Posted By Ashley Wood
Hi, take a look at this company www.hardall.co.uk they manufacture what you are looking for. These are normally stand alone in the sense that they have a fusible link that closes the damper when it get hot. The only word of caution I have is this, I have carried out hundreds of fire risk assessments on blocks where these devices or similar have been fitted. A large proportion would never operate because the chutes are stacked up with waste. This is due to the fortnightly waste collection policy and the bins becoming full to over flowing, as residents use the chutes the waste backs up! I have recommended in many cases the installation of a small water based mist or sprinkler system to damp down the fire. Again, these are self contained units.

Hope this helps?