How many heads are required before a Fire Department Connection (FDC) is necessary?

The requirement for a Fire Department Connection (FDC) is based on the capacity of the sprinkler system and the number of sprinkler heads installed. The correct answer, which indicates that 20 heads are necessary before an FDC is required, reflects standard practices and codes that dictate the need for additional water supply beyond what the system can provide on its own.

An FDC is designed to allow firefighters to connect their hoses to the building's sprinkler system, providing the additional water needed when the system alone may not be sufficient to fight a fire effectively. This ensures that the system can maintain adequate pressure and flow for suppression efforts.

Thus, when a sprinkler system is designed with 20 or more heads, it typically indicates that the potential fire load is significant enough that an FDC is warranted to facilitate effective firefighting measures by the fire department. This requirement is aligned with the recommendations from fire codes and standards, ensuring the safety and effectiveness of the overall fire protection strategy.