The textbook Propane, Naturally Safe, published last year in Norwegian and German, is now available in an English-language edition.
Authored by refrigeration experts Stig Rath and Harald Erös, the book is described as a best-practice guide for heat pumps and refrigeration systems using propane (R290) and other A3 (flammable) refrigerants in commercial, industrial and residential buildings. Rath and Erös also collaborated on the German edition, while Rath wrote the Norwegian version.
To read an excerpt from the book and to order the English, German or Norwegian editions, click here. The price of the book is €68 (US$80.35) plus shipping. A digital version is not yet available.
“The book is written for key target groups like operators, consultants, manufacturers, installation contractors and refrigeration technicians, all under the motto: ‘Plan safely. Install safely. Operate safely,’” said Erös, Chair of the Austrian Standards Committee for Refrigeration Systems and Heat Pumps and founding member and Chairman of the Austrian Association of Refrigeration.
Propane, Naturally Safe “is the first publication to offer a complete overview of legislation, standards and best practices for the use of hydrocarbons in refrigeration, air conditioning, and heat pump systems,” said Rath, Chair of Standard Norge (Standards Norway) Committee 033 for Heating and Cooling Systems in Buildings, in a LinkedIn post. “By following the guidance in this book, you can be confident that your installation meets all current requirements and is safe to use.”
System types covered include:
- Heat pumps and refrigeration systems in ventilated enclosures
- Systems in separate machinery rooms
- Air-to-water heat pumps and air-cooled chillers
- Air-to-air heat pumps and split air conditioners
- Brine-to-water heat pump
- Exhaust air heat pumps
The book offers practical safety knowledge, including risk analysis and explosion protection documents as well as typical protective measures in everyday service. It also covers design criteria for system layout and sizing, as well as assembly, installation, maintenance, inspection, repair and leak detection. The English and German editions offer Information on EU regulations, standards and directives but not national regulations.
Propane, Naturally Safe addresses the following questions:
- Is there a difference between heat pumps for commercial use and those for residential use?
- Are small charge quantities exempt from risk assessment?
- Is it unnecessary to prepare an explosion protection document for heat pumps?
- Does a hermetically sealed refrigerant circuit mean that no Ex-certified (explosion-proof) equipment is required?
- Does ventilation mean that Ex-certified equipment is not required?
- Why is it problematic to use semi-hermetic compressors without Ex certification – even if they are “tight”?
- Are “possible” and “potential” ignition sources exactly the same?
- Is there any legal requirement for ventilation of cargo compartments in service vehicles?
Another textbook on natural refrigerants, covering hydrocarbons, CO2 (R744) and ammonia (R717), is Natural Refrigerants: Applications and Practical Guidelines, available here. This book presents the experiences and techniques of industrial refrigeration and transfers them to commercial refrigeration applications. It covers the general conditions and legal requirements for the use of natural refrigerants as well as the economic efficiency of the refrigeration systems.
Widespread use of propane
In addition to being used globally in most commercial display cabinets, in Europe propane is increasingly employed in commercial and industrial chillers as well as in residential heat pumps and some home and auto air-conditioning systems.
The latest version (the seventh edition) of the global IEC 60335-2-40 HVAC standard, approved in 2022 and used as a model by individual regions and countries, allows up to 988g (2.2lbs) of R290 in HVAC units located indoors or connected to the indoor space, such as ductless split ACs or ducted central systems; these are subject to room-size limits and other equipment-design requirements. It also allows 4.94kg (10.8lbs) of R290 in outdoor/indirect systems such as air-to-water monobloc heat pumps, among other limits.
However, in the U.S., the use of propane in HVAC is limited by UL’s most recent (fourth) edition of the 60335-2-40 standard, which restricts the use of R290 to 114g (0.25lbs) for all HVAC residential and light-commercial applications. The ASHRAE-15 standard also significantly restricts A3 refrigerant use in residential and commercial applications to less than 150g (0.33lbs) with any larger amount requiring approval by a local jurisdiction’s code officials.
“By following the guidance in this book, you can be confident that your installation meets all current requirements and is safe to use.”
Stig Rath, Chair of Standard Norge (Standards Norway) Committee 033 for Heating and Cooling Systems in Buildings
Last October, UL held the first meeting of a new Technical Harmonization Committee (THC) to develop the fifth edition of UL 60335-2-40. It formed a working group on A3 and A2 (mildly flammable) refrigerants to consider proposals to enable safe use of R290 and other near-zero emissions next-generation refrigerants. ASHRAE has also started an effort to increase the allowable charge of propane in heat pumps to 4.9kg in outdoor/indirect residential heat pumps and air conditioners.
Twenty-three American states have passed legislation that would enable this use of hydrocarbons (in addition to A2Ls), once UL 60335-2-40 and ASHRAE-15 are updated and the U.S. Environmental Protection Agency (EPA) SNAP (Significant New Alternatives Program) has approved.
Last October the EPA announced a Proposed Rule 27 that would establish or update the conditions under which certain refrigerants, including hydrocarbons, would be allowed for new residential and light-commercial air-conditioning and heat pumps and other applications under SNAP.
The Environmental Investigation Agency (EIA) US said in a report last October that it supports full harmonization of U.S. standards on the use of A3 hydrocarbon refrigerants in HVAC equipment with the global standard IEC 60335-2-40. This could enable 78–88% of new air-conditioning and heat-pump equipment in the U.S. to transition to propane (R290) between 2030 and 2035, according to the EIA.
