Graham Coats of energy saving specialists EnergAir gives some tips on to overcome it and boost your company's bottom line.

Graham Coats of energy saving specialists EnergAir gives some tips on to overcome it and boost your company's bottom line. The government's climate change levy has concentrated minds on all forms of energy efficiency, and the means to achieve it. Recently, the emphasis has been on the efficient use of compressed air.

This is timely and reverses the ages old message that compressed air is 'cheap' to produce.

In truth, the leakage from ring main systems, and the inefficient running of compressors off-load, have done much to impair the competitiveness of UK industry over the years Compressed air is generated using electricity, and the fact that its generation is equivalent to about 10% of industry's total electricity usage, rising to 30% in some sectors, highlights why companies have compelling reasons to investigate the potential for energy saving in this area.

Recently, industry specialists have given added momentum to this new discipline by calculating that the operating costs of running multiple compressed air installations without some form of management control can be more than 30% higher than they should be.

And this is just one aspect of a system, although usually the main one.

To get the full picture the compressed air system as a whole needs to be examined, from the air compressor itself, to the dryer and filters which condition the air to the pipe work system that delivers it.

As anyone who has ever been concerned with compressed air systems will know, the most basic problem is leakage.

Indeed, it has been calculated that leakage rates exceeding 50% of site consumption are common across many industries.

For the user looking to save energy, eliminating these levels of leakage is a logical first step, especially as the costs involved are virtually negligible.

But how to go about it?

The first fact that must be borne in mind is that while every effort should be made to keep a compressed air system leak-tight, all systems will have some leakage.

There are however, several ways - basic 'do's and don'ts' that can be followed to reduce the opportunities for leaks: Taking the don'ts first: don't generate at a higher pressure than is necessary - the higher the pressure, the more air that will escape through a given-size hole - and don't keep your whole system pressurised during non-productive hours just because a few items of machinery require a constant supply of compressed air.

In terms of the do's: firstly, isolate parts of the system that require air at different times.

Isolation valves can be operated manually or automatically using simple control devices like time switches or interlocks, or they can be controlled using your building energy management system, if you have one.

Secondly, take advantage of the fact that under the Pressure Systems and Transportable Gas Containers Regulations, you must inspect your compressed air system regularly.

These inspections are an ideal opportunity to find and repair leaks.

Having answered the first question of how to go about leakage elimination, the second is where to look for the leaks.

In most systems the quick answer to this would be: 'just about anywhere! Logically though, the best place to start is at the compressor and then work outwards through pipework and fittings to pneumatic equipment, tools and instrumentation.

The main artery for delivering compressed air is ring main pipe work systems.

In many factories the pipe work is old and a prime source of leaks.

A check of the system for pipe work sections that are leaking or corroded, followed by their replacement, will not only improve the system but will also improve safety.

In addition to the pipework itself, large leaks are often found at connection points where screw fittings or flanges are employed.

These leaks are frequently caused by pipe strain due to inadequate supports, inadequate joints or twisting.

Another potential problem area is where connections to a usage point are made using snap connectors with flexible hoses.

Sometimes several are used together, forming a manifold arrangement.

Such manifolds can leak due to worn connectors and poorly jointed pipework.

In addition, where flexible hoses are used to make connections between the piping network and usage points, leaks can be caused by a number of factors including: damage to the hose, due to abrasion by surrounding objects: strain on the joint because the hose is too long or short, and by deterioration of the hose material, or just by choosing the wrong material, especially where the working environment is aggressive, oily or hot.

Before leaving the subject of connection manifolds, it's also important to remember that all leaks do not occur through large connections.

Many occur through wear on the tubing on small push-in connectors.

Individually, these are of little note but when they are numerous the total leakage can be substantial.

If a compressed air system uses automatic drain traps, these should be 'zero loss' types, and should be checked to determine whether they are functioning correctly.

Some drain traps are not reliable and, in practice, they are often bypassed so that the condensate can be released from the system.

This is undesirable as large amounts of compressed air can be lost.

A way to overcome this is to use electronically operated zero loss condensate traps.

These are very reliable, and by fitting them the requirement for bypassing can be removed.

Filters are an indispensable part of any pneumatic system.

They can, however, be the source of quite large leaks.

Potential problem areas are drainage points on the filter bowls, including poorly sealing automatic drains, badly fitted bowls and bowls that have been contaminated by synthetic compressor lubricant.

Downstream from the filter is not normally the area where the factory engineer would expect to make major savings by reducing leakage.

This is true in the main, but useful contributions to the overall plant savings target can still be obtained by checking such things as connections to regulators, lubricators, valve blocks and sensors, and the internal air seals on pneumatic cylinders, which can cause large leaks Last but not least are air tools.

These can consume large quantities of compressed air in operation.

In many instances their consumption is exacerbated due to leaks that occur at the hose connection and/or the speed control valve.

Worse still, occasionally air tools are left running, even when not in use! Compressed air represents 10% of industrial electrical consumption, but much is wasted.

EnergAir Solutions is a new but highly experienced energy efficiency consultancy, formed to help companies achieve energy saving on compressor installations.

The consultancy concentrates on the compressed air user, putting in place control and monitoring products that will make a noticeable difference in a matter of days.

This is important because compressed air represents 10% of all industrial electrical consumption and in many cases companies use their compressors inefficiently and have inadequate distribution systems.