On doors without door closers it is usually recommended to use three hinges, the top and bottom hinges being fitted approximately 250mm from the door end to the hinge centre, with the third hinge being positioned in the centre of the other two. Equally spaced hinges will minimise warping which may occur with extremes of temperature or humidity on either side of the door, Fig.1, a and b.
Unequally spaced hinges Fig.1, c and d, improve load bearing. This is recommended where the hinges are operating near their load bearing maximum or where door closers, particularly back check door closers, are in operation and the door is in high frequency use.
BS 4787 pt 1 states that normally three hinges are fitted to a door leaf but for doors exceeding 2100mm in height a fourth hinge should be fitted, and that this should be positioned about 200mm below the top hinge.