Being a non-technically-minded sort of guy, I'm failing to grasp the issues here. I recall, as a child, rubbing a balloon against my hair to induce static. My hair stood on end and the balloon would stick to the wall, so clearly, static can build up on plastic surfaces (the balloon, that is, not my hair) and therefore can be present in/on the extraction pipes. Are we saying that this presence of static does not pose a hazard, whereas static on electrically conductive materials does pose a hazard?
Help me out, please, somebody!
Les