WATER CONTAMINATION LEGIONELLOSIS


‘Test results should not be relied upon for regulatory control. The precision of test data is nowhere near good enough for making critical decisions.’ He added: ‘Many of us feel that more


testing – done properly – would have contributed to fewer deaths. However, many of us know for certain that the inaccuracies in tests have confused the picture and the positive predicted value is so dismal that there is very little correlation between detected levels and cases of legionella.’ Webinar participants generally agreed


Testing samples from hot water systems is vital for preventing bacteria contamination


that innovation in the field of testing and hazard control would still be an important part of protecting people from Legionnaires’ disease in the future and would be accommodated within the standard as a possible means for the responsible person to validate their hazard control. ‘New methods will fit into the management process as they emerge; this is better than setting prescriptive standards for testing that are possibly open to corruption,’ added McCoy.


Instead, 188P focuses on helping those


responsible to establish a robust control system. It includes examples of process flow diagrams; hazard analysis procedures; verification and validation summaries; and a hazard analysis of critical control points (HACCP) plan document (see below). ‘Validation is critical because you must


make sure that the hazard control measures do actually work and verification is the evidence that the plan is actually being implemented,’ said McCoy.


ASHRAE also believes there is no


requirement for new laws to support the standard because existing US federal occupational health and safety laws cover the protection of employees and visitors to buildings. As well as the mammoth damages claimed, these laws also carry the threat of prison sentences. It is anticipated that litigators will use the new ASHRAE standard as a reference point for deciding whether the right processes were in place before an outbreak. If 188P is adopted it could have an


impact on how water systems are managed and maintained in over five million US buildings. ‘All healthcare buildings and all buildings with cooling towers will have to have this process put in place,’ said McCoy. ‘A very small number will not need a water management plan, but only a very small number and the person responsible will need to reassess this every year.’ Other contributors to the webinar said


that many building managers would not have the necessary expertise to implement solutions or adopt a management standard like 188P and so would need to seek outside help. ASHRAE confirmed that it expects there to be ‘a scramble for expertise’ when the standard is adopted. ‘Over time the market will develop,


but that is not a matter for the standard committee as there is no requirement for an outside expert as part of the team,’ said McCoy. ‘We decide what needs to be done and the market will deal with the supply and demand issues.’ CJ


ASHRAE standard Proposed new ‘188P’ will target legionellosis


Due for publication later this year, the proposed new 188P standard covering the prevention of legionellosis associated with building water systems, will be approved by the American National Standards Institute (ANSI) – which means local building authorities can adopt it directly into their state regulations. Standard 188P outlines


the process by which building operators should manage hazard levels. The relevant manager will be required to take ‘formal’ responsibility for controlling legionella in building water systems – including potable water, not just


48


cooling systems. There are similarities with the UK’s long-established Code of Practice L8, but there are also significant differences because L8 is heavily reliant on risk assessment. ‘That implies a quantitative approach, but legionella cannot be assessed that way – it needs to be assessed in terms of hazard,’ said McCoy. ‘L8 spends a lot of time trying to document things that can’t be documented. Our standard is about quantitative assessment of hazard and hazard control, not risk.’ The standard sets out


how they should establish a team with assigned


CIBSE Journal February 2012


responsibilities and how that team should operate a system of hazard analysis of critical control points (HACCP). ‘The standard says


what to do, but it does not say how to do it,’ explained McCoy. ‘We don’t think it should be prescriptive because the site-specific measures are the most critical factors and it is, therefore, very hard to standardise a recommendation for control. ‘If you try to be prescriptive you create more problems than you solve,’ he added and pointed to the numerous guidance documents


already available with specific recommendations for technical aspects of water treatment, including chlorine concentrations and temperature control. However, McCoy


outlined the importance of the building team establishing their own control limits for legionella in their water systems and then confirming and validating those limits. Every known hazard


must be identified and the frequency and methods of monitoring established along with the corrective actions that should be taken if limits are exceeded, he said.


ASHRAE is, in effect,


adopting a method that was developed by the US Army (and later adapted by NASA and the food safety industry) and applying it to a building-related issue that is spiralling out of control. About 120,000 people


are thought to have died in the US since the cause of the disease was established more than 30 years ago. ‘This is an astonishing


number of deaths for a wholly avoidable disease,’ said McCoy. He added that there had


been a 217% increase in annually reported cases from 2000-09, and each case costs the US taxpayer $34,000 to treat. www.cibseashrae.org


www.cibsejournal.com


Lisa F. Young/Shutterstock.com


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