ERIKS UK have been involved in managing energy issues as part of overall maintenance strategies for over ten years, including site-wide audits and specialist services, as a result of recent energy price rises however; a rush of customer enquiries concerning basic provision for energy saving has arrived from manufacturing and processing sites that have not previously considered it a high priority. In order to help address the basic issues and make a first step towards practical and effective energy saving ERIKS UK is releasing a series of guides, each one dedicated to a different area of energy saving in the production environment.
Stephen Cordingley ERIKS UK Energy Saving Manager is responsible for the implementation of ERIKS UK Air Leakage Surveys and here highlights the potential energy savings that can be gained by reducing leakage in compressed air systems.
“Leakage is the largest single waste of energy associated with compressed air usage, for example, leakage rates exceeding 50% of site consumption are common in our experience. Compressed air is obviously generated using electricity, the price of which has virtually doubled recently, and when you consider that on average 10% of industry´s total electricity usage is dedicated to air generation, rising to 30% in some sectors, the potential figure for overall wastage is immense.”
The first and most obvious step is to survey the area, identifying leaks and listing them, ERIKS UK physically tags individual leaks that occur at fixed positions and attribute a severity to them, allowing an estimate to be made for potential savings. The wastage estimate can then be offset against the capital cost of fixing the leaks. Stephen Cordingley, “in most cases, fixing leaks is a fairly straightforward case of replacing worn fittings, seals, valves, manifolds and air preparation equipment, and/or modifying working practices. The cost estimates are useful because they put the savings into perspective, as most remedial work has a pay off period of just a few months.”
The severity of leaks is gauged in four levels: Light, Medium, Heavy, and Severe, these levels correspond to an equivalent leak size of 0.5mm, 1.0mm, 2.0mm and 4.0mm respectively. The cost estimate for leaks of these sizes obviously varies greatly based on shift patterns, the cost of electricity and the efficiency of air generation on each site, however, a good rule of thumb based on current costs and two eight hour shifts puts the cost of a ‘Light´ leak at £120 per year, up to a severe leak that will cost anything up to £8,000 per year.
Detecting leaks is actually a straightforward matter when you have the right equipment, and you know where to look. A survey of a medium sized plant by an experienced team can be achieved in around three hours utilising an ultrasonic detector that is designed for the task. Good ultrasonic detectors can detect leaks from over 50 feet away even in noisy plant areas and provide an accurate estimate of the severity of the leak. ERIKS UK also photograph all the leaks that are detected and list them, providing a quick visual guide for the maintenance personnel or any contractors that are asked to perform the repairs.