In fact it is unique among other testing laboratories in the way that it performs wind uplift testing it uses full scale roof sections measuring 12 feet by 24 feet to obtain an accurate view of.
Fm roof uplift ratings.
Roof projects new fm global reviews roof plans to determine resistance to anticipated wind uplift pressures and fire spread potential.
The following information is needed to conduct a thorough review of new roof installations and re roofing projects.
Fm approvals have classification ratings 1 60 1 90 or 1 120.
These ratings actually apply to wind uplift pressure in pounds per square foot and are not directly related to.
Because fm approvals requires a 2 1 safety factor roofs with field of roof uplift forces of 30 pounds per square foot are the maximum for 1 60 ratings and 37 5 pounds per square foot are the maximum for 1 75 ratings etc.
The misconception is that these numbers correlate to wind speeds of 60 90 or 120 miles per hour.
Because fm approvals requires a 2 1 safety factor roofs with field of roof uplift forces of 30 pounds per square foot are the maximum for 1 60 ratings and 37 5 pounds per square foot are the maximum for 1 75 ratings etc.