The BS750 Fire hydrant is normally used by the fire service, it is made of ductile iron or cast iron according to BS 750 .
Commodity    Standards    Style
Fire hydrant    BS750    On the ground
Typical technical data :
1.    Dimentions according to BS750 Type 1
2.    Flange drilling to EN1092-2:1997  
3.    Copper outlet : 3.1 Internal diameter :64mm
3.2    Type of threads: V thread
3.3    Threads per 25.4mm : 5 1/3 nos