Samson 3241 User manual

Competence in Functional Safety
Functional safety of globe
valves, rotary plug valves, ball valves and butterfly valves
MANUAL
SMART IN FLOW CONTROL.

2
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
SAMSON
AIR TORQUE · CERA SYSTEM · KT-ELEKTRONIK · LEUSCH
PFEIFFER · RINGO · SAMSOMATIC · STARLINE · VETEC
Founded in 1907, SAMSON has since become a worldwide
leader in the manufacture of expertly engineered control
valves.
SAMSON has over 50 subsidiaries, amongst them noted
manufacturers of special valves.
With these subsidiaries, SAMSON is represented in over
80 countries to assist its customers on all continents.

3
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
Table of contents
1 Scope ...............................................................................................................................................................4
2 Validity of this manual ........................................................................................................................................4
3 Intended use of this manual.................................................................................................................................5
4 General aspects of functional safety.....................................................................................................................6
4.1 Standards, terms and abbreviations .............................................................................................................6
4.2 Determining the safety integrity level ............................................................................................................8
4.3 Hardware fault tolerance ............................................................................................................................9
5 Intended use of control valves in safety-instrumented systems................................................................................10
5.1 General control valve requirements............................................................................................................12
5.2 Globe valve requirements.......................................................................................................................... 13
5.3 Ball valve requirements .............................................................................................................................15
5.4 Butterfly valve requirements.......................................................................................................................16
5.5 Rotary plug valve requirements..................................................................................................................18
5.6 Proof tests and service life .........................................................................................................................18
6 Installation, piping and wiring ...........................................................................................................................19
6.1 Mechanical and pneumatic installation.......................................................................................................19
6.2 Electrical installation .................................................................................................................................20
6.3 Installation of control valves.......................................................................................................................20
7 Applicable device documentation ......................................................................................................................22
8 Appendix 1 – Manufacturer‘s declarations .........................................................................................................22
9 Appendix 2 − Example of a checklist for a final element......................................................................................30

4
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
1 Scope
Valves and the associated actuators are used to isolate pipelines in safety-instrumented systems. Alternatively, they can
also be used for pressure relief, i.e. by completely opening valves.
2 Validity of this manual
This manual applies to control valves manufactured by the following companies within SAMSON:
 SAMSON AG
 LEUSCH GmbH Industriearmaturen
 PFEIFFER Chemie-Armaturenbau GmbH
 VETEC Ventiltechnik GmbH
Refer to the manufacturer‘s declarations in Appendix 1 of this manual for the valve models concerned.
The individual versions of the valves can be identified by their nameplates
10 EB 8310-7 EN
Markings on the device
2 Markings on the device
2.1 Actuator nameplate
The nameplate is stuck on the diaphragm casing. It includes all details required to identify the
actuator:
2 Conguration ID
3 Serial number
4 Actuator area
5 Bench range in bar
6 Bench range in psi
7 Operating travel in mm
8 Operating range in bar
9 Operating range in psi
10 Permissible supply pressure pmax in bar
11 Permissible supply pressure pmax in psi
12 Symbol indicating fail‑safe action
Actuator stem extends (FA)
Actuator stem retracts (FE)
Manual override
14 Connecting thread
15 Diaphragm material
16 Date of manufacture
7
4
14
15 12 6
5
8
9
10 11
SAMSON 3271
Made in Germany
Var-ID
3
2
Serial no.
16
Fig.1: Nameplate
Example of a nameplate for a Type 3241
Valve with Type 3271 or Type 3277 Pneumatic
Actuator manufactured by SAMSON AG
12 EB 8015 EN
Markings on the control valve
2 Markings on the control valve
2.1 Valve nameplate
6 8
12 13
10 11
14 15 16 17 18
1…5 9
SAMSON
20
21
19
Fig.1: Valve nameplate
1…5 PED (Pressure Equipment Directive), "Art. 4, Abs. 3"
ID of the notied body, uid group, and category
6 Type designation
8Material
9Year of manufacture
10 Valve size:
DIN: DN · ANSI: NPS· JIS: DN…A/B
11 Pressure rating:
DIN: PN · ANSI: CL · JIS: K
12 Order no. with modication index
For after-sales service orders: AA prex
13 Position in order
For after-sales service orders: conguration ID
14 Flow coefcient:
DIN: KVS · ANSI: CV · JIS: CV
15 Characteristic:
%: equal percentage · Lin: linear · NO/NC: quick opening
16 Seat/plug seal:
ME: metal (see section3.3)
HA: carbide metal
ST: Stellite® facing
KE: ceramic
PT: soft seal with PTFE
PK: soft seal with PEEK
17 Seat code (trim material) · On request
18 Pressure balancing:
DIN: D · ANSI: B · JIS: B
19 Flow divider:
1: StI · 3: StIII
20 Country of origin
21 PSA version

5
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
3 Intended use of this manual
This manual is intended to assist planners and operators during the integration of control valves into a safety loop as
part of the safety function and to enable them to safely operate control valves.
This manual contains information, safety-related data and warnings concerning the functional safety in accordance
with IEC 61508 and concerning the application in the process industry in accordance with IEC 61511. It does not con-
tain any particular details on other safety requirements, such as explosion protection or electrical safety.
Safety-instrumented systems are to be commissioned and maintained by qualified personnel only. Refer to the corre-
sponding mounting and operating instructions of the valve.

6
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
4 General aspects of functional safety
4.1 Standards, terms and abbreviations
Abbreviation Designation Description
SIL Safety Integrity Level One of four discrete levels for specifying the safety integrity requirements
of the safety functions to be allocated to the E/E/PE safety-related systems,
where SIL 4 has the highest level of safety integrity and SIL 1 has the lowest.
MTBF Mean Time Between Failures Mean time between two failures
MTTR Mean Time To Restoration Mean time between the occurrence of a failure in a device or system and its
repair
HFT Hardware Fault Tolerance Capability of a functional unit to continue executing the demanded function
in case of faults or deviations.
λsd Failure rate for all safe detected
failures
λsu Failure rate for all safe undetected failures
λdd Failure rate for all dangerous detected failures
λdu Failure rate for all dangerous undetected
failures
SFF Safe Failure Fraction Fraction of non-hazardous failures, i.e. the fraction of failures without the
potential to set the safety-related system to a dangerous or impermissible
state.
PFDavg Average Probability of Failure on
Demand
Average likelihood that a dangerous safety function failures occurs on
demand.
TITest Interval between life testing of the safety
function
Average likelihood that a dangerous safety function failures occurs on
demand.
Low demand
mode
Low demand mode of operation Low demand mode is where the frequency of demands for operation made
on a safety-related system is no greater than one per year and no greater
than twice the proof test frequency.

7
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
Abbreviation Designation Description
MooN Voting “M out of N“ (e. g. 2oo3) Classification and description of the safety-related system regarding redun-
dancy and the selection procedure used.
• “N“ indicates how often the safety function is carried out (redundancy).
• “M“ determines how many channels must work properly.
Example: Pressure measurement in 1oo2 architecture
A safety-instrumented system decides that a specified pressure limit has
been exceeded if one of two pressure sensors reaches this limit. In a 1oo1
architecture, there is only one pressure sensor.
MooND Voting “M out of N“ with diagnostics
Relevant standards
Norm Designation
IEC 61508
Parts 1 to 7
Functional safety of electrical/electronic/pro-
grammable electronic safety-related systems
IEC 61511
Parts 1 to 3
Functional safety – Safety instrumented systems
for the process industry sector
VDI 2180
Parts 1 to 5
Safeguarding of industrial process plants by
means of process control engineering
Terms and definitions
Term Definition
Dangerous failure Failure with the potential to set the safety-related system to a dangerous or inoperative state.
Safety-related system A safety-related system carries out the safety functions needed to establish or maintain a safe state,
e.g. in a plant.
Example: Pressure measuring instrument, logic unit (e.g. limit switch) and valve form a safety-related system.
Safety function A defined function carried out by a safety-related system in order to establish or maintain a safe state of
the plant, under consideration of a specified dangerous incident.
Example: Pressure limit monitoring

8
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
4.2 Determining the safety integrity level
The achievable safety integrity level (SIL) is determined by the following safety-related data:
 Average probability of failure on demand (PFDavg)
 Hardware fault tolerance (HFT)
 Safe failure fraction (SFF)
The following table in accordance with IEC 61508 and IEC 61511 shows how the safety integrity level (SIL)
depends on the average probability of failure on demand (PFDavg). It is based on low demand mode of
operation, i.e. the frequency of demands on a safety-related system is no greater than once per year.
Safety integrity level (SIL) PFDavg (low demand mode)
4≥10-5 to <10-4
3≥10-4 to <10-3
2≥10-3 to <10-2
1≥10-2 to <10-1
PFDavg in low demand mode of operation according to IEC 61508-1, Table 2
The sensor, logic unit and final element form a safety-related system that performs a safety function.
Sensor
e.g. pressure
measuring instrument
PFDavg ≤X % ≤X % ≤X %
Logic unit
e.g. PLC
Final element
e.g. valve
The average probability of failure on demand (PFDavg = sum of sensor, logic unit and final element failures) must be within
the range of the demanded safety integrity level (SIL) in case of demand as listed in the above table.

9
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
4.3 Hardware fault tolerance
In the process industry, the achievable SIL classes for sensors, final elements and non-programmable logic modules,
such as isolating amplifiers and relays, are restricted in accordance with IEC 61511 as shown in the following table.
Safety integrity level (SIL) Minimum required hardware failure tolerance (HFT)
1 0
2 1
3 2
4 Special requirements (refer to IEC 61508)
Minimum required hardware failure tolerance (HFT) according to IEC 61511-1, Table 6, for the process industry
The minimum required hardware failure tolerance can be decreased by one if the following requirements are met:
 The device is proven in use.
Take this into account when selecting devices!
 The device only allows process-relevant parameters to be set, e.g. measuring range, upscale or downscale function
in case of failure.
Final elements do not have any configurable functions.
 The process-relevant parameters of the device are access-protected, e.g. by jumper or password.
Final elements do not have any configurable functions.
 The function requires a SIL less than 4.
A final element has a single-channel design, resulting in a hardware failure tolerance (HFT) = 0. This results in a single-
channel application up to SIL 1 or up to SIL 2 for proven-in-use devices.
At least two redundant devices are required for SIL 3 with proven-in-use devices.
At least three redundant devices are required for SIL 3 without proven-in-use devices.

10
Competence in Functional Safety
Functional safety of globe valves, rotary plug valves, ball valves and butterfly valves
5 Intended use of control valves in
safety-instrumented systems
Responsibility
The reliability of mechanical components is significantly affected by the operating condi-
tions and, as a result, by systematic failures. This needs to be taken into account when
selecting and sizing devices.
Safety-instrumented function
During normal operation, the signal pressure is applied to the pneumatic actuator. To
meet the requirements of the safety-instrumented function, the actuator is usually vented
by a solenoid valve. The force of the actuator springs moves the valve to its end position,
i.e. the valve is either completely opened or closed.
The end position of the valve must not be impeded by mechanical equip-
ment, such as travel stops or handwheels, under any circumstances.
When the signal pressure is applied to the actuator again, the valve moves to the corre-
sponding position. If the actuator is to be locked after a case of demand, this must be
ensured by the operator using suitable means.
Operator
Features of final elements
 Contact with the process media may cause systematic failure and, as a result, affect the
safety-related availability of the safety-instrumented systems. The influence of specific
process conditions must be analyzed and taken into account during sizing and main-
tenance.
These conditions arise from process requirements. To rule out systematic failure, we re-
commend creating a loop data sheet according to the German standard VDI 2180-5,
section 4 (recommendations for final elements).
In case of doubt, consult the manufacturer for valve sizing.
To reduce systematic failure, diverse redundancies may be advantageous (e.g. globe
valve and ball valve).
Operator