Which Joining Method Is Best for Copper Piping for Domestic Water Distribution?

Naveen Kumar Shivanna, CPD, GPD, LEED GA, a Fire Protection & Plumbing Engineer with Setty & Associates in Baltimore, is working on a renovation job where the specification calls for brazing joints for the copper piping in the domestic water system. However, he is wondering how press fittings compare to brazing from a durability and warranty standpoint, so he went to the ASPE Connect Open Forum to ask our experts their opinions.

It turns out that it’s not an apples-to-apples comparison.

Brazing Pros and Cons

Copper pipe brazing is an old, proven technique using high heat that is a subset of welding, so whether the project allows for open flame to be used will have an impact on the decision to specify brazing.

Brazed joints with filler material must meet low-lead (NSF 61) requirements. A brazed joint warranty is typically limited to the contractor’s warranty period, usually one year, as it depends solely on the craftsmanship of the installer. These joints require more labor, but when done correctly offer a vary durable system.

Also keep in mind that federal guide specifications require brazing for any copper joints below grade.

Press Fitting Pros and Cons

Press joining systems require less labor and meet low-lead requirements, but more pipes may be required to fix a press fitting joint than a brazing joint. They eliminate the need for hot permits on jobs, as some companies no longer allow torches in their buildings, even for repairs. This type of joint usually has a manufacturer’s warranty, including covering installation, but each manufacturer has its own installation procedures that must be performed to meet the warranty’s requirements.

Also, the press tool is specific to each manufacturer so the fittings are not interchangeable.

The Bottom Line

Brazing and press fittings are both reliable and acceptable joining methods for copper pipe. It appears that brazing is preferred for piping 2 inches and above, while press fittings are becoming the norm for piping below 2 inches in diameter. As with anything else in plumbing design, the joining method must meet any code, regulatory, and industry standards. The engineer must balance the pros and cons of each method to provide a solution that meets the needs of the client and the specifications.

Can You Help?

The following recent discussion posts need input. Click on one of the following if you can offer some expert advice.

  1. Is there a minimum distance below the bottom of a 12-inch concrete slab that the pipe has to be?
  2. Is it okay to mix the requirements of the UPC and the IPC?

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