In May, the International Electrotechnical Commission (IEC) released its draft proposal to raise the maximum charge size for flammable refrigerants in commercial self-contained cases from 150 grams to 500 grams. This marks a significant step forward for the North American Sustainable Refrigeration Council (NASRC), which has been working to change the standards to increase the maximum charge limit for R-290 (propane) use in self-contained equipment.
According to Marek Zgliczynski, chairman of the IEC subcommittee responsible for developing the proposal, this standard -- known as IEC60335-2-89 – “is the basis for all regional and national product standards for household or similar commercial-type applications.” The proposed change will “increase the maximum allowable charge of flammable refrigerants in [commercial self-contained display cases], while maintaining the same safety level of the present standard with 150 grams,” he explained.
The current charge limit of 150 grams is severely limiting the use of propane self-contained systems in the U.S. While 150 grams of propane is adequate for small-to-medium-sized display cases, the larger display cases that are prevalent in this country need more propane for cost-effective operation.
The main concerns about higher propane charge sizes relate to safety, as can be expected with an A3 refrigerant. The specific requirements in the IEC’s proposal ensure that cases with 500 grams of propane are as safe as those with 150 grams. These requirements include the following:
- The refrigerant circuit must be hermetically sealed and mechanically protected;
- Construction cannot cause excessive vibrations of circuit piping;
- Airflow is required to avoid flammable concentration beyond the boundary of appliance, certified with a special leak test; and
- Appliance must be installed in a room with a floor area not less than the marked minimum room area.
The proposal has to pass two stages of voting, the first of which will close mid-July. The IEC is accepting comments from stakeholders at www.iec.ch/comment/ until that time. If the draft proposal receives a two-thirds majority in the first vote, it will move to the second and final stage of voting. If the proposal passes the final stage, a new edition of IEC60335-2-89 will be published in early 2019.
Zgliczynski noted that, “this new standard will allow for systems manufacturers to comply with present and future regulations phasing out high-GWP refrigerants globally in this specific market segment.”
According to the NASRC, the main hurdle preventing the widespread use of propane self-contained systems in the U.S. is the slow pace of ASHRAE and UL in revising their standards. To encourage ASHRAE and UL to speed up their timelines, the NASRC encourages interested parties to sign its petition, located here: http://nasrc.org/petition-for-expedited-revision/.
Publication date: 7/4/2018