UL Listed means the valve has been tested by Underwriters Laboratories and meets their safety standards, but the certification process is less comprehensive than FM Approval. UL FM Approved valves have been additionally tested by Factory Mutual Global for performance in fire protection systems, which is a more rigorous standard specifically for fire sprinkler and suppression applications. For most commercial building specifications in the Middle East, UL FM Approved is the preferred certification, though UL Listed alone may be acceptable for certain industrial fire protection applications.