Written by: Nathan Martin, P.Eng | President of O’Dell Associates
Net Zero Carbon initiatives for buildings are of great importance in the fight against global warming. Building operations are responsible for 17% of Canada’s carbon emissions. (CaGBC, 2022) Looking more closely, the ventilation load is 30-50% of a building’s total energy consumption, varying by location. If we want to make a significant impact, we must address this load.
Every engineer is familiar with ASHRAE 62, which is the standard that defines ventilation for acceptable indoor air quality (IAQ) within a building. Few, however, apply the full scope of the standard within their designs, applying the prescriptive ventilation rate procedure (VRP) to every project for calculating building ventilation rate. In ASHRAE 62.1-2022 there is a very subtle change to the name of the standard to encourage designers to take a more holistic approach to indoor air quality.
62.1-2019 – Ventilation FOR Acceptable Indoor Air Quality
62.1-2022 – Ventilation AND Acceptable Indoor Air Quality
Why? This is an excerpt from the Foreward within the standard:
So, let’s put away the hammer (VRP) for a moment and consider a different tool in the ASHRAE 62 toolbox. The Indoor Air Quality Procedure (IAQp), included in the standard since 1981 (Persily, 2015), is an alternate approach to achieving acceptable indoor air quality. The designer is tasked with mass balance equations across a wide array of design compounds (DCs), ensuring their concentrations stay below design limits. The DCs are well documented in the standard, along with references for material emission rates. While arguably more work to calculate, this procedure considers not only ventilation but filtration strategies for achieving acceptable IAQ. OK, it’s a LOT more work to calculate IAQp but totally worth it on the quest for Net Zero! You can also lean on the team at O’Dell Associates, who are proficient in these calculations and can support you through the process. 😊
I offer the following examples of projects where O’Dell has supported IAQp calculations and the impressive results:
| Project | VRP Ventilation | IAQp Ventilation* | Ventilation Load Reduction |
| Warehousing | 14,000-cfm | 2,500 to 3,900-cfm | 64-77% |
| K-12 School | 4,748-cfm | 1,038-cfm | 78% |
| Office | 8,858-cfm | 4,212-cfm | 52% |
| Notes:
1. * Variable depending on filtration measures incorporated 2. Ventilation efficiency (Ez) of 0.8. This will be highlighted in an upcoming blog! |
|||
Clearly, there is a HUGE opportunity to reduce the ventilation air being delivered to a building and still maintain acceptable IAQ. This reduction helps support the electrification and decarbonization of our buildings while mitigating strain on utilities. It also delivers exceptional energy savings to the owner so they can realize reduced costs for the life of the building. Layer in advances in air-side energy recovery technologies, with up to 90% recovery, and we can transform building energy consumption profiles.
Put away the hammer, and let’s learn how to use a different tool to make an impact in building efficiency!
