As it is known, brass alloy is used in the production of water Sanitary Fittings and water valve bodies. Brass is essentially an alloy of copper (Cu) and zinc (Zn). The amount of copper in the alloy depends on the applied production method. Depending on the method, it can be around 55-64% and the amount of zinc is 35-42%. There is also some lead (Pb) in the alloy for ease of casting, forging and machining. The amount of Pb can vary between 1% and 8% in various countries . However, in common practice, the Pb ratio is used between 1-3.5%.
Existence of lead in brass was been a subject of many scientific and commercial discussions in the recent 20-30 years. Obviously, it is accepted totally that Pb has negative influence on health of mankind and is known it has serious damages on nervous system and brain when it is taken to body in certain amounts. Usage of Pb has been banned or restricted in some many industries ( painting, battery, etc ) addition to sanitary fittings industry.
Now, let's take a closer look at what kind of harmful effects lead has on the use of sanitary fittings. There are basically two main sources containing Pb in the production of sanitary fittings. One of them is brass itself. The other source is additive alloys used in the welding or soldering process of nipple, body, etc.
Brass alloy is the main raw material in the production of various parts of water fittings such as bodies, nuts, nipples, spouts, etc. Brass raw material is formed by three different production methods:
Among these, the casting method is the most important and complex process in terms of revealing the Pb effect. Pb is the element with the lowest melting point among copper, zinc and lead which forms the brass alloy. Depending on this physical feature, when melted metal is poured into the mold during casting operation lead starts to solidify firstly . As a result of this phenomen it moves towards the surface walls of the alloy and solidifies there. Therefore, a heterogeneous layer rich in Pb presents on the inner and outer surfaces of a cast brass piece. Water coming into contact with the lead-rich internal surfaces of body dissolves a certain amount of Pb and takes it out together while flow starts.
Lead is used in other processes of manufacturing such as hot forging and machining to obtain various formed parts of the sanitary fittings. Since the temperatur of operation in these methods are lower than melting point of lead, there is no such a similiar movement of the lead element, in alloys obviously . It is not possible for a Pb-rich heterogeneous structure to form on surfaces with these manufacturing methods.
WHO recommends an upper limit for Pb, as for other heavy metals, to be allowed in drinking water. However, some developments that emerged in the USA in the 1990s figured the issue prominently. It has come to the world's agenda and led to changes in standards.
We see that one of the most important milestones of the sector emerged in 1997. With the initiative of Arnold Schwarzenegger, the governor of California at the time, a public act called California Prep 65 was been released and put into practice.
This regulation was covering the components that constitute the sanitary fittings and was bringing a new limit to Pb amount which dissolves and passes into water as a result of contact of parts such as body, nut, nipple, pipe, etc. below WHO limits.
It restricted the amount to a value well below the upper limit values determined by WHO. While the upper limit value given by WHO for the amount of Pb that can be found in drinking water is 40 mg/l , the upper limit value introduced by Prep65 was 5 mg/l. A few years following release of this regulation, 4 more states in the USA accepted this act by putting it into practice. Afterwards, the subject was in discussion among companies and national institutes country wide for some years. The main issue of discussions was the limit values of Pb in water and difficulties for achieving those amounts in manufacturing processes. There were several new additional operations to get rid of these limits in many companies . While these effords keep on to find a proper solution by the following years, AB1953 law prepared in California in 2006. This new law was bringing a new limit to Pb amount in the alloys which come in contact with water in addition to the previous amount of dissolved Pb in water. The amount of Pb in the brass alloys which comes into contact with water should not exceed 0.25% . This value was really a strict limit and started many discussions in the sector.
While these developments were taking place in the USA, EU countries did not remain indifferent to the situation and in the early 2000s EAS (European Acceptance Scheme ) through EN technical committees (TC) responsible for preparing standards was been prepared and been sent to member countries for discussion in 2001. However, in EU countries, the water sanitary fittings and valve production sectors were ranking ahead in Italy and Spain which are quite active to sell products to non- EU countries and to USA extensively and thus a new discussion came out in EU. It was very difficult to manage different alloys for different markets and to keep soe stocks. Furthermore, raw material and wasted material transfers among countries were other difficulties to solve. Concerns for ensuring the continuity of 0.25% lead limit in brass material have upraiseddepending on these complex situation and no consensus has been reached by EU members.
While the EU countries continue to discuss the issue, environmental NGOs brought the issue to the US Senate and as a result of a bill being submitted to the Senate, Law No. S3874 was accepted in the US Senate in 2011. This law, which imposes an upper limit of 0.25% lead on brass alloys in contact with water, was passed by President Barack Obama. It was approved by Obama in the same year and was passed in 2014 after a three-year transition period. It has been decided to come into force in 51 states.
This new situation has deeply affected the sanitary fittings industry. Use of brass with 0.25% Pb, caused serious difficulties, especially in casting and machining operations. Quick alternative alloy solutions began to be investigated to find some ways to overcome these difficulties. Bismuth (Bi) is the neighbor of Pb in the elementary table and has a melting temperature of 270 °C. Bismuth (Bi), has a temperature similar to the addition of lead when added into brass alloy properties, so the properties of the brass alloy did not change much but a short after a while, Bi resources in the world became into vision that they were limited and the amount of Bi produced could not meet the needs. It was seen that he could not give it. Thereupon, companies turned to different alloy research.
Especially in the USA, where lead-free practice has become a law, raw material companies have registered and started production for various alloys under the names of Ecobrass, Ecocast, Federalloy, etc. Of these, ecobrass and ecocast basically have the same alloy, but there are minor element differences in rod (ecobrass) and ingot (ecocast) forms.
Ecobrass and ecocast alloy is an alloy with a high Cu and Si ratio. While normal brass contains an average of 60% copper, the Cu content in ecocast and ecobrass alloys increases up to 75%. An average of 3% Si was added to the alloy to increase its machinability. The Pb rate is below 0.2% in both alloys.
Federalloy alloy is an alloy containing Bi. Its copper (Cu) and zinc (Zn) ratios are around standard brass and it contains an average of 1-2% Bi. Apart from these, another lead-free alloy in use is the alloy mostly used in EU countries and referred to as CC773S in EN norms. In this alloy, copper and zinc are close to standard copper values and the Pb rate is below 0.2%..
In 2011, while EU countries had not yet reached a consensus on EAS, the UK, Germany, France and the Netherlands Certification bodies came together to create a joint agreement on healthy drinking water and started a movement. This initiative movement called 4MSI (4 Member States Initiative) Later on, Portugal also joined the initiative. This initiative is about brass alloys that can be used in sanitary fittings. These countries has made decisions to test raw materials in a few laboratories approved by them with certain specs . They announced that they would not allow any alloy to be used in manufacturing of sanitary fittings out of their approved ones in their territories. In this movement, the German Environment Agency UBA (Umweltbundesamt) has come out ahead and in practice the raw material lists approved by UBA are preferably used within member countries.
On the other hand, within the framework of EU technical legislation, studies on the preparation of an EU directive on the theme of drinking water and including the subject of lead-free brass continues .
