Copper Industry Advises Plumbing
Professionals in Soldering New, No-Lead Copper Alloys.
New Legislation Prompts the Copper Development Association to
Revisit Soldering Techniques for Making Proper Joints.
New federal legislation enacted earlier this year lowered the acceptable levels
of lead that can be found in plumbing components used for potable water
applications. The Reduction of Lead in Drinking Water Act (RLDWA) was designed
to keep the general public safer by reducing exposure to lead that can
potentially contaminate tap water and is typically leached from pipes, faucets
and other plumbing fittings and components.
The Act not only affects the consumer, but also the manufacturers, retailers,
plumbers, contractors and technicians who make, sell and install these plumbing
components and fittings for use in homes, schools, hospitals, offices and
commercial buildings throughout the United States.
Copper tube and fittings have always been lead-free, however many copper alloys
like some brasses and bronzes have included small amounts of lead in their
composition to provide beneficial machining properties, allowing the production
of complex parts. Across the industry, copper-based alloys like brass and bronze
are the most commonly used materials for valves, backflow preventers, faucets
and other plumbing fittings. The significant reduction in allowable lead content
– from 8 percent of the total volume of the component, to a weighted average of
0.25 percent of the total surface area of the component in contact with the
water (wetted surface area) – affects the chemical composition of copper alloys
that can be used for potable water applications, as well as the design of
components made from these alloys.
Concerns related to the cleaning methods, types of fluxes, size of the torch
tips and solderability between copper tube and these new no-lead copper alloys
began to surface as manufacturers began to comply with the RLDWA. To address
these concerns, the Copper Development Association (CDA) conducted laboratory
research and testing out in the field. They found that, in many cases, those
working with the new no-lead copper alloys — which use bismuth, silicon, sulfur,
selenium or other elements in place of lead — were using the incorrect soldering
procedure, particularly when it came to the heating techniques used while making
Story continues below
advertisement | your ad here
“Perfectly good joints can
be made using no-lead, brass and bronze copper alloys as
long as the joint is heated correctly,” said Andy Kireta,
Jr., vice president of CDA. CDA has been recognized as the
industry expert on the use, application and soldering of
copper and copper alloys for over a half a century.
CDA discovered that the most common mistakes when making a
soldered joint with the new alloys occurred during both
preheating and the actual heating process. Because some of
the newer alloys have different thermal conductivity
properties than the older ones, the proper amount of heat
and the location where it is applied play a pivotal role.
“During preheating, we found that many installers began
heating the joint by applying the torch directly to the
fitting or component cup, ignoring the tube while attempting
to bring the entire joint assembly up to soldering
temperature,” said Kireta. “During the soldering process,
once the joint is at soldering temperature, installers tend
to focus all of the heat at one point at the base of the
fitting or component cup while applying solder at either one
point or around the entire joint. Both of these habits are
incorrect, and can lead directly to poor soldered joints.”
The improper application of heat during the soldering
process can result in faulty joints, causing it to leak or
fail. To aid those in the plumbing industry, CDA has
developed a new do-it-yourself video that demonstrates how
to properly solder copper tube and fittings to the newer,
no-lead, brass and bronze copper alloys. The video,
Soldering of No-Lead Copper Alloy Fittings, Valves and
Components, can be seen below and, along with other
helpful instructional videos, is now available on the
CDA YouTube Channel.
Additionally, CDA has written a white paper on the topic
“Recommended Practices for Soldering No-Lead Copper
Alloys”. For detailed instructions on soldering, plumbing
professionals can also refer to the ASTM B828 standard or
CDA Copper Tube Handbook, now also available as a
downloadable app for both Apple and Android users.
# # #