Carbon Dioxide (CO2) Safe Handling and Best Practices
CO2 Material Safety Considerations:
1. Section 1- Physical Properties
An important component of industry safety is knowledge and awareness of the chemicals used.
1.1. Carbon dioxide at room temperature and standard pressure exists as an odorless, colorless gas. With a molecular weight of 44.1g/mole it is heavier than air.
1.2. Carbon dioxide can exist in 4 states of matter; as a solid, liquid, gas or supercritical fluid. Under standard atmospheric pressure CO2 changes from a solid directly to a gas, or, sublimates.
Table 1.1- Physical attributes of Carbon Dioxide
Formula
|
CO2
|
Molecular Weight
|
44.1 g
|
Density (g/L) (gas at 1 atm and 0 °C)
|
1.977
|
Sublimation Point (at STP in °C)
|
-79
|
Solubility (in water) (mL/100 mL at 20 °C)
|
88
|
Vapor Pressure (kPa at 20 °C)
|
5720
|
Relative Density to Air
|
1.5
|
2. Section 2- Safety Considerations
2.1. CO2 presents unique safety concerns in different states of matter.
2.2. As a non-compressed gas, CO2 levels can accumulate in any closed environment and present respiratory hazards when inhaled. There is a risk of suffocation.
2.3. When compressed, CO2 presents additional hazards. If not properly protected, or when heated, pressure can accumulate which could result in a non-combustion explosion of the canister.
2.4. The rapid sublimation of CO2 within compressed lines can rupture valves and cause pressure buildup and release.
2.5. Slow leaks of compressed CO2 into the atmosphere can build into unhealthy levels and may cause respiratory distress, irritation or suffocation. Refer to table 2.1 for concentration related hazards.
2.6. As both a solid and a liquid any contact with skin can result in frostbite.
Table 2.1 Health Hazards Associated With Varying CO2 Concentrations
PPM of CO2
|
Potential Hazard
|
0.1 to 1.0
|
Slight, unnoticeable increase in respiration rate, possible drowsy feeling
|
2.0
|
50% increase in respiration rate, Possible feelings of “chest heaviness”
|
3.0
|
100% increase in respiration rate, Acidosis of blood may occur
|
5.0
|
300% increase in respiration rate
|
10.0
|
Unconsciousness after a few minutes of exposure
|
12.0 to 15.0
|
Unconsciousness immediately upon exposure
|
25.0
|
Possible death after several hours of exposure
|
2.7. Prolonged exposure may also cause ill health. Symptoms may include headache, elevated cardio activity, visual disorientation, labored or rapid breathing, and auditory dysfunction.
3. Section 3- Safe handling best practices
Material safety practices should be adhered to at all times. Failure to do so could result in injury.
3.1. Ensure all work areas are properly ventilated.
3.2. Solid and liquid CO2 should only be handled wearing protective, non-cotton gloves.
3.3. Ensure that skin is covered or protected, by wearing long pants and protective outerwear.
3.4. Eye protection is not required; but it is recommended.
3.5. Ensure proper valves are in place for any compressed canisters.
3.6. In areas where there is a potential for CO2 gas to accumulate, an air quality monitor should be used.
3.7. Compressed air should never be used for any non-business approved purpose, such as cleaning clothing.
Resources:
http://www.epa.gov/ozone/snap/fire/co2/co2report.html Carbon Dioxide as a Fire Suppressant: Examining the Risks. U.S. Environmental Protection Agency: (19 August 2010)
http://msds.chem.ox.ac.uk/CA/carbon_dioxide.html Safety data for carbon dioxide, Oxford University MSDS (February 15, 2007)
http://laws.justice.gc.ca/eng/ Canada Occupational Health and Safety Regulations (November 28, 2011)
http://www.cas.org/products/sfacad/index.html SciFinder Database
http://www.hc-sc.gc.ca/ewh-semt/pubs/air/office_building-immeubles_bureaux/co2-eng.php Indoor Air Quality in Office Buildings: A Technical Guide, Health Canada Environmental and Workplace Health (September 20, 2011)
