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Door sizes

Introduction
Doors and doorsets complying with BS 4787:Part 1:1980
Doors and doorsets NOT complying with BS 4787:Part 1:1980

Introduction

For buildings other than dwellings, the effective clear width of doors is covered in Approved Document M, paragraphs 2.13 to 2.17, most particularly Table 2 (page 28).
The requirements for the spaces around the doors, to allow adequate access for the disabled, are illustrated in Diagram 9 (page 30).
Key dimensions for lobbies with single leaf doors are illustrated in Diagram 10 (page 32) but these layouts, crucially, omit any mention of the minimum recommended lobby width.
This page provides guidance on calculating both door sizes and minimum corridor/lobby widths.

Doors and doorsets complying with BS 4787:Part 1:1980

Condition 1

Situations with a minimum effective clear width of 800mm or 825mm (Refer to Table 2).
... where the door can open MORE than 90 degrees (door stop to door leaf as Diagram 9).
... require a door leaf width of 926mm (co-ordinating width of 1000mm).
... and a structural opening width of 1010mm.
... generating a minimum recommended corridor/lobby width of 1375mm (clear width between wall finishes), assuming that the door ironmongery projects 75mm on each side of the door.

Condition 2

Situations with a minimum effective clear width of 800mm or 825mm (Refer to Table 2).
... where the door can open ONLY to 90 degrees (door stop to projecting ironmongery as Diagram 9).
... are outside the scope of BS 4787 for single leaf doorsets.
... but, to maintain the *26mm sizing of BS 4787 ...
... use a door leaf width of 1026mm (co-ordinating width of 1100mm).
... and a structural opening width of 1110mm.
... generating a minimum recommended corridor/lobby width of 1475mm (clear width between wall finishes), assuming that the door ironmongery projects 75mm on each side of the door.
... or refer to Condition 4 below.

Doors and doorsets NOT complying with BS 4787:Part 1:1980

The calculations below were made using the Leaderflush Shapland Open Widths Calculator.
... for a 44mm thick door leaf in a 94mm x 44mm 'Mono' frame profile. Use the Calculator to view the many other options.

Condition 3

Situations with a minimum effective clear width of 800mm (Refer to Table 2).
... where the door can open MORE than 90 degrees (door stop to door leaf as Diagram 9).
... require a minimum door leaf width of 865mm (Calculator gives 863mm).
... and a structural opening width of 950mm. (Calculator gives 947mm).
... generating a minimum recommended corridor/lobby width of 1315mm (clear width between wall finishes), assuming that the door ironmongery projects 75mm on each side of the door.

Condition 4

Situations with a minimum effective clear width of 800mm (Refer to Table 2).
... where the door can open ONLY to 90 degrees (door stop to projecting ironmongery as Diagram 9).
... require a minimum door leaf of 940mm (Calculator gives 938mm).
... and a structural opening width of 1025mm (Calculator gives 1022mm).
... generating a minimum recommended corridor/lobby width of 1390mm (clear width between wall finishes), assuming that the door ironmongery projects 75mm on each side of the door.

Page last reviewed: 06/02/2008

Legislation, British (and other) Standards, and industry practices, may have changed since the date above. Read our
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