Go
New
Find
Notify
Tools
Reply
  
EQUIPMENT CRITICALITY ANALYSIS Login/Join
 
posted
Hello everybody
Is there any published standard to determine the criticality rating and criticality index for rotary equipments?
Any standard nomber?
Ihave one(norsok 008) but I want to know if there are other published standards.
THANKS in advance.
 
Posts: 41 | Location: IRAN | Registered: 09 March 2006Reply With QuoteReport This Post
posted Hide Post
Not that I'm aware. Is there a way to calculate criticality? I thought it's yes or no to LOss of HSE. production & Economic? Can I view your Norsok 008? Does it tell how to calculate or you have to come out with your own matrix of risk?
 
Posts: 4285 | Location: Borneo | Registered: 13 February 2005Reply With QuoteReport This Post
posted Hide Post
Ali
i'm not aware of any standard that gives you the criticality and i believe you wont find anything reliable. The reason is because the criticality depends on the function and service that the equipment is performing within a system. Thus it cannot be calculated as a standard because it is variable depending on the company policies and function and service.
But on the other side there are many standard to guide you to calculate the criticality and they are basically based on 3 factors; economical criticality (loss of profit opportunities and maintenance cost and operating cost), safety criticality and environmental criticality.
All these 3 factors are correlated to likelyhood of the failure through a matrix relation.
As well you understand that all these factors are depending upon a huge amount of variables.
hope to have been of some help.
 
Posts: 18 | Location: bangkok | Registered: 17 September 2005Reply With QuoteReport This Post
posted Hide Post
ORIGINALLY POSTED BY LUCA
But on the other side there are many standard to guide you to calculate the criticality and they are basically based on 3 factors; economical criticality (loss of profit opportunities and maintenance cost and operating cost), safety criticality and environmental criticality.

THANKS Luca
If possible I am interested to have some of these economical based standard nombers(international standards are prefered).
 
Posts: 41 | Location: IRAN | Registered: 09 March 2006Reply With QuoteReport This Post
<Rui Assis>
posted
Ali-Af,

My first references on this issue were the American norm MIL-STD-882D – Appendix A and, later, the MIL-STD-1629. Take a look at what Quality America Inc. says about it:

http://www.qualityamerica.com/knowledgecente/articles/cre7.1.html

I use "criticality" as being the product: "probability" x "severity" x "delectability" and as Luca said, the classification depends on the specific functions of the equipment being studied and the consequences of a failure to the organization. Therefore, I would recommend that you use common sense and don't get too much limited by norms. I my self have assessed criticality quite a few times and criteria for the above classification used to be long discussed and finally agreed among people involved in every new case.

Regards,

Rui

This message has been edited. Last edited by: <Rui Assis>,
 
Reply With QuoteReport This Post
posted Hide Post
there is an interesting standard that you can download from any search engine: MIL-STD-1629A.
It is a little bit dated but basically nothing changed too much.
 
Posts: 18 | Location: bangkok | Registered: 17 September 2005Reply With QuoteReport This Post
posted Hide Post
quote:
Originally posted by Josh:
Not that I'm aware. Is there a way to calculate criticality? I thought it's yes or no to LOss of HSE. production & Economic? Can I view your Norsok 008? Does it tell how to calculate or you have to come out with your own matrix of risk?


Yes, there are few ways to calculate criticality. I would recommend you start with those two below.

1) MIL_STD 1629A
2) JA 1011 and JA 1012

It is important to understand that there are some similarities between RISK, Criticality and RPN. They have "the frequency criterion" in common. There are much to talk about criticality assessment and analysis, I am new at this forum and I will try to contribute with some of my experience.
 
Posts: 1 | Location: Edmonton, CA | Registered: 16 June 2010Reply With QuoteReport This Post
posted Hide Post
Well, Pls give some examples how do you do it.
 
Posts: 4285 | Location: Borneo | Registered: 13 February 2005Reply With QuoteReport This Post
posted Hide Post
Josh,
A Risk Matrix is a commonly used method. On the X axis we have probability in a logarithmic scale once in 100 years, once in 10 years, and so on, finally many times a year. On the Y axis we have consequence in a similar scale for HSE, Asset Loss and Production loss. Thus the Safety scale may be first-aid case, LTI, single fatality, multiple fatality. Aligned with each of these may be Prodn. loss with a scale of loss of <$1000. <$10k, <$100K, <$1000K, >$1000k. Note that we are not equating single fatality with $100-1000k. All it means is that it is the relative rank in its own scale. We draw up this matrix, and evaluate each system or sub-system and see where it sits in the matrix.
High probability-high consequence means extreme risk, while low probability low consequence means negligible risk, with items sitting in medium, high or very high categories as well, depending on our evaluation of the two variables. Normally, what we call Safety Critical Systems e.g., Fire & Gas Detection or Emergency Shutdown Systems will fall in the Very High or Extreme Risk cells.
Finally High Risk = High Criticality.
We use such matrices when doing e.g., RCM, RBI or IPF. A similar system of PRN is used in FMECA


Regards,
V.Narayan (Vee)
Lead Author, Case Studies in Maintenance and Reliability: A Wealth of Best Practices, 2012, Industrial Press.NY ISBN-13: 978-0831102210
Author, Effective Maintenance Management: Risk and Reliability Strategies for Optimizing Performance, Second Edition, 2011, Industrial Press NY ISBN-13: 978-0-8311-3444-0
 
Posts: 1374 | Location: Scotland, UK. | Registered: 16 May 2004Reply With QuoteReport This Post
posted Hide Post
According to ISO18436-2 level2 the critical equipment to measure on vibrations are rated into a highest frequency of 2 weeks, others are monthly or two-montly based. But in reality we look into the criticallity of breakdown of the onstream efficiency / spare parts avilability / spare parts costs and last but not least availability of rotating equipment personal and of course other issues like QHSE!!
Evaluate after a period of 12 months and look where and what things happened with the machine and look for root causes.
 
Posts: 250 | Location: USA | Registered: 12 June 2008Reply With QuoteReport This Post
posted Hide Post
ALI-AF,
I think everyone on the discussion has given good advice about the need to establish your own "criticality" using Risk Priority Number (RPN) or similar methodology. The consequence of failure impact to Safety, Environment, Productivity, etc. will be unique to each facility.
Next step is Failure Modes and Effects Analysis (FMEA). I believe you can find some data that will help you prioritize which failure modes occur more frequently in machinery.
See the OREDA Handbook as an excellent example of this data.
For rotating machinery shaft seals and bearings would represent a statistically higher likelihood of failure than say impeller wear or shaft failure.
A routine surveillance (visual inspection) of all machinery on startup / shut down and process change plus periodic vibration analysis are a good place to jump into your developing PdM program. . .
Best of luck
 
Posts: 29 | Location: Chesapeake, Virginia | Registered: 15 December 2006Reply With QuoteReport This Post
  Powered by Social Strata  
 


Copyright © 2004-2013 Reliabilityweb.com All rights reserved.