Performing A Leak Survey

The success of a leak survey requires three major elements: knowledge, planning and follow-through. The knowledge component includes an understanding of the compressed air system, including all the subsystems and components.

What are the sizes, types and ages of the compressors? Have they been properly maintained? What about your traps and drains? Are your pressure gauges working and if so, is there adequate pressure for the various areas of use? What are the assigned pressures for these areas? Are there compressed air applications that can be replaced by alternative, less energy-intensive methods? For example, instead of using compressed air for cooling, drying or cleanup, try using low-pressure blowers or fans.

Your knowledge should also include an understanding of your ultrasound instrument, how it works and the techniques of inspection. If you are not too sure about the technology or how to use the instrument, there are training courses available that can help make the inspectors in your facility more competent and effective.

Planning incorporates a number of facets, such as using a map of the compressed gas system and its various components. If no map exists, try taking digital photographs of each section using both long-range and close-up views, and labelling them.

Planning also includes scheduling of the survey or audit. Don’t try to do it all at once. Break it up so that the survey can be performed without negatively affecting other maintenance responsibilities of the personnel assigned to the leak team.

Before the survey begins, have the inspectors walk through the various sections to review their route. The walk-through can help in a number of ways: it can help identify potential safety issues, note any changes needed to the planned route, identify obvious leaks, and help understand what equipment to bring along, such as flashlights, keys or specialized leak inspection attachments.

Another component to planning includes a leak tag/identification method. Once a leak has been located, it should be tagged. The tag number can be used, along with a photograph of the leak, in your report. The identification process is extremely important. The leak rate can be assigned to the leak in a report that can then be used to demonstrate the cost savings and potential environmental impact of stopping the leak.

In addition, the leak identification process can be used to ensure a leak is repaired. It is very costly to leave an identified leak un-repaired. Money is wasted due to the cost of the personnel used to locate the leak. In addition, the cost of the leak will increase for every second it continues.

Follow-through is another important factor. If a leak is not repaired, as mentioned, all the effort and cost of the survey will be wasted. Therefore it is important to use a follow-up method to assure all identified leaks are repaired.

In addition, when a leak has been reported as fixed, the repair should be checked. Sometimes the repair might cause another leak or sometimes the wrong component is ‘repaired’.

Follow-through includes a review of the survey, cost analysis and, when possible, an environmental-impact analysis. A report can then be generated to demonstrate the effectiveness of the survey and the related cost-saving benefits.

Follow-through also includes leak management. Whenever a survey is completed, there are often many identified leaks. One common problem is that the volume of the leaks can seem overwhelming to a maintenance department that is already working hard to meet its daily workload.

It is important to work out a system that will allow for the leaks to be repaired. One method is to prioritize the leak repair so that the most costly leaks, or leaks that can affect production, are repaired first, followed by the next most important later, and so on.

Record-keeping is another important element to the follow-through part of a survey. Some companies provide software that can help. One such program is freeware offered by UE Systems Inc. It is a two-stage software program that combines data management and comprehensive compressed air/gas survey analyses. Users can review annualized and monthly data that include leak cost and greenhouse gas savings.