Which sign requires a quarterly inspection to ensure it is securely attached to the sprinkler riser?

The correct answer is the hydraulic design information sign, which requires a quarterly inspection to ensure it is securely attached to the sprinkler riser. This sign provides crucial data such as the water supply, system demand, and pressure requirements necessary for the hydraulic calculations that determine the effectiveness of the fire suppression system. Ensuring that this sign is secure on the riser is essential because any discrepancies or loss of this information could hinder proper system function in the event of a fire.

The requirement for a quarterly inspection highlights the importance of maintaining an accessible and secure location for this important information. Regular checks help to ensure that the sign remains affixed and that any changes to the system or its components are documented based on the parameters outlined in the hydraulic design sign.

In contrast, flow switch information signs, temperature monitoring signs, and draining instructions signs serve different purposes and may not have the same frequency of inspection mandated by NFPA 25 for secure attachment to the riser. Therefore, understanding the significance of the hydraulic design information sign and its role in the overall fire protection system provides clarity on the inspection requirements.