bolt
builder
compressor
connection
connector
construction
control
distribution
energy
engineer
engineering
equipment
factory
flowing
gas
gear
heat
industrial
industry
installation
installer
instrument
insulation
keeping
metal
part
pipe
pipeline
pipework
plant
plumber
power
pressure
pump
repair
repairman
screw
station
steam
steel
structure
technology
tube
tubing
valve
vessel
warmth
work
worker
yellow