Dear all,

We have some projects where restrooms and locker rooms have windows to the outside environment and are not served by a heating or cooling equipment. We would like to ask whether can natural ventilation be sufficient to comply with section 6.5 exaust ventilation of ASHRAE 62.1 2010? Some references have said that ASHRAE 62.1 2010 requires a mechanical system for exhaust.

Supported by ASHRAE 62.1-2010 definition, where “air, exhaust: air removed from a space and discharged to outside the building by means of mechanical or natural ventilation systems.” and by the fact that the text in section 6.5 does not explicitly mention that mechanical exhaust must be used to meet the requirement, we assume that the requirement can be met by natural ventilation. Since it is possible to perform computer simulation to check the exhaust rates by natural ventilation, we can prove that natural ventilation could met section 6.5 requirement. 

As an example, why must we use mechanical exhaust in a restroom with its door and openings direct to the outdoors? What is the point of expending energy with mechanical exhaust since natural ventilation could be used and the air to be exhausted from the restroom would not bring any harm to another space?

We are looking forward to hearing from you.

Thank you in advance.