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How to fit a drop-down door seal for fire doors

In the event of a fire, smoke can quickly spread from room to room, reducing the visibility and breathable air of the building. This makes fire safety equipment that is specifically designed to minimise air flow, such as drop-down door seals, compulsory for a fire door to be fit for purpose. Here, we discuss the purpose of a drop-down seal, how it works, and how you can install it safely and effectively.

The purpose of a drop-down door seal

When a door is closed, air can still pass underneath. This is somewhat unavoidable as the door would drag and scrape across the floor without any space, making it difficult and impractical to use. Unfortunately, this also means smoke can easily travel under doors during a fire and flood multiple rooms.

A drop-down seal is fitted along the bottom of a fire door and works in unison with a latch on the frame. Once the door closes, a mechanism is activated whereby a seal drops down and covers the gap underneath the door and reduces the risk of smoke passing through.

Installing a drop-down door seal for fire doors can not only save lives, it can reduce air leakage and reduce energy costs.

How to fit a fire door seal
Here is a step-by-step guide for how to install a drop-down door seal.

You will need:
– Drop-down door seal
– Screws
– Tape measure
– Pen/marker
– Screw driver
– Drill
– Engineer’s file

1. You may need to adjust the length of your drop seal to match your door. Measure the bottom of your door (not including the frame) with a tape measure and lock the tape in place.

2. Look inside either end of your drop seal and identify which end has the catch (often a solid black square/circle shape). It is important to check this as you do not want to make the mistake of cutting off the wrong end.

3. Lay your tape measure along your door seal, starting from the above-mentioned end, and use your pen to mark 5mm less than the measurement of your door. Deducting 5mm is very important as it accounts for the opening and closing of the door.

4. Use the saw to carefully and safely cut the drop-down door seal to size, being sure not to remove more than 150mm.

5. File down the side of the seal you cut, making it as smooth as possible. This will be the end of the seal that is fitted on the hinge side of the door.

6. If you look inside the seal, you will see a narrow, triangular gap at the top. Insert the head of your screwdriver into this gap and push upwards to remove the outer shell. Keep this nearby as you will need it soon.

7. On the opposite end, slide out the inner workings of the seal and rotate the catch 180 degrees before reinserting.

8. Place the seal across the bottom of your door and push your pen through the screw holes to mark the correct points of drilling on your door. Remember, the 5mm you cut off must go at the hinge side of the door, and leave enough room for the door to open.

9. Drill holes into your door at the appropriate points.

10. Use the screw driver to insert the screws into the seal and fix it into the correct position.

11. Repeat steps 8-10 for the latch, which will fit on the door frame next to the seal.

12. Place the outer shell back over the seal and close the door to test the newly fitted drop-down seal.

A drop-down seal for fire doors is one of the easiest and most effective ways of stopping the spread of smoke. Get in touch with our team and we’ll be happy to help improve your fire safety with advice about drop-down seals and their installation.