Failure Mode and Effect Analysis of an Elevator Report

Summary

Failure Mode and Effect Analysis (FMEA) is presumably among the most straightforward tools for risk management, as it does not require any complex statistical data. Nevertheless, it is time-consuming and presupposes well-organized teamwork that aims at maximally effective risk prevention. FMEA can be applied to both products and processes and is done through brainstorming, which also contributes to the simplicity of its use.

Applying FMEA for an Elevator

The core question to answer in the process of assessing a certain product with the help of FMEA is how the product can fail. In the course of a brainstorm, the participants offer as many variants as possible. For instance, an elevator can fail in the following ways:

• The elevator does not arrive when it is called for.
  • The lighting inside is out of order.
  • The door does not open or does not close.
  • The door closes too quickly, as a result, no one can enter the elevator.
  • Some of the buttons are impossible to press.
• The elevator stops on the wrong floor.
  • The elevator stops between floors with a closed door and people inside.
  • The emergency button does not work.
  • The cable snaps.

Once possible failures are organized into a list, it is relevant to group them into categories for better visualization. In the given case, the problems that do not completely eliminate using the elevator may be regarded as less serious ones, in contrast to more serious ones that do. The former include the absence of lighting, the malfunction of one or several buttons, and stops on the wrong floors. All of the other failures make it impossible to use the elevator.

The next step is to specify the potential consequences of each failure, which allows a rough estimate of the risks. Three of the failures can be classified as extremely serious due to the danger to people. That danger involves being trapped inside, in the worst case, with no connection, or injuries in case the elevator plunges. Minor effects include staying in the dark and the need to go the whole way or its part up or down the stairs. The consequences need clear and strict prioritizing, which is normally done by assigning priority numbers to them. In the table below, the severity of effects is rated from 1 as the lowest to 5 as the highest.

Other criteria for risk evaluation are occurrence, likelihood, and detection, which stands for the possibility to notice the failure before its consequences are realized. In the case of an elevator, the former seems to be inversely proportional to the seriousness of the problem. Critical failures that bear a threat to people’s health or lives do not happen frequently. As for the detectability of potential problems, it is relatively high when everything, which contributed to the probability of a failure, is taken into account.

Recommendations on Maintenance Approach

Minor elevator failures are a routine phenomenon that is familiar to the vast majority of those who live, work, or study in high-rise buildings. Pedram emphasizes that the probability of breakage is directly proportional to the age of the elevator (2017). In other words, the older the equipment is, the more frequently failures are likely to occur. The design of a particular elevator also factors into the probability of breakages. In addition, the likelihood grows considerably if bad mistakes were made in the process of installation.

As for major failures up to a cable snap, their occurrence is apparently manifold lower. According to Pedram, incidents of that kind are very rare, providing regular and properly done inspection and testing of elevators, which meets the definition of preventive maintenance (2017). Also, he insists on paying special attention to the situations where an elevator fails regularly during the first decade after installation. This is a clear sign of negligence in the process, which may have fatal consequences in the future. In such a case, it is critical to identify the root cause of the problems before they grow more serious (Pedram, 2017). This approach is known as proactive maintenance and is sometimes regarded as a specific preventive strategy.

In addition to preventive and proactive approaches, an elevator needs condition-based maintenance. Its components, similar to those of any equipment, are prone to wear and tear, and hence may need repairing or replacing (Pedram, 2017). Ideally, this should be done as a part of a regular inspection, when there are certain signs of an upcoming failure but the failure itself has not occurred yet. Reactive maintenance, which presupposes restoring the equipment to a proper state after a failure, is apparently the least acceptable for elevators. The consequences of a failure, especially, a major one, are not simply unwanted, but sometimes really threatening. Therefore, prevention in form of correct installation and regular technical servicing is the most reasonable approach to risk management in elevators.

Reference

Pedram, M. (2017). Elevator breakdowns – why they happen & what you can do to prevent them. HITE Engineering Corporation. Web.