Dry ice is often used as a coolant because it is colder than water ice, and that CO2 has no liquid phase in standard atmospheric conditions. When dry ice melts, there is only an increase of CO2 levels but no other residues.
Today, dry ice is used widely in the transportation business for both frozen and non-frozen goods. If the product is directly in contact with the dry ice, it will freeze. Depending on the insulation used, the temperature of the product can vary.
The main advantage of dry ice is that it has twice the cooling energy of water ice and that dry ice will sublimate at a rate of 1% of its total mass per hour in an insulated container (14% at room temperature).
Precautions need to be taken when handling dry ice: the use of cryogenic gloves for example! As dry ice sublimates into gas, it is important not to pack it in a gas tight container otherwise an explosion could occur.
As CO2 is an odorless and colorless gas, it is very important for life safety to always monitor the CO2 level when using dry ice. CO2 is capable of causing asphyxiation at high concentrations!
1kg of dry ice will produce 0.45m3 of CO2 gas. Due to this it is very important to monitor the rooms where the packages are loaded/unloaded and stored.
Workplace exposure limitations | ||
---|---|---|
STEL (short-term exposure limitations) | 15’000 ppm | LTEL (long-term exposure limitations) |
LTEL (long-term exposure limitations) | 8 hours | 5’000 ppm |
PST offers a range of products for CO2 monitoring, from sensors to handhelds, displays and loggers to an integrated monitoring system (including alarming). With the NDIR measurement principle, PST offers a very accurate way of measuring the CO2 levels in the atmosphere.
A range of both Indoor Air Quality and Life Safety products are available, so choosing the correct device for the short or long-term exposure limit is made easier.
Learn more about how CO2 Sensors Work in a previous PST blog.
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