Being mobile auto glass service, I was going to a job to a customers work place, which has a gated entrance. The customer called his boss to let me in when I arrived, in which the gate opened for me. I proceeded to drive thru the gate and instead of making the first left turn with signage, I didn’t see. I drove my 8.5’ van under petroleum pipes. About 5 men ran out in front of me to make me stop. I can tell you that I never felt so stupid in years. No harm done, just a lesson learned.