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Thread: Sil calculation

  1. #1

    Lightbulb Sil calculation

    Hy, can somebody upload a ***** for the next tools:
    SilCore Version 4.5 , or exSilentia (

    [link Point to another website Only the registered members can access] Booth software it is necessary for SIL calculation and PFD quantifications.
    Or please post some examples regarding SIL and PFD calculations.
    Thank you,
    Cos


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  3. #2
    could you please explaine this software

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  5. #3

    Join Date
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    for SIL, please refer to the following; it is in english.

    [link Point to another website Only the registered members can access]
    for PFD,
    "performance of safety systems is measured in terms of the Probability of Failure on Demand (PFD). This attribute is important in the safety world as its values represent a measurement for the safety introduced. The required PFD is expressed in national and international standards as the safety integrity level [1,2].
    These safety integrity levels (SIL) represent discrete levels of reliability depending on the severity of the process or the equipment under control" ... from SafetyUsersGroup.com

    thank you to the original poster.


  6. #4
    thanks

  7. #5
    thanks
    McClaud

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  9. #6
    The concept of safety integrity levels (SILs) was introduced during the development of BSEN 61508 (BSI 2002) as a measure of the quality or dependability of a system which has a safety function – a measure of the confidence with which the system can be expected to perform that function. It is also used in BS IEC 61511(BSI 2003), the process sector specific application of BS EN 61508 ways.
    In particular they recognise that many such functions are only called upon at a low
    frequency / have a low demand rate. Consider a car; examples of such functions are:
    · Anti-lock braking (ABS). (It depends on the driver, of course!).
    · Secondary restraint system (SRS) (air bags).
    On the other hand there are functions which are in frequent or continuous use; examples of
    such functions are:
    · Normal braking
    · Steering
    The fundamental question is how frequently will failures of either type of function lead to
    accidents. The answer is different for the 2 types:
    · For functions with a low demand rate, the accident rate is a combination of 2 parameters
    – i) the frequency of demands, and ii) the probability the function fails on demand (PFD).
    In this case, therefore, the appropriate measure of performance of the function is PFD, or its reciprocal, Risk Reduction Factor (RRF).
    · For functions which have a high demand rate or operate continuously, the accident rate is the failure rate, λ, which is the appropriate measure of performance. An alternative measure is mean time to failure (MTTF) of the function. Provided failures are
    exponentially distributed, MTTF is the reciprocal of λ.
    These performance measures are, of course, related. At its simplest, provided the function can be proof-tested at a frequency which is greater than the demand rate, the relationship can be expressed as:
    PFD = λT/2 or = T/(2 x MTTF), or RRF = 2/(λT) or = (2 x MTTF)/T
    where T is the proof-test interval. (Note that to significantly reduce the accident rate below the failure rate of the function, the test frequency, 1/T, should be at least 2 and preferably ≥ 5 times the demand frequency.) They are, however, different quantities. PFD is a probability– dimensionless; λ is a rate – dimension t-1.

  10. #7
    SilCore Version 4.5 , or exSilentia can make SIL and PFD calculations.
    Can anyone help me??
    Thank you,
    COS

  11. #8
    thank you

  12. #9
    Some tools for SIL and PFD analysis:

    1.ABB,TRAC – Trip Requirement and Availability Calculator
    2. ACM Facility Safety, SilCoreTM
    3. AIM-Asset Integrity Management, SILSuiteTM
    4. Exida, exSILentiaTM SILeverTM
    5. Hima, SILenceTM
    6. Iso Ingénierie, EvoluSIL®
    can somebody help me with one of this, or another else necessary for PFD calculations ??

  13. #10
    Can anyone help me????

  14. #11
    I send you a useful document in mihd.net:

    [link Point to another website Only the registered members can access]


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  16. #12
    SIL cal is mostly used in operating and maintenance phase. Series ISA 84 may allow us to build yourself, basing on the simplified algebraic formulas in Xcel to manage your elements of SRS in your plant.

    Just build it up to save money

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