Why does your smoke alarm upstairs makes a sound every 10 minutes?

Answer 1

The main cause of this is a low battery. Most smoke detectors are designed to send out a low beeping sound (sometimes followed by a flash of the red light in some but not all designs) when the battery is low, to make the home owner aware they need a new battery.
If your smoke detector is wired up to the mains of the house (as the new UK laws state they should be in new homes), then the beeping/chirping will still occur if the backup battery needs replacing.
Once you have changed the battery, you may need to hold the test button down for around 30 seconds, depending on the make and model of the alarm (refer to the manual).

If changing the battery does not resolve the issue, then there is likely dust or dead insects interfering with the alarm. You should clean the alarm with compressed air.

If the alarm is sticky from nicotine, you will most likely have to purchase a new one. Nicotine contains hydrocarbons - and so does fire and carbon monoxide. But nicotine is sticky and therefore almost impossible to clean out of the alarm filters. You should always avoid smoking in the same room as a smoke detector (or even better, don't smoke indoors at all).

Failing that, the alarm might be faulty. If it is a battery operated one, purchase a new one. Or contact your local fire station on the non-emergency number. In the UK, some people such as pensioners are eligible for free smoke detector replacements from the local fire service.
If it is an electrical one, contact the manufacturer or the local fire station on the non-emergency number.

Answer 2

The likely problem is a low battery voltage. Most smoke detectors use 9V batteries and last for a year or more.