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ASCE 7 wind load fundamentals · Lesson 2 of 4

ASCE 7 wind load fundamentals: materials, standards and design constraints

Which ASCE 7 edition sits behind which code, what changed in ASCE 7-22, Kz and the roof zone coefficients, strength level versus allowable stress, the ES-1 test methods, and where published sources disagree.

You will be able to: Match ASCE 7 editions to building codes, read the zone coefficients and enclosure and unit conventions, and place ES-1 test methods and the safety-factor disagreement.

12 min · 11 slides · 10 questions

All lessons in this module
Slide 1 of 11

Which ASCE 7 sits behind which code

IBC 2018 sizes wind loads under its Chapter 16 using ASCE 7-16's ultimate design method.

The 2021 IBC uses the 2016 edition of ASCE 7 for component and cladding wind pressure zones.

The 2024 IBC incorporates ASCE 7-22.

The jurisdiction decides which code edition is in force, so confirm the adopted edition before using any number.

Which ASCE 7 sits behind which codeIBC 2018 and IBC 2021 point to ASCE 7-16, which added Ke, lowered Exposure B Kz below 30 ft and uses ultimate wind speeds. IBC 2024 points to ASCE 7-22, which moves Kd into the pressure equation, has new Kz constants, revised components and cladding graphs and a tornado chapter. An amber band says the jurisdiction's adopted code decides the edition.Which ASCE 7 sits behind which codeIBC 2018IBC 2021IBC 2024ASCE 7-16Ke addedExposure B: lower Kzbelow 30 ftUltimate wind speedsASCE 7-22Kd moves to thepressure equationNew Kz constantsRevised C&C graphsTornado chapterYour jurisdiction's adopted codedecides the edition: confirm it.

IBC 2018 and IBC 2021 point to ASCE 7-16, which added Ke, lowered Exposure B Kz below 30 ft and uses ultimate wind speeds. IBC 2024 points to ASCE 7-22, which moves Kd into the pressure equation, has new Kz constants, revised components and cladding graphs and a tornado chapter. An amber band says the jurisdiction decides the edition.

The code edition sets the ASCE 7 edition, per the sources named on the slide. Which code edition is in force is the jurisdiction's decision.

Sources

Glossary

Ultimate (strength-level) wind speed
The wind speed on the ASCE 7-10 and 7-16 maps, which produces strength-level pressures. Earlier editions mapped allowable-stress speeds instead.
Allowable-stress design (ASD)
A design method that works with lower, service-level loads. For cladding pressures from ASCE 7-16, the ultimate result is multiplied by 0.6.
GCp (external pressure coefficient)
A coefficient that turns velocity pressure into the pressure on a roof or wall zone. Negative values mean suction, and edge zones have the largest values.
GCpi (internal pressure coefficient)
A coefficient for pressure inside the building: 0.18 if enclosed and 0.55 if partially enclosed. Suction outside adds to pressure inside.
RE-2 and RE-3
ES-1 laboratory test methods for edge metal. RE-2 loads the face of fascias and gravel stops outward. RE-3 tests copings with separate front and back face pulls. Which method a product was tested to depends on its geometry and is named in its test report.