Recirculating Hot Water can Corrode Pipes

Recirculating hot water systems, designed to provide nearly instantaneous hot water at the tap, have become a common amenity, especially in hotels and large high-end multifamily residential complexes, where a high level of convenience is expected. The walls in such buildings often contain cable, tel...

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Bibliographic Details
Published in:Consulting - Specifying Engineer 2007-04, Vol.41 (4), p.46-46
Main Author: Villalobos, Jose L
Format: Magazinearticle
Language:English
Subjects:
Building codes
Copper
Corrosion
Design
Engineers
Flow velocity
Hotels & motels
HVAC
Mechanical engineering
Pipes
Plumbing
Water heaters
Water quality
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Summary:Recirculating hot water systems, designed to provide nearly instantaneous hot water at the tap, have become a common amenity, especially in hotels and large high-end multifamily residential complexes, where a high level of convenience is expected. The walls in such buildings often contain cable, telecom, gas, electric, HVAC, security and other service infrastructure. A water-pipe failure within these walls is virtually guaranteed to produce a cascade of costly consequences. Typically, a recirculating pump is used to pump hot water from a water heater through the copper hot-water pipeline, at the same time returning water that has cooled from the hot-water lines back to the water heater to be reheated. When corrosion occurs, several factors may be implicated, including aggressive water chemistry and improperly soldered joints. In most cases, though, the primary, or even sole, culprit is excessive flow velocity. In an effort to ensure instantaneous delivery of hot water, an oversized pump has been installed, with the result that the pipes are literally eroded away by their own contents.
ISSN:0892-5046
1558-2876