BS 5268-7.3:1989 recommends a calculation basis for permissible clear span for ceiling joists with access at a maximum spacing of 610 mm centre-to-centre. It does not cater for the design of the ties of trussed rafters, which are dealt with in BS 5268-3. The uniform and concentrated loads recommended in BS 6399-1 are considered.
BS 5268-7.3:1989 is applicable to both single and continuous span ceiling joists. A typical arrangement is shown in Figure 1.
BS 5268-7.3:1989 is applicable to the species and grades of timber given in BS 5268-2.