Before LEEDuser set up these credit-specific Healthcare forums, there was a general Healthcare forum on which this IEQp1 question was posted. I am reposting the Q&A here for convenience:
Question:
I have a small question regarding ASHRAE standard 170-2008.
On page 5, Table 6-1 which specifies what type of filter to be used within a health care facility, according to the different uses of spaces, and it states that "Inpatient care, treatment, and diagnosis, and those spaces....." should have a MERV 7 filter on the first filter bank, and MERV 14 on the second filter bank.
My question is does it means "Inpatient care, treatment, and diagnosis" as one type of space, or "Inpatient care", "treatment", and "diagnosis" as three separate types?
The reason I want to ask this is because we are doing a LEED HC project at the moment, but there will be no inpatient, only outpatient in the facility, so depends on the interpretation of this table, it will have very different impact on our project.
Answer:
Not having the ASHRAE standard handy, I would think that the phrase is to be considered as one type of space covering things like patient rooms (inpatient care), procedure rooms (treatment), and Ultrasound (diagnosis). The odd thing to me is that the ASHRAE standard is lower than the FGI standard which is double filtered air (each filter being equivalent to MERV 15).
Looking at the HC reference guide, it says to follow the ASHRAE standard AND for mechanically ventilated areas to also follow the 2010 FGI Guidelines. LEED has a policy of following the more stringent guideline.
But you are doing an Outpatient facility which in the US is normally a Use Group B function. I suspect that in your case, the ASHRAE standard is more stringent that the FGI Guidelines. Consider the type of outpatient services that are being provided, the patient population and implement a solution that protects those needs. You may have an AHU that follows the MERV 7/14 in a outpatient surgical suite but another area may be a basic doctor's office that would have a different system.
Another Answer:
Table 6-1 permits a single filter bank of MERV 7 efficiency for "All other outpatient spaces." However, the FGI Guidelines - also referenced in the EQ pr1 requirements have additional filter requirements for certain special spaces within chapter 3 Ambulatory Care Facilities
Answer:
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.
Another answer:
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.