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Home » Study on the practical use of flammable and slightly flammable refrigerants

Study on the practical use of flammable and slightly flammable refrigerants

Climate challenges transition to 2050 objectives, regulations like F-gas are driving the RACHP sector to use lower global warming potential refrigerants. However, some low GWP refrigerants lead to other potential risks such as flammability. Refrigerant classification includes several degrees of flammability and the implementation of these refrigerants into refrigeration systems needs to be carefully addressed. Thus, partnering with ADEME, AFCE asked COSTIC to carry out a study attached about the practical use of these flammable refrigerants.

Regulatory requirements, in particular via EU Regulation 517/2014 on greenhouse gases (known as the F-Gas regulation), aim to progressively reduce the quantity of refrigerants that have an impact on the greenhouse effect. Under these conditions, the programmed reduction or prohibition of certain equipment and fluids, and the strengthening of leakage controls, encourages the replacement of these fluids by other “more neutral” fluids to the environment.

However, some fluids with a low environmental impact do present other risks, such as flammability. The classification has been updated to include a new flammability subclass “2L” for flammable fluids that burn very slowly.

To integrate this new category, the NF EN 378 standard on safety and environmental requirements for refrigeration and environmental requirements for refrigeration systems and heat pumps has evolved. This evolution has made it possible to add the new flammability class “2L” and all the implications for design, load calculation and operation.

This study aims at characterising these flammable fluids during the different phases of the life stages of an installation.

This study aims at characterising these flammable fluids during the different phases of the life stages of an installation. Image credut: AFCE/ADEME

This study aims at characterising these flammable fluids during the different phases of the life stages of an installation. Image credut: AFCE/ADEME

Flammable fluids: definition and characteristics

A refrigerant is a substance (or a mixture of substances) that ensures the transfer of energy in a thermodynamic system. According to the ISO 817 standard (2014), a refrigerant is classified based on 2 criteria: its toxicity (A or B) and its flammability (1 to 3).

The flammability of a fluid is defined by its capacity to propagate a flame from an ignition source.

Combustion is an exothermic chemical reaction between an oxidizer (air, oxygen) and a fuel. A body is said to be flammable when it burns with the production of flames.

The three criteria: lower flammability limit, heat of combustion and burning rate, characterise the different classes of flammable fluids.

The regulatory and normative context

The regulatory and para-regulatory texts that are applicable to flammable fluids can be different and complementary depending on the type of building or the flammability class of the fluid. The next table summarises some essential texts according to the field of application and the type of building.

These texts deal particularly with the specificities of design (calculation of fluid load, safety measures), installation and operation. Depending on the fluids, other texts or standards are also to be considered, such as:

  • The F-Gas regulation (European regulation N°517/2014 of April 16, 2014): tightness control for certain fluids (pure HFC or in mixture);
  • The ATEX directives (directive 1999/92/EC of 16 December 1999 and directive 2014/34/EC of 26 February 2014) and the NF EN 60079-10-1 standard: characteristics of equipment according to the zone, determination of the extent of the leakage zone, protective devices for workers, equipment and protective systems intended for use in explosive atmospheres.
  • The PED Directive (Directive 2014/68/EU of 15 May 2014), the Order of 20 November 2017, the Professional Technical Specification for the in-service monitoring of pressurised refrigeration systems of 23 July 2020: group of fluids and associated requirements, in-service monitoring.

The F-Gas regulation

The European Regulation N°517/2014 of April 16, 2014 on fluorinated greenhouse gases defines 3 main actions:

  • The prevention of fluid leaks with, in particular, a reinforcement of leakage controls
  • The timetable for reducing the amount of greenhouse gases
  • Progressive bans on marketing

The fluids concerned by these requirements are hydrofluorocarbons. By definition, hydrofluorocarbons are HFC fluids and mixtures containing one of the following substances. The fluids concerned by these requirements are A2L fluids.

This is an extract from the report that can be downloaded here (French and English). Registration is required to access the report.