Festo VZXA-K, Instructions, Operation

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Translation of the original instructions
1 About this document
This document describes the use of the above-mentioned product. It contains
additional information for use of the product in safety-related systems (safety
handbook in accordance with IEC 61508).
1.1 Further applicable documents
All available documents for the product è www.festo.com/pk.
1.2 Specified standards
Version
IEC 61508:2010 Part 1,2,4 … 7 IEC 61511:2016
Tab. 1 Standards specified in the document
2 Safety
2.1 General safety instructions
– Only use the product in original status without unauthorised modifications.
– Only use the product if it is in perfect technical condition.
– Use the valve only in the flow direction indicated.
– Take into consideration the ambient conditions at the location of use.
Media
– Only use media in accordance with the specifications
è
16 Technical data.
– Use only media that will not cause dangerous reactions if mixed.
– Do not operate the product with chemically unstable gases, abrasive mediaor
solid materials.
– If water is used: up to approx. 1000 ppm of chloride content is permitted.
Avoid tensile stresses.
– If aggressive media are used: limit temperature of medium to 65 °C.
Actuator
– Do not open the actuator (pressure in the actuator or loaded spring).
– Avoid mechanical stresses on the valve. Do not use the actuator as a lever.
Return to Festo
Hazardous substances can endanger the health and safety of personnel and
cause damage to the environment. To prevent hazards, the product should only
be returned upon explicit request by Festo.
–
Consult your regional Festo contact.
– Complete the declaration of contamination and attach it to the outside of the
packaging.
– Comply with all legal requirements for the handling of hazardous substances
and the transport of dangerous goods.
2.2 Intended use
The angle seat valve VZXA-...-K is intended to shut-off gaseous or liquid media in
piping systems.
–
To control liquid media, use only the product variant VZXA-B-... Use (media
flow under valve seat).
2.3 Training of qualified personnel
Work on the product should only be conducted by qualified personnel. The quali-
fied personnel must be familiar with installation of process automation systems.
3 Information on functional safety
3.1 Operating conditions
– General information on safe operation è 2 Safety.
– Periodic tests (performance test) è 11 General.
– Ambient conditions and additional technical specifications
è 16 Technical data.
3.2 Achievable safety rating
The product is suitable for use as an element in a safety-related system in accord-
ance with IEC 61511.
–
In low-demand mode up to SIL 2
– In high-demand mode up to SIL 2.
Taking into account the necessary minimum hardware fault tolerance of HFT = 1,
the product can also be used up to SIL 3 with a redundant execution of the entire
system.
NOTICE!
It is only possible to determine whether the product is suitable for specific applic-
ations by also assessing further components of the subsystem.
3.3 Safety function
Single-acting valves
The safety function comprises acceptance of the initial position on request. The
request is implemented by removal of the operating pressure.
–
Valves with NO control function: the valve opens completely and remains
open until operating pressure is applied.
– Valves with NC control function: the valve closes completely and remains
closed until operating pressure is applied.
Double-acting valves
The safety function comprises acceptance of the required position on request.
This requires an external power supply.
3.4 Characteristic values
Safety standards (in accordance with IEC 61508) Value
Assessment path (Route of assessment) 2
H
/ 1
S
Type of subsystem (Type of Sub System) Type A
Operating mode (Mode of Operation) Low Demand and
High Demand
Test interval (Assumed Test Interval) T
i
1 a
Confidence level (Confidence Level) 1- á 95 %
Hardware fault tolerance (Hardware Fault Tolerance) HFT 0
Failure rate for dangerous errors (Lambda Dangerous) ë
D
1.36 * 10
-7
/h
Failure rate for dangerous errors not detected (Lambda Dan-
gerous Undetected) ë
DU
1.36 * 10
-7
/h
Mean time to dangerous failure (Mean Time To Dangerous Fail-
ure) MTTF
D
7.37 * 10
6
h
Degree of coverage of dangerous errors through the proof test
(Proof Test Coverage) PTC 95 %
Low Demand Mode
Assumed demands per year (Assumed Demands per Year) n
op
1 / a
Mean probability of dangerous failure on demand (Average
Probability of Failure on Demand) PFD
avg
5.95 * 10
-4
High Demand Mode
Assumed demands per year (Assumed Demands per Year) n
op
1/h
(8760/a)
Mean frequency of a dangerous failure per hour (Probability of
dangerous Failure per Hour) PFH 1.36 * 10
-7
/h
Tab. 2 Safety standards (in accordance with IEC 61508)
4 Further information
– Accessories è www.festo.com/catalogue.
– Spare parts è www.festo.com/spareparts.
5 Service
Contact your regional Festo contact person if you have technical questions
è www.festo.com.
8119907
VZXA-K
Angle seat valve with piston actuator
8119907
2019-08b
[8119909]
Instructions | Operation
Festo AG & Co. KG
Ruiter Straße 82
73734 Esslingen
Germany
+49 711 347-0
www.festo.com