alarm
alert
alertness
assistance
building
button
call
catastrophe
ceiling
danger
detector
device
domestic
emergency
fire
flame
grating
gray
grey
help
hotel
illustration
indoors
isolated
led
message
object
office
precaution
prevention
protection
red
rescue
risk
round
safety
security
sensor
service
signal
siren
smoke
sound
system
technology
warning
watchfulness