Why are uplift psf ratings important in FM standards?

• A. They only affect warranty duration.
• B. Higher psf ratings require more secure attachment for roof systems.
• C. They are unrelated to attachment details.
• D. They are color-related.

Answer: (B)

Uplift psf ratings measure how much wind pressure per square foot a roof assembly can resist without being lifted. In FM standards, these ratings are directly tied to how the roof is attached. When the rating is higher, the attachment must be stronger and more secure—often requiring more fasteners, stronger fasteners, better edge and corner details, and proper seam and attachment methods. This ensures the roof can transfer wind loads safely into the structure at higher wind speeds. It’s not about warranty duration, color, or unrelated factors; it’s about guaranteeing the attachment system meets specified wind-resistance levels.