Home Podcasts THMG164 – Refrigerants Incidents, Part I

THMG164 – Refrigerants Incidents, Part I


In part one of a two-part series, Bob and Mike discuss refrigerants and how they can be dangerous to first responders.

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Complete Show Notes

3:10 Refrigerants Are Everywhere!

  • They’re in every town, every supermarket, and every house, but we don’t really give them much thought

4:55 Halogenated Hydrocarbons

  • Don’t call them freons – Freon is actually a brand name
  • The generic name for these gasses are halogenated hydrocarbon – this just means a hydrocarbon with one of the halogen elements attached to it
  • If you don’t remember, these are most commonly fluorine, chlorine, and bromine
  • Halogenated hydrocarbons are a huge category of organic chemistry, and the gasses used for cooling and refrigeration systems are only a small section of this group
  • Many halogenated hydrocarbons aren’t as benign as refrigerant gasses
  • Refrigerant gasses also isn’t really a good term, because some of the gasses used as coolant gasses aren’t halogenated hydrocarbons and have vastly different chemical-physical properties
  • Examples include ammonia and propane, both of which are very common refrigerants that aren’t halogenated hydrocarbons
  • Propane is also much more common than we might realize – it usually isn’t odorized, so if you’re not looking for a flammable gas that’s heavier than air, you won’t find it
  • Most refrigerants don’t have toxicity at low levels, but that doesn’t mean they can’t hurt you

11:30 How Do Refrigerators and A/C Units Work?

  • We usually see two types of leaks: catastrophic system failure and slower connection leaks
  • Refrigerators and A/C units don’t put cold in – they take heat energy out and transfer it from one place to another
  • Think of a propane tank – liquid is under pressure, and as we relieve the pressure in the tank, the liquid starts to turn into a gas
  • Cooling systems have two separate lines – one is liquid, and the other is gas
  • Liquid turns to gas and pulls heat from the environment as the gas is pumped to another location and turned back into liquid – that stored energy is released somewhere else
  • Due to expansion ratios, if that liquid line lets go, you have a much bigger issue than a small leak in the gas line
  • Small concentrations of refrigerants aren’t usually dangerous, but if they instantly fill a room, we’ll have a concentration that’s harmful to us
  • A lot of first line responders get themselves into trouble because the refrigerant gasses push the oxygen away
  • Lubrication oils in the lines are also released into the air during a leak, which causes a light haze that’s almost always mistaken for smoke
  • We need to have our masks on before we see this “smoke”

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