Installation

How fast smoke can spread!

In the simulation below you can see how quickly fire smoke can take over an entire house. The fire takes place downstairs in the kitchen. The smoke can spread throughout the house through the open doors. Could the residents here escape in time? I don't believe that without a previous alarm by smoke detectors.

The example illustrates three things: how quickly smoke can spread, how important smoke detectors are and that doors are best closed, especially at night. This prevents the smoke from spreading throughout the house in the event of a fire.

Guideline

The DIN 14676 regulates the use of home smoke detectors in Germany. It describes how you should plan, install, operate and maintain smoke detectors in your home. The DIN standard stipulates that the smoke detectors comply with the product standard DIN EN 14604 must fulfil. This regulates, for example, how the smoke detector must be tested so that it is safe.

In which rooms do you have to install smoke detectors?

Most state building codes require smoke detectors at least in:

the sleeping quarters;
the children's rooms;
the corridors if they are escape routes.

You can find this, for example, in the Lower Saxony Building Code (NBauO), §44. So much for the law. It makes even more sense to secure every room (except for the kitchen and bathroom) with smoke detectors.

In which rooms are smoke detectors not useful?

Wherever there is dust, smoke or damp, smoke detectors are out of place. In all of these rooms, the air particles penetrate into the smoke chamber of the detector and lead to false alarms. Therefore, smoke detectors are usually not advisable in the following rooms:

Kitchen;
attic;
garage;
basement;
fFireplace room;
rooms with (heavy) smoking.

In these rooms the danger of a fire is higher than in other rooms. You can therefore arrange heat detectors (also called heat detectors) here. These detectors alert you as soon as the temperature in the room exceeds around 60°C or if the temperature rises very quickly. Particles in the air therefore do not lead to false alarms.

Where should smoke detectors be installed in the room?

Just three breaths are enough. Then you are unconscious at a certain level of carbon monoxide. You can no longer escape from the fire. In Germany it is the fate of around 80% of those who die in a fire. Smoke detectors must therefore alert you as quickly as possible so that you can leave your home quickly in the event of a fire.

To do this, the smoke must be able to creep into the smoke chamber of the detector. So pause before installing a smoke detector. And consider whether this is possible. You can then easily understand many of the following instructions for installing smoke detectors.

Attach smoke detectors as centrally as possible to the ceiling.
Keep a distance of at least 50 cm to walls, beams, lamps, beams or air outlets of your living room ventilation.
One smoke detector is sufficient for rectangular rooms with a size of 60 m².
For L-shaped rooms, install a smoke alarm in each leg of the room.
Does large furniture or screens divide your space into sections? Then also provide a smoke detector for each section.
The room must be a maximum of 6 m high. In higher rooms, you must install the detectors on several levels.
For sloping ceilings of 20 degrees or more, mount the smoke alarm 0.5 to 1 m from the top of the ceiling.
If there are open connections over several floors, place at least one smoke detector on the upper level.
Place smoke alarms in places that are easy to reach later for regular maintenance.

Where must smoke detectors be installed in hallways?

The difference between narrow and wide corridors

We can mentally rule out corridors with a width of more than 3 m. These wide corridors treat the policies like rooms. This means that you only have to place one smoke detector in hallways with an area of less than 60 m².

Length matters too!

Most corridors are narrower than 3 m. Here it also depends on how long the corridor is:

Is your hallway shorter than 15 m? Then a smoke detector in the middle of the corridor is sufficient.
For longer corridors, you must install at least two smoke detectors. Smoke detectors must be no more than 7.5 m from the ends of the corridor. The distance between the two smoke detectors must not exceed 15 m. Otherwise you have to install another smoke detector in between.

And on the geometry!

Is your hallway L-shaped or U-shaped? Then the rule also applies that you mount the smoke detectors so that they are no more than 7.5 m away from the ends of the hallway. It is best if you attach the smoke detector at the intersection of the two legs of the hallway.

Other troublemakers: beams

Beams are the beams on which a floor slab rests. As the name suggests, these are below the ceiling. High beams interfere with the smoke detector because the fire smoke does not reach the smoke chamber of the smoke detector or only with a delay. As a result, your smoke detector will not reliably alert you. The regulations therefore distinguish the height of beams:

Is the beam no higher than 20 cm? Then you can neglect him. You can attach the smoke detector normally to the ceiling or to the beam.
Is the beam higher? Then the joist separates the ceiling into two fields. In this case, arrange a smoke detector in the middle of each of the two ceiling panels.

When is it better to remove smoke detectors?

There are exceptions when it is better to remove smoke detectors. Whenever you stir up a lot of dust. 😉 I mean that in the literal sense. If you are renovating your home and sanding the ceiling, for example, please remove the smoke detector while you work. Otherwise, the dust would quickly soil the smoke detector's smoke chamber. That will either trigger a false alarm. And the condition of your smoke detector suffers as a result. Please don't forget to screw the smoke detector back on when you call it a day. Fires are particularly common during construction phases!

How do you attach smoke detectors?

The classic: with screws

It is safest if you attach the smoke detector with screws. Depending on the smoke detector, attach the base with one or two screws depending on the ceiling:

For concrete ceilings, drill two holes, insert universal dowels and screw on the base.
Use cavity wall plugs for cavity ceilings.
You can screw smoke detectors directly to wooden ceilings.

With glue

You can also stick smoke detectors to the ceiling with some products, for example with:

Double-sided tape (carpet glue);
Tesa power strips;
hot glue;
mounting adhesive;
adhesive pads.

If you use glue, the surface must be clean and level. When the temperature fluctuates, most glues don't stick as well. Adhesives also age, which means that some smoke detectors fall from the ceiling and die. You should be careful if you have sensitive floors so that a fall does not damage your floors. Is your ceiling wallpapered? Then the glue will damage your wallpaper in most cases when you want to remove it.

If you can bear these losses, then you can fix your smoke detectors to the ceiling. As a professor of steel construction please forgive me for preferring bolted solutions. 😉 For me, the disadvantages of the adhesive outweigh the disadvantages, so I screwed on all the smoke detectors.

With magnetic pads

You can also buy magnetic pads for smoke detectors. Attach one adhesive pad to the ceiling and the other to the underside of the smoke detector. The only difference to "normal" gluing is that you can remove the smoke detector. The advantages and disadvantages of glued connections still apply.

In a nutshell: summary of the main points

Install smoke detectors in at least the bedrooms, children's rooms and escape routes.
One smoke detector is sufficient for up to 60 m² (note special cases).
Make sure that the smoke detector is attached in such a way that the smoke can reach the smoke chamber (pay attention to beams, etc.).
It is safest if you screw on the smoke detectors.