Aggregate Industry Case Study: CRH Company: Tarmac, Charlton Ready Mix Concrete Site


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.

Tarmac employ around 7,000 people across a network of more than 400 sites across the UK.

Project Background

Maintenance Manager for all 19 of Tarmac’s Ready-Mix concrete sites across London, Mark Henderson and Higher Apprentice David Evans have established a fantastic and effective way of operating their Tarmac sites. They have a forward thinking ‘preventative maintenance’ strategy that has drastically reduced production downtime to below 1%. As a result, Tarmac sites under Mr Henderson require less maintenance and are able to use pre-planning techniques to schedule contracts ahead of time. Prior to installing Expel, production downtime caused by liquid water, oil emulsion fluids and solid particulates in compressed airlines was a frequent occurrence.

After hearing about several Expel success stories, Mark Henderson chose to buy two Expel units for the Charlton site. Mr Henderson strategically installed the Expel filters to test at this site specifically because this site does not have a refrigerant dryer and has very old and exceptionally dirty compressed airlines. Clearly wanting to put Expel through its paces and comprehensively test the ability of Expel, Mr Henderson could not have been happier with the results.

“My Fitters couldn’t believe it! Expel seemed too good to be true!”

Mark Henderson – Maintenance Manager – Tarmac

Why did Tarmac choose Expel?

Mark’s team installed one of the Expel units before a dust extractor filter on the concrete mixer which they were having to unnecessarily replace on a regular basis because the damp compressed air was causing the dust particles to stick which causes clogging and then needs replacing. Expel completely eradicated the problem of water contaminating the compressed airlines. This means that Expel was able to effectively reduce both their expenditure on replacement dust filters costing around £700-£800 for a set of 8 filters, and the downtime costs associated with stopping production in order to replace the filters.

Due to the money saving and production boosting potential this single Expel unit had for the site, Mr Henderson took the initiative to contact our sales team so he could roll Expel out to all of his 19 sites where equipment was becoming damaged and/or not operating correctly because of damp and dirty air. In particular, Mark Henderson promptly had Expel installed across the newly acquired Euromix sites as they were very run down and in need of good reliable equipment to get them to a more productive standard and Expel fit the brief impeccably.

“My goal is to keep downtime low to ensure consistent production and meet all of our contract deadlines in a timely manner, Expel has been the perfect tool for the job” Mark Henderson, Maintenance Manager, Tarmac.

Mark Henderson was also aware that Expel has the capability of removing the need for a refrigerant dryer for aggregate sites. Although the Charlton site was operating without a dryer, Henderson was desperate to eliminate equipment downtime caused by water in compressed airlines and had considered a refrigerant dryer to try and help with the problem of water. Henderson was sceptical to install a dryer as sites with dryers still suffer issues.

“Even the sites that do have refrigerant dryers are still having problems with water in compressed airlines. For instance, solenoid valves on the bin doors have been sticking.” Mark Henderson, Maintenance Manager, Tarmac.

Most compressed airlines at aggregate sites are long and any water vapour present in the air, by the time it has reached the point of use, has had time to cool and condense to liquid water. Additionally, a refrigerant dryer doesn’t remove oil emulsion fluids or solid particulates which also cause problems to pneumatic equipment. Expel is a 3-stage compressed air filter that is capable of removing ALL of these liquids and particulates down to 1 micron all in one unit. Therefore, a dryer is no longer required because Expel does a better, more cost-effective job when installed correctly.

Expel has been incredibly successful, when placed correctly, more dryers can be switched off and the goal to eliminate water from compressed airlines is achieved.


No dryer required

Reduces Costs

Reduced environmental impact

Reduced downtime


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