background
black
bolt
business
chemical
conduit
connection
construction
control
element
energy
engineering
equipment
factory
faucet
fitting
flow
fuel
gas
gasoline
icon
illustration
industrial
industry
isolated
metal
natural
oil
petroleum
pipe
pipeline
piping
plumbing
power
pressure
pump
sign
silhouette
steel
symbol
system
tap
technical
technology
tube
valve