As someone with responsibility for the compressed air system, you will be expected to guarantee air at the right pressure and flow, but also at least cost. To do this there are two aspects: you need to produce and use compressed air as efficiently as possible. Disproportionate emphasis on efficient generation of compressed air in the compressor house, may lead to other factors such as the value of effective maintenance and user behaviour being overlooked. Here the role of maintenance in a reliable and energy efficient system.
Compressed air systems rely on effective maintenance for reliability, safety and energy efficiency and compliance with legislation. All of these contribute to a cost-effective compressed air system.
Missing a maintenance service is a false economy, for compressors, ancillary equipment and the distribution piping connections. Effective maintenance not only saves energy it helps address the more critical issue of air supply reliability for processes. For most operations reliability of supply (whether this be pressure, volume or air purity) is paramount. Although energy efficiency receives wide coverage, reliability of supply has even greater business implications, e.g. a metal products manufacturer had paid little attention to its compressed air system, stating that it only represented 4% of the site energy costs. However if the supply failed then the cost of lost production of a number of critical processes dwarfed the energy costs, so improving the system should have been a priority and delivered energy benefits as an added bonus.
Maintaining compressors and air using equipment helps minimise the risk of stoppages, maintaining filter elements and dryers reduces the pressure drop across a system - systems often run at pressures of up to 2 bar above the rated pressure. This is usually to guarantee sufficient air at all times for different production processes. Not only does this consume more energy, it also shortens life of components due to over-pressurisation.
There is a legal requirement to carry out maintenance, this is contained within the Pressure Systems Safety Regulations covering all systems that operate at a pressure above 0.5 bar gauge pressure and contain an air receiver. With reference to maintenance, Regulation 12 – Maintenance states:
“The user of an installed system and the owner of a mobile system shall ensure that the system is properly maintained in good repair, so as to prevent danger”
The PSSR also requires that the compressed air system is inspected regularly by a competent person and that detailed maintenance records must be kept and are also subject to inspection. BCAS runs a series of one day workshops on UK pressure systems legislation and the written schemes of examination requirements. See our website for more details of the next one in Leeds on 7 June.
Effective maintenance is essential to energy efficiency in compressed air systems. High compressed air leakage rates which persist in many systems – hose tool connections being a key offender are an example of an ineffective maintenance programme that does not address the whole compressed air system. The most common causes of leaks are down to maintenance, i.e.
· Manual condensate drain valves left open (to reduce maintenance time)
· Leaking hoses and couplings
· Leaking pipes and pipe joints
· Leaking pressure regulators
Cutting back on maintenance will incur more cost in terms of energy consumed, as well as decreased service life and reduced reliability of components and equipment. Since energy costs are often as invisible as the compressed air itself, few users are aware of the running costs, and are thus less likely to understand the benefits of effective maintenance.
For further independent information and assistance on any aspect of your compressed air energy saving visit: www.bcas.org.uk or email us at This email address is being protected from spambots. You need JavaScript enabled to view it.
