Anhydrous Ammonia Leak

The Downsides of R-717 Ammonia Refrigerant

R-717, or Anhydrous Ammonia, is widely regarded as one of the most efficient refrigerants in the world. Not only is it efficient it also has zero Ozone Depletion Potential and has a Global Warming Potential of zero. So, you have a highly efficient refrigerant with no impact on the climate. It is these two reasons why we have begun to see more and more companies and countries use Anhydrous Ammonia.

In fact Ammonia was one of the very first refrigerants to be discovered and used. This can be said for a lot of the natural refrigerants such as Ammonia, Carbon Dioxide, and the various Hydrocarbons like Propane or Isobutane. All of these were the grandfathers of refrigerants. It was in the 1930’s that CFCs and HCFC were introduced and we began to see the demand for these natural refrigerants start to dwindle.

After all, these newer CFC/HCFC refrigerants didn’t have any downsides. Natural refrigerants did. Carbon Dioxide operated at very high pressures which caused premature failures. Hydrocarbons were flammable. Ammonia was toxic and flammable. Yes folks, Ammonia is rated as a B2L from ASHRAE. This B signifies refrigerants for which there is evidence of toxicity at concentrations below four hundred parts per million. Refrigerants in the 2L sub-classification are slightly flammable and have a burning velocities less than or equal to 10 cm/s (3.9 in./s)

It is directly because of the downsides on natural refrigerants that I mentioned above that we saw the rise of CFCs and HCFC refrigerants such as R-11, R-12, R-502, R-22, etc. When these refrigerants were phased out due to their effect on the Ozone a new king of artificial refrigerants was announced, HFCs. Some of your most common HFCs out there are your R-125, R-32, R-410A, R-404A, and R-134a. These reigned supreme for about twenty years until we realized what impact that they were having on Climate Change and Global Warming.

The world had realized that we substituted one wrong for another. There had to be a better solution then these climate damaging refrigerants, right? Well folks, that is where the age old debate between natural refrigerants and artificial refrigerants come into play. Honeywell and Chemours (Formerly DuPont) have spent countless hours and money on developing a new classification of artificial refrigerants known as HFOs. These refrigerants are said to have very low Global Warming Potential while also being relatively safe. An HFO might be a 2L, but at least it is not toxic as well.

But, the problem is a lot of folks have felt they have been suckered too many times. First it was CFCs, then HCFCs, then HFCs, and now it’s HFOs? Whose to say that HFOs won’t be gone in another ten years? Why invest money into a machine that could be obsolete in a decade, or worse yet, illegal? I swear the ink wasn’t dry on the 2010 phase out of R-22 and we had already started to hear about phasing down R-410A. This constant changing can wear people out.

The appeal of natural refrigerants is enticing. They have been around for centuries. They are not damaging to the climate. These two facts alone ensure that you will never run into a phase down or phase out situation with these refrigerants. The question though is are they worth the risk? Now, when I say risk I’m not talking about Carbon Dioxide, or even Hydrocarbons for that matter. My focal point here is Ammonia.

As I mentioned earlier Ammonia is both toxic and flammable. Now many companies will minimize this and state that it is perfectly fine and safe if the proper precautions, maintenance, and regulations are followed. This very well may be true, but what happens when a mistake is made? If you’re just dealing with a smaller charged application then it’s not too big of a deal. However, if you are using Ammonia refrigerant in large quantities then disaster can strike.

Before I go further I want to preface this with that I am going to get a lot e-mails on this article. It seems that whenever I bring up Ammonia I get a lot of feedback. Some folks for it and some folks against it. Most of the time though it is folks arguing for it. So, in this article I am going to go against the grain here and try to paint you a picture of what can happen when Ammonia leaks or spills can occur and why we should be looking at alternative refrigerants.

A few years back I wrote an article about an unfortunate event in Canada. An Ammonia leak had occurred at a small town’s ice rink. Three workers, who were trying to repair the leak, died due to Ammonia exposure. An entire city block was evacuated by the local fire department. It was a tragedy for the small town. This one event, while extreme, shows you what kind of damage Ammonia can do.

To give you an even clearer picture I searched around Google and pulled Ammonia leak related stories over the past eighteen months. While fatalities are rare, they can still occur. The common theme throughout these leaks is evacuations and injuries. The sheer amount of incidents below should give you an idea of why I am not for Ammonia refrigerant use. (In large charge applications.)


If you are looking at a new system for your plant, factory, ice rink, or whatever else please consider something other then Ammonia. Review the latest HFO refrigerants out there. Or, if you want to stay with natural refrigerants then take a good hard look at Carbon Dioxide R-744. CO2 has made great strides over the past decades and is quickly becoming one of the major players within the refrigerant industry.

If you do end up going with Ammonia though just know that there is a chance of any one of the events I listed above happening at your location. It could be a small leak that is handled right away or it could be a catastrophe like what happened in Canada. Be absolutely sure you schedule proper maintenance and take any and all precautions you can so that you can give your employees and your customers a safe place to work and visit.

Thanks for reading,

Alec Johnson


You may also like