Why Meeting ASHRAE’s Fresh Airflow Regulations isn’t as Easy as You Think

Both ASHRAE and the CDC have stated that one of the most important elements to ensuring a safe return to working in commercial office buildings after the COVID-19 shelter in place mandates have lifted is meeting their standards of fresh airflow. Unfortunately, there is no easy button in BMS systems to increase fresh airflow in commercial buildings, and simply increasing airflow can have negative effects throughout your buildings.

Here are three major categories where changes to airflow can create issues:

1. Tenant comfort

Too much airflow makes tenants feel like they’re in a wind tunnel – Too little and it gets stuffy – Where’s the middle ground? Airflow is supposed to be maintained ‘automatically’ by building automation systems (EMS, BMS, DDC, etc.) although they typically error towards sauna or hurricane due to improper tuning.

Under correct operation, building automation systems should maintain proper airflow to keep comfort <1-degrees from active space setpoint while ensuring proper air exchanges, preventing tenants from being stuck in an ‘airplane’ environment of recirculated air.

2. Indoor Air Quality (IAQ)

Does your office feel stuffy when it’s hot out? Or muggy when it’s cold? These obvious clues point to lack of proper air circulation or air exchanges in a building (ACH). Improper ACH typically occurs within 24-months post-installation resulting from:

  • Changes to minimum airflow settings to zones or individual offices.
  • Improper lockout sequencing to fresh air or economizer dampers
  • Improper control of airflow to zones

Most buildings suffer from a combination of the above three issues leading to 30-40% fresh air losses versus the ASHRAE minimum standard.

3. Energy Consumption

HVAC systems consume less than 50% of energy in most commercial buildings. Most of the energy loss is dictated by how much airflow is delivered throughout the building. Excessive airflow means running your fans too hard and tempering the air too much, leading to massive losses.

Most HVAC systems post-installation error heavily for comfort conditions often inadvertently sacrificing IAQ and energy savings. These setting adjustments typically include:

  • Economizer minimum damper position
  • Zone minimum airflow settings
  • Building pressurization setpoint

Merely adjusting these set points is extremely challenging and must be done on a seasonal basis, often eliminating any payback.

The proper balance between tenant comfort, indoor air quality, and energy savings is immensely challenging – often requiring constant tuning from onsite engineering staff. Additionally, The vast majority of buildings that suffer from one or two of the three listed symptoms are incapable of supporting an onsite, physical onsite engineer.

To combat these issues, Hank provides a true virtual engineer that is comparable to having a real engineer in every space constantly tuning for comfort, IAQ, and energy efficiency.  On average, Hank has been able to keep buildings at 1.5 times that of ASHRAE’s fresh air standard while lowering energy costs.  Click here to schedule a demo of our real-time IAQ dashboard and see for yourself how building owners are using advanced technologies to create healthy buildings.

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