I have two questions regarding Enhanced Indoor Air Quality Strategies Interior Cross Contamination Prevention.

LEED requires projects to “Sufficiently exhaust each space where hazardous gases or chemicals may be present or used (e.g., garages, housekeeping and laundry areas, copying and printing rooms)”    The LEED v4 for Schools reference guide states “ASHRAE 62.1–2010, Table 6-4, lists numerous spaces whose exhaust requirements exceed the 0.5 cfm per square foot (2.54 l/s per square meter) rate. Exhaust rates for these spaces must be maintained at all times, even when the building is not occupied.”

1) What rooms are typically considered to have “hazardous gases or chemicals” for a school? In the past we typically considered only janitor’s rooms and copy/print rooms in the credit.

2) Is there an exemption to the LEED requirement for exhaust to run 24/7 for these spaces? (Especially if this applies to science classrooms/workshops.)

We are working on a high school that will have several spaces that will require exhaust rates as per ASHRAE 2010, Table 6.4 These include:

  1. Washrooms
  2. Janitor and Recycle Rooms
  3. Copy and Print Rooms
  4. Art Classrooms
  5. Educational Science laboratories
  6. Woodwork Shop/Classroom.

Traditionally, the washrooms, janitor closets and copy rooms are exhausted with an exhaust fan and are not returned to the air handling unit for heat recovery.

The Art Classrooms, Physics Lab, and Life Science Labs are on an air handling unit with the remaining classrooms and have the exhaust air returned to a heat recovery wheel.

The chemistry lab is always exhausted with a dedicated exhaust fan and is not returned to the unit for heat recovery.

To satisfy LEED do all these systems need to operate 24 hours a day, which is a concern from an energy use perspective?