Plumbing: Going with the (Low) Flow

  August 22, 2011

I’m Dan Hounsell, editor of Maintenance Solutions magazine. Today’s topic is, plumbing systems and water conservation.

Low-flow aerators that use 0.5 gallon of water per minute (gpm) have become common components within many institutional and commercial facilities looking to save water. These products are required in most public restrooms these days, and they generally have performed well.

But they can create challenges when used with some new energy-saving equipment. On-demand water heaters and battery-saving hydro-generators installed in many restrooms offer two examples of products that might not pair well with low-flow aerators.

Not all on-demand or instantaneous water heaters activate if a restroom has a low-flow aerator, even if the unit is designed to operate at a flow rate of 0.5 gpm. Because a faucet is a mixing valve, the flow drops to closer to 0.25 gpm. Also, the inlet of the water heater might feature a filter that, if clogged with debris, might cause the flow to drop below 0.5 gpm. This flow rate might not be high enough to allow users to wash their hands. The solution might be to install an aerator with a higher flow rate, perhaps 1 gpm.

But a higher-flow aerator creates its own issues. One issue is related to points under the Leadership in Energy and Environmental Design, or LEED, rating system. A 0.5 gpm aerator uses less water by comparison, so it is a larger contributor to LEED. Also, some hydro-generators might require a minimum 1 gpm aerator to activate, resulting in a similar problem as with the 0.5 gpm aerator.


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