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Originally Posted by Nh3 Refrigeration Tech

It is for these reasons that Ammonia Technicians require a ton of training and education.

Flammability vs health hazard are trade offs between high purity HC and ammonia.
Ammonia has been in use along with methyl chloride and sulfur dioxide before CFCs. They're ALL safe if properly contained. Those have been phased out and didn't come back because of serious health hazard when they leak.
Ammonia is right up there in inhalation hazard.

Another concern is that it's a DEA list I precursor. They've figured out a way to dope fertilizer grade NH3 to prevent its illicit use, so that pushes them over to refrigeration equipment to source it illegally. The process of stealing can accompany a massive release which can call for a community evacuation.

There's a recent one. There are quite a few from mid 2000s.
http://www.kentreporter.com/news/113280909.html


As for bringing Ammonia into the Commercial Supermarket business, it is currently illegal to have Ammonia "flowing" into a public (populated) supermarket. With that being said, it is not however illegal to have a Refrigeration system with a secondary refrigerant such as CO2 or Glycol as the "main (primary)" refrigerant that is "flowing" inside the supermarket, and have the Ammonia (R717) as the secondary refrigerant helping cool the Glycol or CO2 on the outside of the building.

Boils at lower levels helping to achieve colder temperatures [0 degrees thru -88 degrees in a full vaccum]).

compared to? It's comparable to R22. Higher than R502. I don't know of any R22 or 404A systems that run below atmosphere.
In fact, current replacement for super cold application of R13B1(super ozone killer with ODP of TEN) is R410A.

Home: R22, R410A, MO99, Nu-99, R134a(auto, refrigeration). All new application is 0 ODP, high GWP

Commercial refer: R-404A, 507 and 22 and some oddballs here and there. 0 ODP, 404 has very high GWP

Comfort cooling: HCFC-123... the only ODP currently allowed for new installs.. but this is a replacement for CFC-11 which operates with sub atmospheric pressure.

For systems using secondary loop system, I'm not sure if ammonia is safer than ventilated HC system. With an HC system, you have just got to make sure that leak is quickly ventilated to bring it below flammable limit.

I think corrosiveness, inhalation hazard.. and desirability to thieves that makes such release even more likely are big hurdles. The only setback for fluorocarbons today is global warming potential which I think is hocus pocus long term effect. Ammonia poses immediate danger to life and a massive exposure liability.

Ammonia is the perfect refrigerant. Unfortunately, it will probably 20 years until the changeover is complete. The largest holdback, is that ammonia is cheap and readily available. All manufacturers despise that. Trust me, there will be a ton of ammonia to glycol systems .

Anhydrous Ammonia Info

Originally Posted by Iceneck

Just out of curiousity...if a rack lost 200lbs of NH3, how great a danger would that pose to people around the store? I know it's heavier than air, but have no perspective about how dangerous it would be.

Hopefully it wouldn't turn into something like this.... http://www.youtube.com/watch?v=sNkdAs1e7Cw

First thing, Anhydrous Ammonia (R717 or Nh3) is not heavier than air. It is in fact lighter than air, the reason most videos show the Ammonia close to the ground is because Anhydrous Ammonia is very much attracted to moisture. Which is why your eyes and any cuts on your skin will burn when you come into contact with Ammonia. More times than not the ground will be wetter (hold more moisture) than the air, unless of course its raining, which is why we normally see Ammonia "hugging" the ground.

Secondly, back in 2009 in Cincinnati, OH/Northern KY there was an Ammonia Release at a dairy plant, they lost over 50,000 pounds of Ammonia, the entire city of Northern Kentucky was evacuated. Luckly for the city it was raining that day which made for a much "better" Ammonia Release. Anyhow I was one of the Hazmat Tech's (Also at the time was employed as an Ammonia Technician) that went into the building to shut the King Valve off that was accedentally opened. If it would not have been for the rain that day, the entire city could have potiently been wiped out. Ammonia Releases are VERY DANGEROUS. Even small ammounts under 100 pounds (Any Nh3 Release under 100 pounds does not have to be reported) have the potiental of severally injuring or even killing thousands of people, if the conditions are right for the situation (release in a populated enclosed area).

It is for these reasons that Ammonia Technicians require a ton of training and education.

As for bringing Ammonia into the Commercial Supermarket business, it is currently illegal to have Ammonia "flowing" into a public (populated) supermarket. With that being said, it is not however illegal to have a Refrigeration system with a secondary refrigerant such as CO2 or Glycol as the "main (primary)" refrigerant that is "flowing" inside the supermarket, and have the Ammonia (R717) as the secondary refrigerant helping cool the Glycol or CO2 on the outside of the building.

Now I hope that this doesnt turn away any potiental Nh3 Operators in the future. Being well trained and educated paired with being cautious, Ammonia Releases like the one mentioned above are rare due to good Maintanence and good Mechanics. Ammonia is a GREAT refrigerant with absolultly NO harmful effects to the Ozone layer, much more cost effective and all around (assuming you have a good understanding and respect for how an Ammonia Refrigeration System operates) better type of Refrigeration Systems (Boils at lower levels helping to achieve colder temperatures [0 degrees thru -88 degrees in a full vaccum]).

I have been an Ammonia Technician for most of my life and I wouldn't rather be doing anything else. I love what I do and I encourage any technician either on the fience about making the move to Ammonia or new to the business to not shy away from Ammonia. Read and learn about it. I am willing to answer any and all the questions I can to help any Nh3 Techs (Vets or Newbies) and any HVAC Techs with any information about how to get into the Ammonia field or tips on good schools for Ammonia Refrigeration.

I hope this helped You sir and the rest of the Tech's who viewed / commented on this thread to better understand the benifits and dangers of Anhydrous Ammonia as a Refrigerant.

Thank You,
-Chris

Originally Posted by icemeister

I wouldn't want one in my back yard.

However, codes are written based on many factors...all which boil down to what is considered as providing the public with a "reasonable" degree of safety. From what was presented in this article, I believe the risk from a few hundred pounds of R717 really isn't as big a deal as once thought.

Bulletproof? No, but what in this life is certain?

Death and taxes.

Originally Posted by ICanHas

icy, do you have any comment on exposure liability towards neighbors that sit higher than the roof level in the event of a major leak?

I wouldn't want one in my back yard.

However, codes are written based on many factors...all which boil down to what is considered as providing the public with a "reasonable" degree of safety. From what was presented in this article, I believe the risk from a few hundred pounds of R717 really isn't as big a deal as once thought.

Bulletproof? No, but what in this life is certain?

icy, do you have any comment on exposure liability towards neighbors that sit higher than the roof level in the event of a major leak?

Earlier I posted about how you would need a pretty sharp engineer to get around the code restrictions concerning NH3 in a supermarket...

Well, I think I found him.

Here's an excellent and informative article he wrote about R717 in markets:

http://ctagroup.com/blogs/ctatalk/wp...ms-CTA.pdf.pdf

He states, among many others things, that there are currently no major code restrictions for its use in supermarkets...with the exception of certain localities where they specifically prohibit it like New Jersey, Chicago and Los Angeles.

It has been recently reclassified by ASHRAE as a B2L refrigerant, meaning it has a lower flammability rating than before.

NH3 is now considered as a safe refrigerant and is currently approved by the EPA's SNAP program.

Now all of this is based on a cascaded or secondary refrigerant system system with the R717 portion housed outdoors, typically as a rooftop package. It's interesting to note that a supermarket is considered as a mixed use facility and as such, the back room and loading docks come under an industrial classification, which would allow for all or part of the ammonia system withing the building.

Still, I think I'd feel more at ease with it all on the roof though.

A snoot full of that stuff will make you run through a brick wall to get away from it. I dont see it ever being around a retail setting for long. A small leak would make people panic that were not used to being around it. It is a great refrigerant.

Couple issues...
1.) service exposure hazard. Ammonia breaks down rapidly in the environment and it is not toxic, however it is corrosive. It will aggressively attack copper in presence of the slightest amount of moisture. In many places including Canada it requires Class 2.3 Poison Gas placards

2.) Theft. Farms are getting hit by meth cooks for the anhydrous ammonia to use in meth production. Works are in progress to dope the agricultural ammonia to poison meth reaction, but such additives are damaging to refrigeration system.

So... refrigeration grade ammonia pure. Yes, there's been thefts where thieves hit up cold storage plants with bicycle tubes and such releasing tons of NH3. In such a quantity, it leads to community evacuation.

Also, depending on the location of roof top skids, a serious leak from roof top unit can expose the system owner to liability (i.e. blows 500 lbs of NH3 from a 50' roof top and wind blows it into adjacent apartment/office buildings)

NH3 is lighter than air, so it rises, however on a humid day, it will rapidly combine with moisture and form a dense fog(that is highly corrosive to copper and flesh) that will linger for a while.

Originally Posted by Juan Madera

They don't like NH3 cuz its cheap and effective.

Going out on a limb here, but i'm betting companies like Dupont will oppose use of NH3 for those very reasons.

As far as R1234yf goes, if I worked for a car manufacturer I'd *love* a switch to R1234yf. Then, you could force people to take their cars to the dealer for service (which they love) because the "GM authorized dealer" will be the only guy in town with the R1234yf equipment. Sh(@, they'll probably even market the new cars using R1234yf as "Green".

Just out of curiousity...if a rack lost 200lbs of NH3, how great a danger would that pose to people around the store? I know it's heavier than air, but have no perspective about how dangerous it would be.

Hopefully it wouldn't turn into something like this.... http://www.youtube.com/watch?v=sNkdAs1e7Cw

There are more techs that can work on 717 than there are on R1234yf. This is the new replacement for 134a...........

They don't like NH3 cuz its cheap and effective. R1234yf is going to cost about 50 buck a pound from what I was told by Emerson. GM will be using it on some of their 2014 production cars.

Also coming soon to a home near you are systems charged with R600 and R290 as the feds ruled that a 'fridge can contain up to 750 grams of it and be acceptable. Hone yer skill gents!

The store I know about has about has roughly
200# NH3
200# Co2
200# 407a

All skids are on the roof.

They have a separate ammonia contractor when any work is required on the NH3 skid.

Ammonia (R717) is a natural (pardon the pun ) for the high stage for a cascade system with a CO2.

The main problem areas I see are twofold:

The building and safety codes (and how they're interpreted) can rule out its use in most cases. If you have a very sharp engineer and/or project manager who is knowledgeable and willing to beat the new paths necessary to allow it in residential neighborhoods...let alone within a public building like a supermarket...then you may have a shot.

Then there's the availability of qualified ammonia technicians. Granted, CO2 is no walk in the park for most of us as it's characteristics are a bit foreign, but NH3, while it acts a lot like what we're used to, it is quite toxic and as such, techs must be fully trained, licensed and experienced to work with it.

R717 is an awesome refrigerant. The new apps allow its use as long as the NH3 is not inside the occupied space, so an intermediary will be used. I'm thinking that a glycol/h2o mix will be the winner. CO2 has way too tight of a liquid/vapor curve and could easily turn to dry ice if system leaks.....

There is an Albertsons a little out of my area that is in the finial stages of finishing a store that has a Co2 skid, Mycom NH3 skid, & 407a skid. not sure of the exact setups, but I know they are cascading.

I believe every new store will use this before I retire. (probably 30 more years)

From what I understand, a store was built on this principle last summer.

I know nothing more, though.

NH3 at markets

I'm wondering how many here think ammonia will someday be used as a primary refrigerant in grocery stores? Obviously not for a direct x system, but as a primary to cool some secondary like glycol, co2, or some other secondary refrigerant. I just read an article that it's being "re-classified" and that re classification may make it available for commercial ref in the future. The article was very pro nh3, saying that the primary charge of ammonia at a typical grocery store presented very little threat to public safety due to the (relatively) small amount of ammonia present.