The sound absorption coefficient for each material can be obtained from the product manufacturer or by using generally accepted measurements. The LEED 2009 Reference Guide includes a table listing the sound absorption coefficient for some common materials, and other sources of absorption coefficients are also available.
Sensors on toilets and faucets are perceived as saving water. However, several studies have shown that while they may offer some hygiene or other operational benefits, they increase water use substantially, due to “phantom flushes” and faucets running longer than needed. If you do choose lavatory sensors, look for models with adjustable flow durations. Although the LEED calculation estimates a standard 30-second use, setting the flow duration to a shorter time interval can help save water.
Plumbing piping must be doubled for interior water fixtures when graywater or rainwater is reused in addition to potable water. This is likely to add upfront costs, while potentially reducing water and sewer charges.
Untreated rainwater, graywater, and blackwater may corrode plumbing systems, or lead to biological growth. Teams should plan for water treatment, filtration, or using corrosion-resistant materials. The use of seawater for toilet flushing, although very uncommon, can cause similar problems.
Meeting reverberation time requirements is usually a negligible or zero cost increase, as long as acoustics have been included in the design from the early stages and no redesign is necessary.
