Corona - Smoke Machines - Smoke Generators - Foggers for Air Balance Testing

Smoke tests conducted in January 2004 at an indoor swimming pool:

"...The HVAC system consists of a 100% outdoor air / 100% exhaust air, heat exchanger system with both fans moving 42,000 CFM. The supply diffusers are all installed in the West wall with half directed towards the pool surface & half directed towards the pool ceiling.

The exhaust grills are mounted in the East wall & at 2 ceiling locations. After testing & balancing was completed, I placed a "Corona Colt 4", 2,645 CFM smoke generator inside the supply fan discharge plenum. I turned the fans off for 5 minutes & let the Colt 4 fill the ductwork with smoke. When I turned the fans on (picture 1 below) we could easily observe the smoke being discharged into the pool enclosure.

Swimming Pool - HVAC - Smoke Test

Picture 1

It wasn't possible to effectively trace the airflow patterns by this method, because the smoke became quickly diluted by the 12:1 ratio of supply air volume vs. smoke volume. So, we settled on a plan to place the generator beside the pool itself. In picture 2 (see below) one can see the smoke being discharged on the side of the pool closest to the wall diffusers.

Colt Smoke Generator - Smoke Test

Picture 2

The smoke was observed being effectively stirred up & dispersed. After 15 minutes of testing, there were no pockets of smoke (or chlorine vapor) that weren't being stirred up & moved across the pool surface & across the ceiling.

The generator was then moved to the far side of the pool, across from the supply diffusers.
Pictures 3 & 4 (see below) show the smoke being discharged back toward the supply diffusers.

Colt Smoke Generator - Airflow Across Pool Test

Picture 3

Colt Smoke Generator - HVAC Extraction Test

Picture 4

The line of smoke traveled for varying distances before being turned back on itself & pushed & pulled into the exhaust grills. Again there were no observable pockets of smoke that were not being scattered by the supply air.

The mechanical engineer, the pool owners and I agreed that the results were conclusive that the HVAC system is doing it's job. The Colt 4 generated an adequate amount of high quality, non-staining, benign smoke for this test.

The visibility with the smoke generator on for 20 minutes & the pool exhaust fan off varied from 60' - 100'. I definitely could not see to the far end of the pool enclosure and it was difficult to see across the width of the room. This was in the Natatorium which measures 75' W x 150' L x (29-42') H. The calculated volume is 353,594 cu ft.

As you can see from the pictures, the visibility with both supply & exhaust fans running (42,000 CFM supply & exhaust air) was barely the full length of the Natatorium - 150'. With both fans running the air exchange rate is 7 Air Changes/Hr (8.6 minutes to replace 353,594 cu ft of air). And, the HVAC system works so well that 12 minutes after turning the exhaust fan off, there was no trace of smoke so; kids could be allowed in to swim.

A final note: During an earlier aborted test we had the Colt 4 and the supply fan running for 20 minutes without the exhaust fan operating. The pool room filled up with smoke to a visibility of about 1/3 of that in picture 1. It was great to see how much smoke this little smoke machine can produce.

Thank you for your assistance..."

Doug Rognlie
Air Balance Associates