By using UV spectra for the O star HD 93521 taken with the ORFEUS II echelle spectrograph, we determine an ‘astrophysical’f value for the S ii λ94.7‐nm line: f=0.00498−0.00138+0.00172, error at 1σ level. This is almost a factor of 30 smaller than the guessed value found in the Kurucz data base ( f=0.1472), which was until now the only one available for this transition. We use our ‘astrophysical’f to investigate the S abundance in two damped Lyα absorption systems (DLAs) observed with the UV–Visual Echelle Spectrograph (UVES) at the European Southern Observatory's 8.2‐m Kueyen telescope. In the case of the absorber at zabs=3.02486 towards QSO 0347‐3819, we find a sulphur column density which is consistent, within errors, with that determined by Centurión et al. by means of the λ125.9‐nm line, thus providing an external check on the accuracy of our f value. For the damped absorber at zabs=4.4680 towards BR J0307‐4945, we determine a high value of the S abundance, which, however, is probably the result of blending with Lyα forest lines.