Domestic Hot Water Recirculation Part 4: Pump Sizing Example

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Designing a domestic hot water recirculation system is not typically difficult. In fact, we see the exact same model recirculation pump used in application after application without incident, as this one pump is typically able to meet the minor head and flow requirements of most recirculation systems. That said it is important to work through the proper design procedures for any recirculation system. A little time up front can save a lot time (and money) after the fact.
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Domestic Hot Water Recirculation Part 3: The Role of the Recirculation Pump

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Whether you are thinking of installing a recirculation pump in a 3-bedroom home or designing a recirculation system for a 20-story office building, the role of the recirculation pump is always the same. Clearly, the pump is moving the water in order to keep hot water at or near the tap—but that’s really a simplified explanation of the pump’s role.
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Domestic Hot Water Recirculation Part 2: Where ASHRAE 90.1 Conflicts with OSHA

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When it comes to domestic hot water recirculation design, OSHA safety provisions and ASHRAE 90.1 energy efficiency requirements have put plumbing engineers between the proverbial rock and hard place. In an effort to minimize the energy penalty associated with mandatory domestic hot water recirculation, ASHRAE 90.1 has created operational parameters for these systems. The problem is that these parameters are in direct conflict with OSHA’s requirements for Legionella prevention.
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Domestic Hot Water Recirculation Part 1: What’s The Point?

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What could have led ASHRAE, and subsequently building codes all over the U.S., to require domestic hot water recirculation systems in non-residential buildings? This relatively bold stance on water conservation is quite simply a reaction to profound water shortages throughout the U.S. – shortages that will only get worse as the population continues to increase.
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How to Avoid Legionella Outbreaks in Domestic Hot Water Systems

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Domestic hot-water systems are frequently implicated as the source of legionellosis (Legionnaires’ disease) outbreaks. Very small quantities of Legionella, the bacteria that causes the disease, is commonly found in the ground, in water, and even in tap water. Legionella is not likely to become a health risk unless it begins to multiply and colonize. If not properly designed or maintained, a domestic hot water system (as well as other open water systems) can facilitate such growth....
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