ProEconomy's Orca system has never failed to control Legionella in a client's premises.

Case Studies

Case study – Birmingham Heartlands Hospital

Birmingham Heartlands is a 700-bed hospital which has a mixed-age infrastructure with a variety of materials and systems. Before 2007 the hospital used a temperature regime fully compliant with HSE and DoH guidelines for controlling Legionella. When they introduced testing, however, they found that Legionella was present.

The first step taken to address the problem was to dose the whole site with sodium hypochlorite. They were keen to get away from using chemicals, however, for COSHH and cost reasons. Furthermore, it wasn’t effective at eradicating Legionella or biofilm. Accordingly, alternative methods were examined, including copper and silver ionisation. Hospitals using the ProEconomy Orca system were visited, and all said it was efficient and cost-effective with a good support service. The final choice of ProEconomy’s system was based on cost, the fact that it used separate copper and silver electrodes rather than an alloy, and the documentation which gave evidence that control measures were working.

An 18-pod Orca system was installed in October 2007. The temperature regime was maintained. Soon after implementation a run of positive samples were traced back to flexible hoses, removal of which solved the problem. There was some concern initially over the effects on the RO unit in dialysis, but tests showed that metal levels on the secondary supply side were all within guidelines. Pre-installation, 50 samples had returned 21 positive results, ranging from 100cfu/L to 9,800cfu/L. Within a month levels had fallen to only five positives from these 21 sites, ranging from 100cfu/L to 2000cfu/L, and within six months this had dropped to zero.

ProEconomy undertakes monthly sampling with analysis at an independent laboratory to determine the presence of Legionella, copper and silver concentrations, temperature and TVC. The hospital selects 21 sampling outlets per month, usually those identified as being at risk of contamination, e.g. low use, blended, etc. These are rotated frequently, depending on results, to ensure maximum coverage. Low levels of copper and silver are used as a diagnostic tool to fault-find on the system. Any issues are few and far between, and down to local engineering problems. The system has proved so successful that within seven months it was installed at two other trust hospitals, Solihull and Good Hope.

In the nine years we’ve been with ProEconomy we’ve never had a reason to question the service. We’ve always received what we’ve asked for.
Tony Wright, estates manager Birmingham Heartlands Hospital


Case Study – Solihull Hospital

This 350-bed hospital is a smaller site with newer buildings than Birmingham Heartlands. As was the case with Heartlands, a temperature regime was applied as the sole Legionella control measure. This proved difficult to maintain. Mixing valves had to be fitted and rubber lined flexible hoses and rubber fittings were attached to several outlets. Water stagnation was also possible due to poor use of outlets and ward closures – ideal conditions for Legionella proliferation.

Following the success of Orca at Heartlands, one copper and silver ionization system, with eight copper and four silver electrode chambers, was installed in January 2008. Prior to installation 30 outlets were sampled, of which seven tested positive (23%). Counts ranged from 100cfu/L to 5,900cfu/L. Both cold and blended outlets showed contamination. One month later these seven were resampled, together with a further eight outlets identified as being at risk. Only one, an original positive, showed the presence of Legionella, and even here the level had fallen from 2,200cfu/L to 200cfu/L.

Results for the last five years demonstrate the level of control exerted by the Orca system: –

In 2013 Solihull asked ProEconomy to test for the presence of Pseudomonas. Of the 271 samples taken in the last four years, only five have shown positive, (1.8%).

ProEconomy undertakes monthly sampling at 21 outlets, with analysis at an independent laboratory to determine the presence of Legionella, copper and silver concentrations, temperature and TVC. Pseudomonas is tested for every six months.


Case Study – University Hospitals Bristol NHS Foundation Trust

University Hospitals Bristol NHS Foundation Trust has Orca systems fitted in seven of its hospitals, beginning with the King Edward Hospital in 2005, and used in conjunction with temperature control. The main reasons why copper and silver ionisation was selected were:-

  • No chemicals were being used on site, so removing any COSHH issues;
  • The Orca system is relatively maintenance free, allowing valuable staff time to be used elsewhere;
  • The biocidal effect is long lasting, which is useful for providing protection in infrequently used outlets;
  • Using some other supplementary disinfection systems resulted in excessive corrosion.

The Trust has found the Orca system very simple to use. Their experience has been that any issues that have arisen have been dealt with promptly by ProEconomy, who have put additional resources in place to resolve complex or unique problems. Tim Evans, the company engineer assigned to the hospitals, has proven to be very conscientious, good at problem solving and prepared to come on site all hours of the day to reduce impact on clinical operations.

Would University Hospitals Bristol recommend the Orca system to others? Yes
Ben Gardiner, Estates Officer

Case Study – Basildon University Hospital

Background: This case study for Basildon Hospital presents data from before and after using a copper and silver ionisation (CSI) system, comprising 99.99% copper and 99.99% silver electrodes installed as a replacement to a failing chlorine dioxide system for Legionella control. The CSI system was used in conjunction with the existing temperature regime and was installed upstream of the water storage tanks to allow adequate build-up of copper and silver in tanks so that good levels were available for distribution to outlets.

Sampling: Samples were taken monthly and analysed for Legionella, by the culture method, and for copper and silver by Inductively Coupled Plasma-Optical Emission Spectroscopy/Mass Spectrometry over a four-year period. Temperature was also measured.

Results: Table 1 shows the results for Legionella counts and water temperature before the CSI was installed. The highest count was observed in the cold water supply to a Thermostatic Mixing Valve (TMV) at 19.6 °C. This shows that keeping cold water temperatures below 20 °C at outlets did not control L. pneumophila s1 at this outlet. The hot water temperature recorded (52.0–59.4 °C) showed the difficulty of keeping hot water temperatures above 55 °C.

Table 1 – Pre-commissioning Results: Legionella spp. and water temperature (August 2011)

Sample description Temp ºC Legionella Cfu/L
Basin Hot TMV 54.2 10000 s1; 10000 s2-14
Basin Cold TMV 18.3 ND
Shower Hot TMV 59.4 18000 s1; 72000 s2-14
R13 Bath Hot TMV 57.7 10000 s1; 20000 s2-14
R13 Bath Cold TMV 19.3 ND
R13 Basin Hot TMV 56.5 1500 np
R13 Basin Cold TMV 19.7 ND
R6 Basin Hot TMV 52.0 36000 s1; 54000 s2-14
R6 Basin Cold TMV 19.6 290000 s1
R6 Basin en suite Hot TMV 52.1 10000 s2-14
R6 Basin en suite Cold TMV 19.1 ND
R6 shower en suite Hot TMV 53.5 ND
Shower en suite MT TMV 41.7 ND
Toilet room Hot MT TMV 58.1 ND

ProEconomy's reputation speaks volumes and the Orca system is highly regarded by those who have installed it.