What is the FM Global drainage philosophy?

• A. Focus on redundancy, reliability, and prevention of ponding.
• B. Maximize drainage speed regardless of redundancy.
• C. Drainage is only secondary to condensation control.
• D. Drainage should mimic natural water flow.

Answer: (A)

FM Global treats roof drainage as a risk-control measure that must work reliably under real conditions. The main objective is to remove water quickly and, just as importantly, to have multiple, dependable paths for that water so a single issue won’t lead to ponding. Redundancy means multiple drains or outlets, so if one path gets blocked, others keep the roof from holding standing water. Reliability means the drainage system and its components are designed, installed, and maintained so they perform over time—considering debris, freezing, and maintenance access. Preventing ponding is prioritized because standing water adds substantial weight, can seep through membranes, and accelerates deterioration, creating larger risk than simply aiming for fast drainage under ideal conditions. This approach is preferred over trying to maximize drainage speed alone, over treating drainage as secondary to condensation control, or over trying to mimic natural water flow, which doesn’t address the engineered, risk-based realities FM Global focuses on.