The Active Sensing System for Lab Exhaust

Maximize your energy savings with on-demand dilution

SmartStackTM is a proprietary, active sensing system that monitors lab exhaust air for 100’s of compounds. The system indexes the exit velocity of the lab exhaust Fans based on the cleanliness of the lab exhaust air.

Continuously monitor the cleanliness of each riser with Photo-ionization Detector (PID).

Index (e.g., “setback”) the high plume fan to lower exit velocity when lab exhaust air is clean, eliminating by-pass air, and/or re-staging the fans, driving significant energy savings.

Be compliant with ANSI Z9.5. When contaminant levels detected above action threshold, “setback” signal disabled and lab exhaust fan returns to maximum exit velocity for full dilution.

How It Works

Continuously sample each exhaust riser

Calibrated photoionization detector (PID) monitors contaminant level

Fan velocity setback when exhaust air is clean:

  • High dilution fans run a min. of 3,000 ft/min, often significantly higher
  • Immediately reduce high dilution fan to meet inlet static pressure (eliminate by-pass air and/or restage fans)

When contaminants are detected:

  • Setback is disabled
  • Sensor protection mechanism enabled
  • All sampled locations must report clear before enabling setback

Various override functions (e.g. occupancy sensor)

Remote performance monitoring via MAP Cloud

The common industry misconception about


Many assume that exhaust fans are required to operate at 3,000 ft/min (minimum). However, this setting is only a recommendation from ANSI Z9.5. The standard also states lower velocities can be used, provided there is sufficient dilution (from ASSE):

“The exhaust stack velocity shall be at least 3,000 ft/min (15.2 m/s) is required unless it can be demonstrated that a specific design meets the dilution criteria necessary to reduce the concentration of hazardous materials in the exhaust to safe levels at all potential receptors.”

SmartStack™ drives significant energy savings where labs and critical spaces are part of day-to-day operations. We provided SmartStack to: