I was contacted today, out of the blue, by a surveyor acting for one of their clients who, it turns out, is fairly local to us.
They had contacted me to ask my opinion as to the suitablility of hinges and door closers that had been supplied by another ironmongery company (as yet unknown) on a project that had been completed less than 3 years ago and that the client had been experiencing problems with ever since.
I was given the weights and dimensions of the doors and, upon asking the nature of the building concerned, was told the doors were situated in one of the local colleges. These were the doors leading on to the corridors from the stairwells and were in a high traffic environment.
All of the doors were fire doors with some being rated 30 minute (FD30) and some 60 minute (FD60) – all were 2040mm high.The FD30 doors were 1275mm wide and weighed 57Kg including ironmongery fittings. The FD60 doors were 1200mm wide and weighed 96Kg including ironmongery.
According to the information that the surveyor had all of the doors had been hung on three 100mm x 75mm Ball Bearing Butt Hinges to BS EN 1935 Grade 13, positioned top, middle and bottom and a Rack & Pinion Overhead Door Closer with Slide Arm and Backcheck to BS EN1154 Size 3. Having been told the manufacturer of both the hinges and the closers I would guess that the hinges cost little more than £2.50 each and the door closer roughly £50.00. It is also important to note that none of the hinges had been fitted with intumescent material (an absolute must on fire rated door sets).
Now, it does not take a rocket scientist to work out that the hinges, the positioning of the hinges and the size and type of door closer are totally inadequate for the sizes, weights and through traffic of the doors. It actually takes a competent, qualified ironmonger.
Starting with the door closers, as mentioned these were a Rack & Pinion type BS EN1154 Size 3 Closer with Slide Arm. As any competent ironmonger knows, a size 3 closer is suitable for internal doors up to 900mm wide only. It should also be noted that a rack and pinion type door closer when fitted with a slide arm will loose efficiency during it’s closing cycle and, most importantly, over the last few degrees. Even if the door closers had been of the correct power size for the door widths, the reduced efficiency of the slide arm would still have meant that the closers would struggle to return the doors to the fully closed position and to keep them there especially with adverse air pressure on the closing face – not a good scenario in the event of a fire.
The correct type of door closer for both the FD3o and FD60 doors should have been either one of the following:
- a) Rack & Pinion Overhead Door Closer BS EN1154 Size 6 with Figure 1 Fixing Standard Scissor Arm Set and Backcheck – approx cost £120.00
- b) Cam Action Overhead Door Closer BS EN1154 Size 6 with Pull Side Side Arm & Channel and Backcheck – approx cost £150.00 (Cam Action Door Closers with Slide Arms do not loose efficiency and would be an ideal choice for a college environment due to the reduced risk of vandalism or abuse by burly teenage lads).
Now for the hinges. A Grade 13 hinge is suitable for doors up to 120Kg and with a high volume of traffic. “Hang on a minute” I hear you say. “Even the heavy FD60 doors are only 96Kg so the hinges fitted must be suitable, right?” Well, in theory I suppose they could… NO THEY ARE NOT! And here is why:
The weight carrying capacity of hinges is based on doors no larger than 2000mm high by 1000mm wide. If you recall, our doors are from 1200mm to 1275mm wide. This increased mass causes increased force on the hinges fitted which needs to be accounted for in a reduction of the mass of the door that each hinge has to carry. There is a method used in the industry to calculate this extra side load which I will note bore you with now but if we take the 1200mm door widths as our example we need to increase the actual weight of the door by 33%. You can see then that on a 96Kg door this takes the adjusted weight to over 120Kg without any other considerations.
We also need to adjust the weight due to the increased force at the head of the door due to the action of the door closers. For standard door closers with no backcheck facility the calculated weight needs to be increased by 20%. For door closers with a backcheck facility the increase is far greater being 75%.
A final adustment should then be made for the degree of use that the doors will be subjected to: Light Use – 10%, Extra Heavy Use + 10%.
Taking all of these points in to consideration we actually end up with adjusted door weights of 154Kg for the FD30 Doors (up from 57Kg) and 246Kg for the FD60 Doors (up from 96Kg). We can see from this then that a hinge designed for doors 120Kg would be unsuitable for both door types.
We have suggested that the FD30 doors be fitted with hinges to BS EN1935 Grade 14 (160KG) and the FD60 doors require a hinge capable of carrying 250Kg. Approximate costs will be £15.00 each and £35.00 respectively. Whilst the weight carrying capacity of hinges is calculated on the basis of fitting 3 hinges it should also be noted that the hinges we have suggested would be very close to their maximum capacity. For this reason we have recommended that 4 hinges are fitted. Ideally they should be fitted two at the top and two at the bottom which is the best position on wider doors and those fitted with with door closers. However, as these will be replacing the existing hinges they will need to be fitted two top, one middle and one bottom. AND ALL WITH INTUMESCENT MATERIAL.
If you look back at the prices for the items I have suggested you will notice that they are substantially more expensive than the items currently in situ. However, there is a simple explanation for this in that they are properly specified and suitable for their intended use and will continue to work with little maintenece required for at least the next 20 years.
If you would like any advice on the correct ironmongery to use for any given project wether it be residential, commercial, industrial of educational please do not hesitate to contact me through our web site at www.blackironmongery.co.uk