What are some of the typical flaws in current plumbing designs?
KNIGHT: With regard to flaws in plumbing design, some thermostatic mixing valves (TMV) are simply not designed for the jobs for which they are being specified. With some brands, one can only truly control system “temperature creep” by accessorizing the TMV with supplemental controls, such as placing an aqua-stat on the pump. This option, however, is in direct conflict with OSHA’s recommendation for Legionella risk reduction, as it allows complete plumbing systems to stagnate during periods of no fixture demand. CSE: What technologies are available to deal with Legionella and scalding? What are their advantages and disadvantages? KNIGHT: Legionella control systems are classed as “biocide treatments” or “thermal treatments.” There are pros and cons to both, but both clearly benefit from the ability to deliver the treatment to all points within the plumbing system. A new technology gaining traction integrates electronics for water temperature and flow control at the point of use. Electron
