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Portable water vapour handwashing - an update

Published 14th January, 2010 by Neil Nixon

Portable water vapour handwashing - an update

An important part of the development of the Vapawash handwashing unit invented by Duplex Cleaning Machines has been the biological testing programme, running parallel to the manufacturing process of the prototypes.

Duplex commissioned a series of tests carried out by the Infection Research Laboratory at the Queen Elizabeth Hospital in Birmingham.

These tests were structured to assess the effectiveness of the prototype unit with a view to incorporating the latest ideas into the design of the production unit.
Using a transient bacteria E coli K12 NCTC 10538 applied to the hands of 15 volunteers the average Log10 reduction achieved using the Vapawash unit with Duplex Vapasan soap was 4.14. This result was obtained over a washing cycle of 50 seconds and compared with a Log10 figure of 4.7 which was achieved from a longer washing/rinsing cycle of 75 seconds using water and a standard soft soap.

The Vapawash is completely programmable in terms of washing and drying times and in view of that flexibility of operation tests were also carried out with various single volunteers with the Vapawash unit set at washing times of 20, 30, 40, 50 and 60 seconds. These gave Log10 reductions of 2.86, 4.04, 4.18, 4.59 and 4.77 respectively. Again Duplex Vapasan soap was used. In these series of tests the machine outperformed the reference test of a standard soft soap and a wash/ rinse time combined of 75 seconds which returned average Log10 readings of 4.28.

Kevin Scott, general manager of Duplex, said: “We’re surprised and delighted by these results, having set our initial expectations much lower. One of the fundamental principles behind the concept of the Vapawash is to offer a hand washing facility in areas of a building or even outdoors where there is no water or drainage supply installed. To achieve Log10 reduction figures in excess of 4 represents a 99.99% kill rate against the tested media. With a fully automatic, timed operation the integrated washing and drying facility combined in single unit give consistent results. We are on target for the launch of the first production units early in 2010.”

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