Legionella policy plan. Document information

Transcription

1 Field of application RWE Generation NL Valid until Document information Version Version date Authorisation V Health, Safety and Security Manager - R. Kamst Changes made to previous version Conversion of UPI035 to I-035 in accordance with new template Conversion of I-035 to I-035 as part of Sense & Simplicity Purpose of instructions To analyse, manage and document the risks of legionella in drinking and process water systems including (drinking) water systems, (open) cooling tower systems, airconditioning systems and emergency showers as this is basically where the formation of aerosols of water in which the legionella bacteria could be present can occur. Related processes/documents Process Title Code Output Managing HSE risks P053 Input Combatting Legionella WCI sheet 32 Input Operation and monitoring P033 Input Maintenance of installations P080 Page 1 of 9

2 General The Drinking Water Regulations stipulate explicit requirements relating to the quality of mains water and of the mains water system. Both the Drinking Water Act and the Drinking Water Decree as well as the Buildings Decree contain various duty of care provisions aimed at preventing damage to the health of consumers or other users. Put simply, it comes down to the fact that all building owners are responsible for ensuring that the water that comes out of the tap is safe to drink and that the public mains network is not contaminated. In addition, contamination with legionella can occur in wet cooling towers, cooling water systems and process water systems. Wet cooling towers also present a risk to the environment and public health. For that reason, the Environmental Management Act (2009) also applies to wet cooling towers. Employees can also run the risk of becoming infected with legionella bacteria from a wet cooling tower while carrying out their work. Think, for example, of employees who are involved in the maintenance or management of wet cooling towers or cooling water systems. For that reason, the Working Conditions Act and regulations derived from this also stipulate requirements that must ensure that this does not happen and that employees must be protected against this. The employer has the duty of care to prevent employees from being exposed to these risks. Within RWE Generation NL, the general approach to both drinking water systems and process water systems is described in this. This policy plan describes the requirements that the RWE Legionella containment plan that must be drawn up for each site must meet. It must describe the approach and all the containment measures for preventing the possibility of internal or external employees coming into contact with legionella bacteria. Because the drinking water systems and showers connected to them at our sites can also be used by third parties and are therefore regarded as collective drinking water systems, we follow the policy which applies to priority settings. Based on its characteristics, the legionella bacterium is classified in category 2 biological agents in accordance with the Working Conditions Decree. Reports If high concentrations of legionella bacteria are found in drinking water systems or cooling towers (> 1000 CFU/l), then this is to be reported to the Human Environment and Transport Inspectorate (ILT) within 48 hours. The ILT will forward the report to the Municipal Health Service in the relevant region immediately. Page 2 of 9

3 If that is the case, measures to (demonstrably) reduce these concentrations and prevent (further) dissemination must be taken for all infected systems immediately and all users are to be informed immediately regarding the risk. See also below under Description of approach and in the associated table. If a person becomes infected, then this is to be treated as an incident and the Inspectorate of the Ministry of Social Affairs and Employment is to be notified too. Legionella Risk Analysis You are responsible for identifying (or arranging for the identification of) where the legionella bacterium may (start to) grow in your water systems. The containment of these risks is described in the containment plan which details measures for ensuring that growth is prevented in places where the legionella bacterium can grow. A drinking water system consists of pipes and the devices connected to them, from the water meter to the tapping points, including the hot water system. In order for legionella containment to be effective, you must: A. have a risk analysis; B. have a containment plan describing containment measures: the containment measures must be carried out periodically in accordance with the plan; C. keep a logbook; D. arrange for the statutory number of water samples required to be taken by an accredited organisation and analysed by an accredited laboratory every six months; E. report an exceeding of the standard relating to legionella in drinking water to the ILT and take the correct measures; F. in the case of a serious exceeding of the standard relating to legionella in drinking water, notify your customers/users regarding this by means of collaboration with the Inspectorate and the Municipal Health Service. At site level, this policy is to be implemented by means of a legionella containment plan describing containment measures to ensure that employees do not (or cannot) become infected with the legionella bacterium (Legionellosis) A. Have an up-to-date risk analysis By carrying out the risk analysis, you identify the risks associated with where the legionella bacterium may (start to) grow in your drinking water system. Parts which must at least be included in the risk analysis and for which a risk assessment must be provided are shown below. A description of what is expected from you for each part can be found by visiting and an overview of all the individual tapping points present as well as the different types; installation drawings, diagrams and technical descriptions of the drinking water system must be up-to-date; Page 3 of 9

4 an overview of all parts of the system that can heat up to above 25 C unintentionally; an overview of all pipe sections that are not refreshed at least on a weekly basis; an overview of devices for protecting pipe sections that are not refreshed (e.g. fire hose reels); a description of the way in which hot water is produced. This must include details on how the temperature of the water supplied is measured; if hot water (sub-)ring mains are present, the return temperature of the hot water must be at least 60 C in each (sub-)ring main; an inventory of all mixing water pipes which are longer than five metres; an inventory of all hot water tapping points where a minimum temperature of 60 C is not reached; the risk analysis must cover the whole drinking water system. Exceptions to the above are possible in certain cases. Drawing up a containment plan: An inventory must be drawn up of all the water flows in which aerosol formation may occur; A risk analysis must be carried out by a BRL 6010-certified company. That analysis will show where legionella bacteria may grow in the inventarised water systems; A legionella action plan must be drawn up based on this risk analysis by a BRL 6010-certified company. This will state the measures that must be taken in order to mitigate the legionella risks present in the system; RWE Generation NL is obliged to carry out measures in order to reduce the growth of legionella bacteria; Any measures taken must be recorded in a logbook; Water must be checked for the presence of legionella at least twice a year. This measurement must be carried out by a BRL 6010-certified company; RWE is obliged to take measures in order to reduce the number of legionella bacteria if 100 colony-forming units per litre (CFU/l) or more are measured; If the measurement taken shows that there are 1000 CFU/l or more legionella bacteria in the water, then this must be reported immediately to the Human Environment and Transport Inspectorate (ILT) and in addition, containment measures are to be taken immediately. An HSE report on this will also need to be produced. Modifications to the system or the use thereof must be handled in accordance with the MOC procedure and the possible new risks of the development of legionella bacteria must be identified again by means of a risk analysis by a BRL 6010-certified company. In this case too, a legionella action plan will then need to be drawn up and followed. Page 4 of 9

5 Content of the legionella containment plan The legionella containment plan is to contain the following information: a systematic description of the relevant system(s); a description of the critical aspects of the system(s) including situations involving the shutdown of a system or parts of a system; a drawing or diagram showing the current set-up of the system including the parts that are temporarily out of use; a description of the correct and safe operation of the system; a description of the regular maintenance activities, periodic inspections and management of installations; a description of all checks to be carried out, including the check for the presence of legionella (in order to check the effectiveness of the measures); an overview of the levels of action that are applied (physical, chemical and microbiological including legionella) where (emergency) measures are taken, including a description of those (emergency) measures. 100 CFU/l is a prescribed level of action for humidification systems and other water systems where measures must be taken or existing measures must be tightened up; a description of the measures that will be taken in the event of an emergency. A logbook is to be kept with the containment plan and the following are to be noted in it: the containment measures carried out; maintenance work carried out; the modifications made to the installations; the modifications made to the maintenance of the installations; the results of checks carried out (analysis results and inspection results); general features relating to the operation of the installations; the details in the logbook are to be kept for at least 3 years and the frequency of all the works described are to be clearly specified; the management is to be kept regularly updated regarding the effectiveness of the legionella containment plan. Page 5 of 9

6 Cooling water systems and cooling towers Because the conditions and risks in cooling water systems can vary greatly, regular inspections and checks are also required here. These can be subdivided into the following categories: visual inspections; operation of dosing equipment and analysers; use of chemicals; clarity of cooling water; water analyses; microbiological testing. Overview of cooling towers within RWE Generation NL Category Distance to residential area Cooling tower present at Category 3 < 600 m Amer power plants Category 4 > 600 m CHP Moerdijk Category 4 > 600 m CHP Inesco Category 4 > 600 m CHP Swentibold Inspections and checks Category (according to BREF) Category 1 - Highest risk Category 2 Category 3 Category 4 - Lowest risk Periodic check for legionella (minimal) Monthly Quarterly Quarterly to annually Annually, preferably in the autumn Page 6 of 9

7 Description of approach Category-based approach Category 1, 2 or 3 Approach Category 4 Approach < 100 CFU/l A < 1000 CFU/l A CFU/l B ,000 CFU/l B ,000 CFU/l C 10, ,000 CFU/l C 10, ,000 CFU/l D and E 100,000-1,000,000 CFU/l D and E > 100,000 CFU/l F and E > 1,000,000 CFU/l F and E Approach A Approach B Approach C Approach D System is completely under control, no action necessary; Check via the treatment programme to make sure that all doses are in order and that no further action is necessary; Fence off the immediate vicinity. Only personnel who need to carry out work on the water flow in connection with the disinfection to be carried out will have access to the fenced off area. They are to wear at least face masks (type P3) as respiratory protection. Take action in order to reduce the value below 1000 CFU/l. After disinfection (apply biocide after a period of 24 hours, for example), arrange for legionella measurements to be carried out again. Carry out the actions specified from approach C. Check whether personnel/visitors could have been exposed to aerosols from the source of contamination. It should be investigated as to who has been in the immediate vicinity of the source of contamination. In the case of a cooling tower which is close to the public highway where there are high levels of passenger traffic (built-up environment) or falls within category 1, 2 or 3, it is recommended for the Municipal Health Service to be informed. Own staff and any visitors are to be screened to find out whether or not they have been in the immediate vicinity of the source of contamination and if they have, when and for how long. If necessary, arrange for them to be examined for symptoms of legionella infection. Page 7 of 9

8 Approach E In the case of a water flow and/or cooling tower which falls within category 4, it is recommended for the HS&S department at the site to be informed and for action to be taken in order to reduce the value below 1000 CFU/l. Adjust the management plan in line with this. Carry out the actions specified from approaches C and D. Carry out disinfection offline. The open system is to be taken out of operation as soon as possible. Inform the HS&S department as soon as possible. Inform the water quality manager regarding the disinfection measures planned. Enclosed systems may remain in operation if it can be ensured with certainty that it is not possible for people to come into contact with the water. The disinfection plan as specified in action level D is to be carried out. After carrying out disinfection, the whole procedure is to be repeated again. If it is decided to carry out an internal inspection of the system or the cooling tower and possibly cleaning, a face mask is to be used. The system can be put into operation again. Once the system is circulating normally again, a sample of the water is to be taken and tested for legionella. It should be realised that depending on the method of analysis used, it will be necessary to wait for a certain period of time before examining the results. Extreme care must be exercised during that time. It may be necessary to repeat the procedure depending on the results. Take action in order to reduce the value below 1000 CFU/l. Adjust the management plan in line with this if necessary Approach F Carry out the actions specified from approach E. Organise consultation with the competent authority pursuant to the Environmental Management Act and the Municipal Health Service. Page 8 of 9

9 Terminology & abbreviations Abbreviation/term WCI sheet CFU/l Meaning Working conditions information sheet Colony-forming units per litre Sodium hypochlorite Chlorine bleach lye (NaClO) FO Free oxidant Aerosols An aerosol is a colloidal (small particle which is bigger than a molecule) mixture of dust particles or liquid droplets dispersed in a gas. Their size is in the order of 0.2 to 200 microns and they can penetrate the lungs. Biological agents category 2 Working Conditions Decree an agent that can cause human disease and might be a hazard to the health and safety of employees but which is unlikely to spread among the population, while there is usually an effective prophylaxis or treatment available; Point for attention Hiring of temporary shower units for overhauls or maintenance shutdowns Always get the supplier to provide a legionella-free declaration. This will demonstrate that measures have been taken in order to prevent contamination or infection from these systems. Page 9 of 9