The Dollars and Sense of Water Conservation

by Richard Silberman — The steady drumbeat of articles in the media about the impending scarcity, and rising cost, of water in the United States is catching the attention of the commercial real estate community. As examples, consider these recent headlines:

• “Severe Drought Has U.S. West Fearing the Worst” — The New York Times, February1, 2014
• “Water is Scarce — and Undervalued” — The Wall Street Journal, March 25, 2013
• “Water Rates Poised to Rise Further as Utility Debt Grows” — Bloomberg News, October 14, 2013

Indeed, the rise in water and sewer rates has far exceeded the rise in cost of other utilities over the last 25 years in the U.S. (see accompanying graph). Fortunately, there is a bounty of no- and low- cost actions that commercial building owners and managers can take to reduce their water usage without compromising the quality of the work environments they provide to tenants and employees. Here’s an overview of many such actions as applied to some of the most water intensive systems in their buildings: plumbing systems, landscaping and irrigation, sanitary water fixtures, and cooling towers.

Plumbing Systems

A considerable amount of water can be lost from commercial building plumbing systems due to leaks and excessive water pressure. Damaged joints, construction disturbances, ground shifting and settling, pipe corrosion, and frost damage can all be responsible for leaks in distribution systems. Excessive water pressure can exacerbate the water lost through these leaks.

Quantification of plumbing system losses, and target leak detection and repair, can be helped by a distribution system audit. A prescreening system audit should first be completed. A prescreening audit is a preliminary estimate of losses in the system by quantifying verifiable uses in the system compared to the total supply coming into the installation. Whether a full scale system audit needs to be conducted can be partially determined by the results of the prescreening audit.

The goal of a full scale audit is to prioritize the leak detection efforts from the results. The full scale audit is an in-depth analysis of the distribution system that includes the steps in the prescreening audit along with mapping the distribution system, verifying accuracy of meters, and testing distribution controls and operating procedures. Detailed data on system uses that can help quantify losses in the system are also part of the effort.

Elimination of leaks

It is estimated that 14 percent of the nation’s water supply is lost through water main leaks. Even a small leak can result in an enormous amount of lost water. Consider this: a bad toilet leak can easily result in over 1,000 gallons/day of wasted water. Eliminating leaks doesn’t just saves water, but also saves dollars and reduces the chances that a leak will cause major property damage. A leak detection strategy needs to employ regular onsite testing methods for detecting leaks along water distribution mains, valves, services, and meters. This is especially important in older facilities with large, old and deteriorating systems. There are two methods for instituting a leak detection strategy, which can be used individually or in concert with each other:

• Automated Sensors/Telemetry — monitoring software in conjunction with remote sensors which can alert building personnel to leaks, fluctuations in pressure, problems with equipment integrity, and other concerns.
• Visual Inspection Program — such a program may include pipe inspection, cleaning, lining, and other maintenance efforts to improve the distribution system and prevent leaks and breaches from occurring.

Reduction of water pressure

The practice of reducing water pressure in the building can significantly reduce water usage. Reducing pressure can decrease leakage, reduce water flow through open faucets, and reduces stresses on pipes and joints. It may also reduce the rate of system deterioration resulting in fewer repairs, extending the life of the system, and reducing repairs on end-use fixtures and appliances. One way this can be achieved is through the installation of pressure reducing valves on street mains as well as on pipes within buildings.

Water Efficient Landscaping and Irrigation

Landscaping and irrigation practices are often interwoven. Landscaping refers to any activity that modifies the visible features of an area of land. Irrigation is supplemental water that must be added to make up the difference between landscape water requirements and the natural precipitation in an area. Both offer significant opportunities for water conservation and efficiency.

Water Efficient Landscaping

Designing a water efficient landscape is an important component of a water conservation program. Water efficient landscapes using native and other “climate-appropriate” materials can reduce irrigation water use to better withstand drought, reduce drought loss or damage, and require less time and money to maintain. Contrast this with traditional landscapes surrounding commercial buildings which typically require large amounts supplemental water (irrigation) to thrive. This supplemental water can be a significant part of a building’s overall water use. Maintenance techniques that translate into a landscape requiring less water is also part of water efficient landscaping. Both traditional landscapes and nontraditional landscapes such as cemeteries and golf courses can be positively influenced by these principles.

Water Efficient Irrigation

When irrigating a landscape, if water isn’t applied evenly, brown and dry patches will develop. As a result the landscape will subsequently be grossly overwatered in order to keep these spots green. This is why a key efficiency concept associated with irrigation systems is distribution uniformity, or how evenly water is applied over the landscape.

It is important to judge all facets of the irrigation system for a sustainable building, from initial irrigation system design, to consistent ongoing management and maintenance, through to installation. Taking a less than comprehensive approach will result in poor system performance, and possible losses of irrigation of more than 50 percent due to evaporation, wind, and the other aforementioned facets.

Another important issue, which will dictate the amount and timing of the water applied to a landscape, is the irrigation schedule. As seasons change, so does the amount of water a landscape requires, and a watering schedule should be developed to reflect this reality. Merely watering the same amount all year long will result in overwatering, which can actually cause more damage to plant materials than under-watering. It can also damage streets, curbs, other paving and building foundations.

Sanitary Water Fixtures

Sanitary water use (washing, bathing, flushing) accounts for 40 percent of all water used in commercial buildings — more than any other water use. Of all sanitary water used the majority (75%) is for toilet flushing. There are many no- and low- cost practices that can be applied to sanitary fixtures to save water:

• Regularly adjust and maintain automatic sensors to ensure proper operation.
• When performing maintenance, replace worn parts and adjust mechanisms to ensure they are meeting manufacturer equipment specifications.
• Establish a user friendly method for tenants and cleaning or custodial crews to report leaks and fix them immediately.
• Recycle used parts such as tank trim and metal flush valves
• If non-water urinals are used, clean and replace the sealant, cartridges, or other materials regularly per manufacturer recommendations.
• Post water awareness information to encourage efficiency from users.
• Install low flow showerheads — replace standard 4.5 gallon/minute showerheads with 2.5 gallon/minute models. This can reduce shower water used by up to 34 percent.
• Install aerators on faucets — installing aerators is easy and can reduce water faucet usage by up to 60 percent with typically no perceived change in pressure by users. Other options include metered faucets, self-closing faucets and automatic sensor controlled faucets.
• Install expansion tanks and pressure reducing valves, and reduce water heater settings where appropriate to prevent pressure relief valves from discharging water.

Cooling Towers

Cooling towers are among the biggest users of water found in commercial buildings, and as such are prime targets for water conservation. A cooling tower regulates temperature by dissipating heat from recirculating water used to cool chillers, air-conditioning equipment, or other process equipment.

No- and low- cost actions available to commercial building owners and managers to reduce water usage in cooling towers include:

• Measuring the amount of water lost to evaporation. Some water utilities provide a credit to the sewer charges for evaporative losses, measured as the difference between metered make-up water minus metered blowdown water.
• Installing flow meters on make-up and blowdown lines to calculate and understand your “cycles of concentration.” Check the ratio of conductivity of blowdown and make-up water. Work with your cooling tower water treatment specialist to maximize the cycles of concentration.
• Evaluating your make-up water quality and customizing your cooling tower water treatment regimen to minimize your actual number of cycles. Depending on your make-up water, treatment programs may include corrosion and scaling inhibitors along with biological fouling inhibitors.
• Reading conductivity and flow meters regularly to quickly identify problems. Keep a log of make-up and blowdown quantities, conductivity, and cycles of concentration. Monitor trends to spot deterioration in performance.
• Using acid treatment such as sulfuric, hydrochloric, or ascorbic acid where appropriate. When added to recirculating water, acid can improve the efficiency of a cooling system by controlling the scale buildup potential from mineral deposits.

About the Author: Richard Silberman is Co-President and Managing Director of Healthy Buildings, a firm which provides environmental solutions to commercial building owners and managers. He is also an instructor of the course “Environmental Health & Safety Issues” offered by BOMI International as a prerequisite for the RPA certification.

Learn more at www.bomi.org

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