Scalding versus Legionella – balancing the risks.
Until recently, thermostatic mixing valves (TMVs) were installed as a matter of course in hospitals and care homes to prevent scalding incidents to patients and residents.
Health and Safety Executive’s guidelines HSG274 Part 2* says that: “The use and fitting of TMVs should be informed by a comparative risk assessment of scalding risk versus the risk of infection from legionella.” However, an alternative technology has emerged which offers a mechanical solution to deliver safe, temperature controlled water at the point-of-use.
The risk of scalding depends on the use and the user. A low level of risk could be a habitual user who is familiar with the outlet and the type of mixer, for example, healthcare workers using a particular basin for regular hand washing. An intermediate risk level could be hospital visitors who use the public facilities when visiting patients. Although unfamiliar with the facilities, they have no sensory or mobility issues and are able to use the washbasins safely, especially if there are visual warnings about hot water.
HSG274 Part 2 guidelines suggest that: “Where a scalding risk is considered significant … then type 3 TMVs [TMV3] that are pre-set and failsafe should be provided.”
To failsafe, the hot water must shut off if the cold water fails and vice versa. The most serious scalding risk is where the user is fully immersed in either a shower or a bath. There are also key cohorts where the scalding risk is significant, for example the very young or elderly, those with sensory loss, the infirm or significantly mentally or physically disabled people. Here the guidelines recommend the use of TMVs for sinks or hand washbasins.
In public areas within healthcare facilities the risk of scalding increases when users are unfamiliar with the facilities. Where there is high frequency usage by visitors, pressure-balancing mixers can provide an intermediate anti-scalding solution. The ceramic cartridge, sensitive to pressure changes, has an internal shuttle that continually adapts to the incoming hot and cold water supply pressures, ensuring a constant mixed water temperature at the outlet. If the cold water supply fails, the hot water is reduced to a trickle. This, coupled with a pre-set maximum temperature limiter, means a significantly reduced scalding risk.
Advances in anti-scalding technology and infection control have led to a multitude of products that offer different solutions for patient, staff and visitor safety in healthcare environments. Certainly, the technologies are not mutually exclusive and are not always complex.
It is possible to control Legionella and provide scalding safety for most situations, to accommodate the comparative risk levels.
For further information call 01491 824449 or visit www.delabie.co.uk