Format Conversion Factor Kf and Resistance Factor φ

The resistance factor φ and the format conversion factor K_F are applied to design strengths based on the design criterion.

The resistance factor φ is a safety factor listed in NDS Table 2.3.5 and N2. It comes from φ_s in ASTM D5457 4.1.1 Table 1.

The format conversion factor converts from values to be used for ASD design to those to be used for LRFD design. It is listed in NDS Tables 2.3.6 and N3 and comes from of ASTM D5457 4.1.1 Table 2.

The values of φ and K_F for each design criterion, and whether it applies for each material, are given in the table below:

Criterion	Sawn Glulam SCL	CLT	I-joist	φ	K_F	Sawn, Glulam, SCL	CLT	I-joist
Bending	F_b	F_bS	Mr	0.85	2.54	K_F, φ	K_F, φ	K_F**,φ
Tension	F_t	F_tA	n/a	0.80	2.70	K_F, φ	K_F, φ	n/a
Shear	F_v	F_vt_v	V_r	0.75	2.88	K_F, φ	n/a	K_F**, φ
Rolling shear	n/a	F_sIb/Q	n/a	0.75	2.00	n/a	K_F, φ	n/a
Axial compression	F_c	F_cA	n/a	0.90	2.40	K_F,φ	K_F, φ	n/a
Compression perp. to grain	F_c^	F_c^A	n/a	0.90	1.67	K_F φ	K_F, φ	n/a
Bearing resistance	n/a	n/a	R	0.75	K_F**	n/a	n/a	K_F, φ
Stiffness	E	EI_eff	EI	n/a	n/a
Buckling stiffness	E_min	(EI)_app-min	n/a	0.85	1.76	K_F,φ	K_F, φ	n/a
Shear stiffness	n/a	n/a	K	n/a	n/a

K_F*, φ* - Indicates that the criterion is not implemented in generic Sizer but may be in custom versions.

K_F** - Indicates that the value of K_F for I-joists is not the one listed in table but must come from the manufacturer. On the advice of an I-joist manufacturer, the the program currently uses the same KF values for I-joists that it does for other materials.