Main Factors of Valve Selection Function and Piping System

Function and service considerations
Valves serve the purpose of controlling the fuids in building services piping.Nalves are produced in avariety of design types and materials.
Proper selection is important to ensure the most efficient,cost-effective and long-lasting systems.
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
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 dropd) velocity
5. Operating conditions
 a) Condensation
 b)Frequency of operation
 d) Overall sizelspace available
 e) Manual or automated control
 f) Need for bubble-tight shut-off