have the following expertise:

The 4 Member States group agreed on a common procedure to accept materials on a common Composition List. This procedure is described in Part B of this document.

1.2.    Structure of the Composition List

The Composition List contains different categories of metallic materials.

A Category is defined as:

a group of materials with the same characteristics in respect of their field of application, behaviour in contact with drinking water and restrictions with regard to water composition and/or surface area.

The Composition List contains the categories’ range of compositions.

Each category has one reference material.

A Reference Material is defined as:

a material falling within a category for which the characteristics of metal release into drinking water are known and reproducible, the composition is strictly controlled and the elements of interest will be at or near the upper limit of acceptability. Possible effects of some constituents to inhibit the metal release have to be taken into account.

Under each category commercially available metallic materials accepted for use in PDW will be listed. The materials may only be used for certain products due to the restrictions with respect to the surface area (Table 1).

—   Product Group A: up to 100 % contact surface

For pipes in a buildings installation the same material can be used for all diameters. A single material can contribute to nearly 100 % of the surface in contact with water e.g. copper, galvanised steel or stainless steel. The evaluation of the conditions for safe use must assume the maximum possible percentage. The acceptance of a composition for the use as pipes includes the acceptance for all uses (e.g. fittings, components, etc.).

This group also includes uncoated metallic pipelines in water supply systems and water treatment processes.

—   Product Group B: up to 10 % contact surface

Fittings or ancillaries can be produced from one material or from slightly different materials throughout the buildings installation. The most common are made from copper alloys that contain lead. Due to their potential to release lead to water there is a need to restrict the total surface contact of products made from these alloys. For assessments of materials for these products a contribution of 10 % water contact surface area is assumed.

This group also includes metallic parts of pumps and valves used in buildings installations.

—   Product Group C: less than 1 % contact surface

For technical reasons, there might be a need to produce small parts from compositions not accepted for the Product Group B, fittings and ancillaries. Other compositions with higher release rates may be accepted in these devices as long as their use will not significantly increase the total contamination of drinking water. The use of such compositions should be restricted to parts that do not exceed 1 % of the total surface in contact with drinking water; for example, the body of a water meter would need to be produced from an accepted composition for Product Group B but a moving part may be produced from a material listed for Product Group C.

This group also includes metallic parts of pumps and valves used in water supply systems and water treatment processes.

1.3.    Data required for assessment

Acceptance of metallic materials is based on results of long term tests on a rig test according to EN 15664-1. The minimum test period is six months and which can be extended. Additional requirements for the testing according to EN 15664-1 are described in 1.4 and 1.5.

Acceptance of a reference material for a category requires acceptance of results from the EN 15664-1 test carried out with different waters (see EN 15664-2) representing the normal range of compositions of drinking waters in the EU.

To add a material in a category, a comparative test against the reference material is required using EN 15664-1. For comparative testing it is sufficient to use a local drinking water, provided that the water is suitably corrosive (see EN 15664-2).

The following information shall be provided:

1.4.    Specification of test specimen

For the testing of a material according to EN 15664-1 the test specimens have to be of a certain composition.

All elements exceeding 0,02 % could be of relevance and have to be declared for the composition of the material to be listed. For impurities below 0,02 % it is the responsibility of the producer of the alloys/materials to guarantee that no release occurs with the potential to cause negative health impacts.

The composition of the test specimens shall be as follows:

1.4.1.    Reference materials

The test specimens submitted for testing a new reference material and the test specimens used as reference materials for the comparative testing have to meet the following requirements:

Note: The composition of the reference material should be accepted before testing is started. The range of composition should be very narrow and the reference material should represent a worst case material in respect of the metal release of concern for the category.

1.4.2.    Candidate materials for comparative testing

For the candidate materials the range of composition and its allowed impurities have to be defined. Comparative testing is possible, if the defined range of composition of the candidate material complies with the definition of an existing category of materials.

The composition of the test specimens used for testing has to be more restricted than the defined range of composition of the material. Based on the knowledge about copper alloys the composition of the test specimens has to meet the following requirements:

For other non-copper alloys these requirements may be different.

1.5.    Water analysis

If a new reference material is tested the contact water according to EN 15664-1 has to be analysed for all elements exceeding 0,02 % in the composition of the declared material with the exception of:

For comparative testing the analysis of contact water may be limited to certain elements specified for each category in the composition list.

1.6.    Acceptance criteria

Table 2 proposes the acceptable contributions from metallic PDW to the overall concentrations of metals at consumers’ taps. It is based on the acceptance values for chemical and indicator parametric values in the DWD. The acceptable contributions were derived using the following principles:

In the case of other parameters not listed in the DWD, the following criteria have been used:

In order to allow time for the development of natural protective layers, it is proposed that the test procedure simulates a conditioning period of three months, in which a slight non-compliance with the reference concentration is tolerated.

1.7.    Adding a Reference Material for a Category or a Material not falling under a listed Category

The addition or change of range of an alloying element may move an alloy outside a Category and this change may significantly influence the metal release characteristics of the material. In this case and for an alloy representative of a Category (Reference Material) the following information shall be provided.

1.7.1.    Acceptance of a Reference Material

For the assessment of the test rig results (according to EN 15664-1) the arithmetic mean of the equivalent pipe concentrations MEPn(T) shall be considered.

For all periods of operation (T) an average of the MEPn(T) of the three test lines in one rig is calculated: MEPa(T).

The material can be accepted for a product group with the assumed contact surface a (see Table 1), if:

are met for all tested drinking waters.

The test may be extended up to 1 year, if criterion II is not met. In this case the material is acceptable, if

is met for the tested drinking waters, where criterion II was not fulfilled.

The complete set of available data has to be considered. For the test rig according to EN 15664-1 these are:

If stagnation samples were analysed in addition to the requirements in EN 15664-1 this data shall also be considered for the assessment.

The Committee of Expert shall decide, whether the data available is of sufficient quality (e.g. no major difference of the three test lines, interpretation of outliers) for an assessment to be carried out and if so decide whether to accept the material based on the above mentioned criteria. Accepted materials will be added to the Composition List together with the Category as the Reference Material.

1.8.    Adding Materials to the Composition List within a Category of materials

Where the constituents of a candidate material for approval are shown to fall within a Category, the material can be added to the Composition List provided that a comparative test run against the respective Reference Material in a standardised rig test, EN15664-1, using one water defined in EN15664-2 shows satisfactory results.

For each material, the following information shall be provided:

1.8.1.    Acceptance of a material by comparative testing

For the assessment of the test rig results (according to EN 15664-1) the arithmetic mean of the equivalent pipe concentrations MEPn(T) shall be considered.

For all periods of operation (T) an average of the MEPn(T) of the three test lines in the rig is calculated: MEPa(T).

For the Reference Material MEPa,RM(T) of the three reference lines shall be considered.

The material can be accepted for a product group with the assumed contact surface a of the Reference Material (see Table 1), if:

are met for the tested drinking water.

The test may be extended up to 1 year, if criterion II is not met. In this case the material is acceptable, if

is met.

The complete set of available data has to be considered. For the test rig according to EN 15664-1 these are:

If stagnation samples were analysed in addition to the requirements in EN 15664-1 this data shall also be considered for the assessment.

The Committee of Expert shall decide, whether the data available is of sufficient quality (e.g. no major difference of the three test lines, interpretation of outliers) for an assessment to be carried out, and if so decide whether to accept the materials based on the above mentioned criteria. Accepted materials will be added to the Composition List for the Category of the Reference Material used for comparative testing.

Excerpt 2 of the ‘ACCEPTANCE OF METALLIC MATERIALS USED FOR PRODUCTS IN CONTACT WITH DRINKING WATER. Common Approach. Part B – Common Composition List’ presented in chapter 2.

Copper alloys

Copper-zinc-lead alloys

1.8.1.1.    Category

Elements for consideration in the migration water:

Lead, nickel, copper, zinc

Addition of:

For each element: Acceptance factors in comparison to the mentioned reference material

1.8.1.2.    Accepted alloys

Accepted for the following product groups

Product group B

Product group C

Basis for Acceptance

German Co-normative Research Report RG_CPDW_01_074

Dossier John Nuttall (March 2006)

Accepted for the following product groups

Product group C

Basis for Acceptance

German Co-normative Research Report RG_CPDW_01_074

Dossier John Nuttall (March 2006)

Copper-zinc-lead-arsenic alloys

1.8.1.3.    Category

Elements for consideration in the migration water:

Lead, nickel, arsenic, copper, zinc

Restrictions for the use of metallic materials with respect to water composition (health based)

Based on the results of ongoing dedicated research (by industry), the alloying elements (constituents) and the impurities will be limited such, that the alloys can be used in any drinking water.

Accepted for the following product groups

Product Group B

Product Group C

Basis for Proposal

Dossier John Nuttall (March 2006)

Addition of:

For each element: Acceptance factors in comparison to the mentioned reference material

Copper-tin-zinc lead alloys

1.8.1.4.    Category

Elements for consideration in the migration water:

Lead, nickel, antimony, copper, zinc, tin

Addition of:

For each element: Acceptance factors in comparison to the mentioned reference material

1.8.1.5.    Accepted alloys

Accepted for the following product groups

Product Group B

Product Group C

Basis for Proposal: German Co-normative Research Report RG_CPDW_01_074, Dossier John Nuttall (March 2006)

Coppers

Copper

1.8.1.6.    Category

Elements for consideration in the migration water:

None: no need for comparative testing

1.8.1.7.    Accepted alloys

Accepted for the following product groups

Product group A

Product group B

Product group C

Restrictions for the use of metallic materials with respect to water composition (health based)

The formation of the copper compounds on the surface of copper pipes and consequently the dissolution is strongly influenced by minor components of the water composition. In some water compositions, the rate of leaching of copper may be unacceptably high. Member States may need to offer guidance to the water industry and to suppliers and installers of copper pipe on restrictions that may need to be introduced on use of copper pipe in water compositions where excessive leaching of copper might occur.

Further research into the compatibility of copper with certain compositions of water needs to be carried out using harmonised procedures for investigation and evaluation.

Basis for Proposal

Research results and practical experience in several Member States are needed to characterise the conditions for safe use.

Note

The contamination of drinking water by copper pipes depends on several characteristics of water composition. There is no consensus view on their combined action and interaction at this time. In particular, there is inadequate information on the range of compositions of drinking water where non-compliance with the DWD is likely to occur.

Tinned Copper Tubes and tinned Copper Fittings

For tinned copper tubes and tinned copper fittings as base material copper according to 4.3.1 is used. On this substrate material a tin layer is deposited by different processes. By diffusion of copper ions into the tin layer the formation of an increasing intermetallic phase consisting of tin and copper (η-phase = Cu6Sn5) is formed.

1.8.1.8.    Category

1.8.1.9.    Accepted alloys

Accepted for the following product groups

Product group A

Product group B

Product group C

Basis for proposal:

Leaching tests

a

:

rig tests in representative German drinking waters, published: A. Baukloh, S. Priggemeyer, U. Reiter, B. Winkler, Chemically inner tinned Copper Pipes, Less Copper in Corrosive Drinking Waters, Metall 10-11 (1998) 592 - 600.

b

:

Rig tests according to DIN 50931 (rig test): Technical report DVGW/TZW, 2000

Already existing approvals without restrictions in drinking waters

Galvanised steel

1.8.1.10.    Category

The zinc coating resulting from used in the galvanising process shall comply with the following requirements.

1.8.1.11.    Accepted alloys

The zinc coating resulting from used in the galvanising process complying with the following:

Guidance on restrictions for the use of metallic materials with respect to water composition

The following formula is proposed as a means identifying water compositions where corrosion rates for galvanised steel is acceptable.

pH ≥ 7,5 or free CO2 ≤ 0,25 mmol/L

AND	Alkalinity ≥ 1,5 mmol/L

AND	S1 < 2 (definition of S1 below)

AND	Calcium ≥ 0,5 mmol/L

AND	Conductivity ≤ 600 μS/cm at 25 °C

AND	S2 < 1 or S2> 3 (definition of S2 below)

concentrations in mmol/l

concentrations in mmol/l

Accepted for the following product groups

Product group A

Product group B

Product group C

Basis for proposal

There are regulations with respect to water composition in France (DTU 60.1/NF P 40-201) and in Germany (DIN 50930-3). These limits are based on practical experience but are expressed in different ways. The proposal covers mainly the same water compositions as both regulations. The proposal takes into account available results from research in Germany and co-normative research.

The proposal incorporates also the recommendations given EN 12502-3 with regard to the risk of localised corrosion. This localised corrosion frequently leads to deterioration in water quality as a result of corrosion products of iron.

The proposal is based on results that have been obtained with galvanised steel pipes with lead concentrations between 1,0 % and 0,6 % in the zinc layer, assuming a similar behaviour of pipes with lower lead concentrations.

Carbon steel

Carbon Steel for pipes and tanks

Carbon steel without permanent protective layers is not suitable for use in contact with drinking water.

Carbon Steel for ancillaries

Unprotected carbon steel can be used for specific applications (e.g. pumps, valves) and only for small surface in contact with water.

1.8.1.12.    Category

The constituents and impurities should not exceed the maximum limits stated below:

1.8.1.13.    Accepted alloys

The constituents and impurities should not exceed the maximum limits stated below:

Accepted for the following product groups

Group C

Basis for proposal

Draft Italian Regulation

Calculation of possible impact on DW

Cast iron

Cast iron for pipes and tanks

Cast iron without permanent protective layers is not suitable for pipes and fittings in contact with drinking water.

Cast iron for ancillaries

Unprotected cast iron can be used for specific applications (e.g. pumps, valves) and only for very small surface in contact with water. Their composition needs to be regulated.

1.8.1.14.    Category

The constituents and impurities should not exceed the maximum limits stated below:

1.8.1.15.    Accepted alloys

The constituents and impurities should not exceed the maximum limits stated below:

Accepted for the following product groups

Group C

Basis for proposal

Draft Italian regulation

French regulation

Calculation of possible impact on DW