1. General

This website is a design guide to BS 5950: Part 1 now denoted as BS 5950-1: 2000[1]. The symbols used are generally the same as those in BS 5950-1: 2000.

1.1 Material, section dimensions and tolerances

The structural sections referred to in this design guide are of weldable structural steels conforming to the relevant British Standards given in the table below:

Table – Structural steel products

For full details of the British Standards, see the reference list at the end of the Explanatory Notes.
Product Technical delivery requirements Dimensions Tolerances
Non alloy steels Fine grain steels
Universal beams, Universal columns, and Universal bearing piles BS EN 10025[2] BS EN 10113-1[3] BS 4-1[4] BS EN 10034[5]
Parallel Flange Channels BS 4-1[4] BS EN 10279[7]
Angles BS EN 10056-1[8] BS EN 10056-2[8]
Structural tees cut from universal beams and universal columns BS 4-1[4]
Hot Finished Hollow Sections BS EN 10210-1[9] BS EN 10210-2[9] BS EN 10210-2[9]
Cold Formed Hollow Sections BS EN 10219-1[10] BS EN 10219-2[10] BS EN 10219-2[10]

1.2 Dimensional units

The dimensions of sections are given in millimetres (mm).

1.3 Property units

Generally, the centimetre (cm) is used for the calculated properties but for surface areas and for the warping constant (H), the metre (m) and the decimetre (dm) respectively are used.

Note: 1 dm = 0.1 m = 100 mm
  1 dm6 = 1 x 10–6 m6 = 1 x 1012 mm6

1.4 Mass and force units

The units used are the kilogram (kg), the Newton (N) and the metre per second (m/s2) so that 1 N = 1 kg x 1 m/s2.  For convenience, a standard value of the acceleration due to gravity has been generally accepted as 9.80665 m/s2.  Thus, the force exerted by 1 kg under the action of gravity is 9.80665 N and the force exerted by 1 tonne (1000 kg) is 9.80665 kilonewtons (kN).