Hi.
I am looking into certifying a Healthcare facility in Sweden with LEED for Healthcare. The preliminary design of the project building does not include dehumidification of the HVAC system, does this mean that I won’t be able to certify? Or are there any circumstances where the humidity factors in ASHRAE 170 can be discarded?
Kindly
Emil Andersson
Susan Walter
HDRLEEDuser Expert
1296 thumbs up
February 10, 2012 - 3:47 pm
Emil,
You may want to check out the Alternative Compliance discussions going on in International Projects and talk to Veronika Sundberg also from Skanska. She is a regular on these boards. The humidity issue is something that is likely US focused and is embedded in our regulations. The alternative compliance pathways would likely be your best bet. I doubt that you can completely discard humidity factors. You may also want to contact GBCI for additional guidance. I'm betting your project will be the first LEED HC project to use this kind of compliance path.
S
james moler, p.e.
mgr systems engineeringturner healthcare
46 thumbs up
March 2, 2012 - 8:36 am
The ranges for humidity in ASHRAE 170 are pretty broad and it may be possible to show that in the local climate, humidity within the building will be within the required range for all but exceptional weather conditions. The inquiry mentions dehumidification is not provided. The upper limit in Table 7.1 is 60%RH for most spaces. If the prelliminary design meets the air change rates and temperatrure ranges in the standard, it is likely that the humidity will also be within the specified range. Typically the lower limit is the challenge - during cold winter months. A recent addendum to Standard 170 reduces the lower limit to 20% - a level that is generally achievable in most cold climates without added moisture if the ventilation system uses recirculating air or enthalpy exchange energy recovery ventilation systems. People, meals, showers, cleaning activity adds moisture to the building and a fairly tight envelope retains it. Losses are from air exchange and a 100% OA once through ventilation system requires energy recovery under the LEED EA pr2 Minimum Energy Performance.