alarm
alert
alertness
background
bus
business
carbon
ceiling
control
danger
detector
device
domestic
electronic
emergency
equipment
fire
fireproof
flame
heat
house
indicator
indoors
interior
modern
monoxide
object
office
prevention
protect
protection
rescue
room
safety
security
sensor
sign
signal
siren
smoke
sound
subway
symbol
system
technical
technology
train
transport
warning
white