I am a fire fighter of 23 years. I have seen fires that have occurred from static discharges. Airless spraying is one I remember in particular. The gun of a fiberglass spray rig was not bonded and when the atmospheric condition got right there was a discharge and ensuing fire.

If you are making a dust collection system for saw dust the best piping is metal. Running a wire inside plastic pipe to make a bond will cause particles to accumulate and hang up dust. Just make sure that the pipe has a common ground with the machinery that it is hooked up to it.

A study has been done recently is the fire trades concern static discharge at gas stations. It seems that most occur when the occupant starts fueling and then on a cold day gets back in the car and then slide back out to shut the nozzle off. The static builds up just like it does when you slide your feet across a carpet as you slide across the seat. Touch the metal part of your car before touching the nozzle to release the static electricity.