The LWF Blog
Passive fire protection for Building Professionals – Part 10March 26, 2020 9:39 am
In LWF’s blog series on passive fire protection for building professionals, contractors and those with an interest in structural fire protection issues, we aim to give an overview of the important role passive protection plays in the overall fire safety provision of a building.
In part 9, LWF talked about fire doors and the need for third-party accredited door sets and installers. In part 10, we look at fire door components, specifically the hinges.
The selection and purchase of a fire door and frame and the quality of the installation must be undertaken with the highest level of quality in mind in order to achieve the required levels of passive fire protection in a building. There are, however, other elements of the fire door which must bear scrutiny – fire door components.
The hinges used to attach the fire door to the surrounding frame must be rated adequately for purpose. The standard used to rate hinges is BS EN 1935:2002 Building hardware. Single-axis hinges. Requirements and test methods.(https://shop.bsigroup.com/ProductDetail/?pid=000000000030118674).
Even the smallest fire door should use a recommended grade 11 hinge, which is a hinge that has been fire tested and can maintain a door up to 80 kg in weight.
However, it is common for reputable fire door installers to use a grade 13 hinge when installing fire doors. Grade 13 hinges are able to support more door weight than a grade 11 hinge and are generally more resilient. The hinges are often tested alongside the doors they are recommended for use with and are most commonly made of steel, although brass hinge use is popular too.
Up to 2002, BS 7352 indicated that a grade 8 hinge would be sufficient to be fitted to a fire door. However, BS 1935 replaced that guidance and the more recent standard requires a grade 11 hinge as a minimum for new fire door installations. If a fire door was installed in 2001 and has hinges of grade 8 or higher, it remains appropriate for continued use until it is replaced.
Fire doors tend to use a minimum of three hinges rather than two, as seen on domestic and non-fire doors. This is not only to carry the weight of the substantially constructed door but also helps to prevent the door from bowing in the event of a fire. Additionally, the ongoing wear on the hinges from bearing the weight of the door and opening and closing cycles can be exacerbated by the use of door-closing devices. It is therefore good practice when selecting the correct hinge grade when using a self-closing mechanism to opt for a hinge that is capable of carrying up to 20% more than the actual door weight.
The door manufacturer will specify whether intumescent pads are used behind hinge blades. These are not always required for 30 minute fire doors but are always required for 60 minute fire doors. These should generally be used, if required, as packers in preference to combustible hinge packers. The screws for hinges will also be specified or supplied with door sets, however as a general rule of thumb these will be no less than a Number 8 gauge screw and will penetrate the door or frame by no less than 35mm. melting point of all materials used in door ironmongery is required to be no less than 800 degrees centigrade which offers steel and brass as the preferred materials and rules out aluminium, plastics and zinc alloys.
In part 11 of this series, LWF will continue to look at fire door components. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.
While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.