Category Archives: Event Tree

Fault Tree+ Training – International System Safety Conference

Reliability Workbench FaultTree+

Fault Tree Analysis – Why you do it and what you get from it.

Minimal Cut Sets: Combinations of component failures that cause system failure.

Failure Models: How to put numbers into a Fault Tree, so you can get numbers out.

System Quantification: A brief overview of the calculations used to quantify a Fault Tree.

Friday the 13th Webinar: Reliability Workbench Upgrades 13.0.2

Although some might have superstitious feelings about Friday the 13th. We have chosen to hold a webinar to get you away from all the coffee talk. For Friday the 13th we have come up with a special preview of our next version of Reliability Workbench which is also version 13 (specifically 13.0.2). Join us for this special webinar, on Friday October 13th at 12 PM Eastern Time, to get an early look at the new features that have been added. We have added significant changes to the report viewer interface, updated Prediction stands, data linking to the Allocation module, new DLL functions, expanded IEC 61508 calculations for both the Fault Tree and FMECA modules, a new Fault Tree failure model, and a brand-new results dialog for the FMECA module, complete with ISO 26262 functionality. There’s plenty to get excited about.

Please register by clicking: HERE

As always if you have any questions, comments or feedback please let me know.

Best Regards, Jeremy

jhynek@isograph.com 

Best Kept Secret in Isograph’s software

Secret might be the wrong word to use here, it could be a matter of just asking myself or technical support the right questions. Even if you’ve been using Reliability Workbench, Availability Workbench, AttackTree+, or Network Availability Prediction for years, you’re probably still finding new features and tips and tricks to help you out in the software. Maybe one day you discovered a time-saver and thought to your self “what else can this software do to make my day easier?”

While there are plenty of helpful features in Isograph’s software to make your day easier, perhaps none is so powerful, incredibly useful, and so under-utilized as Plugins and the DLL. These features allow you to extend the power of Reliability Workbench, Availability Workbench, Attack Tree, and NAP tools to absurd heights. From creating macros for accomplishing tedious tasks, to automating fault tree construction, and even adding new features to the software that we haven’t even thought about, the Plugins and DLL can do it.

As always if you have any questions or need additional information on our products please feel free to contact me

Jeremy Hynek
Isograph, Inc.
jhynek@isograph.com
801 610 0045

Diverse CCF models in FaultTree+, presentation from RAMS 2017

Some of you might have noticed we have introduced a new website. This will allow us many advantages over the old site, however, the blog posts have been delayed a bit.

We recently attended the RAMS symposium in Orlando Florida. Where Joe Belland presented his paper on “Diverse CCF in Fault Trees”.

 

Joe RAMS

 

A full copy of this paper is available:

Diverse CCF in FT -Final

How To Use Your Settings in Reliability Workbench (FaultTree+)

We have collected commonly asked questions by our 1000’s of users. Some of the questions that we’ll answer along the way include:
Why do my cut sets show gate names with an asterisk next to them?
OK, so I enter a “failure rate.” Is that failures per… hour? Year? Geological epoch? What are the units?
This fault tree takes ages to calculate. Can I speed it up?
Fault tree uses approximation methods for solving the tree? Do I have any control over that?
My computer crashed and I lost 3 hours of work! Can I create automatic backups of my project?
What if I want to see MTTF on my fault tree, instead of Q?
I have a plotter. How do I print the whole tree on one piece of paper?
Can I force scientific notation in the results?
What if I don’t want to delete the inputs to a gate when I delete the gate?
I really love the font Comic Sans. Can I use that in my fault tree?
Also, chartreuse is my favorite color. How do I set that as default?
How do I set default options, so I don’t have to reset these every time I start a new project?

We’ll also look at the useful and often-overlooked Report Options. Did you know that you can force the diagram to be black & white for printouts? Or make the fault tree symbols bigger? Or change the order of the pages?

What is a LOPA and how can one use ETA to address it?

If you are looking for LOPA information chances are you probably already know what a LOPA is. For any of you are not familiar with a LOPA study, it could mean any number of things. However, for us a LOPA is an acronym meaning: Layer Of Protection Analysis. A LOPA can be a good and logical beginning, or addition, to your PHA (Probabilistic Hazard Analysis) studies. Which leads us to our next acronym ETA (Event Tree Analysis). Event tree analysis diagrams can be an effective approach to tackling your LOPA studies. Since this is probably easier viewed than described please take the time to watch our webinar addressing this topic:

 

Reliability Workbench Version 13… What’s New

As a follow up to our Webinar: What’s New in Reliability Workbench 13 Webinar I have included a recording of the meeting.

In addition to some minor visual upgrades the significant new features in Reliability Workbench 13.0 are:

  • The FIDES Prediction standard has been added to the Prediction Module.
  • 217Plus has been upgraded to version 2015.
  • The NPRD library has been upgraded to NPRD-2016.
  • The FMD 2016 failure modes library has been added to the NPRD parts library. FMECA blocks created from the NPRD library will now also have their failure modes automatically created where appropriate.
  • The SN29500 prediction standard has been updated to edition 2015-04.
  • IEC 61508 failure models have been extended to allow for high demand system frequencies (PFH values) to exclude detected failures.
  • Fault tree modularization has been made more efficient for projects that contain disconnected fault trees.
  • Sensitivity calculations may now be performed for IEC 61508 dormancy averaging. This applies when the dormant failure model is set to IEC 61508 in the project options dialog.

 

 

Linking Fault Tree and Event Tree

Event Tree Analysis (ETA) complementing your Fault Tree Analysis (FTA) is like putting salt on your popcorn. Event tree diagrams provide an excellent way of showing the possible outcomes of a hazardous event (often modelled in a FTA study). An ETA diagram is a simple, logical and easy to read diagram that breaks down data to show the possible consequences of failures in an FTA study.Event trees provide an inductive approach to reliability and risk assessment and are constructed using forward logic.

FaultTree+ in Reliability Workbench includes integrated event tree analysis. The event tree model may be linked to the fault tree model by using fault tree gate results as the source of event tree probabilities. FYI, if you already have a copy of FaultTree+ the Event Tree Software is included!

Please register for this educational Webinar: Linking FaultTree+ and Event Tree Analysis on Jun 2, 2016 11:00 AM MDT at: CLICK HERE

Flow Regulator ET

We appreciate your support of Isograph. If you have any general questions or comments please feel free to contact me.

Sincerely,

Jeremy Hynek
Isograph, Inc.
Director North American Operations
801 610 0045
jhynek@isograph.com

 

Fault Tree model from a schematic recap

Thank you to everyone that attended our last meeting “building a Fault Tree from a schematic”. I realize that there were many that were not able to attend the meeting. The warning that there are limited seats held true and the meeting did fill up leaving many of you to wonder what the proper logic was to modeling the schematic posted.

Not to worry, the meeting was recorded and can be accessed from the following link:

Since everyone in the meeting was muted watching the recording is almost as good as being there.

However, don’t miss the chance to watch this weeks meeting live where we will be showing how to create various reports on the model we built last week. The same goes this week… please sign up to save a place in the meeting.

https://attendee.gotowebinar.com/register/8450527877752487681

As always please contact me with any questions.

Best Regards, Jeremy

Jhynek@isograph.com

Is your modeling logic…logical?

When modeling (or modelling for those of you in the UK) your system in a Fault Tree or Reliability Block Diagram do you ever wonder if your logic is covering all possible failures or properly accounting for redundancy in your system?

Try your hand at modelling the included schematic in a Fault Tree or Reliability Block Diagram (RBD) then join us on a Webniar, Friday at 10am PST, to see if your model matches up with the model one of our support experts comes up with. If you do not have access Fault Tree Analysis or RBD software please let me know and I will lend you software to use during this meeting.

schematic

The safety system is designed to operate as follows: should a runaway reaction begin, the temperature sensor (TS1) and pressure sensor (PS1) will detect the increase in temperature and pressure and start the safe shutdown process. The provision of two sensors is for redundancy; only a single sensor needs to register the unsafe reactor conditions to engage the safety system. Should either TS1 or PS1 detect a runaway reaction, two things will occur: 1) a signal will be sent to the controller (CON), which will close the electric valves in each reactor input (EV1 and EV2), and 2) the alarm (ALARM) will sound, signaling the operator (OP) to close the manual valve in each reactor input (MV1 and MV2). In order to stop the runaway reaction, BOTH inputs must be shut down. However, only one valve on each input needs to be shut. So only MV1 or EV1 must be shut to stop input 1, but at least one valve on input 1 and at least one valve on input 2 must close to stop the inputs to the runaway reaction. Note that EV1 and EV2 (and only these components) are powered by the electrical grid; all other components have independent battery backups or power supplies.

 

 

Registration URL: https://attendee.gotowebinar.com/register/7009501341095130369