A2L refrigerants – myths and realities (Pt 3)

In the third of a series of articles, Karl Richardson of Logicool Air Conditioning & Heat Pumps presents an unbiased look at the myths and realities of the new “mildly flammable” A2L gases.

It has taken me some time to write the third of these articles simply because it could be deemed as quite controversial with regards to some of the subject matter regarding tooling for A2L refrigerants and, specifically, R32.

However, having spent the best part of two years researching the subject and the impact this change to new refrigerants will likely have on our industry, I am becoming increasingly frustrated by the lack of knowledge amongst those who really should know better and the lack of advice being offered by others to those who really need it.

R32 production in the UK and Europe is happening right now. Split systems commonly available in R410A are going to change wholesale to R32 in the next twelve months. You as a purchaser of air conditioning equipment have little say in the matter.

So lets get right down to it and firstly talk about tooling and training. You go to your local trade counter/wholesaler for advice and they tell you that to install R32 systems you need new gauges, a new reclaim unit and a new vacuum pump.

Lets have our first reality check shall we? Lets talk about tooling and, before we begin, the following text is entirely my opinion. Please make your own decisions and draw your own conclusions.

Training

Myth: “My engineers need retraining”

Reality: No they don’t.

R32 is an HFC. Current F-gas, 2079, CITB courses cover HFCs. They do not cover specific refrigerants.

Concerned about flammability? Get your engineers on a course for hydrocarbons. That way you will be covering your bases with regards to health and safety and managing your clients’ questions.

Your engineers do not need to be trained to handle R32 refrigerant if they are already F-gas qualified.

You, as a manager or business owner should consider taking some voluntary training on awareness of R32 and A2L refrigerants.

Vacuum pumps

Myth: Your trade counter may tell you that you need a new vacuum pump.

Vacuum pumps remove air from pipework. They are not reclaim units.

If your expert tells you that you can get an electrical spark from a vacuum pump then please ask what energy and what concentration of R32 refrigerant and air is required to cause combustion? Where is the R32 when this spark will happen? The system should be devoid of refrigerant.

If they have these figures at hand and can convince you otherwise then they know more than all of the experts I have been speaking to over the last two years. When you install your first R32 systems in the next few months, consider that, even if you are re-using existing R22, R407C or R410A pipework, you will not be allowing any trace of R32 to enter your vacuum pump.

Reality: Common sense required.

Check the specification of your existing vacuum pumps with the manufacturer, not the re-seller. Do they already have a back-flow adapter installed? Do you really need a new one? Are any coming to the end of their life? You may have ten engineers and ten vacuum pumps. Plan your tooling requirements going forward. Use common sense. Don’t send your engineer into an un-ventilated stairwell with a vacuum pump (or reclaim unit) you purchased in 1996.

Manifold gauges

Myth: You need new gauges

Reality: No you don’t.

There is a 3% difference in pressure between R410A and R32. It’s not difficult and you really should not be getting told that you need new gauges. Same oil, almost identical pressures, same line connections.

Do you need to replace some gauges going forward? Plan ahead and buy R32/R410A gauges when you need them and do consider digital.

R32 bottles do come with a left-hand thread. You really should be buying left-hand thread bottle connectors and putting them on your engineers vans.

Reclaim units

Myth: You need a new reclaim/recovery unit

So you need a new reclaim unit because you are going to recover some R32 refrigerant? There is very little R32 equipment installed in the market. Are you servicing or installing? Do you need a reclaim unit to install this equipment?

Reality: Yes, but maybe not right now.

You install a 3.5kW wall mount pre-charged with R32. Two months later you get a report from site of a failure. Your engineer arrives and when he/she investigates the system it’s evident that there has been a leak. There won’t be any refrigerant in the system and, of course, you won’t need one because your engineers will not have installed it so that a leak can occur!

We are not talking about large VRF systems here. These are not presently available for sale in the UK. We are discussing split systems with a limited refrigerant charge.

There is every chance during these summer months in the UK that your manufacturer will run out of stock of current R410A product and offer you an R32 equivalent. These are typically split systems up to 14kW with a base charge and little potential additional refrigerant charge.

Your current reclaim unit already recovers R32 as it is a component of R407C and R410A. In the latter it constitutes 50% of the mixture. The other half is R125.

R125 nullifies the flammability of R32. That is its main purpose. Assume you have a significant leak on a large VRF. Are you recovering 50% R410A and 50% R32?

If you are in a well ventilated area and you have to recover a few kilos of R32 then I would advise that you really should purchase a new reclaim unit. Having a single component refrigerant does not allow us to start topping up systems again. In the event of a leak, detect, repair, reclaim, recover and recycle.

The best solution is to look at your current tooling and put a strategy in place. Please do not immediately consider purchasing ten sets of gauges, ten vacuum pumps and ten reclaim units because the bloke on the trade counter told you to and you have been offered a good discount. That is of course, unless you want to and you can afford to do so.

Let’s be brutal about this. You, as a business owner, can look at this from an engineering, management and commercial point of view. Why not purchase one or two reclaim units and keep them at hq? Do you have an imminent and significant order for copper, cable tray, insulation and refrigerant? Do a deal. Give the order to the company that gives you the best deal including all of those ancillaries AND a new reclaim unit.

So that’s tooling and training covered. All you need to do now is purchase a shiny new R32 unit.

Your engineers don’t need training. Your pipe run is less than the pre-charged amount and you don’t really need new tooling right now, but there is a reclaim unit on the way following a deal done with your wholesaler due to the five miles of copper tube you have just purchased. You have great engineers, the best in the industry in fact. What could possibly go wrong? It’s not even really flammable despite the fact that it is, officially, flammable.

As I said in one of my previous articles, if you really try very, very hard, you can ignite R32. It won’t be spectacular but it can be done.

So there isn’t an issue. Until your client asks you “Why is there a flammable sticker on my new air conditioning unit?”

EU regulations require that all R32 and A2L equipment must have a clear and visible flammability logo on the equipment that you are installing. If, and when, you get the call from your client, please ensure that you have all of the facts at your disposal. I have tried to answer these questions in both of my previous articles which can be viewed by clicking on the links below. All manufacturers should offer training. Most do but some currently do not. My own business, Logicool, also offers training with regards to awareness of R32 and other A2L refrigerants. Much of the detail on that course is already in these articles. The point is not to sell you a lovely new R32 unit but to provide you with the education that you need.

There are also other providers such as Cool Concerns who are much better suited to detailed training and are completely independent.

Charge limitations

The one thing that really is not being discussed at present is limit charges and LFL.

Reality: Like it or not, R32 is “mildly-flammable”.

There is a limit on any potential charge that you can add to an “occupied space”.

R32 as with all other flammable substances, has an LFL or lower flammability limit. This limit is used to calculate how much R32 in a space could potentially cause combustion.

There are two calculations for LFL as seen in the graphic above. The second calculation (M = 6.0 x LFL5/4 x ho x A½) is the current one that we should be using for R32 application and is reflected in current legislation. They are shown here to illustrate the potential complexity of what we as responsible professionals need to begin to understand right now.

I won’t explain the above in full now but may do so in Part 4 of these articles. Below is some simple facts that explain the impact of this calculation. This will be done in the way of illustrating two typical applications where the impact of the LFL and the minimum/maximum charge limitation take effect and one where it does not.

In most comfort cooling applications you will be able to design and install air conditioning equipment without making this consideration. However, simply not knowing and not understanding this fact is not an option.

Lets make this as simple as we can from the start and look at some clear evidence.

Example 1

You have a new application which is a small office measuring 3m x 3m. There is very little wall space due to the size of the room. You choose to select and install a small floor mounted unit. The maximum charge before additional safety measures are required in this instance is 1.187kg.

Have a look at the R32 products being offered by your manufacturer of choice and you may realise that currently, there is a notable absence of floor/console units.

Example 2

You have been asked to quote for air conditioning in a comms room with a back-up and rotate facility. The room is 5m x 5m. The pipe run is 40m.

You have used 400W/m² as a reasonable calculation and select 1 x 10kW wall mounted system.

The maximum charge before additional safety measures are required in this scenario is 5.14kg.

One particular 10kW wall mounted system, currently available in the UK and Europe has a maximum charge of 6.8kg.

Therefore one leak from this system would equate to a potential 6.8kg of LFL refrigerant into the space, therefore exceeding the limit charge of 5.14kg

In this instance you are exceeding the maximum charge limit of 39 x LFL and will need to consider the installation of leak detection or mechanical ventilation.

There is an argument that an IT Room is “not an occupied space”. Two IT engineers installing additional IT equipment counters that argument.

Example 3

You have been asked to design and install air conditioning in an office measuring 10m x 20m. You are installing cassettes or ducted fan coils. You have selected two 14kW twin-split systems.

The maximum charge before additional safety measures are required in this scenario is 17.77kg.

The maximum charge of 2 x 14.0kW R32 condensing units of one system currently available on the market with a pipe-run of 100m is 6.8kg per system. Total 13.60kg.

In this instance no additional safety measures are required. This should reassure you that most comfort cooling applications will not be affected by this calculation but consideration should always be taken.

One thing we need to stop doing, and stop doing right now, is over-sizing air conditioning equipment. This is particularly the case for comms and IT rooms.

I now ask you to consider my earlier potential question from your client, “why is there a flammable sticker on my new air conditioning unit”? Imagine if that client is the health and safety officer of a chemical plant.

Your response should start with M = 6.0 x LFL5/4 x ho x A½

The final myth – R32 is the future

Myth – “I told my client that R410A was future proof. Now the manufacturers are forcing me to change to R32 so that they can sell more equipment.”

Reality: EU Legislation is forcing the adoption of R32. Part 1 of this series looked at these facts in some detail.

Let’s look at the our refrigerants for air conditioning equipment since 1990:

1990 – R22
2000 – R407C
2003 – R410A
2016 – R32

There is no guarantee that any refrigerant is “the future”. Will R32 stay for many years? In my opinion I do believe that for split systems, it will.

R32 is a single component, low-GWP refrigerant. It has a lower refrigerant charge than R410A. It is stable and the pressures and application are almost identical to that of R410A. The benefit to the manufacturers is that they can potentially produce 3.5 x R32 units instead of 1 x R410A unit. This allows continued growth whilst meeting strict EU limitations on CO2 impact.

There has been no major announcement of R32 in DX VRF for the UK. There have been mutterings from some manufacturers and it may well happen but is it the future for VRF? For splits, it may well be R32 for the immediate future. However, VRF is potentially changing and observation of current manoeuvrings in the marketplace indicate what is likely to happen in that sector. That is another discussion for Part 5 of this series of articles.

I am happy for anyone who spots any errors or inaccuracies here to point them out to me. I will edit where I need to so that this can allow for a 100% accurate document for those who read it. This should already be accurate but I know that there are some senior industry professionals who are influential with regards to legislation and I welcome any feedback that can improve this article and help better educate our industry in a time of change.

Related stories:

A2L refrigerants – myths and realities (Pt 2) – 20 May 2016
Having looked at why Europe is moving towards lower GWP A2L refrigerants, in the second part of this article Karl Richardson of air conditioning distributor Logicool looks at the issue of flammability. Read more…

A2L refrigerants – myths and realities (Pt 1) – 14 May 2016
In the first of a series of articles, Karl Richardson of Logicool Air Conditioning & Heat Pumps presents an unbiased look at the myths and realities of the new “mildly flammable” A2L gases. Read more…