What is dead Air Space & Why is important for my smoke alarm installation in my home

Smoke Alarms are vital for your home. They are made to be installed on ceilings (and when necessary, on walls) to detect smoke. However, there are areas in your home where they should not be installed, in the dead air space.

When we are at sleep, our sense of smell is lost, which eliminates our capacity to detect smoke and early warning signs of fire. This means it’s vital that smoke alarms are installed strategically to give us enough time to get to safety. They should be placed in areas where the air is not blocked from circulating.


Dead air spaces are areas in a property that gets air trapped which stops smoke from moving into that area. When a Smoke Alarm is installed in this area, the smoke may not reach it and trigger the alarm.

In a fire, smoke travels by rolling up the surface of the walls within the property. If the smoke is rolling against a surface with a sharp corner, then the smoke will not roll through that corner. Instead, it will float within the pocket of trapped air, leaving the space after the sharp corner unable to detect smoke as it is stuck in an air bubble.

Generally, dead air spaces can be found in property spaces that contain cathedral ceilings, corner junctions between the wall and roof or between exposed floor joists.

That’s why when installing Smoke Alarms you need to know where to install them. They should be in a position where they can detect smoke before it crawls into a dead air space.


Since dead air spaces appear in the corner of rooms and between exposed roof beams, here are some places you need to avoid:

  • Corners of rooms
  • Near A/C vents, windows that open, and ceiling fans
  • Near warm areas of the property like bathrooms and saunas
Other areas that you should avoid when installing smoke alarms:
  • Anywhere within 1.5 meters of a fluorescent light as the electromagnetic interference may affect the smoke alarms
  • In the kitchen, since this is an area with constant heat and smoke

If the Smoke Alarms in your investment or your own property happen to be located in dead air spaces you’re facing a big challenge. This is why it pays to use licensed and trained electricians for your Townsville properties smoke alarm installs!