#1 2016-05-30 18:03:59

rgeng

Member

SIL in the report

Good evening,
first of all, Thank You for Your great software.
I've downloaded it this afternoon and now I'm trying to understand the use of the program with the standard example.

Generating the report with that example, I've notice also few rows concerning SIL in the report.
Concerning SIL, I saw  SIL 1  from 0.001 to 0.01,  SIL 2 from 0.0001 to 0.001, etc.
But, if we consider PFD, (probability of Failure on demand - ref.IEC 61508), these values should be 10 times greater: so, SIL 1 from 0.01 to 0.1 (RRF=risk reduction factor = 1/PFD --> from 10 to 100), SIL 2 from  0.001 to 0.01 (RRF from 100 to 1000) and so on.
Or didn't i understand well, and perhaps is there another meaning for the SIL for the quantities in the report? I searched something concernig Sil in the help, but i've found no information concerning that part of report.

Anyway, many thanks for Your fantastic software.

Roberto (from Italy)

Emmanuel

Administrator

Re: SIL in the report

Good morning Roberto,

you can check the documentation of XFTA (the fault tree calculation engine) at this address http://www.arbre-analyste.fr/doc/lib/ex … manual.pdf. The paragraph related to the Safety Integrity Levels is page number 25.

Maybe this will help you.

Regards.

rgeng

Member

Re: SIL in the report

Hi Emmanuel, thank You.
Infact in the documentation of XFTA - see page number 27 - the values of PFD are correct, according IEC 61508 (for example from 0.01 to 0.1 for SIL 1, from 0.001 to 0.01 to SIL 2 and so on).

Instead, in the Report generated by the program , it appears:

SIL

La tabella riporta l'andamento SIL nel tempo.
SIL    limite inferiore    limite superiore    sojourn-time    rapporto
1    0.001                         0.01               181.743    0.020747
2    0.0001                0.001              16.7648            0.00191379
3    1e-005                0.0001                     0    0
4    0                         1e-005             0

To Note:  the values of the legend in the table of the report -see table above - are ten times greather than PFD tha we could have
I.e in the table above, SIL 1  from 0.001  to 0.01 - Instead, the values of the limits of PFD for SIL 1  should be from 0.01 to 0.1, according to the standards.

Is it just a problem of the values of the legend in the table?

Regards

Emmanuel

Administrator

Re: SIL in the report

Ok, I understand. I think there is an error in the SIL table returned by XFTA.

I will add this problem to the road-map.

Thank you for your contribution. If you have any other suggestion, please don't hesitate to contact us.

Regards.

cousten

Member

Re: SIL in the report

Hi,
the problem of SIL table is still in the version 2.3.2.
Regards