Selection

Valves serve the purpose of controlling the fluids in building services piping. Valves are produced in a variety of design types and materials.Proper selection is important to ensure the most efficient, cost-effective and long-lasting systems.

Function
Valves are designed to perform four principal functions: 1. Starting and stopping the flow　2. Regulating (throttling) the flow　3. Preventing reversal of the flow　4. Regulating or relieving the pressure of the flow

Service Considerations
1. Pressure　2. Temperature　3. Type of fluid    a) Liquid　　　　　b) Gas; i.e., steam or air　　　　　c) Dirty or abrasive (erosive)　　　　　d) Corrosive　　4. Flow　　　　　　a) On-off throttling　　　　　　b) Need to prevent flow reversal　　　　　　c) Concern for pressure drop　　　　　　d) Velocity　　5. Operating conditions　　　　　a) Condensation　　　　　b) Frequency of operation　　　　　c) Accessibility　　　　　d) Overall size/space available　　　　　e) Manual or automated control　　　　　f) Need for bubble-tight shut-off

Valve Design, Materials, and Approvals
Valve Design Choices
　　1. Multi-Turn　　　　a) Gate　　　　b) Globe/Angle-Globe　　2. Quarter-Turn　　　　a) Ball　　　　b) Butterfly-resilient seated　　3. Check (backflow prevention)　　　　　a) Swing　　　　　b) Lift　　　　　c) Spring-actuated　　4. End connections

Materials
1. Bronze (up to 550°F at 150 psi/up to 600 psi at 150°F) 1/4"-3"　　　　2. Cast Iron (up to 450°F at 250 psi/up to 500 psi at 100°F) 2"-24"　　　　3. Ductile Iron (up to 650°F at 125 psi/up to 600 psi at 100°F) 2"-12"　　　　4. Stainless Steel (up to 650°F at 125 psi/up to 2000 psi at 100°F) 1/4"-12"

Approvals
1. Manufacturers Standardization Society (MSS)　　　　2. Fire protection (UL® and FM)　　　　3. State and local codes.