This International Standard specifies construction characteristics, optical qualities and heat current circuit, as well as the tolerances, tests, marking and designation of heated glass panes for ships' rectangular windows of the heated series according to ISO 3903. It includes the conditions to comply with the safety of ships in times of frost and/or snow, particularly during manoeuvres in port. Heated glass panes are used on ships principally for the windows of wheel-houses and bridges, as well as in enclosed locations used for look-out and manoeuvring purposes. This International Standard specifies heated glass panes which are intended for use at temperatures down to −40 °C.