Ammonia as Refrigerant
The events in Fernie where three people lost their lives due to exposure to high levels of ammonia refrigerant have caught our attention. The facility is for recreation; skating, curling. Ammonia is commonly used in these facilities so the public rightfully asks whether these places are safe. Why is this toxic gas used at all? Is it handled safely?
Technical BC Fernie Incident is a link to the Technical BC analysis of the incident. Their focus is the technical and mechanical details that led to the incident. WorksafeBC will be releasing their report with the focus on worker safety.
Ammonia is used as a refrigerant because it has higher energy efficiency compared to the alternatives, 3-10% better. It is less expensive to install as well. It is rated as a B2 refrigerant, meaning moderately toxic and moderately flammable. Because of this there are codes for mechanical rooms that are designed to prevent the public and workers from being exposed.
In an ice rink, the code essentially establishes a way to maintain two layers of separation between the public and the ammonia refrigerant. Vessels containing the refrigerant are either outside or enclosed in a sealed fire proof room. The refrigerant is not circulated in the floor, but typically a calcium chloride salt brine is circulated in piping under the ice, and through a heat exchanger where the refrigeration system removes the energy. If there is a leak of the brine, there is little hazard. If there is a leak of ammonia, it is either contained and vented in a controlled way from the enclosure, or it leaks into the brine, dissolves in the water and is contained within the brine piping system.
All these safeguards are designed to buy time. An arena full of people would not be exposed to ammonia, and there would be time to safely evacuate everyone in the event of a leak.
The workers who are in the mechanical rooms working on the equipment are required by WorksafeBC to wear protective gear, and each situation being analyzed for the appropriate level of precaution. Up to 35 ppm is safe, annoying but safe. Above that to 300 ppm a respirator and face mask is required. Ammonia dissolves in water, we are mostly made of water, so it dissolves in our tears, sweat, sinuses, etc. At high concentrations above 300 ppm there is not adequate oxygen available and a full self contained breathing apparatus is required.
It is widely used in food preparation in BC. The fruit industry, fish packing and preservation both on shore and on the boats, cold storage, warehouse freezers all use ammonia refrigerant.
The Paris Accord dealing with greenhouse gas emissions encourages industry to move towards refrigerants with a lower greenhouse gas potential. Ammonia has no greenhouse gas potential, along with other natural refrigerants such as hydrocarbons and CO2. Hence we likely will see more ammonia used as refrigerant in the future.
Incidents like Fernie teach us harshly how to work with this stuff safely. The link above to the Technical BC site details how the accident happened. There were a series of decisions made that led to the accident. WorksafeBC and Technical BC is in process of going to all facilities who use this refrigerant to make sure that it is handled safely from the standpoint of the public and the workers. WorksafeBC has a program with four phases; first the ice rink facilities were visited and procedures examined. Then the refrigeration contractors who install and maintain these sites. We have been involved and have developed safe work procedures for all the circumstances we would run into. Then food preparation facilities, then other refrigerant installations will be examined. I will have another blog post on the fourth phase and what that means.
What I got out of the incident report are two things. First the detailed technical descriptions clarified what happened. In my experience this stuff doesn’t just fall apart like that, and indeed it didn’t just fall apart. A series of technical decisions were made that exacerbated the problem. Second, and this is of interest more generally, each decision made the necessary level of knowledge and understanding higher to deal with the next situation that would arise. Let me explain.
First, in 2012 or so, the age of the chiller barrel reached is expected life span. 25 years. The city started the budget allocation process for replacement. The contractor had given them this information, a budget number and from then on it was up to the city to do what it knows how to do; allocate money, find a contractor qualified for the work, and run the project to replace the thing. It was all within the capabilities and skills of the participants.
Then the budget proposal fell off the list for some reason. The necessity of replacing this unit was lost in the many things needing done. The level of understanding required to recognize the priority of replacing this chiller was higher; in fact other consultants missed it. The manager of the facility didn’t know either. It didn’t happen, it wasn’t advanced in the budget process.
Toward the end of the 2016-2017 winter season ammonia was detected in the calcium chloride brine, both by smell and by analysis. This new information required a decision whether to run the plant the next year. During the year prices were acquired for replacement, but the money wasn’t budgeted and the chiller was started for the 2017-2018 winter season. This decision made everything that proceeded afterwards likely and extremely difficult to deal with safely.
In the report there are indications that the severity of the problem wasn’t clear to either the contractor, the city or the plant operators. There wasn’t enough information; how large was the leak, was it going to get worse, how fast would it deteriorate.
Nassim Taleb talks about making decisions under uncertainty. The important information isn’t the details or likelihood, but the consequences. I know that these things can fail slowly or quickly, and it is unpredictable. Precise analysis can be made, but in this situation the thing needed changing. The consequences of the decisions made at this point were catastrophic.
Shortly after startup, the leak got worse. One night the ammonia detector alarmed, the monitoring company called the fire department, they attended the site along with the operator. They had high levels of ammonia in the room, and the surge tanks were banging and vibrating. Let me explain. The water and salt mixture is pumped through the floor and the chiller barrel. It is open at the top, in a surge tank. The ammonia was escaping from the chiller barrel, through the brine piping and out the surge tank. The vibration and banging was indicative of a serious leak.
This situation required a high level of technical knowledge. The fire department is not trained at this level, and cannot be, and the rink operator didn’t have the knowledge either. So the decision was made to isolate the leak by closing valves on the brine system, essentially making it part of the pressure vessel. But the piping wasn’t designed to handle the pressure.
That made a sudden release just a matter of time.
The next step is of personal interest, because this is typically the situation where I show up. When reading the report I asked myself what I would have done in the situation with what I know and could have known. A refrigeration mechanic was dispatched from Calgary, and either didn’t know what he was walking into, or didn’t have the understanding to recognize the situation.
I would guess that of all the refrigeration mechanics in the province who would respond to such a call, maybe 1/4 of them would recognize what the situation was. The situation had developed to a point where a very high level of technical expertise was required to survive. Not only technical; it was unsafe to walk into the room, so getting information from the operator was critical. What do you mean you isolated the leak in the chiller barrel? That is impossible. Then having the wherewithal to recognize and convince everyone that it was a potential catastrophe, and lay out a course of action that would diffuse the situation without loss of life.
But no, the three of them were doing a routine maintenance task when the piping came apart, releasing the ammonia brine mixture and giving them seconds to find a way out of the room while blinded and coughing. They didn’t make it.
Further mistakes and problems with the installation became apparent over the next days.
I suspect I am not the only one who feels angry, disgusted, sad and afraid. We make a living dealing with these and other situations, and plan to retire and get a sun tan on the beach, not at work. There are two conclusions I have come to.
- Decisions made early are easy. The situation is not going to get better, so make a decision. It will only get more complicated and expensive. Clear communication with the client as to the situation and potential consequences is necessary.
- Uncertainty is the rule. There is no way of knowing what is going to happen. All we know are the negative consequences. In all installations, either ammonia or HFC refrigerants, the consequences of failure are easy to figure out. Those are the important facts upon which to base a decision.
2015 Calendar Bird Edition
The Great Horned Owl on the cover page was taken across the street from where I live. During the summer when I took the dogs out before going to bed I heard a screech sound that was unfamiliar. A bit of research indicated it may be a young Great Horned owl, so I went looking the next time I heard it. Two showed up in a tree, and I managed to get this shot.
January
The Hawk Owl is seen in our area in the winter time. They nest further north, and individuals searching for hunting grounds are seen often in the high country. This one was beside the road on the way to Salmo surveying a field for voles to eat.
February
This Great Blue Heron was seen at Bird Marsh Creek, a very nice place to spend an hour.
March
The Blewett side of the old Taghum bridge is a rich environment worth checking regularly. One day this spring the light was golden and the Trumpeter Swans were posing for photos. This is a young bird who was being watched carefully by the adults.
April
The steely gaze has to do with the blood on it’s beak; are you edible (yes), can I take you down (no). Then it looks away for a more promising source of a meal. This was at Kokanee Park, and this Pygmy Owl let me get quite close.
May
The Townsend Solitaire is one of the early arrivals in the spring, and is quite pretty with it’s subtle colors. This was taken at Kokanee Park in March.
June
Harlequin Ducks arrive in May to nest on the shores of the cold fast flowing rivers. They look like they have neoprene wet suits with painted markings. The males stay around for a short while long enough to fertilize the eggs, then leave the females to hatch the young and teach them how to survive. This was taken on the Salmo River in May.
July
The Varied Thrush is common but not easy to see. They stick to the underbrush and move silently to disappear. Their hollow whistle is heard in the evenings during the summer. They look like a robin with a black stripe on their breast. This was taken on Clearwater Creek road in June.
August
The Common Loon can be seen on the West Arm of Kootenay Lake. This shot was taken at Kokanee Park in May.
September
We are privileged each year to see the Osprey nest and produce young. This is near Woodbury, and was taken in the middle of July.
October
This Hermit Thrush posed for 15 seconds at Champion Lakes this fall. They usually are very shy and hard to get a photo. It was taken in the middle of June.
November
The Northern Flicker is a common visitor to our yards, but I never tire of their colors. This was taken near home at the end of July.
December
Another sighting at Marsh Creek park. I had flushed this Wilson’s Snipe a few times in my walks, so I was watching for it. It saw us as we approached the swamp, hid behind some bushes. I stood still for about 10 minutes until it decided it was safe. It came out from behind the bushes and found a large beetle in the mud with it’s long beak. It took some chewing to break it and swallow it.
2015 Calendar, Mammals edition
The two calendars for 2015 have been received with enthusiasm, so I wanted to tell the stories behind each shot. They are all local, taken by Derek Kite in his travels, sometimes between jobs.
The cover page is a grizzly bear female followed by two cubs. The shot was taken early October 2014 at Gerrard. Myself and three others left home early to get there at first light. The sow came down onto the beach, crossed the bridge, climbed a hawthorn tree to eat a few berries, then wandered down the east side of the Lardeau river. We moved a mile downstream and watched her swim across the river. The light was perfect, the subject awe inspiring.
January
February
In early August 2014 I was walking the dogs on the beach at 6 mile. Just as it got dark bats appeared and were flying around us. The dogs were looking wondering, and I decided I had to get a photo. Thus began a rather long and involved process of figuring out how to get a picture of a small very fast flying creature that only was available for about 15 minutes every evening in enough numbers to even contemplate the feat. There were a few things in my favor; the mayfly hatch was healthy, and the bats would leave their roosts, fly back and forth on the shoreline before spreading out to feed during the night. The location was limited in size by docks and the shape of the shoreline. I finally managed to get a couple decent shots.
March
Columbia ground squirrels are quite common in our area. I was driving down Six Mile Lakes road and noticed something sticking up from the road. It was a lone squirrel. I took a couple shots, not particularly interesting, but noticed a second one running across the road where it stood with the first one. Much better. All I had to do was take the photo.
April
Six Mile Lakes road near the end of July. This is a Golden Mantled ground squirrel, and the young were busy running about. One was eating a seed so it’s sibling wanted to share.
May
One of the young grizzlies. It was looking up at it’s mom hoping to get a taste of some berries she was picking in a bush. We were concerned that the branches would break and she would fall on the little one.
June
Yellow bellied marmots are common in the summer on rock piles. This is in Nelson just past Maglio Building Center. The two young marmots were getting cuddly, training for a life of leisure where they sleep most of they year to awake, reproduce and eat grass. As long as they don’t get run over or eaten by a predator able to move the large rocks they hide under.
July
A muskrat. I saw this on the Columbia River at the Waldie trail. A neat spot worth visiting, every time I go there I see something different. This muskrat was on the shore eating some weeds and allowed me to get close.
August
The river Otter graces our lake with it’s antics. This one was at the old Taghum Bridge on the Blewett side last winter.
September
The second of the bear cubs coming down the beach following it’s mother.
October
Another pair of Golden Mantled ground squirrels. This was right beside the road up Six Mile Lakes road, and one came out of hiding from it’s den.
November
A chipmunk posed for me at Apex.
December
The grizzly sow enjoyed hawthorn berries, gently picking it with her tongue.
R-22 Phase Out
R22 is now priced well above the alternatives. It will be getting more expensive every year, so the time to change to something new is upon us.
My goals are to not have more than two R-22 replacements that I need to stock. There are currently two families of replacements, one the R407* with two refrigerants, one for air conditioning and one for medium temperature refrigeration. The second family is the MO99 types, which are drop in replacements. There are medium temperature refrigeration and air conditioning types.
The 407C and siblings require a change in the oil, removing part of the mineral oil and replacing it with POE. New compressors for almost all applications now come with POE oil, and the replacement of the oil in an existing system is not too difficult. The last time we went through this with the CFC replacements taught us that being religious in removing all mineral oil was not necessary, in fact those who did it by the book caused themselves lots of grief as the POE oil lacked cooling and lubricating characteristics that the equipment at the time required. So a change would be to evacuate the R-22, change driers and any rubber seals or gaskets, change the oil in the crank case, then recharge with 407C. The system would have less capacity than R-22, and the head pressure would tend to be higher. The POE oil will clean the inside of the system, loosening up any oxide scale or anything else that is in the system, bringing it back to the compressor crank case. This is why filter driers are necessary. It will not be trouble free in all instances. The atom size of the HFCs is smaller, so an R22 system which doesn’t leak may with the new refrigerant. Systems that need all the capacity will have less, changing for example the balance point on a heat pump system.
The MO family of refrigerants have additives (some hydrocarbon) that will in most cases circulate the mineral oil. The rubber seals will need to be changed however. The capacity loss is similar to 407 C as well as the head pressure characteristics. The green house gas potential of this refrigerant is substantially higher than the 407* family. In some cases POE oil will need to be introduced into the system by an oil change to ensure adequate oil return.
I plan on using the 407C family of refrigerants. The oil changes and drier installs will insure proper oil return and filtering of the system.
In some cases, due to the age of the equipment it may be advisable to replace the system. These changeouts are not trouble free, and an old system may simply be not worth the time involved to sort out all the problems.
As for MP39, which we have used extensively as an R12 replacement, as well as a 134A replacement, we will be using an MO family. It has the added capacity that we enjoyed with MP39. We are stocking it and using it now. MP39 is very expensive and we will no longer be stocking it.
Some low temp systems use HP80, which is also becoming very expensive. We will be changing these systems to 404A which works very well. We will be working with our customers to prepare the systems for a change. The oil will need to be replaced, and there may be some capacity issues.
We can get R22 for the time being, and equipment is available for R22 as long as it isn’t shipped charged. This change will take some time; there is a vast amount of R-22 equipment in use. For customers who have multiple pieces of equipment we will change the systems gradually, reclaiming the R-22 for use in other systems until the lot is changed over.
The HCFC refrigerants and drop in blends will tend to become more and more expensive as time goes on. The HFC’s have become quite reasonable in cost. This tends to make the cost of changing more palatable. Systems whose operation are critical should be looked at and a plan of action decided upon. A failure may precipitate action, but if the last time was any indication, reliability is not guaranteed with the use of a new refrigerant.
Fall Birds
With the change of weather we are seeing a different population of birds in our area. For a while we saw migrating birds passing through. Now we are seeing the ones that stay around for the winter. Here are some photos that I have taken over the last while.
 |
| From 2011 Birds |
 |
| From 2011 Birds |
A juvenile male Wood Duck spent a month or so at Kokanee Park while putting on the adult plumage.
 |
| From 2011 Birds |
I had flushed Wilson’s Snipes at the park a few times, but on this late afternoon where the light was beautiful, this Snipe was quite tolerant of my being near.
 |
| From Nelson Waterfront Nov 2011 |
This song sparrow put on quite the show for me, stretching and contorting itself. I like these photos of small birds hiding in the weeds.
 |
| From Nelson Waterfront Nov 2011 |
This Hooded Merganser was seen on the Nelson waterfront.
 |
| From Nelson Waterfront Nov 2011 |
A Horned Grebe caught some lunch.
R-22
R-22 and any HCFC blends such as MP-39 or HP80 have seen substantial price increases over the last while. This is due to the phasing out of HCFC refrigerants that started in 2010. Each year there are new surcharges, and the last increase this fall put the price above alternatives.
I will be starting to stock the alternative refrigerants in the new year and will be proposing a changeover strategy for your equipment. The best way is a gradual changeover, taking advantage of repairs to reclaim the HCFC refrigerant and replace it with an alternative. That would minimize the cost and over time all your equipment will be updated.
The new alternatives promise to be much less troublesome than the R-12/R-502 changeovers from a decade ago. They don’t require changing the lubricants and have good performance characteristics.
Our plan is to select a range of alternatives that cover the three pressure characteristics and use them. There are literally dozens on the market right now.
Enjoying the Kootenays
The Kootenays are a beautiful place to live. It would be a shame to live here an not enjoy what we have.
I carry a camera with me in the truck and take advantage of the opportunities that present themselves to take some photos. I’d like to share some over the next few months.
I was doing a job in Balfour last winter. It was wet and snowy. This woodpecker was drilling into a snag at the back of my customer’s building. I tried to get some pictures, but he would move around behind the snag. After a few unsuccessful shots I went to do the job. After an hour or so we came out and he was still working away. This time he didn’t hide.
Efficiency and Comfort
A commercial heating and cooling installation must fill opposing goals; comfort, energy efficiency, reliability, quiet.
A recently completed project had all these goals.
It was imperative that the temperature be comfortable, there be adequate ventilation. The work performed in the space is very detailed and technical, at the same time repetitive. Uncomfortable staff results in mistakes and low productivity.
There was a working system consisting of an old atmospheric gas burner furnaces with air conditioning condensing units. There was an opening for fresh air. The duct work was adequate.
We installed two high efficiency furnaces, each serving a floor. The furnaces have variable speed ECM motors, and two stage gas burners. We haven’t run the system in the winter months, but in the spring it worked well. The heating would run on low fire and low fan, gently warming the space. The occupants hardly knew the system was running.
We installed indoor coils above the furnaces tied to heat pump outdoor units. This gives the owner economic choices when it comes to heating. Currently natural gas is inexpensive, so the heat pump operation is limited to warmup on cool mornings. The cooling is 15 SEER. When the system is running in cooling it isn’t drafty or noisy.
We installed mixing dampers on both systems, along with a relief air hood. They can be run in 100% fresh air mode, or modulated to maintain discharge temperature, or minimum ventilation air. There was an existing Delta control board which we use to fine tune the control. We implemented a free cooling algorithm, where a call for cooling first tries to satisfy demand with fresh air. At the current loads in the space, we disable dx cooling at 19c. We have found that the occupants don’t notice slightly warmer temperatures if the air is fresh.
We also implemented a building purge and cool down cycle. The building has a south-west facing wall with large windows. It gets the sun until it sets in the evening. Previously, the building would continue warming up in the evening, and when everyone showed up in the morning, the outside walls and furnishings were warm. It would take a number of hours running dx cooling to bring the temperature down. The cool down cycle starts after midnight and runs the fan with full open dampers to cool the space down to a degree above heating setpoint. There are a number of logic checks to prevent cooling things down and needing to run the heat to make it comfortable.
The results have been satisfactory. A July hot day, the system shut down at 5PM and went on setback. The building warmed up to 29C. After midnight the fans came on, and by 6am the building was at 22C. The low outside was 16C. The mechanical cooling didn’t come on until around 11AM when building came out of the shade of it’s neighbor and started warming up. The current draw for the various components makes 1 hour of dx cooling equivalent to 7 hours of fan at full speed. In the hottest conditions we cut the equivalent of 2 hours of dx runtime, or approximately 20%.
We and the client are quite satisfied.
If you would like us to sort out a similar problem, please contact us.
Derek Kite
250-352-0199
Kite Refrigeration
We provide refrigeration and air conditioning services in the Trail, Castlegar, Nelson and Kaslo B.C. area.
Air conditioning service and installation. We install conventional hardware and the LG line of single and multi zone splits.
Controls. We service many different brands of refrigeration and building DDC controls.
Refrigeration. We service install anything from grocery store racks to small commercial refrigeration and freezers.
Heat pumps. We service and install air source heat pumps for residential and commercial applications.
We work on environment boxes used for industrial testing.
Contact us at 250-352-0199
Email derekkite@kiterefrigeration.com
Kite Refrigeration 