I have to say I'm curious as to why it needs to be impact resistant?
Perhaps try contacting Chubb Fire Safety, I know they do fire protection for prisons, so if they exist I expect they would be installed there.
Good luck 
I am glad mine are not impact resistant.
Made it easier to smash the faulty one off the ceiling at 3am :)
Stephen, maybe a litte steel cage over each one with a hole where the button is. And a rubber tipped broom handle 
Are the smoke detectors in the right place?
Ever since I have lived in this house, there has been one in the kitchen and it goes off all the time with just a little bit of smoke from cooking. I think I might relocate it to the other side of the doorway into the loungeroom, so that it doesn't go off when cooking.
Have you ever read what is written on the bottom of your smoke detectors. They have radioactive materials in them.
When I went to Battery World to ask if they had a radioactive free fire alarm that chap said no sorry they don't they need to be radioactive to detect the smoke. We then got talking and he told me that old folks like to use lithium batteries in them because that means they don't have to change them every year like most of us do on April Fools Day.
He said that the lithium batteries have to travel by truck as they are not allowed to be taken on airplanes.
(Hubby tried to stupidly resurect a lithium battery for one of the many gliders we have and luckily he'd just bought one of the protection glove things for a battery from Hobby king so when the batery exploded the flames only shot out in one direction and it was only half a metre away from him when it exploded. It took out a plane in front of it and it singed the wall that was 2 metres away from it. His guardian angel was on full alert thank goodness).
Is there any reaction that occurs with the lithium and the smoke detectors? Any link with home fires? Just thinking aloud.
Lithium Ion batteries are prone to catching fire when incorrectly charged, or when used at their limits (they are able to discharge very high currents). The RC plane batteries are about 50x bigger capacity than anything you'd use in the home. Most RC peeps do charge in the firebag or box just in case, lucky your hubby did - but bit silly to try and resurrect a dead one, Li packs are bloody dangerous if you play with them
There is no chance that the 0.01g of radioisotope in a smoke detector would "react" with the battery that is not in contact with it.
Top marks from trying to start a conspiracy theory your post is exactly how it starts
i don't reply to too many threads but this one I do have some expertise in. For a start don't mount any smoke detectors on the wall because as a rule that will be the last place the smoke will travel, obviously as heat rises it hits the ceiling and then moves across. If you ever get to watch a video of how fast a fire can take hold in a room then you will see that having the detectors in the right place are critical.
Domestic smoke detectors are made in two general formats. Ionisation and Photo-electric. Ionisation detect fast burning fires from natural sources such as wood and paper with large smoke particles, Photo- electric detect smouldering fires from synthetic products like seat cushions and plastics with small smoke particles.
If your sandwich maker is destroying them then have you got the right detector in the right place. If you are buying them from a hardware store then probably not. Ionisation near the kitchen and photo electric everywhere else is the rule of thumb. Go to your nearest electrical wholesaler ( where electricians buy their stuff ) and they should set you straight.
Annoys the hell out of me when people buy the cheapest detector they can find when you consider what's at stake. Your home and family are surely worth the best you can afford.
Having said that any detector can false alarm but the more you pay the less trouble you should have. Without pimping brands buy a Clipsal, Brooks, or PSA. They have been in the game way before anyone else. Not broom proof though
Agree with Waynos, we have hard-wired SDs with Li-Ion backup batts.
Also, not 100% sure about other states, but in Vic, there's no requirement to have a SD anywhere near a kitchen. They need to be located near bedrooms only (ie; passage between bed doors within certain distances, off entry where beds may be located), stairwells etc. The misconception that they need to be where you cook your food is incorrect. They need to be near sleeping areas or habitable areas isolated by sound to where the SDs are located.
See basic diagrams in the attached link for Class 1A buildings.
www.fire.nsw.gov.au/page.php?id=443
