Rating System

LEED BD+C: New Construction, LEED BD+C: Schools, LEED ID+C: Commercial Interiors, LEED BD+C: Core and Shell, LEED O+M: Existing Buildings

Rating System Version

v2 - LEED 2.2, v2 - Schools 2007, v2 - LEED 2.0, v2 - LEED 2.0, v3 - LEED 2008

Inquiry

RE: an engineered natural ventilation method to a production/storage area. The prescriptive method in ASHRAE Std 62.1 which requires all natural ventilated area to be within 25 feet of operable wall or roof openings. Instead of the prescriptive method, we propose that the normal practice in Thailand, using wind operated roof cowls, to be adopted as the engineered natural ventilation method. The effectiveness of the method is proven in many other similar buildings in the same industrial park and it is an approved/acceptable design method to IEAT, whom is the local authority having jurisdiction to approve all building and building services design. In tandem with the above natural ventilation option requires the building flush-out to be performed using outdoor air to maintain an internal temperature of at least 60oF (15.6 oC) and relative humidity no higher than 60%. From the ASHRAE data for Annual Dehumidification Design Conditions (see Attachment 3), the design condition for Bangkok is 30.2/26.7 oC which is equivalent to an outdoor relative humidity of 76%. The naturally ventilated spaces which form the majority of the building area do not have any means for dehumidification and as such, will likely to have the same relative humidity as the outdoor condition of 76%. We are unsure if this applies to this application as to reduce the relative humidity to less than 60% during flush-out period while the occupied condition thereafter will be likely to be higher than 60%. Therefore in the space which is naturally ventilated and not heated or cooled, is it necessary to maintain the temperature and humidity requirements stipulated in the credit language during flush-out? Will these approaches be acceptable with regards to our natural ventilation proposal?