In my petroleum refinery, two new diesel hydrotreating units are licensed to Haldor Topsoe. These two units are in the pre-commissioning phase of the project life cycle. My question is about hydrogen quench control valve failure status. In all of these valves, the characteristic of failure to close was considered. Based on my experience, the hydrogen quench valve failure status is failure to open. Would you please let me know the reason for this scenario for hydrogen quench valves?