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Legionella Monitoring Control and Prevention

Storage and Distribution of Hot and Cold Water

Requirements: The Owners and Operators of Water Distribution Systems have the legal responsibility to ensure that the risk of Legionella contamination to Users of the systems is controlled. Such systems would be found in Hotels, Hospitals, Schools, Leisure Centers, Public Conveniences, Residential Homes….  Inadequate maintenance of Hot and cold water systems as well as poorly designed or installed systems can lead to health risks.

Current Legislation and Guidance Documentation

  • Health and Safety Commission (HSC) Approved Code of Practice and Guidance L8 (2000).

  • The Health and Safety at Work etc Act 1974
  • The Management of Health and Safety at Work Regulations 1999
  • COSHH Regulations 1999
Operation

The Health and Safety Commission (HSC) Approved Code of Practice and Guidance L8 (2000) stresses that whilst the tasks required to be undertaken to control the risk, from Legionellosis, may be contracted out to external specialist service providers, the responsibility to ensure the competence of such services, remains entirely with the systems owners and operators. 

Records

Records are the critical activity to enable the system Owner or Operator to demonstrate that suitable and adequate assessment and monitoring procedures are in place.

Records are divided into two distinct areas:

Risk assessment Records: These records should contain details referring to Risk Assessments undertaken on the existing and new systems and will contain details of both the use and non use of the system. Records should be retained for the period to which they apply, and for a minimum of two further years.

Monitoring Point Records

Records of measurements from the identified and declared Temperature Monitoring points. Monitoring records must be retained for at least five years. These Risk Assessment and Monitoring Point records are in addition to any Personnel Training records and notes, any cleaning and disinfection procedures with associated certificates, and results of any chemical analysis.

Summary of Responsibility

It is the responsibility of the operator to ensure that the operation of any system does not present a risk to the health and safety of users of the system, including employees, visitors to site or to the general public.

Risk Assessment

The operation of the system should be assessed on a two yearly frequency or when there is reason to suspect that the operation of the system is no longer valid.

 

For example:

  • A change of water supply
  • Temperature Monitoring results
  • Persistent legionella positives
  • A case of legionnaires disease is associated with the system.
Temperature Monitoring for Hot and Cold Water systems

For all hot water clarifier systems, the water Inlet temperature and the outlet temperature should be continuously monitored.

 

Hot water should be stored at 60°C and distributed in such a manner that it reaches the tap outlets at 50°C within 1 minute of the tap being turned on.

 

If water is not drawn from the system on a regular basis, for example: daily, the temperature of the stored water, must be raised to greater than 60°C for a minimum of 1 hour before being used.

 

To meet the recommendations of the current Legislation and Guidance, water storage systems will normally require an independent temperature monitoring system.

 

A typical site could require up to 1000 temperature monitoring points: such as taps, storage vessels, mains inlets. The actual implementation will be scalable governed by the number, the size and physical distribution of the points within the site

 

Having to supply water to tap outlets at 50°C can introduce a risk of scolding, this will be of particular concern where children and the elderly could be at risk. 

 

For example:

Children’s nurseries or residential homes. The installation of mixer taps can be employed to enable the temperature to be lower, and safer, at the point of delivery. In these situations it is essential that the temperature monitoring points are correctly positioned.

 

The Eurotherm Data Acquisition system, offers two approaches for use in these applications, each providing a series of unique features:
Network Approach

  • The networking capability of the instruments allow data to be periodically sent to a local server or remote PC, for viewing and subsequent processing.

  • SMS and email notification and alarming allows the system to promote advanced servicing and support.
Non Network Approach
  • On sites where networking is not possible access can be gained to the instruments via a remote radio link or manually, with the aid of a Portable PC or Personal Digital Assistant (PDA) device.
Generic Features
  • Individual probes continuously monitor storage tank inlet and outlet temperatures as well as the cold water feed.
  • Each input is logged, alarmed and stored within the product, typically for up to 3 months, although this period will be dependent upon the system capability.
  • Alarm Indication via Remote Monitoring package.
  • In locations that experience a heavy demand on water supply, metering of usage can be included and calculations used to enable excess usage to be alarmed indicating possible leakage or water miss-use.
  • Eurotherm's Legionella reporting software is a purpose designed package allowing the user to create the necessary reports, based upon standard (included) or customized formats
  • To compliment the hardware systems Eurotherm offer on site support and calibration services further reducing the cost of ownership.