EHS COP Domestic Water (E) 8-04

8/10/2019 EHS COP Domestic Water (E) 8-04

1/22

February 03 Version 1 (E)

Code of Practice for ReducingRisks Associated with Legionel la

in Domestic Services


2/22

Page 1 of 21

Global Code of PracticeHot and Cold Water Services (E)

August 04

CODE OF PRACTICE FOR REDUCING RISKS ASSOCIATED

WITH LEGIONELLA IN DOMESTIC SERVICES

INDEX PAGE NO

Objective 2

Identification and assessment of risk 3

Preventing or reducing the risk from exposure toLegionella 4

Design 4

Operation 5

Inspection and maintenance 6

Cleaning and disinfection 7

- Pre-commission disinfection 8

- Remedial disinfection and cleaning 8- On-line/continuous disinfection procedures 10

- Water supply tank cleaning 11

Monitoring Programmes 12

- Cold water monitoring programmes 12

- Hot water monitoring programme 13- Action levels 14

Actions in the Event of an Emergency 16

Management and the selection, training and competence of personnel 17

Record keeping 18

Responsibilities of designers, manufacturers, importers, suppliers and

installers 19


3/22

Page 2 of 21


August 04

OBJECTIVE

1. To provide recommendations and guidance on precautionary measures required to maintaindomestic (hot and cold water) services in a manner which reduces the risks associated with the

proliferation of Legionella. Environmental Hygiene Services is a business unit of Nalco. The

following recommendations are not intended to replace any local regulations/guidancewhich must take priority when considering Legionellacontrol procedures. In the absenceof local regulations/guidance, the recommendations in this Manual are to be adhered to. In

production of this guidance document, consideration has been given to the global variations

employed for reducing the risk. The recommendations within this document are consistent

with the UK Legionnaires disease: The Control of Legionella Bacteria in Water Systems,OSHA (US), Australian and French guidelines. However, in certain detail, the strictest

guidance available has been deemed as good practice and incorporated into the international

standards for Nalco.

INTRODUCTION

2. This manual deals with engineered water systems which might be used in a way which creates

a reasonably foreseeable risk of legionellosis, in particular hot and cold water services.Although written for Environmental Hygiene Services personnel, this manual may form a

useful part of a site specific written scheme for reducing risk.

3. Humidifiers and air washers, spa bath, pools, water softeners, emergency showers, car washes,fire and sprinkler systems and many other systems using water, operating at temperatures in

excess of 20oC which can generate an aerosol, present a possible risk of Legionellosis.This

manual is specifically written for domestic hot water services, however, the systems

previously mentioned also have a requirement to be risk assessed, utilising similar principles

to those herein described. The key features of this assessment will identify the risk ofLegionella proliferation and the probability of exposing a susceptible population to a

contaminated aerosol. An adequate control scheme and management practices will also be

required. It is acknowledged that various geographical locations will have different

designs/operations of water systems and that local regulations may also differ.

4. System design and operation, methods of routine control, treatment and monitoring of the

water contained in these systems and recommendations for cleaning and disinfectionprocedures are considered. Guidance on the design of treatment programmes will be found in

the appropriate Operations Manual, as provided by the various Ondeo business units.

5. No two systems are identical and this manual can only be considered as a general guide.Where the unique nature of a system takes it outside the recommendations in this manual, the

principles should still be applied (ie as guided by the risk assessment) with appropriate

amendments being agreed between the responsible site representative, the responsible District

Management and the Site Management, with due regard to current regulations/guidance.

6. At all times, Environmental Hygiene Services employees are obliged to conform to local

Health and Safety regulations and any supporting information issued by local Health and

Safety departments. Reference is also made to the Nalco Health and Safety policy. In thismanual the UK Approved Code of PracticeLegionnaires Disease: the Control of Legionella

Bacteria in Water Systems is used as reference. This determines the minimum standardsthat can be applied. It should also be noted that the conclusion of the risk assessment might


4/22

Page 3 of 21


August 04

dictate requirements above this minimum in order to provide the most appropriate level of

programme performance and risk reduction. The reasons for the variation in standards shouldbe noted in the customer file and the log book.

7. It is recommended that effective documentation of the maintenance programme is available.

Log books, specifications and schedules are therefore essential with sufficient detail beingprovided to show that the scheme to reduce risk has been based on a valid Risk Assessment

and that it has been competently and effectively applied and implemented.

8. It is the responsibility of the Site Management, specifically the person on whom the statutoryduty (legal responsibility) falls, to ensure that an adequate Risk Assessment of the water

systems on site is carried out, with details held on file. Further, it is their duty to ensure that

people involved with the control of Legionella have adequate training qualifications and

experience to fulfil their duties in executing the risk management programme.

IDENTIFICATION AND ASSESSMENT OF RISK

9. It is the responsibility of the site management, specifically the person on whom the statutoryduty falls, to ensure that an adequate Risk Assessment is undertaken for the site and that

control measures detailed in the assessment are appropriately implemented. The Risk

Assessment must be current, as it forms the foundations of the whole risk management activity.

10. The Risk Assessment may be carried out by site personnel, if they have appropriate knowledge

and experience, or the task may be contracted out. Environmental Hygiene Services may

undertake this activity on behalf of the customer, but this does not form part of the

normal water treatment programme contract unless specifically detailed in the contractof supply. A competent person who has a sufficient understanding of the systems and the risk

factors must carry it out. They must also have an appropriate level of training.

11. The Risk Assessment will be sufficiently detailed so as to identify and assess the risk oflegionellosis from work activities and water sources on site, and the necessary precautionary

measures. This Risk Assessment must be reviewed if significant changes occur, or every two

years.

12. A Risk Assessment should not be confused with a site survey, which may be undertaken to

provide sufficient information to formulate a water treatment programme, or to enable the

provision of a quotation for future works. Nor should it be confused with asite audit, which

may be undertaken to provide an asset register of all water systems. A trained Risk Assessor,who has detailed understanding of the system and the risk factors, must carry it out. However,

this individual may require the assistance of a site contact person who can provide the

operational details. Both site audit and site survey documentation may form a useful part of

any Risk Assessment.

13. It is not the purpose of the Code of Practice Manual to define the requirements of a Risk

Assessment. An assessment is a requirement of good practice and where sites do not have an

assessment, it will be necessary for Environmental Hygiene Services to inform the responsibleperson on site of this requirement. It is appropriate to inform increasingly Senior Site

Management of this requirement if action is not taken to comply.


5/22

Page 4 of 21


August 04

PREVENTING OR REDUCING THE RISK FROM EXPOSURE TO LEGIONELLA

Design

14. The responsibilities held by Nalco and the customer site with respect to the written

scheme for reducing risk, must be clearly defined in the contract or quotation.Therefore, the respective operational responsibilities held by the various parties shouldform part of the business contract.

15. Good design and installation practice is essential for effective long-term maintenance.

Reference should be made to local standards and publications.

The following points concerning design should be noted if applicable:

(a) Installers should only use approved fittings and materials. Reference should be made

to local standards.

(b) If applicable, water supply tanks and other parts of the distribution system should be

well enclosed to prevent the entry of foreign matter.

(c) Overflows and air vents should be protected by appropriately sized rodent

screens/insect filters.

(d) Water supply tanks should not be oversized; 24 hour maximum storage capacity isrecommended. Multiple linked tanks should be avoided.

(e) Where two or more tanks serve the same system, they should be arranged such that

water flows through all tanks so that stagnation does not occur. This is normallyachieved by connection in series. Pipework should be arranged such that cleaning of

individual tanks can be undertaken without disconnecting the water supply.

(f) Water supply tanks should be readily accessible for cleaning and appropriate valvesand drain points should be fitted to facilitate this. No heating circuit should discharge

into a drinking water tank.

(g) Pipework should be designed and installed such that the entire system can beadequately and quickly drained and refilled.

(h) Pipework should be short and as direct as possible. Deadlegs should be avoided.

Point of use water heaters should be considered for low use or remote outlets.

(i) Cold water supply tanks and pipework should be installed such that heat pick-up is

minimised, eg. do not position close to a heat source, reduce solar gain, use insulating

materials and locate cold supply pipes below hot pipes.

(j) Calorifiers should be capable of heating their contents to the desired temperature

throughout. Stratification should be avoided by means of a shunt pump if necessary.

(k) Calorifiers should be readily accessible for cleaning and inspection and have aworking, accessible drain point.


6/22

Page 5 of 21


August 04

(l) Cold water supply tanks should be of corrosion resistant materials and installed in acool place.

(m) If fitted, accumulators should have diaphragms, which are accessible for cleaning.

(n) If fitted, thermostatic mixing valves should be set to give a temperature of not greater

than 43oC (109oF) and the pipe runs from the circulating main should be as short as

practicable (not more than 2m from the mixer to the shower head). These showers

should be used frequently or flushed regularly.

16. In designing a system care should be taken to address the following, if appropriate to the

system:

(a) Installation and maintenance of filtration equipment.

(b) Installation and maintenance of pre-treatment plant, such as water softeners

(c) Installation and maintenance of continuous disinfection equipment, such as UV units

and chlorine dioxide dosing and control systems.

(d) Installation of automatic monitoring and sampling equipment, such as temperaturedata loggers.

Operation

17. The following general points regarding operation should be noted

(a) Temperatures of 20-45oC (68-113oF) favour the growth of Legionella and these

temperatures should be avoided as far as possible in hot and cold water systems.

(b) Calorifiers/hot water storage tanks should operate at 60oC (140oF) with hot water

distribution giving a temperature of 50oC (122oF) at the taps within at least 1 minute.

The storage capacity and rate of recovery of the calorifier should be selected to meetnormal fluctuations in demand. With large calorifiers shunt pumps should be fitted

and run for 1 to 2 hours during periods of low demand to avoid stratification. Where

more than one calorifier is in use they should be installed in parallel and maintained at

least 60

o

C (140

o

F). If one is frequently out of use, it should be decommissioned anddrained.

WARNING: Above 43oC (109oF) there is a risk of scalding, and warning labels

should be displayed. This is particularly important where young children, the

elderly or those with sensory loss are involved. Where this is the case fail-safe,

thermostatically controlled mixing valves should be used. Such valves can presentshort, moderate temperature sections, which may support Legionella growth.

Continuous disinfection of the water is a viable alternative to temperature control.


7/22

Page 6 of 21


August 04

(c) Where high temperatures cannot be maintained due to operating peculiarities ordesign, then Thermal Disinfection can be applied. This involves raising the

temperature in calorifiers to 60oC (140oF) and circulating this high temperature water

throughout the system for at least 1 hour.

(d) If a calorifier or any substantial part of the system is on stand-by, its temperature

should be raised to 60oC (140oF) throughout for at least 1 hour before being brought

on line.

(e) Cold water supply tanks and cold water services should be maintained at temperatures

below 20oC (68oF), where practicable. Hot and cold water pipes should be insulated.

(f) Where sections of the system remain unused for long periods, a shower in a hotelroom for example, steps should be taken to run good quality water through them to

waste at least weekly or for sufficient time to ensure that their whole length has been

flushed.

Where difficulty is experienced in controlling Legionella colonisation of water

systems or temperature control is difficult for technical or other reasons, then

supplemental disinfection, eg. chlorine dioxide dosing using, for instance, anEnvirox system, should be considered as part of the risk control strategy.

(g) Where sections of a system have not been used or flushed for a period in excess of

one week, then it is recommended that a disinfection procedure should be carried outbefore being brought back into use.

(h) Where sections of a system are to remain unused for long periods, then consideration

must be given to isolating these sections of pipework and draining or possiblyremoving pipework and fixtures completely.

Inspection and Maintenance (Refer to monitoring section of additional details)

18. The following general points regarding inspection and maintenance should be noted:

(a) Calorifier (flow) temperatures should be checked monthly. Temperatures obtainedduring thermal disinfection should also be checked periodically and results recorded.

(b) Water temperatures at all outlets should be checked at least once annually and a

representative number, normally those nearest to and furthest from the calorifier,should be checked monthly (so called Sentinel Taps). Temperature checks should be

taken after running for 1 minute at full flow, for hot taps and 2 minutes at full flow for

cold taps.

(c) Temperature monitoring should be supported with regular microbiological testing

using dipslides, and Legionella testing to check the effectiveness of the control

programme. Legionellamonitoring is recommended in all situations, the frequency oftesting being guided by the risk assessment but as a minimum, quarterly.


8/22

Page 7 of 21


August 04

(d) Where biocides are used as the primary Legionella control and temperatures arereduced, monthlyLegionella samples are required.

(e) In systems where control is lost (eg. failure to maintain temperature or biocide

concentration) then weekly Legionella samples should be taken until control is re-established.

(f) Internal inspection of calorifiers should be undertaken annually, and cleaning and

disinfection should be carried out if there is a build up of scale or sludge.

(g) Accessible pipework and insulation should be inspected annually and refurbished if

necessary.

(h) Water supply tanks should be inspected annually, or more frequently if contamination

is suspected, and cleaned and disinfected if there is a build up of deposits, sludge or

contamination.

(i) Where elevated risk potential has been identified, close monitoring of the system

should be undertaken until the system can be shown to be in a stable operating

condition.

(j) Filters and strainers should be inspected monthly until an appropriate inspection

frequency is established, based on the rate of accumulation of debris. These items and

other pre-treatment plant may require periodic disinfection.

(k) Pre-treatment plant, sodium ion exchange water softening plant and dosing

equipment, such as chlorine dioxide systems, must be checked regularly in

accordance with the manufacturers instructions.

19. In some industries and properties, health care premises for example, specific standards are set.

Where these standards impose a higher frequency of testing or a more rigorous application of

standards, then they override the requirements of this Code of Practice.

CLEANING AND DISINFECTION OF DISTRIBUTION SYSTEMS

20. Cleaning and disinfection may be required under a number of circumstances and a variety ofoptions are detailed in the following paragraphs.

21. When chemical or thermal disinfection is being undertaken, warning notices must be posted.

Physical barriers, or tape, may also be necessary depending upon site requirements.

22. Chlorinated water of volumes greater than 5m3 (5000L) or as determined by local regulations,

must be neutralised before disposal. Similar precautions should be taken when using chlorine

dioxide.

23. Following disinfection, tanks should always be filled with fresh mains water.


9/22

Page 8 of 21


August 04

Pre-Commission Disinfection

The following details are recommendations for pre-commission disinfection. Reference

to local regulations/directives may also be necessary.

24. For installation within buildings:

(a) remove all visible dirt and debris from the water supply tanks and isolate supply and

outlet valves.

(b) fill tank and pipework with clean water, then drain until empty.

(c) re-fill will clean water and add sodium hypochlorite or chlorine dioxide to give a free

residual chlorine concentration of 50 mg/L in the water.

(d) leave tank to stand for 1 hour. If the concentration of chlorine or chlorine dioxide

falls below 50 mg/L then the disinfection time must be extended to 2 hours at 20

mg/L.

(e) open outlet valves, drain water from each draw-off fitting successively working away

from the tank. Close each draw-off fitting when the water discharged begins to smell

of chlorine, or chlorine dioxide is detected using test papers or test strips.

(f) the tank must not be allowed to drain during this operation and if necessary,

additional sodium hypochlorite or chlorine dioxide should be dosed to maintain the

residual concentration as in (d) above.

(g) the tank and pipework should be allowed to stand for 1 hour minimum.

(h) the free residual chlorine or chlorine dioxide in the water discharged from the tapfarthest from the tank should be measured. If after the 2 hour period this

concentration is less than 20 mg/L, the disinfection process must be repeated.

(i) after disinfection, the tank and pipework should be flushed with clean water until the

free residual chlorine or chlorine dioxide concentration, at each draw-off outlet, is no

greater than that of the incoming water mains. The building occupier should also be

warned that some discolouration may occur and that the system should be operateduntil all discoloured water is discharged.

Remedial Disinfection and Cleaning

During normal operation, it is possible for hot and cold water services to becomecontaminated and disinfection will be required.


10/22

Page 9 of 21


August 04

25. Where a system is known to contain hardness or corrosion deposits, or an accumulation of

sludge in pipework, supply tanks or calorifiers then chemical cleaning may also be required.

26. Where a system has had engineering works carried out, such as extensions or alternations,

disinfection will be required. For localised repairs, providing new junctions or fittings are

disinfected before use (immerse for 30 minutes in a dilution of chlorinating solutionmaintained at a minimum of 200 mg/L free chlorine), flushing is all that is normally required.

27. Where a system has not been in regular use and not regularly flushed, ie. out of use for more

than six weeks, disinfection is required before the system is brought back into use.

28. NOTE: Before any remedial disinfection or cleaning is undertaken, a thorough inspection of

the system should be carried out. Equipment that comes into contact with the water, pumps

and vacuums, for example, should be disinfected before use.

29. Disinfection using chlorine or chlorine dioxide:

(a) Remove all visible dirt and debris from the water supply tank and isolate supply andoutlet valves;

(b) Fill tank and pipework with clean water then drain until empty;

(c) Re-fill with clean water and add sodium hypochlorite to give a free residual chlorine

or chlorine dioxide concentration of 50 mg/L in the water;

(d) Leave tank to stand for 1 hour;

(e) Open outlet valves, drain water from each outlet, successively working away from the

tank. Close each outlet when the water discharged begins to smell of chlorine or

chlorine dioxide is detected using test papers or test strips;

(f) The tanks must not be allowed to drain during this operation and if necessary,

additional sodium hypochlorite or chlorine dioxide should be dosed;

(g) The tank and pipework should be allowed to stand for 1 hour;

(h) The free residual chlorine or chlorine dioxide in the water discharged from the tap

furthest from the tank should be measured. If after the 2 hour period thisconcentration is less than 20 mg/L the disinfection process must be repeated;

(i) After disinfection, the tank and pipework should be flushed with clean water until the

free residual chlorine concentration, at each draw-off fitting, is no greater than that ofthe water suppliers mains. Should the system remain unused for more than 1 week,

then the disinfection process should be repeated.


11/22

Page 10 of 21


August 04

30. Where shower heads are found to be scaled, they should be removed and acid descaled, rinsed

and re-fitted

It may be impractical to carry out a full clean and disinfection with system refurbishment. On-

line disinfection may provide an alternative. If this option is taken, the reasons for not carrying

out a full clean and disinfection must be noted in the site maintenance log with full agreementof the customer and confirmed in writing.

On-Line/Continuous Disinfection Procedures

Systems which are known to experience contamination, or where risks associated with

Legionellaare high, may require some form of continuous protection.

31. Continuous disinfection may be undertaken using chlorine dioxide if permitted by local

regulations/guidance. Chlorine dioxide has a designated limit in drinking water of 0.5 mg/Ltotal oxidant in the UK, 1.0 mg/L in France and 0.8 mg/l in the USA (refer to local regulation)

and this can be applied on a continuous basis to hot and cold water services. Unlike chlorine,this product does not add significantly to taste or odour. Chlorine dioxide can be used with

accurate dosing and control equipment to effect control ofLegionella in such systems, with the

additional benefit of providing efficacy against biofilms.

The quantities of chemical in the reservoir, the rate of addition of the chemical and the

concentration achieved at sentinel taps should be monitored on a monthly basis. The

concentration of chlorine dioxide at the Sentinel taps should be at least 0.1 mg/L at cold water

outlets. If biofilm removal is being sought, then ideally >0.4 mg/L C102 is required.

32. On an annual basis, the chlorine dioxide concentration of a representative number of cold

water outlets should be checked and a concentration of at least 0.1 mg/L achieved, unless

biofilm removal is sought, then the concentration should be 0.4 mg/L.

33. Continuous disinfection may be undertaken using chlorine. Continuous chlorination may be

undertaken with a free residual chlorine concentration of 0.5-2 mg/L being maintained

throughout the system. This may be achieved through the use of water meter controlledsodium hypochlorite dosing or electrolytic chlorination.

34. Continuous disinfection may be undertaken using ultra violet radiation. UV units may be usedon outlets from water supply tanks to reduce the risk of organisms entering distributionpipework. Units may also be more effectively fitted at point of use. It should be noted that

UV has no residual effect and therefore has no effect on established biofilms or contamination,

which occur downstream of the unit, unlike continuous chlorine dioxide or chlorine addition,

where biocidal activity will be evident throughout the system.


12/22

Page 11 of 21


August 04

35. Continuous disinfection may also be undertaken using ionisation (the addition of copper and

silver ions). These levels are under constant review and current value should be confirmedbefore using this form of disinfection. It is recommended that the supplier of such units be

consulted. However, it should be noted that systems using hard waters are those with an

operating pH in excess of 7.6 may have difficulties in maintaining clean electrodes in the

ionisation unit, and in establishing satisfactory silver levels. Concentrations of Ag of at least20 g/L and copper concentrations of 400 g/L are necessary at all Sentinel taps, which should

be checked on a rotational basis at least annually. The installation should be checked with the

water supply service provider for compliance with the Water Regulations. This form of

treatment is not allowed under French Guidance (Circulaire DGS 2002/243)

Water Supply Tank Cleaning

Annual inspection may reveal that cleaning and disinfection of the water supply tank isrequired.

36. Tanks may be disinfected using chlorine:

(a) If organic materials contaminate water supply tanks then disinfection with 50 mg/L

chlorine or chlorine dioxide for at least 1 hour (or 20 mg/L for at least 2 hours) shouldbe undertaken before the actions below.

(b) Close inlet valve, drain to level of outlet, plug outlet to distribution system and

remove loose deposits by pump and vacuum.

(c) Remove adherent deposits by chemical treatment and manual cleaning.

(d) Organic fouling should be removed and any stubborn deposits treated withchlorine/biocides/alkali to facilitate removal.

(e) Oil and grease should be treated. Steam cleaning or high pressure jetting can be

undertaken if necessary. Remove all loose deposits.

(f) Fill tank with clean water then drain or pump to waste until empty. Waste must not

be drained through the system at any time. More than one flush may be required.

(g) Remove plug from outlet to distribution system.

(h) Re-fill with clean water and add sodium hypochlorite to give a free residual chlorine

concentration of 50 mg/L in the water.

(i) The tank should be left flooded with chlorinated water for a minimum of 1 hour with

50 mg/L chlorine (or minimum 2 hours with 20 mg/L chlorine).

(j) After standing, the tank should be flushed with clean water until the free residualchlorine concentration is no greater than that of the water suppliers mains.


13/22

Page 12 of 21


August 04

(k) NOTE: Where the volume of wastewater exceeds 5m3 (5000L) it is recommended thatthe water be neutralised before disposal. The method of neutralisation is specified on

the procedure log sheet. Waste must not be drained through the system.

37. Following cleaning, the tank internal surfaces may be painted using a locally approved coating,if appropriate. Tank painting must be carried out on dry, well prepared surfaces and each stage

of the coating must be given sufficient time to cure. Failure to observe these two constraints

will lead to a poor finish, poor quality water and additional remedial works. Where internal

surfaces are in a particularly poor condition, where there are perforations and leaks, or wheretime constraints dictate that there would be insufficient time to allow a coating to cure, the use

of a butyl weldable plastic sheet or fibreglass lining may be appropriate. Time must be

allowed for surface preparation and curing.

38. The repair of internal surfaces can extend the useful life of a tank but this should not be seen as

an indefinite extension, and replacement of badly corroded or damaged tank is advised.

39. Following any refurbishment of the internal surfaces, disinfection must be carried out asdetailed in the preceding protocols, before the tank is brought back into use.

MONITORING PROGRAMMES

Cold Water Monitoring Programmes

40. Monitoring programmes must include

(a) Annual inspection of water supply tank, if appropriate, or more frequent inspection if

contamination is suspected. Cleaning and disinfection to be carried out if inspection

indicates that this is required.

(b) Annual inspection of accessible pipework and insulation. Refurbishing to be carried

out if required.

(c) If applicable, check cold water storage temperatures every 3 months. Temperatures

must be maintained below 20oC (68oF). In some countries this temperature may be

exceeded and so more frequent testing is advised.

(d) If applicable, monitoring of disinfectant level if chlorine, chlorine dioxide or

ionisation are used as part of theLegionella control strategy.

(e) Monthly check of temperatures at the nearest and furthest taps from a storage tank orpipework system, which should be less than 20oC (68oF) after running for 2 minutes.

(f) Temperature checks on all taps/outlets on a rotational basis at least annually.

(g) Annual Legionella testing. If an alternative strategy to temperature control is

employed, more frequent sampling may be required, ie monthly until control is

established.


14/22

Page 13 of 21


August 04

(h) Quarterly on site checks of cold water storage and sentinel taps using Heterotrophic

Plate Count (HPC) Total Count samplers.

41. Monitoring programmes may also include

(a) Quarterly total viable count (TVC) monitoring at the nearest and furthest taps from astorage tank or pipework system, via an accredited laboratory. This is not a test of

drinking water (potability) quality. (See next page).

(b) Cold water systems can also be monitored on a quarterly basis for coliforms, E.coli,amoebae and protozoa. Results from these analyses will indicate the general hygiene

conditions within the system.

(b) QuarterlyLegionella monitoring of sentinel taps (nearest and furthest outlets).

Hot Water Monitoring Programmes

42. Hot water systems generally present a greater risk than cold systems due to the highertemperatures and aerosol producing fittings such as showerheads, and careful monitoring is

essential.

43. Monitoring programmes must include:

(a) Annual inspection of calorifiers where practicable. Cleaning and disinfection to be

carried out accordingly. Removal of accumulated sludge from calorifier base.

(b) Monthly temperature checks at calorifier (maintain minimum 60oC (140oF)).

(c) Temperature checks at all taps/outlets at least annually. A representative number of

taps/outlets should be checked monthly. After 1 minute running, the temperatureshould be 50oC (122oF) at all outlets from a storage tank or pipework system.

(d) Monitoring of disinfectant and disinfection byproduct concentrations to ensure that

they remain within guidelines/regulations.

(e) Annual inspection of accessible pipework insulation. Refurbish as necessary.

(f) Cleaning and disinfection of outlets as inspections require.

(g) Little used outlets flush through and purge to drain weekly.

(h) Shower heads and hoses dismantle, clean and descale quarterly.

(i) Quarterly Legionella testing should be carried out to verify the efficiency of

temperature control scheme. If an alternative strategy is employed, ie chemical

application, monthly or more frequent sampling is required.

(j) Monthly on site checks using HPC Total Count Samplers at calorifier and furthest

point in pipework.


15/22

Page 14 of 21


August 04

44. Monitoring programmes may also include:

(a) MonthlyLegionellamonitoring.

(b) Quarterly TVC monitoring via an accredited laboratory if applicable.

(c) Hot water systems can be monitored forPseudomonasquarterly.

Action Levels

45. HPC Total Count Samplers may be used to monitor the general planktonic bacterial population

in the water, but this will not indicate the presence, or otherwise, of Legionella. HPC Total

Count Samplers do give an indication of the overall effectiveness of control measures, but do

not provide any information on biofilms.

Depending on geographical location, bacterial levels deemed under control may vary. In theUS, levels of less than 500 CFU/ml are recommended whilst in certain European states, counts

are not to exceed normal trends established through regular testing. However, in bothexamples, Coliform andE.colicounts are expected to be negative. Counts for these organisms

indicate a breech in hygiene control.

46. Testing for Legionellato monitor the efficacy of precautionary measures as part of a plannedmonitoring programme provides useful supporting information. It will provide information on

the effectiveness of the control programme and indicate whether further assessment of the risk

is necessary.

47. More frequent Legionellasamples may be required from areas of high risk, eg. aged personshomes, hospital wards with at risk patients. When an outbreak is suspected or has been

identified, Legionella sampling should be undertaken prior to any remedial action.

48. When Legionellatesting has been undertaken, the results should only be presented to the

sites nominated responsible person or their nominated deputy.

The actions in Tables A, B and C are routine responses to test results, for

(a) UK and other European guidance documentation (Table A)

(b) US guidance documentation (Table B).In the absence of local guidance, it is recommended that actions be taken following

the recommendation in table A. This will offer a lower risk rating.

(c) French guidance (Table C) for 1) Spas / thermal bathing waters / hospitals with highpopulations of immune deficient patients and 2) General Hospitals/hotels etc.


16/22

Page 15 of 21


August 04

TABLE A

Legionellabacteria

(CFU/L)

ACTION REQUIRED

Equal to or less than 100 Inform customer, file results and

maintain current control regime

One or two samples above 100 Resample system, review riskassessment and control measure to

identify remedial action

Majority of samples are positiveor a count is above 1000

Disinfection or thermal pasteurisationshould be implemented. Immediately

review risk assessment to identify

remedial action.

TABLE B

Legionellabacteria

(CFU/ml)ACTION REQUIRED

Less than 10 Inform customer, file results and

maintain current control regime

10-99 Prompt cleaning and/or biocidetreatment

More than 100 Immediate cleaning and/or biocide

treatment


17/22

Page 16 of 21


August 04

TABLE C

Legionellabacteria

(CFU/L)

ACTION REQUIRED

1)Less than detection limit(50 CFU/L) Spa/thermal waters etc, acceptable

control. If greater than detection

limit, stop system and clean &

disinfect

2)Less than 1000 General Hospitals/Hotels: Inform

customer, file results and maintaincurrent control regime.

2)More than 1000 Implement all necessary actions toreduce level below 1000 CFU/L.

Remedial action should include resampling of the system and consideration of

continuous disinfection, eg application of chlorine dioxide.

48. Where a system is positive forLegionella, always inform the responsible District Manager andthe customers nominated responsible person or higher in the reporting chain.

ACTIONS IN THE EVENT OF AN EMERGENCY (OUTBREAK OF LEGIONELLOSIS)

49. In an emergency, it is important to ensure all documentation is kept up to date and filedappropriately. All actions and meetings must be noted and copies of file notes, minutes, etc

kept in the customer file. Local Environmental Health regulations should be referred to.

Reference should be made to procedures/guidance at local level.

Under no circumstances should contact be made with the press/media. Any queries of thisnature must be referred to the respective District Management.

50. If the domestic water system is confirmed as being involved in an outbreak of

Legionnaires Disease, then the Environmental Hygiene Services Emergency Response

Programme should be employed.


18/22

Page 17 of 21


August 04

MANAGEMENT AND THE SELECTION, TRAINING AND COMPETENCE OF

PERSONNEL

51. The statutory duty holder, the individual upon which the statutory duty falls on any given site,

is responsible for appointing a person, or persons to take managerial responsibility for

implementing precautionary measures. This person is sometimes called the responsibleperson.

52. It is the responsible persons duty to ensure that all persons involved in the reducing of risks

associated withLegionellahave sufficient ability, experience, instruction, information, trainingand resources to carry out their work safely and competently. Environmental Hygiene Services

training courses may offer a means of supporting this duty. Records should be maintained at

the customer premises and may form part of the log book.

53. Where consultants are used, it is also the duty of the responsible person to ensure their

competency. Training records and other relevant details of field personnel are available for

inspection by site management.

54. The responsibilities and lines of communication must be clearly defined for all persons

involved in this activity. These responsibilities and communication procedures should be

periodically reviewed. This is the responsibility of site management, but it may be usefully

addressed during programme/contract review.


19/22

Page 18 of 21


August 04

RECORD KEEPING

55. It is the responsibility of site management to maintain appropriate records, including:

(a) the names and position of those persons appointed under the written scheme to reduce

risk;

(b) the Risk Assessment;

(c) the name and position of the person or persons who carried out the assessment and

their qualifications;

(d) the written scheme for reducing risk;

(e) details on personnel and lines of communication involved in the scheme;

(f) records of plant use;

(g) records of work carried out by site or sites contractors;

(h) records of implementation of the scheme;

(i) Log books and associated risk assessment should contain as a minimum:

- a description of the system including diagrams and schematic drawings,

identification of water supply tanks, inventory of fittings and identification of

relevant items of pre-treatment plant, volume of water in systems;

- details of the Risk Assessment and the management and monitoring scheme;

- details of inspection procedures;

- records of water temperature, operation of pre-treatment plant, inspection and test

results, cleaning and disinfection operations, any works undertaken on the system,

any works undertaken as a result of inspections or testing (Action Defect Log).

The person carrying out the work should sign all these records.

These log books should also detail the personnel responsible for actions under the

scheme, including contractors and sub-contractors. This Manual may usefully be

included in the written scheme of preventative maintenance. Records should beretained for a minimum of 5 years. Electronic version of log books are also

acceptable. However, electronic files and data should regularly be duplicated in case

of loss of information.

56. It is the responsibility of Environmental Hygiene Services personnel to indicate which records

should be kept by both parties, to establish where they should be kept and who is responsible

for their maintenance. These records should be appropriate to the contractual arrangementswith the site and should include:


20/22

Page 19 of 21


August 04

(a) current contract;

(b) details of the programme and recommendations, which must in the first instance,

comply with the relevant industry standard or this Manual (reference paragraph 14);

(c) any Risk Assessment, water hygiene survey, site survey or asset register undertaken

by Environmental Hygiene Services;

(d) any laboratory test certificates includingLegionella test results;

(e) Completion/Chlorination Certificates or Reports;

(f) site visit reports including any monitoring records;

(g) a contact chain if that is not recorded in (c) above.

57. All records kept in accordance with paragraph 55 and 56 should be preserved throughout theperiod for which they remain current and for at least five years, notwithstanding the

requirement of any relevant quality system.

RESPONSIBILITIES OF DESIGNERS, MANUFACTURERS, IMPORTERS, SUPPLIERS

AND INSTALLERS

58. It is the responsibility of the designer, manufacturer, importer or supplier of plant and watersystems to ensure that risk is avoided or that the system will be safe and without risks to health

when used at work. Site Management should be advised to obtain assurances in this respect.

59. Information should be provided in writing concerning risk, and operation and maintenance.Site Management should be advised to obtain such information.

60. Environmental Hygiene Services is responsible for ensuring the provision of appropriate

Health and Safety information on all products supplied, that limitation of expertise or serviceor products are defined in the contract. Also that personnel employed are appropriate to carry

out tasks competently and safely and carry out the appropriate Risk Assessments, under the

Management of Health and Safety at Work Regulations before commencing work.

Environmental Hygiene Services will also recommend a schedule that will allow both partiesto review the contract covering the Management and Control ofLegionella.

61. It may be necessary for additional testing to be undertaken to ensure that the systems will be

safe for the work intended. This is the responsibility of the supplier. Site Management shouldbe advised of this.


21/22

Page 20 of 21


August 04

62. If the customer cannot agree to the recommendations made, then a programme should be

agreed providing a practical alternative which does not contravene the requirements of anylocal regulations/guidance and still meets the needs of the customer. However, the reasons for

not following our recommendations must be stated on file. This manual is intended as

guidance for the minimum standard. Since these guidelines are deemed the minimum

standard, any deviation to recommendations must be proved to be more effective than thoseoutlined.

63. Nalco will only recommend programmes for which they hold test data to indicate their

efficiency in the control ofLegionellain engineered water systems.

64. It is the responsibility of the customer to inform Environmental Hygiene Services of any

changes in operating conditions. Such changes may necessitate a review of the Risk

Assessment.


22/22

Page 21 of 21

Global Code of Practice

NOTICE:

No warranty as to the completeness of the information is given. There must be an ongoing

programme of due diligence, both observations, record keeping and actions. Regularmaintenance schedules are critical to the operation and safety of the systems included in the Risk

Assessment. Nalco disclaims all liability and responsibility for any direct or indirect loss or

damage that may be suffered through reliance on any information contained in or omitted from

this document, and no person should act solely on the basis of the information contained in thedocument without taking appropriate professional advice about obligations in specific

circumstances.

The Nalco programme is designed to reduce health-related risks associated with the growth of

Legionella within domestic and industrial water systems. However, if the recommendedpractices are followed as outlined, then health-related risks from other waterborne pathogens

will likewise be reduced. While recommendations from Environmental Hygiene ServicesHygiene are designed to reduce health-related risks to ensure the overall health and safety of

your employees, associates, patients, and visitors, no programme can eliminate all health-related risks. In addition, recommended practices presented herein do not guarantee that water

quality within the assessed systems will meet governmental or trade standards. Local

regulations override specific recommendations where relevant.

Nalco Company 1601 W. Diehl Rd. Naperville, Illinois 60563-1198

SUBSIDIARIES AND AFFILIATES IN PRINCIPLE LOCATIONS AROUND THE WORLD

Date post:	02-Jun-2018
Category:	Documents
Upload:	fabriziocervelli350
View:	215 times
Download:	0 times

EHS COP Domestic Water (E) 8-04

Documents