Specification NotesValves are manufactured in accordance with BS 5154 PN25 for series B ratings with ‘long’ face-to-face. Design incorporates disc holder which on sizes 15 to 50 slips on to stem and on sizes 65 and 80 is retained by a threaded ring. Body seat is integeral of the semi-crown type. Sizes 15 to 50 have union bonnet; sizes 65 and 80 have a bolted bonnet. End flanges conform to BS 4504 Section 3.3 with flat face and are normally supplied drilled. Note: Users attention is drawn to BS 4504 Section 3.3 Clause 8 regarding types of gaskets and mating flanges to be used with metric flanged valves. This valve is not suitable for use on group 1 gases or unstable fluids, as defined by the Pressure Equipment Directive 2014/68/EU.