 |
| |
 |
PLUMBING DESIGN
MODIFICATIONS TO REDUCE COPPER CORROSION |
| |
|
Each year pounds of
copper enter the District’s wastewater treatment plant
from corrosion of copper pipes. The City of Palo Alto conducted
a study that revealed that corrosion from newly installed copper
pipes is five times higher than that from older systems.
The following design modifications
may reduce copper pipe corrosion by as much as 50 – 75%.
|
| |
• |
Keep velocities low by
using larger diameter piping when possible. For cold lines,
velocities should be less than eight feet per second and for
hot they should be less than four to five feet per second. Also,
in circulating water systems, specify smaller capacity pumps. |
| |
|
|
| |
• |
Avoid stagnant sections,
and minimize direction and size changes whenever possible. |
| |
|
|
| |
• |
Use compatible materials
wherever you can. When multiple materials do need to be joined,
specify insulating unions. Also, specify copper or brass straps. |
| |
|
|
| |
• |
Prevent electrical currents
by specifying that electrical grounding connections be made
directly to a copper rod driven into the earth. Do not attach
a grounding wire to water pipes. Also, specify that electrical
wires be routed away from water pipes and make sure installers
know not to use galvanized nails that touch copper piping. |
| |
|
|
| |
• |
Avoid induced stresses
and be sure to provide enough support for the pipes and allow
for thermal expansion in the design of a system. |
| |
|
|
| |
• |
Consider non-copper pipe
(e.g., stainless steel) where its use is permitted. |
| |
|
|
| |
• |
If copper pipe must be
used, specify cutting, joining, and clean-up procedures that
minimize corrosion. Require that pipe installation be thoroughly
inspected. |
| |
|
|
| |
• |
Specify non- or low-lead
faucets, valves and appurtenances. Also use low flow fixtures
and appliances, and aeration faucet outlets. |
| |
|
|
| |
• |
Use stainless steel piping
and components for industrial process water supplies, heat exchangers,
chillers, condensers when operating temperatures exceed 140
degrees Fahrenheit. |
| |
|
|
| |
• |
Incorporate coupons or
easy-access inspection points into long stretches of pipe to
make it simpler to monitor corrosion. |
| |
|
|
| |
• |
Provide flanged fittings
or unions for pumps and other devices that must be removed for
maintenance. This reduces the amount of soldering that will
have to be done on aged pipe. |
| |
|
|
| |
|
Reference: "What
Plumbing Engineers and System Designers Need to Know",
produced by the City of Palo Alto. |
| |
|
| |
• |
Dowload a copy of "Preventing Corrosion", a fact sheet for system designers, produced by the City of San Jose |
| |
|
|
| |
|
|
| |
|
