| 1 |
Ball Valve |
On/off isolation for clean liquids, gases, hydrocarbons, and many corrosive services when correctly lined or alloyed. |
Commonly DN15–DN600; pressure classes commonly PN10–PN100 or ASME Class 150–600, depending on design. |
Install with the correct flow direction where specified; provide actuator clearance and support heavy actuators. Avoid using standard full-port designs for throttling unless specifically rated for it. |
Low routine maintenance. Inspect seals, stem area, actuator coupling, and leakage. Seat wear can increase under abrasive, flashing, or frequent-cycle service. |
Verify cavity-pressure relief requirements, fire-safe qualification where applicable, anti-static continuity, lockout capability, and fugitive-emission control. |
Low to medium initial and operating cost; high value for tight shutoff and low pressure drop. |
9.0 / 10 |
| 2 |
Butterfly Valve |
Large-diameter isolation and moderate control of water, air, gases, cooling media, and compatible process fluids. |
Commonly DN50–DN3000; pressure ratings often PN6–PN40 or ASME Class 150–300. |
Requires correct disc orientation, flange alignment, and sufficient clearance for disc rotation. Do not allow flange gaskets to intrude into the bore. |
Generally low maintenance. Check shaft seals, liner or seat condition, disc alignment, fasteners, and actuator travel stops. Elastomers may age with temperature or chemical exposure. |
Confirm pressure-temperature limits, downstream personnel protection, disc clearance, and actuator fail position. Avoid rapid closure that could create water hammer. |
Low for large-bore service; lightweight construction reduces handling, support, and actuator costs. |
8.8 / 10 |
| 3 |
Gate Valve |
Full-flow isolation in pipelines carrying liquids, gases, steam, and some slurries when the design is suitable. |
Commonly DN50–DN1200; pressure ratings frequently PN10–PN100 or ASME Class 150–600. |
Install with adequate stem access and structural support. The valve should normally operate fully open or fully closed; partial opening can cause vibration and seat damage. |
Inspect packing, bonnet joint, stem threads, wedge or slab movement, and corrosion. Exercise periodically where infrequent operation may cause sticking. |
Use isolation and depressurization procedures before servicing. Consider trapped-pressure relief, stem position indication, and pinch-point protection during operation. |
Medium; low running pressure loss but potentially higher weight, installation effort, and maintenance labor than quarter-turn designs. |
8.2 / 10 |
| 4 |
Globe Valve |
Accurate throttling and flow regulation for steam, hot water, chemicals, and other controlled process streams. |
Commonly DN15–DN400; pressure ratings often PN16–PN100 or ASME Class 150–600. |
Observe the specified flow direction and provide actuator access. The higher-flow-resistance body may require additional pump or compressor head. |
Inspect trim, seat, plug, packing, actuator calibration, and positioner performance. Cavitation, flashing, and erosion may require special trim or staged pressure reduction. |
Assess noise, vibration, outlet velocity, cavitation risk, and fail-safe position. Ensure control-loop settings do not cause excessive cycling. |
Medium to high; higher energy consumption and trim maintenance may be offset by precise process control. |
8.5 / 10 |
| 5 |
Check Valve |
Automatic prevention of reverse flow in pumps, compressors, pipelines, water systems, and process equipment. |
Commonly DN15–DN1200; pressure ratings frequently PN10–PN100 or ASME Class 150–600. |
Install according to flow arrow and orientation. Select swing, lift, dual-plate, or axial design based on velocity, pulsation, space, and allowable pressure drop. |
Limited external maintenance, but internal inspection may be needed for fouling, hinge wear, spring failure, seat damage, or deposits. Test after pump or piping changes. |
Control slam and water hammer by checking closing dynamics. Protect against reverse rotation of pumps and compressors and verify correct installation after maintenance. |
Low to medium; relatively simple, but failure can cause costly equipment damage or process interruption. |
8.4 / 10 |
| 6 |
Plug Valve |
Isolation and limited control for dirty liquids, slurries, gases, and services where a compact quarter-turn valve is advantageous. |
Commonly DN25–DN900; pressure ratings often PN10–PN100 or ASME Class 150–600. |
Provide adequate clearance for the lever or actuator. Lubricated designs need a compatible injection system; sleeved designs require correct temperature and chemical compatibility. |
Inspect body seals, stem seals, sleeve or plug surfaces, and operating torque. Lubrication intervals depend strongly on service, cycle frequency, and valve design. |
Manage trapped pressure, hazardous fluid release, and operating torque. Use anti-blowout stems and suitable fire-safe or emission-control features where required. |
Medium; robust in difficult media, though lubricant, seal, and torque-management requirements can raise service costs. |
8.0 / 10 |
| 7 |
Diaphragm Valve |
Corrosive, ultrapure, sanitary, viscous, and solids-bearing fluids where isolation from the operating mechanism is valuable. |
Commonly DN15–DN300; pressure ratings often PN6–PN16, with limits determined by lining, diaphragm, and temperature. |
Install in the recommended orientation and avoid excessive pipe strain. Select wetted lining and diaphragm materials for the actual chemical and temperature profile. |
Diaphragm is a planned wear component. Inspect for cracking, embrittlement, swelling, leakage, and loss of travel; replacement frequency depends on cycles and process chemistry. |
Use compatible materials and protect the diaphragm from overpressure, vacuum, sharp solids, and excessive temperature. Confirm containment and drainage procedures. |
Medium to high; excellent contamination control and corrosion resistance can reduce leakage and cleanup costs. |
8.1 / 10 |
| 8 |
Needle Valve |
Fine metering, instrument isolation, sampling, calibration, and low-flow control. |
Commonly DN6–DN50; pressure ratings can range from low pressure to above ASME Class 600, depending on construction. |
Install with clean, supported tubing or pipework. Keep the small orifice free from debris and ensure the handle or actuator remains accessible. |
Check stem packing, seat shutoff, thread condition, and blockage. Cleanliness and periodic leak testing are more important than frequent mechanical servicing. |
Use correct pressure ratings, double-block-and-bleed procedures where required, and protection against accidental adjustment or injection hazards. |
Medium; low purchase quantity and energy cost, but precision materials and calibration requirements can increase installed cost. |
7.8 / 10 |
| 9 |
Safety Relief Valve |
Overpressure protection for pressure vessels, boilers, pipelines, pumps, compressors, and thermal expansion zones. |
Sizes and set pressures vary widely; selection must be based on certified capacity, relieving scenario, and applicable pressure-equipment rules. |
Install upright unless specifically approved otherwise. Keep inlet pressure loss low, discharge piping supported, outlets safe, and drains arranged to prevent liquid accumulation. |
Requires documented inspection, set-pressure verification, leakage checks, and periodic bench testing or replacement according to regulation and site risk assessment. |
Never isolate or block the relief path without an approved protection plan. Size for credible overpressure cases and route discharge away from people and ignition sources. |
High justified cost; purchase and testing costs are significant, but the valve is essential for preventing catastrophic pressure events. |
9.5 / 10 |
| 10 |
Control Valve |
Continuous automatic control of flow, pressure, temperature, level, and composition in process loops. |
Commonly DN15–DN1000; pressure classes and trim capacity vary widely with flow coefficient, temperature, and service conditions. |
Confirm flow direction, actuator orientation, fail action, instrument-air or electrical supply, bypass philosophy, and accessibility for calibration and trim removal. |
Planned inspection should cover trim, packing, actuator diaphragm or piston, positioner, tubing, calibration, and diagnostic data. Service severity determines overhaul intervals. |
Evaluate cavitation, flashing, noise, vibration, high velocity, fail-safe response, hazardous-area requirements, and emergency shutdown interaction. |
High initial and maintenance cost; can deliver the lowest total cost when it improves control stability, product quality, and energy efficiency. |
9.2 / 10 |