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

caution

warning

barrier

hazard

danger

safety

striped

restricted

restriction

attention

protect

dangerous

secured

inspection

shaft

line

conduit

pit

accident

round

pipework

transportation

repair

heating