I'm wondering if anyone is capable of explaining to a layperson such as myself the difference between the ISO and the ASHRAE options for this credit. I understand that ISO is an international standard and as such may be more appealing to international projects, but why then is there also the additional requirement of thermal controls for the ISO option but not for the ASHRAE option? To my knowledge, you can prove ASHRAE compliance using the Berkeley calculator, which again to my knowledge only looks at air speed control as a vehicle for thermal comfort control, as opposed the ISO option for this credit which would allow for a wider array of control options.
All of that is to say, why put controls in one credit option and not the other? And, is there any perceived benefit from experienced project teams to choose one option or the other?
As a side note, I was planning to choose the controls option for this credit as a means to avoid dealing a partially conditioned gym space that probably wouldn't pass ASHRAE, but seeing that Option 2 still has thermal comfort design AND thermal comfort controls as part of the documentation, it seems unlikely we would be awarded the credit.
Melissa Kelly
Sustainability SpecialistGensler
85 thumbs up
September 23, 2016 - 12:33 pm
Hi Steven,
I think you may be misreading the credit language. It's not a case of two options, but two requirements to meet the credit. Regardless of which standard you select, you must meet the design requirements AND control requirements. This does make the credit much more stringent than it used to be, but I think it acknowledges the fact that design standards based on a mean average comfort level inherently doesn't accommodate everyone.
I'm less familiar with the ISO standard, but my own understanding is that both are based on the same PMV approach, so the main advantage would be alignment with whichever standard was used for design. It'd be great to hear from others who have used either ISO 7730 or CEN/EN 15251 on what their experiences have been like!
Steven Burke
Sustainability ManagerSMMA
10 thumbs up
September 23, 2016 - 12:41 pm
Hi Melissa,
Thanks very much! You are correct, it was user error on my part of misunderstanding the credit language. I agree that I would love to hear some feedback on using the ISO standard also.
There is definitely some tension with the thermal comfort design of projects in the northeast that try to be sustainable by not using full air-conditioning, but that have high activity areas with high metabolic rates, such as gyms, yoga studios, or aerobics centers. It can make it challenging to get those spaces into compliance even if the rest of the project is good!
Thanks for the feedback!