This is a superseded publication. Current BSRIA guidance on legionella can be found in BG 57/2015 Legionnaires' Disease - Risk Assessment and BG 58/2015 Legionnaires' Disease - Operation and Maintenance Log Book.
Whilst legionellosis is a relatively minor problem in terms of the number of cases, compared to other diseases and health issues, its significance lies in the fact that it is the only form of pneumonia known to man which could be reduced or controlled with the assistance of the building services industry.
Guidance aimed at reducing the risk of legionellosis in the UK was introduced by the Government in the early 1990s in the form of two documents:
The Health and Safety Commission: The Prevention or Control of Legionellosis (including legionnaires' disease): Approved Code of Practice (ACOP), (L8) (came into effect 15th January 1992).
The Health and Safety Executive: The control of legionellosis including legionnaires' disease: Health and Safety Series Booklet, (HS(G)70).
These documents indicated that water temperature measurement is a significant factor when assessing risk from legionella in hot and cold water services. (Other factors include water stagnation and cleanliness, system materials, aerosol generation, and the susceptibility of occupants). It soon became apparent that companies appointed to undertake risk assessments were experiencing considerable variations in water temperature measurements. The assessors' interpretations of results were also variable because these often depended on their individual backgrounds and training. As a consequence, clients were taking action based on the results of risk assessments for which the supporting information in terms of temperature measurements was neither repeatable nor reliable.
This application guide describes standard water temperature measurement procedures for hot and cold water services. For companies appointed to undertake risk assessments or routine inspection and maintenance, it explains the main activities which are essential for compliance with the general intent of the ACOP and HS(G)70 documents. For building owners and employers who are required to satisfy their obligations under the Health and Safety at Work etc Act 1974 and COSHH regulations, it provides a means of specifying temperature measurement requirements such that their responsibilities for identifying and controlling the risk have been successfully discharged, in this respect.
The guide also provides advice on the interpretation of temperature measurements. It is hoped that this will encourage greater consistency in the conclusions and actions recommended to those responsible for implementing precautions.
Whilst this document only addresses the HS(G)70 guidance on water temperatures, its principles on planning, measurement and site procedure are equally applicable to health care premises and other major estates.