USGBC Updated LEED-AP-O+M Exam Questions and Answers by niam

LEED v4.1 O+M Reference Guide, p.1132: LEED v4 - U.S.Green Building Council(https://www.usgbc.org/guide/om) 3: What is Blowdown Loss in Cooling Towers?(https://deltacooling.com/resources/faqs/what-is-blowdown-loss-in-cooling-towers).

Cooling tower blowdown is a process used to manage water quality in cooling systems. It involves discharging a portion of the water from the system to control the concentration of dissolved solids and minerals, which accumulate due to the continuous evaporation of water. These dissolved solids can increase the water's conductivity, leading to scale formation, corrosion, and biofouling, all of which can significantly decrease the efficiency and lifespan of the cooling system. By performing blowdown, the system maintains the water quality within acceptable limits, ensuring optimal performance and energy efficiency of the cooling tower.

References:

• The need for cooling tower blowdown due to the accumulation of dissolved solids is discussed within the context of water management practices in cooling systems in the LEED AP O+M documentation. This process is crucial for maintaining system efficiency and is covered under the Water Efficiency category, emphasizing the importance of water management in achieving sustainable building operations.

Installing and maintaining a conductivity meter is a strategy that improves cooling tower water efficiency. Conductivity meters help optimize the cycles of concentration, reducing water and chemical use by accurately measuring the water’s mineral content.

References: The LEED v4.1 O+M reference materials recommend the use of conductivity meters as part of water efficiency best management practices for cooling towers1234.

In determining the number of cooling tower cycles for the Water Efficiency Credit, Cooling Tower Water Use, the parameter that dictates the number of cycles is the one with the fewest calculated cycles of concentration without exceeding the maximum allowable level for that specific parameter. This approach ensures that the cooling tower operates efficiently while also protecting the system from scaling, corrosion, and biological growth by not exceeding the concentration limits of any one parameter.

References:The methodology for calculating cooling tower cycles of concentration is detailed in the LEED AP Operations + Maintenance reference guide, specifically within the section on Water Efficiency Credit, Cooling Tower Water Use. This section explains how to calculate the cycles of concentration based on multiple water quality parameters and emphasizes the importance of not exceeding the maximum allowable levels to ensure system efficiency and longevity.

The LEED AP Operations + Maintenance (LEED AP O+M) V4.1 focuses on improving the sustainability of existing buildings that are fully operational and have been occupied for at least a year12. Administering an alternative transportation survey is appropriate when the daily average or typical peak number of visitors is at least 50% of the regular building occupants. This is because the survey aims to understand and improve the transportation habits of a significant portion of the people interacting with the building, which includes both regular occupants and visitors. By focusing on this group, the LEED AP can identify opportunities to encourage alternative transportation modes, thereby reducing the building’s overall environmental impact.

References:

• LEED v4: Building Operations + Maintenance Guide | U.S. Green Building Council
• LEED AP with specialty | U.S. Green Building Council
• LEED certification for existing buildings and spaces
• LEED O+M Certification & Credentials | Existing Buildings | GBES