Forceful winds and wind-borne debris are the cause of most hurricane damage. Hurricane winds start
at 75 mph. At speeds of 140 mph wind can exert a 130 pound per square foot pressure or 900 pounds
of force on a fan and curb. Forceful winds are not the only problem; wind-borne debris can also cause
detrimental effects to objects and structures.
Miami-Dade County has the strictest test protocols in the country for wind-borne debris and wind
loading tests. Greenheck has gone one step further with the model USGF by third-party testing to the
Miami-Dade County Test Protocols.
These protocols were designed to protect against wind-born debris and severe wind loads.
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Structural Performance per Dade County Protocol TAS 202 (ASTM E-330).
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Large Missile Impact Testing per Dade County Protocol TAS 201.
Structural Performance Load:
A static load that is 1.5 times the design load (195 pounds per square
foot pressure) is applied both positive and negative to simulate wind force loads in each direction.
Large Missile Impact Test:
Is required when objects are located 30 feet or less from the ground. The
test unit is impacted three times with a piece of lumber (2 in. x 4 in. x 6 ft) weighing approximately nine
pounds and traveling at 34 mph. This simulates wind-borne debris striking the fan.
Miami-Dade County test protocols:
Greenheck has gone the extra mile and worked with Miami-Dade
County to design a High Velocity Hurricane Zone standard for rooftop fans. The USGF has become the
first rooftop fan certified and approved by the Miami Dade Building Code Compliance office and Texas
Department of Insurance for use in hurricane zones. The certifications can be viewed on the Miami-Dade
County website under NOA #07-0503.06 or the Texas Department of Insurance Windstorm website.
When severe weather is a threat, don’t specify anything less than the Greenheck model USGF and the
SD curb.
Severe Weather
Applications
