Roymech engineering encyclopedia

Steel Channel Sections BS 4-1:1971 – Dimensions, Sizes & Properties




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Steel channel sections to BS 4-1:1971 are structural steel members with a U-shaped cross-section used for load-bearing and framing applications. This page provides standard dimensions, including depth, width, thickness, mass per metre, and sectional properties. Note that BS 4-1:1971 has been superseded by BS 4:1993 and should not be used for new designs.

This page provides reference dimensions for steel channel sections manufactured to BS 4-1:1971. These sections were widely used in structural engineering and fabrication but have now been superseded by BS 4:1993. The data below is provided for legacy reference, maintenance work, and verification of existing structures only.

Applications of Steel Channel Sections

Steel channel sections are commonly used in structural and mechanical applications where strength, stiffness, and ease of fabrication are required.

  • Structural framing and supports
  • Machine bases and equipment frames
  • Bridges and civil engineering structures
  • Vehicle chassis and trailers
  • General fabrication and steelwork

Advantages and Limitations

Advantages

  • High strength-to-weight ratio
  • Easy to fabricate, weld, and bolt
  • Suitable for a wide range of structural applications
  • Efficient for bending in one direction

Limitations

  • Lower torsional stiffness compared to closed sections
  • Not ideal for high twisting loads
  • Superseded standard – not recommended for new designs

Channels BS 4-1:1971

Dimensions

M=Mass per m , D=Depth of Section, B= Width of Section, T1=Web thickness,
T2=Flange Thickness, R1=Root radius, R2=Toe Rad, Area=Area of Section

Serial Size M D B T1 T2 R1 R2 DT D/T Area
mm kg mm mm mm mm mm mm mm cm2
432 x102 65.54 431.8 101.6 12.2 16.8 15.2 4.8 362.5 25.7 83.49
381 x 102 55.1 381.0 101.6 10.4 16.3 15.2 4.8 312.4 23.4 70.19
305 x 102 46.18 304.8 101.6 10.2 14.8 15.2 4.8 239.3 20.6 58.83
305 x 89 41.69 304.8 88.9 10.2 13.7 13.7 3.2 245.4 22.2 53.11
254 x 89 35.74 254.0 88.9 9.1 13.6 13.7 3.2 194.8 18.7 45.52
254 x 76 28.29 254.0 76.2 8.1 10.9 12.2 3.2 203.7 23.3 36.03
229 x 89 32.76 228.6 88.9 8.6 13.3 13.7 3.2 169.9 17.2 41.73
229 x 76 26.06 228.6 76.2 7.6 11.2 12.2 3.2 178.1 20.4 33.20
203 x 89 29.78 203.2 88.9 8.1 12.9 13.7 3.2 145.3 15.8 37.94
203 x 76 23.82 203.2 76.2 7.1 11.2 12.2 3.2 152.4 18.1 30.34
178 x 89 26.81 177.8 88.9 7.6 12.3 13.7 3.2 120.9 14.5 34.15
178 x 76 20.84 177.8 76.2 6.6 10.3 12.2 3.2 128.8 17.3 26.54
152 x 89 23.84 152.4 88.9 7.1 11.6 13.7 3.2 97.0 13.1 30.36
152 x 76 17.88 152.4 76.2 6.4 9.0 12.2 2.4 105.9 16.9 22.77
127 x 64 14.90 127.0 63.5 6.4 9.2 10.7 2.4 84.1 13.8 18.98
102 x 51 10.42 101.6 50.8 6.1 7.6 9.1 2.4 65.8 13.4 13.28
76 x 38 6.7 76.2 38.1 5.1 6.8 7.6 2.4 45.7 11.2 8.53

FAQs – Steel Channel Sections

What is a steel channel section?

A steel channel section is a structural member with a U-shaped cross-section used for support, framing, and load-bearing applications.

What does BS 4-1:1971 cover?

BS 4-1:1971 specifies dimensions and properties of hot-rolled steel channel sections. It has been superseded by BS 4:1993.

Why should BS 4-1:1971 not be used for new designs?

Because it is an outdated standard that has been replaced by more modern specifications with improved design guidance and material data.

What do the dimensions D and B represent?

D is the depth of the section and B is the flange width of the channel.

Where are channel sections used?

They are used in structural frames, machinery, vehicles, and general steel fabrication.



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