"The Daring Dufas" wrote in message
...

stuff snipped

All of the commercial automatic doors I installed and serviced had a
breakout feature. I should note that it applies to sliding doors. You
may see a little red sticker on the door that instructs you to push
on the door in an emergency. The door will pop loose and swing open.
The commercial doors have all sorts of proximity sensors and safety
features to protect even the dumbest of humans but people still get
hurt. It's a constant battle against the dumb asses of the world. :-)

My dad did forensic engineering when he retired from the Navy. Automatic
doors really do injure people, especially the older doors without enough
sensors. Elderly people who move slowly are the most likely to get slapped
in the butt and knocked down by a door that "thought" that enough time had
elapsed for a person to clear the "swingway." That's why they've added mat
sensors, radar sensors, photocells and ultrasonics to many modern automatic
doors. Someone's grandma got knocked down. Repeatedly.

It's not just the dumb asses - it's the slow movers, too.

Multiple sensors became necessary because often times, maintenance on the
doors is deferred until an accident occurs. My dad continually came across
systems where a single sensor (out of 4) was left functioning and one sensor
is just not enough to figure out whether grandma has actually cleared the
door. As you're probably aware, many of the doors are made to be quite
powerful since they have to close against the significant air pressure that
can occur on windy days. That results in some pretty serious injuries to
elders with fragile bones.

But I can guarantee you from the grisly pictures he often brought home, that
automatic door accidents are a walk in the park compared to elevator
accidents where door closes on someone's arm and the car suddenly drops.
The worst I saw was when some kids got into the elevator room on the roof in
public housing in Baltimore and got caught up and shredded in the
cable/pulley system. There was another case at Syracuse U. where a
repairman cut off all the safety interlocks on a elevator WITHOUT placing
"out of order" signs on each floor as required while he worked on the
system.

There are enough fatal elevator accidents that occur each year to sustain
several law firms that do almost exclusively elevator litigation. A large
portion of elevator mishaps occur because of a failure of the door safety
lock mechanisms. The doors "catch" people and the car drops and, well, you
can imagine the rest. The bigger cars just cut people in two while smaller
cars sort of rip them apart. Often, the head is pulled right off the neck.

--
Bobby G.