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The usual woodworker/house builder rule of thumb is to place the top hinge 6" (150 mm) from the top of the door, and the bottom one 9" (228 mm) from the bottom - the common reason for this is illusion of "foreshortening" and this results in a visual balance of the hinges on the door. If a 3rd hinge is used, it is placed halfway between the top and bottom hinges.

In modern office buildings it is common to see a hinge spacing that doesn't follow the usual rule.

What is the reason for this arrangement of hinges?

image of office door with four hinges - two near the top and the others evenly spaced

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  • $\begingroup$ The door spends most of its life with the middle and bottom hinges in compression (so the door is pressed against the frame and the hinges are only providing vertical support) but the top ones are in tension and doing both vertical and lateral support. $\endgroup$ – Transistor Mar 6 at 10:06
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In the US the top hinge is mounted usually 9-5/8" cl, from the top, 244 to 248mm.

The door in your figure is a self-closing door with the closing box mounted on top. These types of doors are designed for average daily usage of 1250 opening/ closing. This setting is best supported with a hinge(hinges) close to the top to reduce undue torque and lateral dynamic loading on the hinge when the mechanism pushes the door to close.

Another reason is for the solid and heavy doors, the higher mounted hinges help support the weight of the door better.

Some office doors have a steel frame reinforcement embedded inside and have solid bars extending into cylinders in the specially made door jamb with custom-built hinges, so they have everything designed together, sometimes with a wi-fi remote control.

Depending on the utility and function of the door, its design and construction can cover a large spectrum.

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  • $\begingroup$ So you're saying, in effect, that my question title is wrong. This is the usual spacing of hinges on a door that is frequently opened/closed and has a top mounted self closing mechanism. $\endgroup$ – D Duck Mar 6 at 12:59
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    $\begingroup$ no. i just say that in this case they used 2 hinges on top to counter the heavey weight of the door and make it laterally strong on top to work with the force of closure mechanism. see it this way, a heavey door create hi tension on top hinge, high compression on the bottom. but the bottom compression is mostly supported by the jamb. also the self closure creates diagonal torque attemting to break the door off the door jamb, mostly by top vertical moments. so they make the top double hinged. $\endgroup$ – kamran Mar 6 at 15:50
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    $\begingroup$ In settings such as hospitals and other highly regulated and inspected structures, those door closures have to be adjusted to exacting specifications. The only way to keep those performance specs is to have a bulletproof hinge system. Any slop in the hinges or closure attachment will drive you bonkers trying to set the adjustments. You need doors built like a vault. $\endgroup$ – Phil Sweet Mar 6 at 22:08
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There are references and standards for the installation of doors and door hardware. These institutes test various sizes of doors with various qualities of hardware to determine minimum standards.

Your door is not only extra large (appears to be about 3’-6” wide), but appears to be extra heavy with a lead shield inserted into the door.

The location and size (4 1/2” x 4 1/2”) of the hinges has been tested by ANSI and BHMA to insure the door will operate as intended.

Architects and engineers don’t test various hinges for the doors they require, they rely on the recommendation of these institutions.

Btw, the hinges on the small door are just to “balance” the appearance of the overall installation.

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  • $\begingroup$ The black strip in the middle of the door is a flexible plastic gasket. This is in an office building - a hallway with a magnetic access control lock. The blue disks say something like "Fire Door - Keep Closed" or "Fire Door - Keep Shut" $\endgroup$ – D Duck Mar 6 at 21:57
  • $\begingroup$ The hinges are symmetric so the frame can be right or left handed wrt the big door. $\endgroup$ – Phil Sweet Mar 6 at 22:02

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