FAQ

External corrosion protection for MLCP

General comments
Uponor multilayer composite pipe (MLCP) fittings for the Uponor multilayer composite pipe (MLCP) system are tested in combination with the Uponor MLC pipe or Uponor Uni Pipe PLUS in accordance with ISO 21003 and local requirements e.g. DVGW (German Technical and Scientific Association for Gas and Water) worksheet W534.

Uponor fittings with press, screw/compression and RTM technology provide permanent watertight connections.

Surface corrosion protection

Surface corrosion protection

However, protection of metal connectors or metal components in direct contact with building materials is required in the following circumstances:
-    presence of permanent or long-lasting moisture
-    pH value > 12.5

In these cases, Uponor recommends suitable corrosion protection using e.g.
Kebu or DENSO tape. Please follow the relevant manufacturer's instructions.

Important considerations
Permanent or long-lasting penetration of moisture in a building causes further damage to the building itself. High pH values can be caused by dirt, pollution (salts, cleaning agents or extermities) and also by aggressive substances in e.g. cement accelerators or retarders, screed admixtures and quick-setting cement, and by aggressive media like chlorine, ammonia, various nitrate compounds, etc.

Coordination with other companies that are involved in construction is recommended.

Please also keep in mind that requirements concerning thermal insulation and sound protection must be considered according to local technical rules and legal requirements.

Corrosion behaviour of different material combinations

Contact corrosion

Contact corrosion occurs in drinking water delivery systems with copper pipes and galvanized steel pipes if the base metal, in this case the galvanized pipe, is built in the direction of flow after the copper pipe.

Insulation components

To connect steel and copper pipes an insulation component is always required. Generally, brass fittings are used as insulation components because brass can be mounted together with copper or steel. This is documented in EN 806-4, see table 5 below.

Uponor fittings

All Uponor metal fittings are made of brass (copper alloy). Therefore Uponor pipe systems can be connected to copper or steel pipes.

Combination of pipes and fittings/valves made of different metals

Combination of pipes and fittings made of different materials can have an effect to the corrosion lilkelihood of single components.

Remarks are give in below table.

Uponor pipe systems and chlorine

 Contact with chlorine

Uponor pipe systems are installed in different kinds of buildings. In some buildings pipes might get in contact with chlorine.

Inner surface contact

Please read our statement: “Chemical Disinfection”. This fully describes application parameters.

Outer surface contact

If Uponor pipe systems are installed in a chlorine-containing atmosphere (e.g. an indoor swimming pool), Uponor fittings must be protected from contact with chlorine air (e.g. with corrosion protection tape) to avoid damages.

A disinfection of a tap water system is in some cases necessary (bacterial contamination) but it is not the final or a sustainable solution to operate a system.

A disinfection is only needed when a lot of things went wrong in a tap water installation (planning-, installation- and operating failures). First of all it is absolutly necessary to identify the failure/ failures and eliminate them (e.g. stagnation problems, unused pipes or temperature issues). If this was successful a disinfection is maybe necessary to disinfect the installation.

We confirm that the Uponor Mulitlayer pipe (MLC) system and the Uponor PE-Xa system can be used for short-term chemical disinfection in accordance with the standards EN 806 part 4 and the DVGW work sheet W 290 / W 291 and W 557 (A).

We recommend the following chemical disinfection materials:

hydrogen peroxide H2O2 according DIN EN 902

sodium hypochlorite NaOCl according DIN EN 901

chlorine dioxide ClO2 according DIN EN 12671

For the concentration and using time we recommend to follow the instruction of the “DVGW worksheet W 557” table 3.

hydrogen peroxide: H2O2  150 mg H2O2/l for 24h

sodium hypochlorite:  50 mg Cl/l for 12 h

chlorine dioxide 6 mg ClO2/l for 12h

Please keep in mind that every disinfection stresses the materials and devices of a tap water installation and can cause damages. Please avoid to run too many disinfection.

It is highly recommended to perform this by a specialist and experienced company.

Uponor multilayer composite pipe (MLCP) system and double pressing

Double pressing

 It may happen that during the pressing process of a press fitting of the multilayer pipe system (MLC) the battery of the pressing tool empties out and/or does not have enough force. In this case, a second pressing of the fitting may be necessary to complete the pressing procedure. Pressing the fitting twice is not a problem. It is also okay to press some fittings again if a press machine error occurred.

However, if the installer uses the wrong tools for the first press procedure, a second procedure with the right tools will be at his own risk.

PLEASE NOTE: the Uponor press system has been tested and appproved using ONLY Uponor pressing jaws. Other jaws are used at the installer’s own risk.

General comments

The Uponor multilayer composite pipe (MLCP) system is a precision-design plumbing system. The dimensions of individual Uponor MLCP system components such as pipes, fittings and tools align perfectly. This forms the basis of Uponor’s system approvals.

Uponor supplies all necessary components and offers many added benefits to support the pressing process. However, Uponor has no influence on the procedure itself. The installer is always responsible and accountable for the pressing process.

Recommendations for pressing tools

For the pressing process of the Uponor MLC and Uni Pipe PLUS pipes and the Uponor MLC press fittings you could use the Uponor S-Press electric tool UP 75 (1007082) as well as the Uponor S-Press tool UP 75/110 (1083612) in conjunction with the Uponor pressing jaws UPP1.

You may use instead of the Uponor pressing tools other pressing tools, like the following, in conjunction with the Uponor pressing jaws UPP1.

All pressing jaws/units should be maintained in a time period mentioned in the manual. For the usage in tap water and/or heating system we suggest at least one inspection each 3 years.