Good morning Everyone, For valve SIL calculations, do we need to include the failure rates of all valve components, such as the solenoid, actuator, and valve body? Should the actuator and valve body also be included?

I'll hold my hands up: I've been quiet in here for longer than I would have liked. Project work took over, and the community hasn't had the attention it deserves. That's changing from this week. Here's what's coming: - Decision Review Live is back — Friday 17th July, 6pm. Bring a real grey-area decision from a live project and we'll work through it together. - A new cohort of the nuclear programme opens in September — more on that shortly. - Q&A is coming back, running bi-weekly. - New SILVerify features are in development and will be live soon. - More case studies and guides on the way. Got a question sitting in your drafts? Post it, and let the community do its thing.

Quick one for Premium members. I've just published a lesson called "Nuclear Runs on a Safety Case" as part of the Get into Nuclear Foundations unit — it's included free with your Premium membership, no VIP upgrade needed. It's the piece that explains why nuclear safety works on argued cases rather than checklist compliance, which is a key concept to grasp when coming into the industry. I want to make sure it's actually landing before I finalise the full course, so if wouldnt mind, go through it and tell me: Did the "argument vs. compliance" distinction make sense, or did you have to reread it? Was there a point where you thought "wait, what?" Anything you'd want explained differently to make it click faster? Drop it in the comments here, or reply directly on the lesson. Genuinely want the rough edges

Good day everyone, I have few questions on SIL Calculation. I have a PILZ controller in SIF and try to make some calculation by hand. Controller has DI and DO with CPU. 1. If I would like to calculate PFDavg for Controller then I should combine DI, DO and CPU PFD avarage, correct? (No redundancy at DIs and DOs) For ex, PFD input, single + PFD output, single+ PFD CPU = 2,20 x 10^-4 + 1,30 x 10^-5 + 6,20 x 10^-5 (See please certificate) 2. As you see the certificate shows only PFD but not λ DU. Can I calculate my λDU from PFD as referencing the formula below? PFDavg = (λDU * T)/2 . Actually, the certificate does not say what T has been taken into account on PFD calculation as well, but I am going to take it as 1 year. 3. CPU Part: 773103 ( PNOZ m1p ETH) ; Certificate Link: https://www.pilz.com/download/open/PNOZmulti_TUEV-Sued_BM_M6A-020132-0284-R01_R4_4_valid_2030-Jun-24_1002803-BM-34.pdf Thank you!