August 22, 2022

Lessons Learned from Unprecedented Building Water Demand Swings

Unprecedented Building Water Demand and Use During Pandemic Shutdown

An empty downtown street during the early days of the pandemic. While nearly empty offices and commercial buildings led to unusual decreases in water use, residential properties experienced dramatic increases in water demand with so many people staying home.

With the many facets it takes to maintain commercial buildings, it takes a devoted type of worker with the right acumen to successfully pull it off. A key trait is the ability to adapt quickly when a problem or disruption arises.

The most jarring example inevitably stems from the pandemic’s early days and the massive shifts in occupancy within many buildings and facilities. Large commercial and residential properties faced several challenges, including one challenge many didn’t expect: changes to the management and maintenance of their water supply (and, ultimately, water infrastructure as a whole). While most of the world was at home, residential buildings needed to accommodate higher, often unprecedented water use. Inversely, hotels that once saw 80 percent or more average occupancy dropped to only a few guests at most, leaving countless taps, fixtures, and booster systems unused. Stadiums and other large venues faced similar issues.

As the world continues to inch closer towards full normalcy, now is the time to assess the key takeaways so that we all remain fully prepared for when the next problem or disruption occurs – whether from pandemic resurgence or because of some other unworldly circumstance. Regardless, accommodating unprecedented shifts in demand isn’t as easy as simply turning a valve or flicking the lights off and walking away. There’s a lot to consider when it comes to adjusting to changing water needs at your facility, and the top three most important considerations are pressure, sanitation, and temperature control.

Pressure: Under, Over, and Just Right

Booster Pump System, Water Pressure Management in Unoccupied Buildings

Metropolitan Industries variable speed packaged booster pump systems utilize programmable logic controllers to deliver precise pressure control to efficiently accommodate varying building water demands. Despite unusually low occupancy and water demand in restaurants, hotels, and offices during the early days of the pandemic, proper water pressure management was a necessary measure to prevent interruption to basic building plumbing operations upon return to normal water use.

Pressure is a significant challenge as it impacts all areas of your water infrastructure, especially in large commercial and institutional plumbing systems. Water systems are sized based on the number of fixture units in a particular building. Engineers used a graph known as the Hunter’s Curve to estimate load demands in various plumbing systems. This chart is used as a reference to estimate the peak demand flow in plumbing systems based on typical profile use in the types of buildings that the chart identifies. At the start of the pandemic, many buildings experienced drastic and even extreme changes to their usage demands for the first time. We still rely on water pressure to supply water to every fixture, but pressure also helps some newer valves function properly. This doesn’t mean, however, that higher pressure is always the answer.

Buildings that experienced a dramatic drop in use — such as hotels, restaurants, and stadiums — suddenly had more than enough pressure, but this can be detrimental. If pressure remains high, leaks, gasket blowout, and fixture damage can occur. Inversely, an increase in the work-from-home population and a decrease in going out in the evenings left large, multiunit dwellings struggling to keep up. Without adequate pressure, basic functions such as turning on a tap stopped working as planned and crucial sanitation functions — flushing a toilet or doing laundry — were interrupted. In addition to this presenting a health risk, it can also become a legal issue depending on building codes in your area.

Buildings with old, constant speed booster systems (especially those with out-of-date logic controls) faced the biggest challenge. While newer booster systems and programmable logic controllers allow for easy adjustment, landlords and owners with older equipment had no way to accommodate. In these cases, mandated water metering was the easiest option for reducing the risk of equipment damage.

Hunter's Curve - Estimating Loads in Plumbing Systems

In 1940 Roy Hunter, at the request of the US Department of Commerce, prepared a report detailing “The Methods for Estimating Loads in Plumbing Systems.” This report includes a graphical curve engineers use to estimate load demands in various commercial, institutional, and industrial plumbing systems.

A Steady Flow for Sanitary Systems

Self Priming Pumps Sit Above Wells, Easing Building Sanitary System Maintenance

When the flow of water in sanitary systems dramatically decreased during the pandemic shutdown, an unexpected consequence in many commercial buildings was the obstruction of lines due to the accumulation of solids, which in some cases, led to pump damage or failure. The accessibility of Self-Priming Pumps, stationed above the well rather than below, allow for easy cleaning when maintenance is required.

Along with flush valves no longer functioning if pressure falls too low, wastewater systems are susceptible to blockages if an extended shutdown occurs without necessary preparation. This may not cause any immediate issues but can lead to significant problems over time.

For example, when restaurants or dining halls (such as those on university campuses) shut down systems that normally would have a large regular flow of water in the sanitary system changed to very little or no flow at all. Fats, grease, and normal solids found in these types of systems would settle out in the piping. When use returned to near normal levels, these solids obstructed lines could lead to back-ups and pump damage or failure. For older pumps sitting in wet wells, removing blockages becomes a costly, time consuming, and hazardous process. The easiest way to mitigate potential issues is by running hot water to flush the system and regularly verifying the operation of all pumps. Fortunately, modern equipment is designed for easy maintenance and greater control.

Self-priming pumps are designed for easy cleaning and sit above rather than in the well. Similarly, intelligent/connected pump controllers, such as Metropolitan’s LMS II and the Ion IntelliPump, allow you to quickly assess pump status and even receive alerts if issues occur.

Staying Out of Hot Water with Fixed Temperatures

MetroMix for the Maintaining of Hot Water Temperature Control in a Building Plumbing System

During extended times when building occupancy and water use is extremely low, it is highly recommended to continue heating water to avoid bacterial growth and subsequent contamination to the potable water supply. Master Mixing Valves, such as the MetroMix by Metropolitan Industries, allow for the storing of water at necessary hot temperatures to help protect the building water supply.

Pressure can affect hot water by eliminating the balance necessary for temperature-actuated shower valves to function properly. Maintaining a steady temperature in your water supply remains crucial for human health, as well.

At first, it may seem wasteful to heat water if there’s no one to use it. After all, wouldn’t it be more environmentally friendly to power down and save energy? The short answer: No. Letting your water sit as part of a green initiative simply creates the perfect breeding ground for legionella and other bacterial growth. Legionella already exist in our potable water supply but are contained with treatment and temperature. When water sits, especially in the warmer months where it can remain in a tepid range (~90 degrees), bacteria develop and the entire system will likely need to be treated and flushed, eliminating any of the cost and environmental savings that might have been achieved.

A master mixing valve allows you to store water at a hotter temperature to eliminate bacterial growth (~140 degrees) and help prevent contamination. These mixing valves should be left on despite downtime and, with a valve such as our MetroMix, you can schedule temperatures based on use, allowing you to save money and the planet without risking health issues.

We won’t try to argue that there’s an upside to the extended bouts of downtime many industries have seen. However, the lessons learned as a result are important and leave business better prepared for the future. We were here to help when this all started, and we’ll still be just one phone call away the next time the unexpected occurs, but with the above in mind and the right equipment in place, you might not need to pick up the phone.

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