Which types of sprinkler heads can be utilized on dry systems?

Sprinkler heads used on dry systems must be specifically designed to function effectively under conditions where the system is not filled with water. Dry pipe systems operate by holding pressurized air or nitrogen in the pipes until a fire triggers the sprinkler head, allowing the water to flow from the supply through the opened head.

The correct response identifies that upright heads, sidewall heads, and listed dry pendants can all be utilized in dry systems. Upright heads are designed to direct water downward and can be installed on dry systems, particularly in areas where it is acceptable for water to flow immediately upon activation. Sidewall heads, which typically discharge water off the side wall rather than downward, are also suitable in scenarios where the system is not obstructed and water can flow freely during activation. Listed dry pendants are specifically made for dry systems, ensuring functionality without the risk of trapping water in the system before activation.

Mismatched options might limit the user to a single type of sprinkler head, which would not accommodate the necessary flexibility of installation or the conditions required for effective operation. By allowing a variety of head types, the correct answer accommodates different installation needs and ensures that the system will function properly in various environments.