15A-3-107. Amendments to Chapter 16 of IBC.

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A research copy — for the controlling text, always check the official state or federal source. Not legal advice.

Effective 3/17/2026

(1)In IBC, Section 1605.1, Exception 2 is deleted and replaced with the following:

"2. Where the allowable stress design load combinations of ASCE 7 Section 2.4 are used, flat roof snow loads of 45 pounds per square foot (2.15kN/m2) or less and roof live loads of 45 pounds per square foot (2.15kN/m2) or less need not be combined with seismic loads. Where flat roof snow loads exceed 45 pounds per square foot (2.15kN/m2), the snow loads shall be in accordance with the following in load combinations including both snow and seismic loads. S as calculated below, shall be combined with seismic loads.

S = (0.15 + 0.016 (A-5))Proof, where S shall be greater than or equal to 0.15 Proof.

Where:

S = Weight of snow to be used in combination with seismic loads

A = Elevation above sea level at the location of the structure (ft/1,000)

Proof = Design roof snow loads, Pf or Ps, psf

For the purpose of this section, snow load shall be assumed uniform on the horizontal projection without including the effects of drift or sliding. The Risk Category factor used in calculating Pf may be considered Risk Category II."

(2)In IBC, Section 1605.1 a new Exception 5 is added as follows:

"5. ASCE 7-22 Section 2.3.6 Equation 6 shall be modified to 1.2D + Ev + Eh + L +f2S and 1.2D + Ev + Emh + L +f2S with f2 = (0.15 + 0.016 (A-5)) where the roof snow load exceeds 45 pounds per square foot (2.15kN/m2). Where A = Elevation above sea level at the location of the structure (ft/1000). f2 = 0 for roof snow loads of 45 pounds per square foot (2.15kN/m2) or less."

(3)A new IBC, Section 1608.1.1, is added as follows:

"1608.1.1. Drifts on adjacent structures. Section 7.7.2 of ASCE 7 referenced in IBC, Section 1608.1, is deleted and replaced with the following:

7.7.2 Adjacent structures. At lower adjacent structures, the requirements of Section 7.7.1 shall be used to calculate windward and leeward drifts. The resulting drift is permitted to be truncated."

(4)A new IBC, Section 1613.1.1, is added as follows:

"1613.1.1 Effective Seismic Weight. In ASCE 7 12.7.2 and 12.14.8.1 as referenced in Section 1613.1, Definition of W, Item 4 is deleted and replaced with the following:

4. Where flat roof snow load, Pf, exceeds 45 pounds per square foot (2.15kN/m2), the snow load included in the effective seismic weight shall be calculated, in accordance with the following equation: Ws=(0.15 + 0.016(A-5))Pf >=0.15 Pf.

Where:

Ws = Weight of snow to be included as effective seismic weight

A = Elevation above sea level at the location of the structure (ft./1,000)

Pf = Design flat roof snow load, psf.

For the purposes of this section, snow load shall be assumed uniform on the horizontal projection without including the effects of drift or sliding. The Risk Category factor used in calculating Pf may be considered Risk Category II for use in the formula for Ws."

(5)A new IBC, Section 1613.1.2, is added as follows:

"1613.1.2 Equivalent Lateral Forces

(ELF)Procedure. In ASCE 7 Section 12.8.1.1 the first paragraph is deleted and replaced with the following: Where the design special acceleration parameter Sa determined in accordance with either Section 11.4.5.1 or Chapter 21 is available, Method 1 shall be used to determine the seismic response coefficient, Cs. Where Exception 2 of Section 11.4.5 applies, Method 1 shall not be used. The lower bound for the seismic response coefficient, Cs, provided in Eq.12.8-6 or 12.8-7 shall be applicable for both Method 1 and Method 2."

Amended by Chapter 47 , 2026 General Session