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THMG172 – Scrubbin’ Some Ammonia


In this episode, Bob and Mike explore a real life ammonia leak submitted by a listener.

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Complete Show Notes

7:15 The Situation

  • Listener responded to an ammonia call in a neighboring city
  • Company was offloading liquid ammonia from a commercial ice maker and running the product out of the tank and into a 55-gallon drum using a garden hose
  • Someone called because they smelled ammonia – there was no active leak
  • Ammonia water was running into grates on the side of the street

8:00 Ammonia and Tanks

  • Ammonia is a gas at standard temperature and pressure – when compressed inside a tank, it turns into a liquid that’s very similar to propane
  • Tank is in the process of being purged – means the pressure inside the tank is being reduced and the gas is being piped through a hose going into a 55-gallon drum
  • Essentially left with clear Windex
  • Latent heat of vaporization – every time a bubble is liberated to refill the tank’s headspace, the liquid gets colder
  • As it gets colder, vapor production (and pressure) goes down to the point where it’s not vaporizing anymore
  • In this situation, we’d see a frost line somewhere on the tank – best option would be to slow down the purging so you could evacuate the entire tank

16:15 What Would Bob & Mike Do?

  • They probably wouldn’t do anything – instead, they’d let all of the ammonia leak out of the tank on its own
  • We can smell ammonia at very low concentrations, which means we get out before it can harm us
  • If the fire department isn’t familiar with ammonia, it makes sense that they would overreact
  • Conversion factors and PID – ammonia is toxic before it’s flammable
  • When anhydrous ammonia touches us, it becomes a very basic solution

25:50 Metering and Ammonia

  • Start with your nose – we can smell ammonia at very low concentrations
  • Single gas meter – helps you confirm you’re dealing with ammonia
  • PID – helps you determine the concentration
  • Catalytic bead sensor – helps you make sure you’re not reaching any explosive limits
  • pH paper – ammonia will be basic once it hits water, so you know you have ammonia if your paper turns blue

31:30 PPE Selection and Ammonia

  • Mike would approach the scene in bunker gear
  • If his PID readings quickly went through the roof, he’d change into vapor-tight protection
  • Bob would determine whether he could ventilate – changing the air allows you to change your tactics and response
  • Mike would put his mask on as soon as he started smelling ammonia
  • Remember that if you see a visible cloud, it’s a liquid leak – if you don’t see a visible cloud, it’s a vapor leak

Have a question? Send an email to feedback@thehazmatguys.com or leave a message on our Haz Mat Guys comment hotline: 843-628-1484

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