Digest 1b Definition of IAQ - (aka Dry Ice)

[Guest guest]

:

I would not recommend dry ice on the following basis:

1. It does not uniformly generate CO2 (seen more in larger spaces), so

you have to wait longer and the decay curve is affected by the non-uniform

emission/conversion.

2. I don't like handling Dry ice.

3. I find CO2 compressed gas is easier to transport and control.

I would recommend (and have done this for years):

A. Method 1 (preference)

1. CO2 in a smaller compressed gas cylinder that you can wheel into a

place.

2. Keep the place unoccupied.

3. Release CO2 into local area (room).

4. Use a fan or leaf blower to distribute well.

5. Get over 6000 ppm up to say 10,000 ppm; stop gas release.

6. Measure with CO2 datalogger for every 1 min (I use a Qtrak, not an

endorsement).

7. Leave the space and come back in 30-120 minutes (depends on

anticipated decay rate).

8. Check to see if <1000 ppm. If so you should have plenty of data.

9. Plot Log-Concentration (ppm) (y-axis) v time (hours) (x-axis).

Ignore the beginning curve (1-7 datapoints of local distribution

variation)

Ignore last set of datapoints where it is hitting the asymptote

(regional diffusion interference effects and poor resolution).

Use excel or the like to do a straight line fit.

The Slope of the line (x-coefficient) is equal to - ACH.

If you are in a pinch. A small CO2 fire extinguisher will work for a room.

Air exchange can be looked at within a room or group of rooms using multiple

CO2 meters.

B. Method 2

Use ASTM D6245-98, Standard Guide for Using Indoor Carbon Dioxide

Concentrations to Evaluate Indoor Air Quality and Ventilation, 2002.

In-situ measurements and accounting for occupancy.

Tony

.......................................................................

" Tony " Havics, CHMM, CIH, PE

pH2, LLC

5250 E US 36, Suite 830 Avon

IN 46123

www.ph2llc.com

off

fax

cell

90% of Risk Management is knowing where to place the decimal point...any

consultant can give you the other 10%(SM)

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[Guest guest]

Another source of compressed pure CO2 is from carbonated soft drink suppliers BeargLife Energy Associateswww.LifeEnergyAssoc.com20 Darton StreetConcord, MA 01742 Digest 1b Definition of IAQ - (aka Dry Ice)

:

I would not recommend dry ice on the following basis:

1. It does not uniformly generate CO2 (seen more in larger spaces), so

you have to wait longer and the decay curve is affected by the non-uniform

emission/conversion.

2. I don't like handling Dry ice.

3. I find CO2 compressed gas is easier to transport and control.

I would recommend (and have done this for years):

A. Method 1 (preference)

1. CO2 in a smaller compressed gas cylinder that you can wheel into a

place.

2. Keep the place unoccupied.

3. Release CO2 into local area (room).

4. Use a fan or leaf blower to distribute well.

5. Get over 6000 ppm up to say 10,000 ppm; stop gas release.

6. Measure with CO2 datalogger for every 1 min (I use a Qtrak, not an

endorsement).

7. Leave the space and come back in 30-120 minutes (depends on

anticipated decay rate).

8. Check to see if <1000 ppm. If so you should have plenty of data.

9. Plot Log-Concentration (ppm) (y-axis) v time (hours) (x-axis).

Ignore the beginning curve (1-7 datapoints of local distribution

variation)

Ignore last set of datapoints where it is hitting the asymptote

(regional diffusion interference effects and poor resolution).

Use excel or the like to do a straight line fit.

The Slope of the line (x-coefficient) is equal to - ACH.

If you are in a pinch. A small CO2 fire extinguisher will work for a room.

Air exchange can be looked at within a room or group of rooms using multiple

CO2 meters.

B. Method 2

Use ASTM D6245-98, Standard Guide for Using Indoor Carbon Dioxide

Concentrations to Evaluate Indoor Air Quality and Ventilation, 2002.

In-situ measurements and accounting for occupancy.

Tony

.......................................................................

"Tony" Havics, CHMM, CIH, PE

pH2, LLC

5250 E US 36, Suite 830 Avon

IN 46123

www.ph2llc.com

off

fax

cell

90% of Risk Management is knowing where to place the decimal point...any

consultant can give you the other 10%(SM)

This message is from pH2. This message and any attachments may contain

legally privileged or confidential information, and are intended only for

the individual or entity identified above as the addressee. If you are not

the addressee, or if this message has been addressed to you in error, you

are not authorized to read, copy, or distribute this message and any

attachments, and we ask that you please delete this message and attachments

(including all copies) and notify the sender by return e-mail or by phone at

. Delivery of this message and any attachments to any person

other than the intended recipient(s) is not intended in any way to waive

confidentiality or a privilege. All personal messages express views only of

the sender, which are not to be attributed to pH2 and may not be copied or

distributed without this statement.