LEGIONELLA - World Health Organization
LEGIONELLA - World Health Organization LEGIONELLA - World Health Organization
10.4 Designing regulations Basic principles need to be observed when developing new regulations. There needs to be an overall aim, which in this case is to reduce the risk and incidence of legionellosis. The aim is achieved by applying a set of specific requirements, each of which should have a specific and stated purpose. Compliance with requirements should be measurable and (where appropriate) enforceable. Monitoring regimes should be defined, and corrective action to remediate noncompliance should be described. Specific health-based targets might be established for the incidence of illness or outbreaks. Such targets can be useful in undertaking cost–benefit analyses as part of a regulatory impact assessment. If Legionella testing is included in requirements, target concentrations and responses to detections should be specified. In some cases, there may need to be a balance between different regulatory requirements. For example, in the case of water distribution systems, avoiding temperatures between 25 °C and 50 °C will reduce the risk from Legionella; however, regulations designed to reduce the risk of scalding can require that hot-water temperatures be kept below 50 °C or even below 45 °C. This can be achieved by lowering water temperatures throughout distribution systems or by installing thermostatic mixing valves close to the point of water use. In either case, greater levels of maintenance will be required to compensate for loss of temperature-based control of Legionella. 10.4.1 Managerial responsibilities, registration and notification Regulations should identify managerial responsibilities associated with systems, and should include requirements for the training and competence of operators. Requirements could also be included for registration of devices with regulatory authorities. Consideration should be given to notification requirements in the event of serious non-compliance. 10.4.2 System assessment and design System assessment should include inspections of buildings and surrounding areas to identify potential sources of Legionella and to evaluate the risk associated with devices, taking into account design, location and operating conditions. A risk assessment could include consideration of: • the potential for conditions that could favour the survival or growth of Legionella • the potential for production and dissemination of aerosols • design features, such as deadlegs, the position of air intakes or cooling tower exhausts, and the presence of drift eliminators in cooling towers • control measures to minimize risks (e.g. automated biocide dosing, flushing, cleaning and general maintenance) LEGIONELLA AND THE PREVENTION OF LEGIONELLOSIS
• operating conditions, such as temperature ranges in water distribution systems, and whether devices are operated continuously or intermittently • the location of devices in relation to exposure of vulnerable groups. The risk assessment should determine whether existing control measures are sufficient and operate effectively. If they are not sufficient, additional measures should be identified. Guidance on appropriate control measures can be provided in codes of practice referenced within regulations. In addition, regulations can identify specific control measures to be applied, such as: • application of temperature controls for water distribution systems • use of biocide dosing as part of an ongoing water management programme • regular flushing of water systems • frequencies of cleaning and inspection • use of drift eliminators on cooling towers. A number of design features can influence the growth and dissemination of Legionella; for example, reducing the occurrence of circulating water temperatures between 25 °C and 50 °C, minimizing stagnant water, installing biocide dosing systems and installing drift eliminators on cooling towers. Cooling towers should be located so that outlets are not close to air intakes or windows of adjacent buildings. Consideration of such features is fairly straightforward when designing new systems, but can present difficulties when dealing with existing systems. The inclusion of design requirements within regulations should be considered. Some existing regulations deal with design, and others do not. 10.4.3 Operational monitoring and verification Operational monitoring procedures need to be identified for each control measure. Operational monitoring can take the form of testing for defined parameters and inspection programmes. Regulations should include the requirement to institute operational monitoring systems. Operational monitoring requirements regarded as essential could be defined (e.g. the frequency of testing or inspection of cooling towers or water distribution systems). Further guidance on the design and implementation of operational monitoring could be provided in codes of practice and referenced within regulations. In addition to operational monitoring of individual components and control measures, verification procedures need to be identified. Verification provides reassurance that WSPs as a whole are operating effectively. The process can be undertaken by owner, operators or regulatory authorities, and regulations should specify who is responsible. Verification can include testing for Legionella. LEGIONELLA AND THE PREVENTION OF LEGIONELLOSIS
- Page 137 and 138: Kingdom to 66% in Spain (Starlinger
- Page 139 and 140: Agency, Legionella Section, United
- Page 141 and 142: Given the complexity of distributio
- Page 143 and 144: Chapter 8 Natural spas, hot tubs an
- Page 145 and 146: Spas “Natural spa”, denotes fac
- Page 147 and 148: Rare cases of Legionnaires’ disea
- Page 149 and 150: Process step P pework Water n hot t
- Page 151 and 152: Hosepipes may sometimes be used to
- Page 153 and 154: Hot tubs that are not effectively d
- Page 155 and 156: Nutrients — control measures Bath
- Page 157 and 158: Various additives may also be used
- Page 159 and 160: • descriptions of any significant
- Page 161 and 162: Table . Examples of m crob olog cal
- Page 163 and 164: Chapter 9 Disease surveillance and
- Page 165 and 166: Exposure histories allow cases to b
- Page 167 and 168: F gure . Invest gat ng a s ngle cas
- Page 169 and 170: Box . (cont nued) Since the incepti
- Page 171 and 172: Country United Kingdom All reported
- Page 173 and 174: F gure . Annual reported cases, - 0
- Page 175 and 176: Training opportunities Trainees in
- Page 177 and 178: Box . Example of terms of reference
- Page 179 and 180: ecause doing anything more could un
- Page 181 and 182: 9.4 Case studies This section descr
- Page 183 and 184: 9.4.4 Concrete batcher process on a
- Page 185 and 186: Chapter 10 Regulatory aspects David
- Page 187: • validation of the effectiveness
- Page 191 and 192: 10.4.6 Outbreak investigation and n
- Page 193 and 194: hot water (e.g. health-care facilit
- Page 195 and 196: General prevent on Country DW Wp SB
- Page 197 and 198: Country General prevent on DW Wp SB
- Page 199 and 200: Chapter 11 Laboratory aspects of Le
- Page 201 and 202: • detection of the bacterium in t
- Page 203 and 204: Method Sens t v ty (%) PCR • Rapi
- Page 205 and 206: 11.2.2 Detecting Legionella antigen
- Page 207 and 208: DFA has been used successfully with
- Page 209 and 210: • Serologic testing can be used f
- Page 211 and 212: Although not all strains can be rel
- Page 213 and 214: Generally, any water source that ma
- Page 215 and 216: During outbreak investigations, swa
- Page 217 and 218: • other Legionella species that d
- Page 219 and 220: Appendix 1 Example of a water syste
- Page 221 and 222: Weekly water system check list Week
- Page 223 and 224: Appendix 2 Example of a 2-week foll
- Page 225 and 226: Travel Work/travel in the UK: ❑ Y
- Page 227 and 228: Checklist of local places Health/sp
- Page 229 and 230: Appendix 3 Example of a national su
- Page 231 and 232: Strictly Confidential 2 Hospital Ac
- Page 233 and 234: Glossary aerobic bacteria Bacteria
- Page 235 and 236: health-care acquired Legionellosis
- Page 237 and 238: surveillance The process of systema
• operating conditions, such as temperature ranges in water distribution systems, and whether<br />
devices are operated continuously or intermittently<br />
• the location of devices in relation to exposure of vulnerable groups.<br />
The risk assessment should determine whether existing control measures are sufficient and<br />
operate effectively. If they are not sufficient, additional measures should be identified. Guidance<br />
on appropriate control measures can be provided in codes of practice referenced within<br />
regulations. In addition, regulations can identify specific control measures to be applied, such as:<br />
• application of temperature controls for water distribution systems<br />
• use of biocide dosing as part of an ongoing water management programme<br />
• regular flushing of water systems<br />
• frequencies of cleaning and inspection<br />
• use of drift eliminators on cooling towers.<br />
A number of design features can influence the growth and dissemination of Legionella; for<br />
example, reducing the occurrence of circulating water temperatures between 25 °C and 50 °C,<br />
minimizing stagnant water, installing biocide dosing systems and installing drift eliminators<br />
on cooling towers. Cooling towers should be located so that outlets are not close to air intakes<br />
or windows of adjacent buildings. Consideration of such features is fairly straightforward<br />
when designing new systems, but can present difficulties when dealing with existing systems.<br />
The inclusion of design requirements within regulations should be considered. Some existing<br />
regulations deal with design, and others do not.<br />
10.4.3 Operational monitoring and verification<br />
Operational monitoring procedures need to be identified for each control measure. Operational<br />
monitoring can take the form of testing for defined parameters and inspection programmes.<br />
Regulations should include the requirement to institute operational monitoring systems.<br />
Operational monitoring requirements regarded as essential could be defined (e.g. the frequency<br />
of testing or inspection of cooling towers or water distribution systems). Further guidance on<br />
the design and implementation of operational monitoring could be provided in codes of<br />
practice and referenced within regulations.<br />
In addition to operational monitoring of individual components and control measures, verification<br />
procedures need to be identified. Verification provides reassurance that WSPs as a whole are<br />
operating effectively. The process can be undertaken by owner, operators or regulatory authorities,<br />
and regulations should specify who is responsible. Verification can include testing for Legionella.<br />
<strong>LEGIONELLA</strong> AND THE PREVENTION OF LEGIONELLOSIS
Change language