In what situation can the 30-minute rule for air pressure restoration be waived?

The 30-minute rule for air pressure restoration may be waived in refrigerated spaces below 5° Fahrenheit. This exception is due to the unique operational challenges faced in such low-temperature environments. When working within these conditions, the integrity of the refrigeration system can be jeopardized if air pressure restoration takes longer than the specified timeframe. The ability to maintain efficient cooling and control humidity becomes critical, so if air pressure restoration requires more time, the urgency to safeguard the equipment and the product being stored justifies the waiver of this rule.

In other contexts, such as earthquake-prone areas, high temperatures, or systems equipped with backup compressors, the standard practice of air pressure restoration typically remains in effect to ensure safety and operational consistency. While these scenarios may pose their own concerns, they do not inherently affect the integrity of the refrigeration system in the same way. Therefore, the specific condition of extremely low temperatures specifically justifies the need to waive the 30-minute rule.