迄今为止，R-290 的 150 克装料限制阻碍了其更广泛的应用，将其使用范围缩小到独立的冷藏箱或需要使用多个冷凝装置以实现更高的容量。更新后的 UL 标准提高了这些商用独立显示器的充电限制，具体取决于它们是开放式还是封闭式设计：
- 开放式电器（无门）的最大充电限制为 500 克。
- 封闭式电器（带门或抽屉）的最大充电限制为 300 克。
对 UL 60335-2-89 标准的批准更新是 R-290 在商业制冷领域更广泛采用的关键第一步。尽管原始设备制造商应该开始规划他们的设计周期以实现这些充电增加，但在更高充电的 R-290 系统可以在美国和加拿大实施之前，还需要获得其他监管部门的批准。其他理事机构的待批准包括：
- 环境保护署 (EPA) 的重要新替代品政策 (SNAP) 计划；
- 美国采暖、制冷和空调工程师协会 (ASHRAE) 15 制冷系统安全标准；
对于许多美国业内人士来说，R-290 充注限制的增加代表了这种天然制冷剂发展的合乎逻辑的下一步。甚至在 UL 批准之前，一些具有可持续发展意识的运营商已经与当地的建筑规范管理员合作，实施 R-290 收费较高的系统。此外，自 2019 年以来，欧洲已经实施了 500 克 R-290 充注限制，当时国际电工委员会 (IEC) 根据其 IEC 60335-2-89 标准批准了独立式商业展示柜的增加。
For many years, the use of flammable refrigerants — such as the A3 hydrocarbon R-290 (or propane) — has been a keen area of collective focus among the regulatory bodies governing refrigerant safety standards in commercial refrigeration. Offering excellent energy efficiencies and very low- GWP, this natural refrigerant has long been approved for use in applications with a maximum charge limit of 150 grams. Recently, the Underwriters Laboratory (UL) has approved the second edition of its UL 60335-2-89 standard, which includes higher R-290 charge limits that would expand its potential uses in commercial refrigeration.
To date, R-290’s 150-gram charge limit has hindered its wider adoption, narrowing its use to self-contained refrigeration cases or requiring the use of multiple condensing units to achieve higher capacities. The updated UL standard raises the charge limits on these commercial stand-alone displays based on whether they have an open or closed design:
- 500-gram maximum charge limit in open appliances (without doors).
- 300-gram maximum charge limit in closed appliances (with doors or drawers).
The 500-gram charge in open appliances raises the limit to 13 times the lower flammability limit (LFL) of R-290, while the 300-gram charge limit in closed appliances is eight times that of R-290’s LFL.
From an application design perspective, these higher charge limits will help OEMs to increase system capacities while capitalizing on R-290’s high efficiency and low-GWP rating (GWP=3). For contractors, consultants, and end users seeking to meet sustainability objectives or comply with refrigerant regulations, self-contained R-290 cases have become integral to their overall refrigeration strategies.
The approved update to the UL 60335-2-89 standard is a key first step in the path toward wider R-290 adoption in commercial refrigeration. Although OEMs should begin planning their design cycles to enable these charge increases, other regulatory approvals will need to take place before higher-charge R-290 systems can be implemented throughout the U.S. and Canada. Pending approvals by other governing bodies include:
- Environmental Protection Agency’s (EPA) Significant New Alternatives Policy (SNAP) program;
- American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) 15 safety standard for refrigeration systems;
- Model Code updates in the upcoming code revision cycle; and
- State and local building code updates.
For many U.S. industry insiders, the R-290 charge limit increase represents a logical next step in the progression of this natural refrigerant. Even prior to the UL approval, some sustainably minded operators have worked with their local building code administrators to implement systems with higher charges of R-290. In addition, a 500-gram R-290 charge limit has been in place in Europe since 2019, when the International Electrotechnical Commission (IEC) approved the increase under its IEC 60335-2-89 standard for self-contained commercial display cases.
After years of speculation, the commercial refrigeration industry in the U.S. can begin planning for the use of systems with larger charges of R-290 — enabling higher-capacity refrigeration while benefiting from R-290’s proven efficiencies and lower-GWP rating. Emerson is prepared to support this transition by developing R-290 qualified compressors that will help OEMs and stakeholders to achieve regulatory compliance, fulfill their sustainability objectives, and reduce energy consumption.