Which type of harness is not suitable for rescue operations where devices may apply significant force?

A Class 1 harness is designed primarily for work positioning and is not intended for rescue operations where significant force may be applied. This type of harness does not provide adequate support for survivors or rescuers during falls or dynamic loads, making it unsuitable for environments where a high level of safety and strength is necessary.

In contrast, Class 2 and Class 3 harnesses are designed for more demanding applications, including rescue scenarios. Class 2 harnesses typically offer additional support and safety features needed for industrial environments, while Class 3 harnesses provide full-body support, allowing for effective distribution of forces in the event of a fall or when performing rescue operations. Given these specifications, the lack of adequate force management in a Class 1 harness makes it inappropriate for rescue situations.