Which type of machines are permitted in Class III locations under specific conditions?

In Class III hazardous locations, which are associated with the presence of easily ignitable fibers and flyings, the use of standard open-type machines is permitted under specific conditions. These machines are designed to limit the potential for sparks, which is a key safety consideration in environments where combustible materials are present.

Open-type machines, when properly rated and installed, can be designed to minimize the risk of ignition from electrical components, which is critical in environments that may have combustible dust or fibers. There are usually additional requirements for these machines, such as proper housing to contain any potential ignition sources, maintaining cleanliness to prevent dust accumulation, and ensuring appropriate maintenance practices are followed.

In contrast, other types of equipment or machines may not meet the necessary safety standards for Class III locations. Heavy-duty hydraulic machines or portable generators could present risks due to their operational characteristics and potential for generating sparks or heat, while thermal imaging cameras may use components that are not suitable for environments with combustible materials unless specifically rated for hazardous locations.