Cover story

Flushingaway pathogens with direct technology

Delabie marketing manager Carole Armstrong examines how cistern-flush toilets can increase the risk of bacterial contamination in public washrooms and how direct flush technology provides a hygienic and sustainable alternative for care facilities

In the fight against bacteria and germs, the toilet is an obvious source of harmful pathogens. In care facilities this intensifies if the toilet is also used to dispose of vomit and faecal deposits when a resident becomes unwell. Received wisdom says that when we flush the toilet harmful pathogens are flushed away and regular cleaning will remove any germs and bacteria from contaminated surfaces. However, in 2015, an American study reinforced the hypothesis that flush toilets play a role in the airborne transmission of infectious disease by producing microbe- contaminated bioaerosols when flushed.¹ Following a contamination episode, a French hospital found that the epidemiological source of infection was the toilet cistern. Cisterns increase the contamination risk because water is stored at ambient temperatures in ideal conditions for biofilm development.

This, in turn, provides a safe haven for bacteria to develop. These bacteria are released in an aerosol plume during flushing, but they can also spread back through the pipes and colonise the system. Flushing is essential for effective hygiene, so airborne pathogens cannot be eliminated completely. However, could removing the cistern reduce the risk of infection? The alternative to a cistern-flush mechanism is a direct flush system which connects directly to the water supply.

A self-closing valve discharges a pre- determined flush volume without the need to store water in a cistern. Direct flush technology uses the system pressure to rinse the pan, so there is no water stagnation, no scale deposits and no build-up of impurities upstream of the flush mechanism.

Direct flush improves hygiene The Water Supply (Water Fittings) Regulations 1999 require the contents of a toilet pan to be cleared effectively by a single flush of water.2


cistern flush mechanisms may not have sufficient dynamic pressure to ensure a hygienic rinse with a single flush, and a 40 to 60-second refill time can cause additional problems.

Replacing the cistern with a direct flush valve has several advantages in terms of hygiene. Firstly, the flush volume can be adjusted to suit the system’s dynamic pressure and ensure an effective single rinse. Where necessary, the flush can also be adjusted for ecological or smaller children’s toilet pans.

TEMPOMATIC electronic WC flushes automatically if the user forgets


That reduces the aerosol flush plume and prevents unhygienic splashing on the toilet seat and floor, removing the risk of slipping on wet floors. In addition, since there is no refill time, the full flush is

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instantly available for subsequent users, delivering an effective flush every time. Hygiene can be further improved by installing an electronic flush mechanism, for example, Delabie’s Tempomatic flush valve. No manual contact is required, so the toilet is accessible to any user, regardless of age, mobility or level of independence.

An automatic sensor detects the user and flushes the valve automatically if they are unable to pass their hand in front of the sensor or if they forget. Furthermore, an automatic duty flush can be programmed to flush the pipework every 12 or 24 hours when not in use, preventing stagnation in the system and reducing biofilm development. Cistern-flush toilets are usually installed through habit but, although they are ideal for domestic usage patterns, the mechanism is not designed to cope with the regular and intensive use experienced in public buildings. Heavy-handed users can easily break fragile mechanisms. Damage can often occur through voluntary vandalism where the user takes out their frustration on the facilities, or involuntary vandalism where the user is not familiar with the facilities and unwittingly breaks the mechanism. Depending on water quality, watertight seals which are sensitive to scale and impurities, quickly wear out with repetitive use. This inevitably leads to leaks and reduced flushing capability. According to Thames Water, a leaking toilet can waste up to 400 litres of water • May 2020


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