In this article, the team at BCAS provides advice on how to reduce air leaks in your compressed air system.
This guide looks at why minimising air leaks can make a positive impact on energy reduction – and your bottom line.
All compressed air systems experience leaks and in the past, this may have been ignored, as they pose no immediate health and safety concerns. However, the current climate means we’re much more aware of the energy which is being wasted and the costly effects of leaking air.
One 2mm hole in your pipework could cost over £1,249 per year in wasted energy, so it’s more important than ever to take measures to reduce air leaks. Our simple guide will help you to identify common leak sources are take easy steps to reduce leakage.
Let’s first start with the source of the leak. There a four common leak sources to be aware of, these include:
- Air-using equipment left running when not needed
- Manual condensate drain valves left open
- Leaking hoses and couplings
- Leaking pipes and pipe joints
It’s important to check these areas regularly, as leaks need to be monitored constantly. We would suggest carrying out a leak survey at least twice a year, so you keep on top of any changes in the system.
Next, we take a look at the different steps which can be taken to reduce compressed air leaks and manage the amount of energy wasted.
- Under pressure
When pressure drops in the system it means the generating pressure is set much higher than necessary. To resolve this issue, start by identifying where the pressure drop originates and take action to fix the cause and regulate the pressure.
The issue of a drop in pressure could be due to:
- System component constrictions (e.g. valves, bends)
- Undersized piping
- Pipework installation (e.g. no ring main)
- Identify the leak
As air leaks aren’t hazardous to health and safety, it’s easy to become complacent if there is a small leak. However, as we mentioned a small leak can have significant effects on energy usage, so it’s essential to take action.
To reduce leaks, we suggest conducting an out-of-hours survey where you can walk the site listening for any leaks – it should be easy to hear any leaks when the site is quiet.
Following the survey, we would recommend implementing a leak management programme. This way you can mark the leaks and record them on a site plan and grade the priorities, such as fixing the largest leak first.
Finally, encourage users to report leaks so they can be identified and repaired as soon as possible.
- Pressure reduction
Once you’ve identified any leaks and repaired them, then it’s time to speak to your supplier about reducing the generation pressure at the compressor. Understanding the system pressure is critical when it comes to leakage reduction and reducing energy usage.
Fixing a leak will increase the pressure of air. This can not only have an impact on your system but also put your projected savings at risk.
The pressure drop should be less than 10% of the compressor’s discharge pressure, as measured from the compressor outlet to the point of use.
If one section of the plant required much lower pressure, we would suggest running a dedicated low-pressure compressor or to regulate the pressure down that line. It’s important to not generate higher pressure than is required.
When it comes to the energy used, on average it is found that for every 1 bar g additional generation pressure there is a loss of 7% in specific energy. And so, keeping the pressure low can help to reduce your operating costs.
- Zone out
The design and installation of the pipework can help with saving energy and so when considering leak reduction measures, it’s important to consider the pipework currently in place.
Here we’ve outlined some examples of how you can change the pipework to be more efficient:
- Spilt the system into zones and pressurise each as required
- Remove or isolate redundant piping
- Use vales to isolate parts of the distribution network
- Select large radius bends instead of elbows
- Support piping to minimise movement and sagging to reduce leaks and build-up of fluid
When looking at the pipework network remember not all parts of the network operate to the same hours or pressure and so it’s possible to save energy by zoning the compressed air system.
Top tips from BCAS
If you’re planning to purchase equipment to save energy, it’s important to make sure you compare alternatives based on the whole life cost of the equipment, not just the initial capital outlay. If you don’t research and look into the comparisons, it could result in higher costs further down the line, which haven’t been projected.
For more information, please speak to a BCAS member who can assist in this area by emailing firstname.lastname@example.org. And to download a free copy of the leak-fixing guide click here.