Hi everyone,
I'm currently performing a PRM assessment of an Office building. ASHRAE 90.1 - 2016 has condensed in its appendix G all prescriptive information to model the Baseline building. It is also known that the Proposed Design must follow all the X.4 (mandatory provisions), incluiding the 6.4.3.8 - DCV.
However, it is not clear anywhere in the standard (specially on appendix G) or in the User's Manual that the Baseline building HVAC systems must be modelled with DCV, which I consider quite strange the absence of this prescription. Particularly on Section G3.1.2.5, there seems to be no specification as what to model on the Baseline when the Proposed models DCV.
Can please someone point me in the right direction? Do I must model DCV in the Baseline Building's systems/spaces? Are we to follow the same rules as per the Proposed Design (6.4.3.8)?
Thank you all in advance!
Regards,
Luis Andrade
Tyler Thumma
7GroupLEEDuser Expert
67 thumbs up
April 5, 2024 - 11:25 am
DCV is required in the Baseline for systems with outdoor air capacities greater than 3,000 cfm serving areas with an average design occupancy density exceeding 100 people per 1,000 ft2. This is based on ASHRAE 90.1-2004 Section 6.4.3.9 and is inferred by ASHRAE 90.1-2016 Section G3.1.2.5 exception 1.
Luis Andrade
2 thumbs up
July 26, 2024 - 12:52 pm
Hi Tyler,
Thank you for your response!
As per my understanding, mandatory provisions were to be modelled in the Baseline building as well for previous 90.1 versions. However, the 2016 version is one that intends the Proposed Design to follow the mandatory provisions and the Baseline Building to follow the Appendix G, hence my doubt. Additionally, I think that exception is there to allow the modelloing of different outdoor airfow rates between the 2 buidligns for a given space IF DCV is modelled in the Proposed (minimum OA rates are then different between the 2 models).
Still, better be safe than sorrow and will model DCV in the Baseline, as the "Baseline Air-side HVAC" tab on the MEPC does state that we should consider DCV under those conditions.
Thank you for your help!