This document provides the results of a comprehensive assessment of the state of the art on the use of flammable refrigerants, in particular from class A3. Refrigerants from class B (toxic) are excluded from this scope. This document includes the following elements: • A segmentation of the refrigeration, air conditioning and heat pump market, making use of existing studies and research, including an assessment of safety-related barriers to the uptake of flammable refrigerants in particular from class A3 across all relevant applications; • An assessment of the way risk assessments is used in existing standards for refrigeration, air conditioning and heat pump equipment and in other standards and a review of available risk assessment research to be taken into account including identification of potential needs for additional research; • Analysis of: • the relationship between risk and increased charge; • the acceptability of increased risk compared to the risk presented by other technologies; • the options for additional mitigation methods if the risk increase is unacceptable; • Review of existing standards and work programmes and identification of standards that should be further updated under existing or future standardisation requests based on relevant product safety legislation, in particular with regard to allowable charge sizes of flammable refrigerants, taking into account available technology as well as emerging research and development; • Identification of options for performance based requirements that result from risk assessments to enable the use of all flammable substances; • Identification of options for risk minimisation and for offering flexibility in application of mitigation measures. eptable.