Difluoromethane, CH2F2, methylene fluoride, carbon fluoride hydride – however you label it, R32 refrigerant has been around since the early days of hydrofluorocarbon (HFC) refrigerant development.
However, it is about to come into its own, particularly in the heating, ventilation and air conditioning (HVAC) sector which accounts for a high proportion of refrigerant usage in fixed applications, throughout Europe and the UK. Why? Because HFCs with a high global warming potential (GWP) are being phased out and low-GWP refrigerants will be needed for the next-generation of air conditioning and refrigeration equipment.
Manufacturers have responded by introducing new products with lower GWP refrigerants, including R32, which has a GWP of 675 (compared with the current industry ‘favourite’ refrigerant – R410A – which has a GWP of 2,088). R32 also has a high cooling capacity and high efficiency. All this, plus other significant advantages (see box, p21), makes R32 an increasingly popular choice as the go-to refrigerant for air conditioning manufacturers.
So, what’s not to like? Well, R32 does exhibit some flammability, which meant that in the early days of HFC blend development, it was used as a component of a refrigerant blend rather than as a pure fluid.
Martyn Cooper, commercial manager at the Federation of Environmental Trade Associations (FETA), explains: “By being part of a blend, its flammability could be suppressed by the other components to ensure the blend was non-flammable. As such, it is a principal component in the R407 family of refrigerants and is 50% of the blend in the main air conditioning refrigerant – R410A.” (R410A is a 50/50 mixture of difluoromethane (R32) and pentafluoroethane (R125)).
AN ALTERNATIVE
With the requirement to move to lower GWP refrigerants under the F-Gas Regulation, R32 was looked at again as a pure fluid. It was clear that an alternative was needed to R410A and it was also clear that any alternative would be flammable (there have been no non-flammable alternatives to R410A).
Hence, many of the air conditioning manufacturers have started to use R32 as an alternative to R410A (although R32 cannot be retrofitted into R410A equipment because of its flammability – albeit low).
FETA’s Cooper again: “Any R32 installation will come under the refrigerant safety standard BS:EN 378:2016. This standard specifies how to calculate the maximum charge size for a system, based on where it is, what it is and who will be near it.
“A2L refrigerant installations also come under the scope of DSEAR – the Dangerous Substances and Explosive Atmosphere Regulations (as indeed do all refrigerant installations). This requires that a formal risk assessment is carried out for each installation.”
The refrigerant classification system – created by the American Society of Heating, Refrigerating and Air-Conditioning Engineers and adopted in the UK – is simple to grasp: refrigerants are defined either as ‘A’ for lower toxicity or ‘B’ for higher toxicity. A1 is non-flammable, A2L is lower flammability, A2 is flammable and A3 is higher flammability. The same categorisation rules apply to the ‘B’ classed refrigerants.
None of the flammable refrigerants (class 2L and above) will ignite if the concentration level in a room stays below their lower flammability limit (LFL). International and European safety legislation and standards such as ISO5149 and EN378 define requirements to remain far below the lower flammable limit in case of accidental leakage.
Paul Collins, technical manager at Panasonic UK, believes that safety concerns surrounding R32 are overblown: “Not only is R32 refrigerant a more efficient and environmentally friendly alternative to R410A, but it is also equally as safe to use.
“There have been concerns surrounding the fact that R32 gas is partly flammable. However, it is extremely difficult to ignite. In the rare case where a fire was to start, R32 burns at a slower speed than walking pace – at 6.7 cm/s, as opposed to propane’s burning velocity of 46 cm/s – reducing the likelihood of any damage.”
Besides, ultimately, we are going to have to become more comfortable with flammable gases in our environment and the result will be the HVAC industry having to upskill, says Tim Mitchell, sales director of air conditioning distributor Klima-Therm.
“On top of this,” he says, “arguably, flammability will drive collaboration in the construction process and will force the installation of HVAC equipment very much to the fore on the critical path. As a result, the days of rushing to finish a job and moving swiftly onto the next one will have to end.”
But, provided care is taken during installation, flammability is not such a big issue, Mitchell believes. He offers this analogy: “Flying is inherently dangerous – hurtling along at hundreds of miles per hour in a metal tube is not a sensible thing for humans to do. Yet, flying is one of the safest modes of transport because the checks and balances during the plane’s manufacture, its maintenance procedures and pre-flight checks make it so.”
TECHNOLOGY
Adoption of best available technology is the solution to meeting our long-term greenhouse gas emissions reductions and maintaining running cost efficiencies for end users, according to James Henley, product development manager at Daikin Applied UK. “The threat of regulatory sanction is always in the background, but our sector will respond better to carrot than stick.”
Daikin Applied has launched a generation of air-cooled scroll chillers using R32 refrigerant. Henley says: “Switching to R32 has allowed us to achieve a 10% improvement in seasonal energy efficiency ratio, compared with the equivalent equipment using R410a.”
More significantly, he adds: “A chiller using R32 has a 63% lower CO2 equivalent charge than a similar capacity R410a counterpart.” This is because R32 requires two-thirds the charge of R410A because it is a better refrigerant – it has a higher cooling capacity.
He continues: “In the event of any leakage of refrigerant gas to the atmosphere, that is a major difference and marks a considerable technical advance in line with the aims of F-Gas regulators, who are seeking to dramatically reduce the global warming potential of the refrigerant gases used by our industry.” It also means an end user can significantly reduce its potential impact on the environment and meet all of its legislative obligations with no loss of performance, he says.
Henley believes that, in the end, it will be the market – not regulators – that drive change: “End users will be on the lookout for the best available cost-effective performance and the lowest potential environmental impact, and R32 is an important part of that strategy.”
BOX: Training on flammable refrigerants
The Air Conditioning and Refrigeration Industry Board (ACRIB) has prepared a specification for training programmes for low GWP refrigerants, including R32. The ACRIB training specification focuses on refrigerants that have a flammable (A3) or low flammable (A2L) classification.
As a result, BESA Training and Logic Certification have developed qualifications (see www.is.gd/efodoh and www.is.gd/uhepap). They advise that there is a network of authorised training providers that offer training and issue certificates for the training in handling of these refrigerants.
Although training and qualifications that focus just on hydrocarbon refrigerants have been on the market for some time, ACRIB developed this new specification to ensure that training could be broadened to include areas such as: the difference between flammability classifications; methods used to calculate maximum safe charge sizes; equipment and component compatibility; and key safety and environmental standards and regulations to take into account when preparing method statements and risk assessments.
Original equipment manufacturers supplying R32 refrigerant-based air conditioning systems also offer training courses in how to use it safely. These include (but are not limited to) the below:
● Daikin UK has successfully trained around 1,000 installers on the use of R32 refrigerant since the launch of its ‘R32 System Installations - Are You Ready?’ course in November 2016. Designed and launched by Daikin UK and delivered at its nationwide training facilities, the course provides installers with the essentials on installing, commissioning and servicing R32 systems, in line with the 2015 F-Gas Regulation and EN378 update (www.is.gd/siboxa).
● Panasonic hosts training days at its HQ in Bracknell, Berkshire and recently released a CPD training course on R32 that allows installers to become more familiar with R32 and understand how to safely install and maintain the refrigerant (www.is.gd/tosuxa).
● Toshiba has joined forces with industry training organisations Business Edge and the Practical Refrigeration Training Centre to roll out its flammable refrigerant training programme (www.is.gd/icuviv).