What should be remembered when working with hot substances?

When working with hot substances, it is crucial to remember that proper safety measures must be in place to prevent accidents and ensure the safety of all personnel involved. The need for piping with an entry and exit shut-off valve ensures that hot substances can be managed safely. This setup allows workers to control the flow of materials and avoid accidental spills or burns that could arise from mishandling.

Having shut-off valves means that when a task is being performed, the hot substance can be isolated, significantly reducing the risk of exposure to heat. This precaution is essential when maintenance or adjustments are necessary, as it helps create a safer working environment.

Additionally, while other options may touch on practices related to working with hot substances, they either lack the same level of preventative measures or do not address the critical safety precautions needed. For instance, the requirement to release pressure before handling promotes safety but doesn't encapsulate the broader review of managing hot substances as effectively as the presence of shut-off valves.