The type. Only photoelectric alarms comply. If the cover doesn't say photoelectric, it's an ionisation unit and it has to come out, no matter how new it is.
The date. Every alarm has to be replaced within ten years of the manufacture date printed on the back. That's the manufacture date, not the day it went up, and it applies whether or not the alarm still tests fine.
The power. Either hardwired 240V with a backup battery, or a sealed 10-year battery. The old style that takes a 9-volt battery once a year doesn't comply.
The positions. One inside every bedroom, one in each hallway connecting bedrooms to the rest of the house, and one on any storey that hasn't got a bedroom on it. He also checks how close they sit to ceiling fans and air con outlets, because a compliant alarm in a bad spot is a slow alarm.
The interconnection. Press the button on one and the rest of the house should sound within a few seconds. Glenn tests from each alarm, not just the one by the door, because a wireless set can lose a unit at the far end of the house and still seem to work.






