To specify the correct hinge there are a number of factors that need to be taken into consideration. The majority of situations are straightforward and present few problems, however it is important that specifiers recognise where special care is required to ensure long and trouble free operation. Because of the wide variety of circumstances that exist it is impossible to be prescriptive, however the following is intended to draw attention to some of the potential problem areas and explain some of the principles involved.
Factors to consider when specifying hinges
Is it a fire, smoke or emergency escape door?
How heavy is the door and what are the door dimensions (height, width and thickness)?
What is the door’s construction and are there any unusual features that could affect the hinges?
Where is the door situated e.g. internal or external; is it near the coast or in a swimming pool?
What level of use/abuse will the door be subject to e.g. office, hospital or school corridor?
What other items of hardware are to be fitted, that may affect the hinge performance, typically door closers or door stops?
Any other unusual features involved eg. door has radius top or the door is a bifold.
Forces operating on a door
There are two main forces that the hinge has to cope with. The vertical load; and, as hinged doors are side-hung, the horizontal or lateral load.
The vertical load is a direct result of the gross door weight.
The horizontal load is created by:
The door weight
The door height to width ratio
Where the hinges are positioned.
The wider the door is in relation to its height, the greater the side load that the hinges and their fixings have to support.
Locating the hinges
It is usual for at least three hinges to be fitted on doors; their positioning is determined by the size, weight and construction of the door and its intended use.
Top and bottom hinges must be as far apart as reasonable, to maximise their ability to cope with side load.
Consider any other factors that will increase the loadings of hinges and their fixings.
Additional hinges are needed for tall doors, to prevent warping (doors taller than 2200mm should be fitted with four hinges).
Hinges for use with doors of excess width
Wider doors obviously increase the stresses exerted on the hinge. This must be allowed for by a reduction in the maximum mass of the door leaf supported by each class of hinge. The factors by which the door mass has to be adjusted for excessive widths are calculated by dividing the door height by its width. For a factor of 2 or greater, no allowance has to be made. The percentage leaf mass increases are shown in the Side Loading calculations in the table here.
Adjusted Door Weight
Calculating the Adjusted Door weight enables the correct grade of hinge to be specified. Click here for calculation table.
Door leaf 2040 × 928 × 45mm x 65kg door in school corridor with backcheck door closer.
65kg + 75% (backcheck door closer) + 10% (Heavy use) = 125kgs adjusted door weight. Specify 4 x H102 hinges fitted per door leaf
Door leaf 2040 × 1100 × 45mm x 75kgs on office door with non backcheck door closer
75kgs + 15% (increased door width) + 20% (door closer) = 104kgs adjusted door weight. Specify 3 x H207 Hinges per door leaf
If you have any doubts over the correct specification, please contact
our technical department for advice.