12
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
5.1 General control valve requirements
Responsibility
For each application, the user must specify the following conditions:
Maximum/minimum transit time OPEN
CLOSED or CLOSED
OPEN
Permissible leakage rate
Maximum/minimum supply pressure of the compressed air network
Air capacity available in relation to pressure
Connecting pipe cross-sections must be adhered to.
Operator
Nominal size
(connection length
≤
2 m)
K
VS
coefficient
0.16 · 0.32
1.4
4.3
–
Connection
Pressure (bar)
4
1 and 3
4
9
≥
1.4
≥
DN 6
≥
DN 8
≥
DN 10
≥
DN 4
≥
2.5
≥
DN 4
≥
DN 6
≥
DN 8
≥
6
≥
DN 4
≥
DN 6
Note: A larger nominal size is needed when the connection length exceeds 2 m.
Example: Connecting pipe cross-sections required for SAMSOMATIC Type 3963 Solenoid Valve
Manufacturer
SAMSON uses calculation methods to predict the transit time and to size the pneumatic
hook-up. SAMSON can support users in selecting devices on request.
The seat shut-off performance (leakage rate) must be tested at regular intervals by
performing plausibility checks while the process is running or
measuring it on a leakage test bench.
The type of test depends on the application.
The external leakage (fugitive emissions) must be tested at regular intervals, e.g. by spray-
ing with foaming agent.
The conditions depend on the process requirements.
Manufacturer
Operator
