CHS 21x3.73 IMCA · Weight & Dimensions

IMCA, cold-formed sections · Circular Hollow Section

Circular Hollow Sections (CHS) are round tubular profiles with the most efficient cross-section for compression. Used for columns, trusses, and architectural structures.

Also known as: Caño estructural redondo (Argentina)

The CHS 21x3.73 steel profile weighs 1.6 kg/m (1.07 lb/ft). Cross-sectional area: 202.372 mm². Moment of inertia Ix = 0.79 cm⁴, Iy = 0.79 cm⁴.

Cross-section (not to scale)

Gauge equivalent: 3.73 mm ≈ 9 gauge (Manufacturers Standard Gage)

Dimensions

Property	Metric	Imperial
Thickness (t)	3.7 mm	0.15 in
Diameter (d)	21 mm	0.83 in
Weight	1.6 kg/m	1.07 lb/ft

Section Properties

Property	Metric	Imperial
Area (A)	202.37 mm²	0.314 in²
Moment of inertia (Ix)	0.79 cm⁴	0.02 in⁴
Moment of inertia (Iy)	0.79 cm⁴	0.02 in⁴
Elastic section modulus (Sx)	0.75 cm³	0.046 in³
Elastic section modulus (Sy)	0.75 cm³	0.046 in³
Plastic section modulus (Zx)	1.13 cm³	0.069 in³
Plastic section modulus (Zy)	1.13 cm³	0.069 in³
Radius of gyration (rx)	0.62 cm	0.246 in
Radius of gyration (ry)	0.62 cm	0.246 in