Since a danger is related to the intrinsic properties of an agent like a chemical substance, it is usually not possible to act on the danger without changing the substance. In many cases however this “dangerous” property contributes to its reactivity and thus to what makes it interesting. On the other hand, it is most often possible to act on a risk since the risk is related to the level of exposure which can be managed by reducing the probability of such exposure. This can be achieved by reducing the level or the frequency of common or accidental emissions or, in some circumstances, by using protecting means as for example in various occupational settings.
Managing the health and/or the environmental safety is thus more a matter of managing quantitatively and globally a risk rather than focusing on the intrinsic properties of chemicals. It is not always easy for scientists from regulating bodies or industry to convince about this because often the public perception or understanding of a dangerous property is often simpler and greater than that the perception of a real level of risk.
For example, in case of an accident or technical incident, it is more “dangerous” to be in an airplane high in the sky rather than sitting in car but, although everybody knows that quantitatively the probability or the risk of car accidents is much higher, most people remains more impressed by the danger that represent airplane accidents.
A chemical with a very dangerous intrinsic property may also contribute negligibly to a risk when its contribution is compared to the global risk of this kind produced by other sources. For example, the contribution of atmospheric emissions of HF, a very “strong” acid to acid rain is relatively negligible when compared with the contributions of other and less strong acids like nitric and sulphuric acids.
In some circumstances, it may even happen that the use of a chemical with a more dangerous property can even decrease a health or environmental risk if its use contribute to quantitatively reduce significantly the global sources of the same risk.
The greenhouse effect varies with the emissions of greenhouse gases but within a range, the system will reach a certain level of dynamic equilibrium. Quantitative variations in the greenhouse effect can have different origins including changes of the solar activity or in the equilibrium of greenhouse gases between their ocean and atmospheric concentrations, … Meanwhile, it is clear that the rapid release in the atmosphere since the last century of huge amounts of CO2 previously “stored” of “fossil fuel” (wood, coal, oil, …) as a result of all combustion processes combined to the emission of huge amounts of methane due to agricultural practices (ruminants, rice production, …) can potentially contribute to impact the present greenhouse equilibrium. Similarly, the emissions of industrial chemicals like fluorocarbons which have a greenhouse potential would contribute to these changes.
The challenge is thus to determine the relative risk and thus the quantitative contribution of each potential source to the greenhouse effect increase and identify the most efficient means to manage efficiently the significant reduction of this global risk but without creating other risks.
When signing the Kyoto Protocol in 1997, signatory countries governments agreed to put in place measures aimed at stabilising emissions of all main greenhouse gases at 1990 levels by the years 2008-2012. Together with NOx, CO2 and methane emitted from all forms of combustion and/or biodegradation processes account for more than 90% of this impact . Six other gases produced industrially and of important socio-economical added value were included in the protocol because of their intrinsic global warming potential and despite their actual limited net contribution to the burden of greenhouse gases.
Stabilising the global emissions means neither a phase-out nor even a phase-down of specific compounds. Indeed, governments have recognized that HFCs are important alternatives to replace CFCs and HCFCs, and acknowledged that HFCs production will continue to increase, as long as there will be CFCs to be replaced. The general objective being to avoid an increase of the global warming effect , the energy (and thus CO2 emissions) saved through the efficiency of some products can be traded against any direct contribution.
In the Kyoto Protocol context , HFCs are being treated as one of a ‘basket’ of greenhouse gases for these trades.
In 1986, the Montreal Protocol regulated substances that deplete the ozone layer and this landmark environmental agreement between politicians, regulators, scientists, NGOs and industry that resulted in the phase-out of chlorofluorocarbons (CFCs) and other ozone depleting products which included some chlorinated solvents. Further amendements of the Protocol include now the phase-out at median term of the intermediate generation of CFC substitutes, the H-CFCs (hydrochlorofluorocarbons) whose ozone-depletion potential are already at least 90% less than those of CFCs
To help consumers around the world to play their part by changing purchasing decisions in key sectors for their health and welfare, industry had to find technical solutions to this serious problem – what alternative to propose i.e. to the refrigeration and air conditioning industry to replace the widespread use of chemicals which had so many beneficial chemical properties. Indeed, the refrigeration and air conditioning industry, which used CFCs as refrigerants, was just one of the industries which faced this problem.
The HFCs (hydrofluorocarbons) are a family of hydrocarbons containing one or several fluorine atoms. The main difference with the CFCs is that these molecules contain no chlorine atoms and thus have no ozone-depleting potential. Members of this family of compounds have the appropriate thermodynamic properties to be used as technically and economically effective refrigerants fluids alternative to CFCs and H-CFCs. They are also particularly energy efficient in these applications.
They were developed to this end by the fluorochemical producers and brought to the market in unprecedent time. Despite the tight deadlines imposed by the new regulations these products are now amongst the chemicals THE MOST RIGOROUSLY TESTED FOR THEIR HEALTH, SAFETY AND ENVIRONMENTAL IMPACT .
The HFC (hydrofluorocarbons) became among the most rigorously tested industrial chemicals ever for their health, safety and environmental properties. These extensive studies showed that these products have no intrinsic potential to impact the ozone layer and offer the same beneficial characteristics as CFCs – they are non-flammable, they do not contribute to photochemical smog (lower atmosphere ozone pollution).
With regards to their toxicological evaluation, international programmes tested thoroughly the various HFCs and demonstrated in general their high safety, their low level of toxicity ande of environmental impact.
For some of the reasons explained relative to risk management and perception, there is sometimes some confusion in the debate over global warming and the use of HFCs as substitutes of CFCs and H-CFCs. Misinformation in this area has forced to argue over the relative merits or pitfalls of particular aspects or intrinsic properties of each refrigerant rather than looking at its performance as a whole.
This does not help to accelerate the process of CFC phase-out and there is still a high level of CFC use in Europe. It is vital that the facts are objectively and responsibly communicated to ensure that informed decisions are made, allowing to maximise safety, health and environmental performance whilst meeting some essential society’s needs such as the cold chain involved in food preservation and the eco-efficient insulation of buildings.
HFCs have been demonstrated to offer a broad range of combined benefits, probably more than any other alternative : HFCs are non-flammable, of very low toxicity, do not contribute to photochemical smog and are highly energy efficient thus minimising the greenhouse emissions due to the energy consumption during the life time of the appliance.
HFCs will contribute no more than 1-2% to manmade global warming by the middle of the next century, and that is if we assume a worst case in which not only that industry stands still and uses the same refrigerants for the next 60 years, but also that emissions remain at their historically high levels.
The fact is that, as HCFCs where in a transitional phase, HFCs are now a vital and safe solution to the challenging environmental issue that ever hit mankind : the ozone layer preservation and its recovery. without HFCs, we would not be able to phase out CFCs as quickly while maintaining the vital role refrigeration and air conditioning play in our society. .
All these facts on HFCs show that they are part of the solution, not of the problem.
Because HFCs offer similar technical and beneficial characteristics, particularly a low level of chemical reactivity they can usually replace CFCs in existing equipment, with only minimal modifications. Users of hydrocarbons and ammonia, on the other hand, have to take into account flammability and toxicity . Major modifications or even relocation, involving significant capital expenditure and appropriate training of reliable staff, may therefore be required before existing equipment can be used safely.
International Governmental Conferences and Meetings around the world have acknowledged the products of the HFCs family as important replacements for CFCs and the HCFCs in their most important applications including refrigeration, air conditioning and insulation foam blowing agents. Even if some countries expressed their intention to phase them out on the sole basis of their intrinsic global warming potential, there is no national or international regulation in place yet.
In brief, when evaluated on the appropriate criteria, the HFCs show a clean bill of health from Cradle to grave.
it does not represent a risk for the safety of the user (i.e; maintenance personal) or the public.
it contribute to the best possible “eco-efficiency” of the appliance in which it is used (ex : a cooling machine) in order to minimize its environmental impact, i.e. on the greenhouse effect and climate change essentially due to the energy consumption and associated C02 emissions of the appliance throughout its lifetime.
It should be technically sound to deliver reliable and cost-effective service.
Practically, there is no such thing as a perfect refrigerant. All candidates, although technically efficient with regards to energy efficiency for example have undesirable intrinsic properties with regards to health, safety and the environment :
Originally dangerous refrigerants like Hydrocarbons or Ammonia were the only available refrigerants.
To resolve these issues, CFCs and later on HFCs were developed, since they were particularly safe and energy efficient, in refrigeration and in insulation performance.
Coming back to dangerous refrigeration systems would be meaningful only if this would bring a significant benefit to the environment
The safety of consumer, public and maintenance operators is a priority, particularly when this is not detrimental to the environment.
Given the lack of benefit from the use in refrigerators of hydrocarbons for the global warming impact point of view, why significantly increase the risk by introducing millions hydrocarbons sources instead of suppressing this risk simply from the liability point of view ?
Despite comprehensive safety measures bound to its toxic risk, hydrocarbons releases are not uncommon and human injuries and also fatalities are regularly reported .- already with common lighters- in each country all over the world. Such releases also regularly leads to evacuation and even sometimes to panic.
The problem is that there is a lack of standards governing the safety of use of flammable refrigerants. In some countries like France they are simply forbidden in public areas
Of course leakages can happen with HFCs, but since HFCs are safe even at very high concentrations, the health risk is very low.
The reduction of the potential impact of HFCs on the greenhouse effect is based on the minimisation of leaks and on the recovery of used HFC material.
In refrigeration applications for example, leakage rates for new HFC systems, which are now generally of a much higher /design standard than CFC systems, are significantly much lower than was the case with CFCs. With technological progress these rates are continuing to improve. HFC systems are now matching the low leakage rates which are mandatory – for safety reasons – for alternative hydrocarbon and ammonia systems. This makes both environmental and economic sense.
Despite comprehensive safety measures bound to its toxic risk, ammonia releases are not uncommon and human injuries and also fatalities are regularly reported in each country all over the world. Such releases also regularly leads to evacuation and even sometimes panics.
As the use of hydrocarbons in low capacity refrigeration is very recent, few hydrocarbon accidents have been reported up to now, but it must be reminded that both fire and explosion should be expected , and that some recent cases have recently attracted a broad attention of the informed/ interested experts.
Of course leakages can happen with HFCs, but since HFCs are safe even at very high concentrations, the health risk is very low. Cases where human consequences were observed are exceptional and were not due to to toxicity but simply to an asphyxia in confined spaces where the leaked HFC replaced the oxygen . The real consequence associated with a local HFCs leak is therefore the accidental release of a gas whose quantitative contribution as such to the greenhouse effectis completely insignificant.
It can also be underlined the residence time of HFCs in the atmosphere is much shorter than the residence time of CO2 (above 500 years !) and thus that the impact of an accidental release is furthermore relatively limited in time.
If modern systems are /designed and maintained to keep leakage to the minimal levels demanded by regulation for the proper containment of potentially hazardous refrigerants such as hydrocarbons and ammonia, then these same systems contain HFCs so that they cannot leak and contribute in any way to global warming. Containment of non toxic, non flammable and more energy efficient (thus less CO2 producers over the lifetime of the material) – Responsible Refrigeration – is the challenge and the real answer.
To further reduce the specific risks of these different refrigerants, additional investments are and will be required, to comply with health and safety regulations or with environmental commitments. In terms of good use of money, it will be in most cases by far cheaper to reduce the global climate impact of refrigeration units by decreasing significantly their HFC emissions and by improving their energy efficiency than to implement and monitor continuously the necessary safety measures needed to keep at its minimum the risk of toxic or explosive refrigerants.
It must also be noted that potential liabilities issues progressively introduced in the EU legislation will strongly favour the use of safe HFCs versus hydrocarbons and ammonia.
The HFC Market is growing steadily. In many applications, HFCs offer the optimum solution, combining safety in usewith excellent technical performance. In systems /designed for low leakage rates and high energy efficiency they are often also the most environmentally acceptable solution. As a result, they are now the refrigerant of choice for many in the refrigeration and air conditioning industry. Furthermore, because of their inherent safety characteristics, they are also being used by the pharmaceutical industry as propellants in medical aerosols such as asthma inhalers.
It was always known there would be no technical panacea for the CFC substitution that a number of different solutions would be required and the market would therefore fragment. This has happened in Europe in the domestic refrigeration market, for example, where hydrocarbons are being used as well as, or in place of, HFCs. The reverse is true in the USA where hydrocarbons are not used in domestic systems because of flammability concerns.
For every application, it is important that the user makes an accurate and global assessment of the safety, health and environmental requirements and balances these against cost and technical performance, using this equation to assess all of the options. It is only in this way that an informed decision can be made about the most appropriate system to use.
The way forward is “Responsible Refrigeration”. The perfect zero impact refrigerant has not yet been developed and, since everything man does – including breathing – has an impact on the environment, it is unlikely it ever will.
Responsible Refrigeration – improving safety and health, and minimising the environmental impact of a refrigeration system through good system /design, through maintenance and service of equipment, through training of /designers and engineers and through recovery and recycling – is now industry’s focus.
So propane is only explosive if it is emitted, ammonia is only toxic if it is emitted and HFCs are only greenhouse gases if they are released into the atmosphere.
Provided people are given facts rather than emotion, they can make informed, responsible decisions about future safety, health and environmental impact. As governments around the world acknowledge, facts demonstrate that HFCs and the many associated industrial sectors have a vital role to play in this future particularly for such essential aspects as food preservation and air conditioning in the many places where extreme climate conditions make normal life and feeding very difficult.