## What is Adjusted Door Weight and how do I calculate it?

When specifying a hinge, it’s critical that you check the weight of the door and ensure that the hinge can carry that weight. However there are some additional factors to consider too.

The concept of adjusted door weight refers to the additional strain put on a hinge by these factors.

DOOR WIDTH

It’s obvious that a wider door will put more strain on a hinge than a narrow door. As a simple rule though, if the door height is at least twice the width then there is no additional side loading that needs accounting for.

However, if the door width is more than half the height, then that extra width increases the door’s ‘adjusted weight’. For instance, as soon as a 2M high door is wider than 1M, you need to allow extra hinge weight loading to cope with this.

The table below will show how the adjusted weight increases with the width of a 2M high door;

DOOR CLOSERS

We often fit door closers without realising that they put additional strain on the door’s hinges.

To calculate this, firstly you need to know if the door closer has a back check function or not.

A door closer without a back check adds 20% to the doors adjusted weight.

A door closer with a back check adds a massive 75% to the doors adjusted weight!

For example, an 838 x 1981 x 45mm door weighing 55kg with a back check closer fitted will have the following adjusted weight; 55kg + 75% (41.25kg) = 96.25kg

EXTRA HEAVY USE OR ABUSE

Finally, an allowance is sometimes made for extra heavy use doors of an additional 10% on the adjusted door weight.

As another example, a 1150 x 2040 x 45mm door weighing 80kg in a busy office lobby with a non back check closer fitted will have the following adjusted door weight; 80kg + 23% for extra width (18.4kg) + 20% for the door closer (16kg) + 10% for extra heavy use (8kg) = 122.4kg

Once you have taken all these factors into consideration, you can now decide what grade of hinge is required. We will be publishing details of the BS EN 1935 hinge grading system on this blog soon!

Please do get in touch if we can help you further. We are trade only suppliers to commercial and refurbishment contractors, fire door manufacturers and installers, facilities management and maintenance companies.

Review of this page due February 2023. Please note that advice given is advisory only and to the best of our knowledge at time of writing. We cannot be held responsible for loss or damage incurred as a result of actions taken based on this article.