Wednesday, August 21, 2013

Is it September yet?

It must be nearing quickly, as I already went to South Dakota in early August for the annual motorcycle rally. And I’m now seeing school busses on my drive to work. ASHRAE was in Denver this summer, a few issues were resolved, most notably the 40 fpm issue reported in my last blog. I have finally rolled off the USGBC’s Indoor Environmental Task Group, but can report that LEED V4 has been fully certified and will be out in the next few weeks.

We had hoped to get ASHRAE 55 2013 out in time to be referenced by the new LEED, but it will probably be in an addenda. ADPI is still the best way to prove compliance to 55 with overhead air distribution; both 55-2103 and the next ASHRAE Handbook (Applications) should be aligned to reference each other to make this proof easier to validate. I have actually been working on this, clarifying this relationship since about 1981, so I’m glad it is finally all coming together. I suspect the secret was to outlive all those who couldn’t grasp the reality of this relationship.

AHRI Standard 885 is one of two compliance paths in LEED V4 for schools. The prerequisite of 40 dBA (typically about 31 NC) for the classroom HVAC system can be substantiated by either AHRI 885 or the ASHRAE Handbooks. As there is still no reference in the ASHRAE Handbooks to the joint ASHRAE AHRI research study (RP755) conducted in the late 90’s at NRC Canada on the transmission of sound from plenum located sound sources into a room, which has been in 885 all along, I suspect AHRI 885 will be the primary documentation path. The spreadsheet associated with 885 makes both calculation and documentation quite easy. The incoming chair of TC 2.6, Sound and Vibration, has made the inclusion of the RP755 results in the Handbooks a priority, but until that happens, 885 is the best validation method.

I now have 3 of the 6 promised articles published in ASHRAE Journal. The first was on adjusting adjustable diffusers, primarily linears (which are seldom adjusted, it seems), the second was on the tradeoff between energy and comfort, and the third was on the validation of high turndown VAV systems, based on recent ASHRAE research. The next one will be on area factors for balancing diffusers and discussing why we really can’t publish them anymore, as the instrument used has become a significant variable. We will be posting them on the Krueger website when all six are out there.   

Authored by: Dan Int-Hout, Chief Engineer Krueger