Dezincification?

[mechcad8]

I am tring to conform to a specification that says the pipe fittings that we use must "be resistant to de-zincification if they are intended to come into contact with water" Brass fittings are our preferred choice for economic reasons.

To my knowledge all brass fittings that have a Zinc content of greater than 15% may be subjected to a certain amount of dezincification. The fittings that are used are manufactured from brass to BS EN 12164 CW614N or BS EN 12165 CW617N. The material composition for these is:-

Chemical 614N % 617N %
Cu 57.0 - 59.0 57.0 - 59.0
Al 0.0 - 0.05 0.0 - 0.05
Fe 0.0 - 0.3 0.0 - 0.3
Ni 0.0 - 0.3 0.0 - 0.3
Pb 2.5 - 3.5 1.6 - 2.5
Sn 0.0 - 0.3 0.0 - 0.3
Others 0.0 - 0.2 0.0 - 0.2
Zn Remainder Remainder

The fittings have been successfully used on our products for years with no problems. Does anybody know whether this material is resistant to dezincification?
If yes what justification can I use?

Many thanks

 

[unclesyd]

You are going to have a hard time with the dezincification certification as the zinc level is so high, well above the 15% you mentioned. A zinc content of 15% is normally the cut off when specifying dezincification limits on components, especially valves. The only inhibitor in your compositions is the Tin and there isn’t enough to be beneficial.