USGBC Updated LEED-AP-BD+C Exam Questions and Answers by ozzy

Makeup water meters, conductivity controllers and overflow alarms

According to the Water Efficiency Prerequisite for Indoor Water Use Reduction, cooling towers and evaporative condensers must be equipped with makeup water meters, conductivity controllers and overflow alarms to reduce water consumption and prevent water waste. These devices help monitor and control the water quality, flow rate and level of the cooling system, and alert the operators of any malfunctions or leaks.

As per the LEED AP Building Design + Construction (LEED AP BD+C) V4 resources, the installation of makeup water meters, conductivity controllers and overflow alarms is a requirement for cooling towers and evaporative condensers under the Water Efficiency Prerequisite for Indoor Water Use Reduction. This prerequisite aims to reduce indoor water consumption by setting baseline and efficiency standards for fixtures, fittings, appliances, equipment and processes. For cooling towers and evaporative condensers, the prerequisite also requires efficient drift eliminators that reduce drift to a maximum of 0.002% of recirculated water volume for counterflow towers and 0.005% of recirculated water flow for cross-flow towers. For more detailed information, you can refer to the web-based reference guide in the credit library atUSGBC’s official website.

The project should first conduct a feasibility study to identify the quantity, quality, timing, and reliability of available alternative water sources. Potential sources may include graywater, rainwater, foundation drainage, condensate, or treated wastewater. The study should compare supply with anticipated nonpotable demands, evaluate storage and treatment requirements, identify regulatory constraints, and estimate capital and operating costs. Metering is important after a viable system has been designed because it verifies performance and identifies abnormal consumption, but meters cannot compensate for an inadequate or unreliable source. Treatment-energy analysis is also necessary, but it should occur within the broader feasibility assessment. Establishing whether sufficient reusable water is actually available is therefore the essential first step in developing an effective water-reuse strategy.

The combined strategies produce a 35% reduction in potable-water consumption: 25% from efficiency measures plus another 10% from harvested rainwater. Under the WEc2 Whole-Project Water Use approach, that level of reduction reaches the four-point performance tier represented by Option C. The whole-project method evaluates applicable water end uses collectively rather than treating plumbing fixtures, irrigation, process water, and alternative supplies as unrelated measures. Rainwater used for suitable nonpotable applications reduces demand on municipally supplied potable water and therefore contributes to the calculated reduction when properly included in the project water balance. The project must document baseline demand, proposed demand, end-use assumptions, alternative-water availability, storage, treatment, and intended uses to demonstrate the claimed reduction and earn the corresponding points.

A compliant water meter is a device that measures and records the total potable water use of the building and associated grounds. According to theLEED V5Reference Guide for Building Design and Construction, a compliant water meter must meet the following requirements1:

•It must be permanently installed and measure the total water use of the building and grounds.

•It must have a remote communication capability or be readable from a location that is accessible to building management.

•It must have a data storage capability of at least 18 months, or be connected to a system that can store data for at least 18 months.

•It must have a resolution of 0.5 gallons (2 liters) or less, or the smallest unit of measure that is appropriate for the expected water use of the building.