hatch

steam

protection

water

manhole

street

hot

city

main

vapor

hole

smoke

urban

metal

technology

sewer

damage

emergency

iron

central

energy

white

heat

construction

circle

stop

zone

tape

red

security

caliduct

control

well

caution

warning

loss

barrier

hazard

danger

industry

safety

striped

restricted

restriction

attention

protect

dangerous

secured

supply

pipework

heating

conduit

power

consumption

accident

transportation