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.
Tyler Thumma
7GroupLEEDuser Expert
60 thumbs up
November 6, 2020 - 8:44 am
This is a great question. ASHRAE 62.1-2010 moved the exhaust requirements to a new Section 6.5, since exhaust requirements apply to all buildings, regardless of the procedure (VRP, IAQ, natural ventilation) used to determine outdoor air intake flow rates. However, you seem to be correct that there is no language requiring the exhaust to be mechanical, especially given the language of "natural ventilation systems" in the definition.
I would think that if you could demonstrate through simulation that the exhaust rates achieved through natural ventilation meet the requirements of Table 6-4 for all occupied periods, then this would be acceptable.
Adriana Hansen
ManagerCTE - Centro de Tecnologia de Edificações
118 thumbs up
November 6, 2020 - 9:11 am
Dear Thumma,
Thank you very much for sharing your knowledge and interpretation on this subject!
We also thank you all for the excellent work that 7group does sharing its expertise here at LEED user.