Do door stops have to be of particular thickness?

[Guest ModDoo]

What are the requirements for door stops (part of the frame-usually nailed to the lining of the door) in FD30 doors? Assuming adequate intumescent seals are fitted into doors/linings does the door stop need to be of a certain thickness? I seem to get different information from my suppliers and a web research hasn’t made me any wiser

[Tom Sutton]

Fire doors were tested early seventies to BS 476 Part 8 and the frame door stops was 1 inch (25mm) with no intumescent seal. This could be achieved by fixing an addition 1/2 inch (12mm) glued and screwed to the existing door stop. In the late seventies intumescent seals were introduced and it was found that 25mm fire doors stops were were not necessary.

In 1987 a new standard was introduced BS 475 Part 22 which tested not only the fire door but the frame as well (fire door sets) the frames had 12mm door stops and intumescent seals which passed the new test.

Now we have certified fire door sets part 22 and older part 8 fire doors therefore if you are fitting a new fire door, it should be a part 22 certified fire door set. However part 8 fire doors can be acceptable and occasionally none fire doors can be upgraded depending on a fire risk assessment.

[Guest John pluto]

lots of different information on door stops but do the stops need to be hardwood or softwood glued then pinned or screwed just need to clarify 12 mm or over x 25 or wider 

Thanks ? 

[Neil ashdown]

If you are fitting a new fire door then the door leaf manufacturers installation instructions or fire performance certification will state door frame and rebate stop requirements. 

If you are working on old fire doors and without the possibility of checking with the manufacturer work on 12mm minimum thickness so long as intumescent strips are fitted. If intumescent strips are not fitted, my advice is to fit them.

FD20/FD30 = softwood or hardwood   FD60 = hardwood only     You can use pins or screws, but stops must be securely fixed.

[Guest Andrew]

In our housing association, due to the age of the buildings, there are instances where doors are not provided with intumescent strips and cold smoke seals, however, 25mm door stops are provided, which meet a recognised and accepted previous standard. 

Since the 25mm door stops are already present, can we wait to install intumescent strips and cold smoke seals until refurbishment of the doors?

[Neil Ashdown MAFDI]

It is understood that fire doors offer improved performance when fitted with intumescent edges seals and obviously smoke seals, so this would be a matter for your fire risk assessment.  

[Mike North]

The attached may be of interest

Determination_on_the_suitability_and_sufficiency_of_a_fire_risk_assessment_in_a_hotel....pdf

[Neil Ashdown MAFDI]

At a hotel

[Mike North]

But it can be used as the basis of an argument