Corrosion Companies 

Anode Companies (9), Casing Spacer Companies (6), Cathodic Protection Companies (2), Cathodic Protection Equip. Companies (1), Closure Companies (15), Corrosion Coupon Companies (2), Flange Insulating Companies (12), Hot Tap Companies (10), Hot Tap Equip. Companies (13), Pig Companies (21), Pig Launcher-Receiver Companies (17), Pig Signal Companies (14), Pig Tracker Companies (15), Pipe Coating Companies (4), Pipeline Cleaning Companies (12), Pipeline Pigging Equip. Companies (2), Rectifier Companies (6)

Electrical Companies 

Cable Tray Companies (13), Electrical Cable Companies (8), Electrical Enclosure Companies (14), Electrical Fitting Companies (9), Generator Companies (7), HVAC Companies (10), Switch Companies (9), Transformer Companies (10)

Energy Companies 

Drilling Companies (22), Electric Companies , Gas Energy Companies (1), Nuclear Companies , Oil & Gas Companies (61), Oil & Gas Pipeline & Refinery Companies (15), Solar Energy Companies (6), Water Companies , Water Energy Companies , Wind Energy Companies (12)

Environmental Companies 

Clean Room Companies (2), Pollution Control Companies (5)

Equipment Companies 

Boiler Companies (32), Burner Companies (19), Compressor Companies , Cooling Tower Companies (14), Damper & Louver Companies (14), Dehydrator Companies (1), Dryer Companies (12), Engine Companies (10), Equipment & Tool Fabricating Companies (13), Fan & Blower Companies (11), Filtration Companies , Flare Companies (19), Furnace Companies (4), Heater Companies (18), Heat Exchanger Companies (45), LACT Unit Companies (6), Meter Run Companies (9), Motor Companies (8), Oven Companies (7), Oxidizer Companies (18), Pump Companies , Refrigeration Companies (4), Scrubber Companies (15), Separator Companies (43), Stairway & Walkway Companies (1), Steam Companies , Tank & Vessel Companies 

Fastener & Hardware Companies 

Beam Clamp Companies (3), Bearing Companies (21), Belt & Pulley Companies , Bolt, Nut & Washer Companies (29), Chain Companies (11), Gasket Companies (25), Gear Companies (33), Hose Clamp Companies (9), Hose Companies (19), Hose Reel Companies (3), Pipe Clamp Companies (6), Spring Companies (15), Wire & Cable Companies 

Instrument Companies 

Burner Instrument Companies (2), Controls Companies (1), Flow Instrument Companies (30), Gas Sensor Companies (1), Level Instrument Companies (35), PLC Companies (2), Pressure Instrument Companies (30), Sampling Companies (2), Temperature Instrument Companies (28), Thermowell Companies (9), Transmitter Companies (5)

Materials Companies 

Conveyor Companies (32), Crusher Companies (21), Foundry Companies (1), Metal Companies , Mineral Companies , Mining Companies , Mining Equipment Companies (22), Mixer Companies (17), Screener Companies (11), Structural Steel Companies (1)

Miscellaneous Companies 

Consulting Support Companies (2), Defense Companies (1), Fabrication & Manufacturing Companies (24)

Pipe, Flanges & Fitting Companies 

Bleed Ring Companies (11), Expansion Joint Companies (36), Fitting Companies , Flange Companies , Flex Connector Companies (8), Pipe Companies , Pipe Guide & Anchor Companies (4), Pipe Repair Clamp Companies (15), Pipe Support & Hanger Companies (7), Pulsation Dampening Companies (13), Quick Coupler Companies (16), Rupture Disk Companies (10), Saddle & Split Tee Companies (14), Spec Blind Companies (21), Straightening Vane Companies (17), Structural Steel & Tubing Companies (19)

Safety Companies 

Eyewash & Shower Companies (3), Fire Alarm & Detection Companies (7), Fire Hydrant Companies (16), Fire Sprinkler & Suppression Companies (6), Flange Safety Spray Shield Companies (7), Lockout/Tagout Companies (1), Noise Suppressor Companies , Personal Protection Equipment Companies (6)

Valve Companies 

Backflow Preventer Valve Companies (5), Ball Valve Companies , Block & Bleed Valve Companies (21), Butterfly Valve Companies , Check Valve Companies , Choke Valve Companies (23), Control Valve Companies , Diaphragm Valve Companies (10), Diverter Valve Companies (13), Gate Valve Companies , Globe Valve Companies , Needle Valve Companies (21), Pig Valve Companies (11), Pinch Valve Companies (16), Plug Valve Companies , Polymer Valve Companies (21), Pressure Regulator Valve Companies (16), Relief Valve Companies (64), Slurry Valve Companies (12), Solenoid Valve Companies (10), Tank Blanketing Valve Companies (3), Vacuum Breaker Valve Companies (4), Valve Actuator Companies (69), Valve Chainwheel Companies (4)