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The Importance of Bi-directional Fire Door Testing in the United Kingdom

Aligning with Approved Document B and BS EN 1634-1:2014 + A1:2018 Standards.

Timber fire door manufacturers are often challenged over whether fire doors should be fire resistance tested form both sides. This article will discuss the necessity of testing in both orientations, highlighting the relevant sections of Approved Document B and standards such as BS EN 13501-2 and BS EN 1634-1:2014 + A1:2018.

A fire testing engineer writing down notes while testing a fire door


The convention to test timber fire doors by exposing the opening side only has been a long-established practice and is supported by standards BS 476-22:1987 and BS EN 1634-1:2014+A1:2018. The rationale is that the door leaf on the opening side shrinks relative to the closing face which causes the lead edges to bow towards the fire and away from the frame (which is fixed to the supporting construction). This results in a growing gap between the leaf edge and frame that allows the egress of hot gases and flames, ultimately compromising the integrity of the door. When tested in the opposite orientation, the gap between the leaf and frame remains relatively consistent throughout the test normally resulting in better performance.


Despite the industry convention, the requirement to test fire doors from both directions has been included in Approved Document B as far back as the 2000 edition. In fact, the only exception to this is lift landing doors which can be tested from the landing side only.

MHCLG Testing

In the aftermath of the Grenfell Tower fire, MHCLG (Now DHLUC) commissioned their own series of fire door tests on both GRP and Timber fire doors. The timber fire door testing comprised of 25 different timber fire doors and were tested from both directions. Whilst on average, exposure on the opening side performed 3 minutes worse relative to exposure on the closing side, almost one fifth of the doors tested performed worse when exposed on the closing side. It was concluded, therefore, that fire doors (regardless of material) should be exposed from both sides, and this has remained a requirement within subsequent editions of Approved Document B and other national building regulations across the UK.

How UKTC can help in your testing requirements?

At United Kingdom Testing & Certification (UKTC), we prioritise safety and compliance above all else. As the fire safety landscape evolves, so too does our commitment to helping door set manufacturers meet ever-rising expectations and legislative standards. We are always ready to share our knowledge and assist with any queries for your testing requirements.

Are you looking to find out more information? Contact us at or call us on 01355 433122; our experienced team will be happy to help.


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