First let’s agree with the many studies that show at 1000 ppm CO2, both children and adults show reduced mental acuity as demonstrated by tests.  And let’s also agree that most schools have lousy ventilation.  By the afternoon in particular, there are many studies showing 2000 to 3000 ppm CO2 is common in schools, especially in poorer communities.  ASHRAE OKs up to 1200 ppm (700 ppm over ambient which is now in cities 450 to 500 ppm)

Now let’s look at converting ice to gas: 1 # dry ice = 8.566 ft3 of CO2 gas.

If we use a small room  20 x 16 x 8 ft =  2560 ft3 (I use this size because it is the size of the room in which dry ice killed 3 people and put 7 in the hospital), then the 8.566 ft3  is 0.33 % of 2560 ft3.   And  0.33 % CO2  = 3300 ppm CO2 which is unhealthy.

But you are adding that 1# of dry ice CO2 to the CO2 already in the room.  If they follow ASHRAE then 3300 + 1200 = 4500 ppm

If they are one of those schools with the poor ventilation, then they are way over OSHA PEL of 5000 ppm – for children!

NOW THE KICKER. The most common size of dry ice blocks is 10 pounds.  If that gets converted even partially to gas, there are some serious CO2 levels.  And remember also that the gas is colder and denser than the room air and will tend concentrate more toward the floor.  And children’s breathing zones are lower than those of adults.

I don’t think we can chalk this up to hysteria without knowing a lot more.

Monona

On Wednesday, February 28, 2024 at 11:34:58 AM EST, Info <info**At_Symbol_Here**ilpi.com> wrote: