Section 01 Alternatives to HCFCs in the Refrigeration and Air Conditioning Sector 26 where all switches (e.g. thermostats and lamp switches) have been removed from the refrigerated compartment. A leak into the room where the unit is placed will disperse and not result in dangerous concentration. Propane (R-290) and Propylene (R-1270) have more appropriate properties to replace R-22. Several hydrocarbon mixtures were also introduced as replacements for CFCs and HCFCs. On several markets hydrocarbons have been used in smaller commercial refrigeration equipment and air-cooled chillers. Safe use of hydrocarbons requires training of those involved in the design, installation and servicing the equipment. Standards and regulations adapted for use in RAC systems are important so as to avoid the exposure of technicians and users to danger due to irresponsible practice. Today there are international product standards that cover small hermetic systems (having a charge of approximately less than 150 grams) that allow them to be installed in most places provided that proper design precautions have been taken. For larger systems the product standards refer to “relevant national and international standards i.e. EN378 and ISO 5149” (gtz-Proklima, 2008). If the charge of hydrocarbons can be kept low versus the air volume in the room (typically 8 grams/m3) the risk of creating flammable mixtures is eliminated. The compatibility of oils in connection with hydrocarbons is sometimes an underestimated question since high levels of miscibility have caused many system failures when hydrocarbons have been introduced without proper redesign. This report will not discuss the retrofit of existing HCFC systems to hydrocarbons as the evaluation of an old unit designed and located without consideration to the refrigerant flammability is in most cases complex and will need to be done in accordance with international as well as national legislation. It can be said that there is obviously much less risk involved in systems with a charge below that which can create an explosive environment in the room or if the whole refrigeration system is placed outside i.e. air cooled chillers. The information on design of hydrocarbon systems presented here will be relevant in considering when hydrocarbons are used, but additional requirements will often apply. Safety related to operation as well as service must always be carefully evaluated before a flammable refrigerant is applied. There are several markets where retrofits are carried out and the information is often available on the internet. See www.Hydrocarbons21.com. I nternational standards have to some extent been adapted to accommodate safety requirements for hydrocarbons but uncertainty on regulations still remain in some applications. There is a significant interest in hydrocarbons on the market since they are good refrigerants, and as a result the number of components and systems is gradually increasing. However due to safety considerations and the small market outside domestic appliances, many components are not approved by the manufacturers. There are concerns over liability and unclear regulations even if the components function. Due to the potential damage a failure can cause the requirements are higher, in many cases, for components for flammable refrigerants than for those that are non flammable. If there is a lack of approvals the challenges for the technicians involved increase as they cannot fully rely on manufacturers’ validation which specifies that the particular component fulfils all relevant pressure and safety standards. For most applications the relevant components are available from some source, but they can be more difficult to find and the cost is sometimes higher. For systems with refrigerant charges above 150 grams and/or a charge over approximately 8 grams/m3 air in the room (charge limitations can vary depending on country and application) the safety requirements increase and it often