Hot Tapping is when you join a connection to a pipe while it is still in operation and then either drill or cut and opening in that pipe. Hot tapping is usually conducted on pipes however can be completed on storage tanks and pressure vessels. By adding the hot tap it allows a connection without depressurising or disrupting the service.
Although hot taps are common, they can be hazardous, therefore should only be carried out when it is impractical to stop the system from operating. Due to their dangerous nature, hot taps need to be inspected in their design and tested to ensure that safety is primary.