1

AV Technology helps companies prevent profits evaporating into thin air

There is no doubt that energy sustainability is one of the ‘hottest’ topics on the political agenda around

the world. In an era of soaring energy costs, reducing energy consumption in industrial operations is

vital, not just for the environment, but also for bottom line profitability. However in many industrial

plants energy is simply ‘leaking away’: often unnoticed, sometimes ignored.

For plants using steam or

compressed air in their processes,

energy wastage through leaks can be

significant. Although typically small

in nature, collectively over 12

months these leaks can cost

companies tens if not hundreds of

thousands of pounds. In addition to

increased energy costs, such leaks

can cause accelerated corrosion and

equipment failure as well as

presenting unacceptable health and

safety risks.

Detecting leaks by normal visual or audible methods can be ineffective, especially for small leaks in

noisy environments. The condition monitoring engineers at Stockport based AV Technology (AVT) have

considerable experience in leak detection using ultrasonic detection techniques across a broad spectrum

of industries. This complements their portfolio of other condition monitoring disciplines, which include

thermography, vibration and oil analysis.

During a leak, a fluid (liquid or gas) moves from a high pressure to a low pressure and as it passes

through the leak site, a turbulent flow is generated. This turbulence has strong ultrasonic components

and typically the larger the leak, the greater the ultrasound level. Both steam leaks and air leaks can be

detected using the same instrument.

Ultrasound is a high frequency, short wave signal and therefore the intensity of the ultrasound produced

by a leak drops off rapidly as the sound moves away from its source. For this reason, the leak sound will

be loudest at the leak site. Ultrasound is considered to be relatively "directional" and therefore locating

the source of the leak in many applications is fairly straightforward using a handheld portable ultrasonic

detector. The instrument converts the high frequency sound signal into an audible sound which is also

registered on the instrument’s meter.

2

Air Leaks

In a typical plant that has not been well maintained the air leak rate may equate to between 20 and 30

percent of total compressed air production capacity. By comparison, pro-active leak detection and

repair can reduce leaks to less than 10 percent of

compressor output.

In addition to being a source of wasted energy, leaks

have a knock on effect on overall operational

efficiency. Leaks cause a drop in system pressure,

which can make air tools function less efficiently,

adversely affecting production. In parallel by forcing

the equipment to run longer, leaks shorten the life of

almost all system equipment (including the

compressor package itself). Increased running time

can also lead to additional maintenance requirements

and increased unscheduled downtime. While leakage

can come from any part of the system, the most

common problem areas are:

• Couplings, hoses, tubes, and fittings

• Pressure regulators

• Open condensate traps and shut-off valves

• Pipe joints, disconnects, and thread sealants.

Steam Leaks

Steam leaks are typically found at valve stems, pressure regulators, connection flanges and pipe joints.

If leaks are ignored, they can cause a drop in system pressure, resulting in heat loss and lower operating

efficiency. At a pressure of seven bar (100psi), an orifice of just 3 mm can cause the loss of 25000 kg of

steam per annum. This multiplied by the steam production cost per kilogram gives some measure of the

annual cost implications. Other contributory factors are boiler efficiency but this is largely dependant on

boiler type, usage and maintenance regime.

Addressing steam leaks will have a similar impact to that of installing loft insulation in the home where

the cost is recouped over a period of time as opposed to an immediate benefit attributed to the routine

condition monitoring.

3

Summary

AVT have developed proprietary methods to measure and quantify the losses arising from both air and

steam leaks. With energy conservation gaining momentum across all industry sectors, AVT’s experience

in ‘leak management’ is bringing significant cost savings to a growing number of companies. In particular

AVT have seen a strong emphasis on energy conservation within the Food and Beverage sector, with

steam and air losses at the top of the agenda.

4

AV Technology Limited AVTECH House Birdhall Lane

Cheadle Heath, Stockport Cheshire SK3 0XX

Tel: 0161 491 2222 Fax: 0161 428 0127

enquiries@avtechnology.co.uk www.avtechnology.co.uk

AV Technology operates an ISO 9001: 2000 QA system and applies a strict health and safety policy.

AV Technology Ltd is a leading multi-discipled consultancy with over 30 years’ experience. Our portfolio includes:

Consultancy: • Condition Monitoring • Facilities • Maintenance • Noise & Vibration • Structural Integrity • Training

Products: • Acoustic Emission Sensors • Condition Monitoring Systems • Lubrication & Filtration • Silo Weigh • Structural Monitoring Systems • Vision Systems

Services: • Condition Monitoring • Lubrication Management • Maintenance Solutions • Noise & Vibration • Strain Gauging • Structural Monitoring • Visual Inspection