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 ASCE 7-22 Overhang Soffit Pressures

  • ASCE Standards
  • ASCE7-22
Chris Rosencutter's profile image
Chris Rosencutter posted 11-01-2022 08:41 AM
In the new ASCE 7-22 the following graphic is provided to illustrate Overhang pressures.  My question is why does note 3 indicate that pw is based upon the "Positive pressure at Roof Overhang soffit", but then the graphic shows the pressure acting in either the positive or negative direction? It appears that only the positive is used in the overhang calculation (Equation 30.7-1).

Ronald Hamburger's profile image
Ronald Hamburger

I believe you are misinterpretting the figure and note.  Note 3 states that the soffit pressure, ps, is equal to the wall pressure pw, not that the wall pressure is dpeendent on the soffit pressure.  The arrows are shown in two different directions because just as with any location on the building envelope, depending on the wind direction relative to the location of the surface, pressure can either be positive (pushing in ) or negative (sucking out).