10 free OHST practice questions in the real exam format, covering the official content areas, with an explanation for every answer.
OHST Practice Test 1Tutor mode
Question 1 of 10
Hazard Identification and Control
Maintenance will open the inlet flange of heat exchanger E-101 in the process flow diagram shown. Valves V-2 and V-3 have already been closed, locked and tagged. Which additional valve must be closed and locked to keep process liquid from reaching the open flange?
Process flow diagram: feed and recycle to reactor R-101
Arrows show the direction of flow. Dots mark line junctions. Figure not drawn to scale.