I have a large law school project (300k SF) comprising multiple new construction "wings" that tie into several existing structures of various stories. The predominant program is classroom and faculty/administrative offices, but about 50k SF that spans 4 stories within one wing contains the law library which operates 24/7 unlike the remainder of the facility. Interpretation IC 90.1-2007-05 allows different baseline systems based on different building types per G3.1.1 Exception a. Question 1: Does 90.1 identify different "building types" according to table 9.5.1? If so, is it reasonable to use System 5 just for the portion of the facility that contains the library?
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Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
November 13, 2012 - 10:18 am
G3.1.1a only applies to situations with a totally different use or heating fuel source. A law library in an academic building is not the degree of difference that would enable the application of exception a in my opinion. However, exception b would likely apply based on the difference in schedule. This would allow you to use a system #3 for the library.
SmithGroup BG+LU FW
SmithGroup16 thumbs up
November 13, 2012 - 12:07 pm
Thanks Marcus. The criteria listed in exception b can be quite cumbersome to document for a large project such as this (peak thermal loads that vary by more than 10 btu/sf-F compared to the average of other spaces served by the system or schedules that differ by more than 40 full load equivalent hours per week). Question 1: Can the AE elect NOT to take this exception? Question 2: Is the comparison of space peak load and average peak load intended to be made at the HVAC System (i.e., AHU) level (floor by floor) or the System Type Level? Is the comparison intended to be made based on peak cooling loads only? It doesn't make sense to look at peak heating since perimeter spaces might exceed the average by more than 10 btu/sf-F in many cases.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
November 13, 2012 - 12:33 pm
Exceptions must be applied. Sounds like you could easily apply the schedule difference. Just state that it is more than 40 hours different
and you are done.