Aggregate Case Study: CRH Company: Tarmac, Hothfield Works Asphalt Plant

“Expel has made a massive difference, I’m really impressed with it”.

Jason Etheridge – Plant Manager – Tarmac

About the customer

Tarmac, a CRH company, is the UK’s leading sustainable building materials and construction solutions business.

With 150 years of experience to their name, Tarmac is a national network of local businesses, combining the knowledge and expertise of two of the construction industry’s most iconic brands: Tarmac, pioneers and inventors of the modern road, and Blue Circle, the company that patented Portland Cement.

Project Background

Prior to installing Expel, the site was experiencing prominent issues around the bitumen pumps. The area is particularly susceptible to rapid temperature changes as the wind tends to catch the area. This meant that moisture would occur in the compressed air lines and cause faulty operation of the pneumatic equipment causing a profound amount of downtime.

Further problems with moisture in the compressed air lines were occurring with the pneumatic panel by the mixing deck. The moisture would cause problems such as bin doors and rams to stick, as well as failing solenoid valves. The site would then have the expenditure of rectifying this damage and the maintenance teams would have the added pressure of replacing this equipment as quickly as possible in order to minimise production downtime.

The silos were another area of concern because the occurrence of liquid water, oil emulsion fluids and solid particulates can result in serious safety concerns because when the aeration pads on the silos are exposed to moisture from the compressed air lines it can cause, bridging, ratholing and even the caving on a silo. Not only does this cost thousands of pounds to replace but it also creates huge safety concerns to staff members is a silo is at risk of collapsing.

The maintenance team were also manually draining the air receiver tank which was resulting in issues like pressure loss occurring due to air escaping during manual draining, water building up in the tank which would end up entering the compressed air lines and continuing down the lines which would damage pneumatic valves and equipment.

air compressor water traps

How did Original AVG help the Tarmac site?

The site installed 4 Expel units at point of use in these critical areas and an extra AVG Auto Drain for the air receiver tank in September 2020. One year on and Plant Manager Jason Etheridge could not be happier with the results of using Original AVG products.

The Plant Manager noticed a dramatic reduction in downtime caused by pneumatic failures since installing the Expel units. The solution to eliminating all problems with liquid water, oil emulsion fluids and solid particulates in the compressed air lines is to remove the source of the problem immediately before the area in need of protection. Expel is the most superior means of protecting your pneumatic equipment against these harmful compressed air contaminants because unlike a traditional compressed air filter, Expel can guarantee that 99.999% of liquid water, oil emulsion fluids and solid particulates are continually removed from the area it is protecting down to 1 micron. Expel offers a bespoke approach to compressed air filtration because it does not require ANY replacement filter elements, so the performance of Expel does not drop over time and always operates at optimum performance levels.

For these reasons the Expel filters successfully eradicated all the problems across the problem areas including at the mixing deck, the bitumen pumps and at the silos.

Furthermore, the problems caused by manually draining the air receiver tank were eliminated by installing an Original AVG Auto Drain. These issues were solved because the Auto-Drain has zero pressure loss, so air is no longer lost whilst water is drained. Additionally, the Auto-Drain continually and automatically drain any water build up, this prevents excessive liquid water from continuing down the air lines.


Improved Site Safety

Reduced Downtime

Reduced Maintenance

Reduced Costs


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