What condition must backfire flame arrestors meet to be approved?

Backfire flame arrestors are crucial safety devices used on certain types of boats with fuel systems, particularly those that use gasoline. The correct condition for these devices to be approved is that they must comply with specific safety standards. This compliance is essential because it ensures that the arrestors function effectively to prevent flames from escaping the engine compartment into the boat, which can prevent fire hazards and protect the lives of those on board.

Safety standards often refer to testing performed by recognized organizations, such as the American Boat and Yacht Council (ABYC) or other national safety agencies, which set criteria for construction, materials, and performance. Adhering to these standards guarantees that the backfire flame arrestors will reliably perform their intended function under a variety of conditions.

The other options do not reflect necessary criteria for approval. Bright colors do not add to the safety features of a flame arrestor. The cheapest option might save money initially but could compromise safety and effectiveness, which could lead to dangerous situations. While installation is important for functionality, it does not constitute a necessary condition for the device's approval or compliance with safety standards.