Visite nuestro sitio en Español: Confiabilidad.net    RSS | Contact

Articles: Reliability Engineering

Removing Barriers to Reliability

Effective planning and scheduling are foundational elements for successful work management.

Well-defined and implemented planning and scheduling processes ensure that a plant’s most important work will be done safely, efficiently and at the right time. Duke Energy professionals work diligently at improving their Midwest and Carolinas fleet’s work processes through a Barrier Process. Work exceeding Estimated vs. Actual Hours targets is flagged, categorized and documented by technicians in the CMMS. These exceptions are reviewed weekly at a Barrier Meeting and assigned to plant personnel responsible for removing identified barriers. Barriers such as incomplete planning, incorrect parts, poor communication or coordination, scope creep, etc., result in unsafe situations, a frustrated workforce, plus a 10 - 20% productivity loss. With a clear focus on safety and asset reliability, Duke’s planning and scheduling processes are sustainable and continuously improving because the Barrier Process energizes the Plan-Do-Check-Act cycle for reliability.

Risk & Criticality: Understanding Potential Failure

by Terry Nelson

Many businesses and public service organizations use a hope-based system for managing risk. But most business and physical risks can and should be managed by a more proactive approach.

Risk Calculation Methodology

By Terry Nelson

In response to Brian Webster's article (Understanding & Comparing Risk), Terry Nelson requested the opportunity to supply additional information relating to his article in the Oct/Nov 2011 issue of Uptime.

Risk Management in Military Aviation

Risk management in military aviation has been a formal discipline in the field since the 1960's. The risk standards issued by the Department of Defense in 1969 was entitled "DoD Standard Practice for System Safety", MIL-STD-882. Air Force wide, the examples set forth in this standard have been used as though they were a required set of probabilities rather than examples. The semi-quantitative approach used today is further devalued by manager's arbitrary use of the Hazard Risk Matrix levels to mandate action. This paper examines the alternatives available today and recommends incorporation of a quantitative approach for more fidelity in risk management at all levels of management.

Editors Note: Although this paper is aimed at military aviation, the information on risk assessment and management is applicable to most industries as well.

Risks of Using PM Templates

by Anthony "Mac" Smith and Tim Allen

Some 50 years ago, a small group at United Airlines, led by Tom Matteson (then VP - Maintenance Planning) created a new way to define PM tasks for the 747-100 airplane. It was so successful that virtually every airplane since then has employed this methodology. We have known this process as Reliability Centered Maintenance (RCM) since the 1970s.

Saving Cost by Reducing Reliability?

The Relationship Between Reliability and Maintenance Costs

Introduction

When we say Reliability, do we actually mean Availability? Under certain circumstances, the two are numerically the same, but that is only in a specific set of cases. 

Selling Reliability

What would you say if someone asked you to give your company a million dollars from your maintenance program? You would probably laugh, look puzzled, or straight out bludgeon the poor guy. If you did have that much money available you would have already given it, right? WRONG! The fact of the matter is that we give away millions of dollars from our maintenance budgets all of the time but to the wrong places. The money is tied up in inefficiency. There are several inefficiencies that plague our maintenance programs today. They range from lack of direction, poor historical data collection, and lack of admittance. The problem is that the longer the inefficiency goes on the harder it is to break.

Simultaneous Testing

For inexpensive components and inexpensive tests, simultaneous tests involve many components under test loads/conditions at the same time for the purpose of quickly acquiring data and producing test analysis as the failures occur. In simultaneous testing the suspensions (censored data) become important details for use in the statistical analysis. Most simultaneous tests are accelerated to generate the data in a short period of time although this carries the risk of introducing unexpected failure modes (but this can also be useful information for anticipating field failures).

Snakes, Hazard Recognition & RPN - What Is a Hazard?

By Stan Moore

What Is a Hazard? Any situation that could result in a preventable injury or illness.

Expounding on that, a hazard is any situation or condition that could present a threat to equipment, the environment, limb, or life. Hazards can be caused by human actions, or they can exist in the environment and pose no safety issues until there is interaction.

Software Reliability

Software does not wear out but it does fail and most failures are due to specification errors and code errors with only a few errors in copying or use. The only software repair is by reprogramming and adding safety factors is almost impossible. Software reliability improves by finding errors and fixing the errors but estimating the number of errors which canse failures is extremely difficult as many branches of software code may lie dormant and unused until special events occur to make the latent failures obvious. Software failures are not often time related but are more software code page dependent. Software reliability is improved by extensive testing to disclose the failures and then fixing them to repeat the test all over again to validate the fix did not generate more failures and to continue the search of other latent defects.

Sudden Death Testing

For expensive components and expensive tests, sudden death tests involve a few components that tie-up a test frame as they are heavily loaded under the same test loads/conditions with several items being run at the same time. When one of the items fails the entire test frame is shut down so that you have 1 failure (this is the sudden death!) and several suspensions because the unfailed units are survivors as the test is halted until the test frame is loaded with new samples for resumption of the life test. Opening the test frame (instead of tying up the frame until all samples have failed) is cost effective. If three units can be tested simultaneously and the test is halted on the first failure, then perhaps we will literally have only 4 failures and 8 suspensions for preparing the Weibull analysis. Will the 4 sample + 8 suspension data set be different than if all 12 samples had been run to failure?-the answer is yes, they will be different, but will they be significantly different-the answer is no to the significant difference. So, as with simultaneous testing the suspensions (censored data) become important details for use in the statistical analysis. Most sudden death tests are accelerated to generate the data in a short period of time although this carries the risk of introducing unexpected failure modes (but this can also be useful information for anticipating field failures).

Taking Care of Business

The Benefits of Implementing Reliability Engineering

by Fernando Vicente

Over the past several years, reliability has become an ever-increasingly important topic and component in the organizational continuous improvement tool box.  Higher plant reliability reduces process and equipment failures,  and as we all know, failure disruptions decrease production output, which in turn, limits gross margin.  Additionally, equipment failures also increase the probability of having a catastrophic environmental accident and the potential for increasing safety related accidents.

 

The Critical Role of the Reliability Engineer

Introduction

Swagelok has been in business for over 60 years, manufacturing the highest quality valves and tube fittings. We are also a privately held company with sales distributors and warehouses throughout the world that supply excellent support and service. Swagelok has been a successful company as viewed by its end-customers, having the highest quality products on the market.

The Dreaded Saturday Phone Call

By Noah P. Bethel

What's worse than a slip ring flashover on a critical wound rotor motor? A slip ring flashover on a critical wound rotor motor. . . on a Saturday!!! Yes, the dreaded Saturday phone call came to Flanders Electric from a local mine when a coal conveyor motor blew the slip rings. Unfortunately, the motor was not repairable in the field. However, the mine was in luck. They had a spare motor in place and ready for exactly this type of situation. The mine personnel were thinking the problem was behind them and couldn't get any worse, at least not until they pushed the start button.

The Effects of Maintenance on Reliability

Publisher's Note: I will caution you that a) Bill Brinkley comes from the commercial Aviation industry where reliability is not optional and b) he pulls no punches when speaking to industrial maintenance professionals. I an interested in hearing what you can take away from this paper that was presented at IMC-2007. You can email me your comments or you can post them here.

In an airline environment, maintenance is king. An aircraft receives about 17 man-hours of maintenance for every flight hour. That may seem excessive - unless you are the one riding in that aircraft. So - the question is, do aircraft really break all that often and do they need that much maintenance? Are they that unreliable? The answer, of course, is no.

Aircraft are designed to be reliable, so why perform all that maintenance? Over ninety percent of the maintenance performed on an aircraft is preventive or servicing in nature. Preventive maintenance is done to maximize availability of the aircraft for operational service and minimize the number of failures occurring at inconvenient times or places.

©2012 Reliabilityweb.com