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Today’s blog post comes from the October edition of Aircuity’s monthly newsletter, Aircuity Monitor. In this issue you’ll learn why turning your air change rates down at night is not a good substitution to using the Aircuity DCV technology. You’ll also read about Michigan State University’s basis for the safe, sustainable labs concept case study and you’ll find out where to find Aircuity at upcoming conferences and trade shows!

 

Just Turn it Down at Night

One question that we get asked every so often is, “well can I just turn down my air change rates (ACH) at night instead of using Aircuity?” The answer is simple – you could, but not without impacting the health and safety of lab occupants. The 2015 ASHRAE Handbook, Lab Chapter 16 notes that lab use at night cannot be predicted and labs may take upwards of one hour to clear. The new ASHRAE guidance recommends lower unoccupied rates only when lab can be assured to be “clean” at night. Excerpts from the handbook state, “…ventilation designers need to confirm that premise applies: that is, when the workers cease their activities and leave the laboratory, the contamination hazard is significantly reduced. Lab processes that continue unattended or erratic occupancy patterns may eliminate the opportunity.”

Depending on the type of lab (i.e. teaching vs research), occupants may enter the lab outside of the set “occupied” times, being exposed to the build-up of containments from the lower levels of fresh air ventilation. Additional containment exposure may happen when researchers first enter the building in the morning. After running at lower air change rates overnight containment levels take a while to drop back down after the “occupied” ventilation rate kicks back in.

Here is data from a lab where Aircuity was monitoring, but demand control was not turned on yet. Instead, they were using an occupied/unoccupied strategy and operating at 2 ACH unoccupied and 6 ACH occupied. There is a notable amount of total volatile organic compound (TVOC) build-up overnight. In this case, if researchers were to enter the lab during occupied hours, but before the occupied air change rates had cleared out they would have been exposed to an unhealthy level of contaminants.

 

Chemical Exposure Period

 

This next graph shows the TVOC levels “recovering” after the lab switched from unoccupied back to occupied ventilation rates in the morning. It took from 6:00 AM until7:30 AM for TVOC levels to reach background levels.

 

TVOC levels

 

Although all labs may not be targeting 2 ACH as their unoccupied rate, the data shows the risks associated with using nighttime setback without demand control ventilation. Similar results are expected at an unoccupied rate of 4 ACH, except the event would clear out a little more quickly.

Could you do it and save energy? Sure… but not without risks to occupants’ health.

 

Michigan State University Case Study: A Basis for the Safe Sustainable Labs Concept

Michigan State

In 2012 MSU selected Aircuity as a basis for the university’s integrated design approach, the Safe Sustainable Labs Concept, based on several prior Aircuity installations that were already creating measurably better environments on campus. Today MSU’s airside program consists of 268 lab installations in 7 buildings that are saving the university well over half a million dollars a year! Equally as important as energy savings is the ability Environmental Health and Safety personnel have to closely monitor events occurring in the space. Continue reading full case study

 

Upcoming Aircuity Conferences

There are a few more tradeshows scheduled before the end of the year for Aircuity. If you haven’t made it out to see them yet, try to fit one of the below in your schedule!

ERAPPA 2017

October 29 – November 1, 2017

Washington, DC

 

Tradeline College & University Science & Engineering Facilities

November 16 -17,  2017

St. Petersburg, FL

For more information about Aircuity and how we can provide you with their demand control ventilation solutions contact us today at 860.291.8886, email Tom Proietti or Cheryl McIntosh. You can also visit us on the web. Don’t forget to follow us on social media: Twitter, LinkedIn, Google+ and YouTube!

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