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29  minimizing risk legionelllosis 29 minimizing risk legionelllosis Document Transcript

  • ANGUS CONSULTING MANAGEMENT LIMITED POLICIES AND PROCEDURES Number: 29POLICY: MINIMIZING THE RISK OF LEGIONELLOSISIssued To: A.C.M.L «Company» «Address1» «Address2» «City», «State» «PostalCode»Date: January 12, 2006PRESIDENT’S DIRECTIVE:It is the direct responsibility of each and every A.C.M.L. Site Project Manager toensure that this policy and procedure is adhered to fully. The Site ProjectManagers will be held FULLY ACCOUNTABLE for the implementation andongoing maintenance of the program. Upon receipt of this policy and Procedure theA.C.M.L. Project Manager is to immediately ensure their site meets or exceeds therequirements listed. Audits by A.C.M.L. head office staff and inspections byA.C.M.L. Health & Safety Representatives will occur on a regular basis. Anydeficiencies will be reported to your respective site senior managementrepresentative. Non compliance will not be tolerated. Don CampbellEach A.C.M.L. managed facility will implement the following measures to ensurethe safe operation of building water systems to control the risk of occurrence ofLegionellosis.SUBJECT Legionella – An Overview Legionellae are bacteria. When legionellae are present in aquatic environments, the risk of transmission of infection to humans depends on the presence of several factors: conditions favourable for amplification of the organism; a mechanism of dissemination (e.g. aerosolization of colonized water); inoculation of the organism at a site where it is capable of causing infection; bacterial strain-specific virulence factors; and the susceptibility of the host. Habitats Under certain circumstance within manmade water systems, the concentration of organisms may increase markedly, a process termed “amplification.” Conditions that are favourable for the amplification of legionellae growth include water temperatures of 25-42 C (77-108F) stagnation, scale and sediment, biofilms and the presence of amoebae. There is an indication that growth of Legionella is influenced by certain materials. Natural rubbers, wood and some plastics have been shown to support the amplification of Legionella, while other materials such as copper inhibit their growth.
  • Transmission of Legionnaire’s DiseaseData suggests that in most instances transmission to humans occurs when watercontaining the organism is aerosolized in respirable droplets (1-5 micrometer indiameter) and inhaled by a susceptible host. Survival in nature is generally outsidethe scope of building engineering and management practices. Amplification,dissemination and transmission can be influenced by engineering design andmaintenance practices. Subsequent events are influenced by the individual’shealth.The most effective control for most diseases, including Legionellosis, isprevention of transmission at as many points as possible in the disease’s chain oftransmissions.A variety of aerosol-producing devices have been associated with outbreaks ofLegionnaire’s disease, including cooling towers, evaporative condensers,showers, whirlpool spas, humidifiers, decorative fountains and a grocery storeproduce mister. Aspiration of colonized drinking water into the lungs has beensuggested as the mode of transmission in some cases of hospital-acquiredLegionnaire’s disease.Numerous investigations have demonstrated that cooling towers and evaporativecondensers have served as the sources of Legionella-contaminated aerosolscausing outbreaks of community- and hospital-acquired infection. Outbreak-associated transmission via cooling towers and evaporative condensers has beenmost commonly documented when those infected have been in close proximity tothe contaminated devices.Showerheads and tap faucets can produce aerosols containing legionellae indroplets of respirable size. Epidemiologic studies and air sampling conductedduring outbreak investigations have established the role of aerosols produced byshowers and tap faucets in disease transmission. The aeration of spa pools canresult in formation of potentially contaminated aerosols. A range of pathogenicmicro-organisms, including Pseudomonas aeruginosa and L. pneumophila, havebeen found in spa pools.Associated RisksMost healthy people have a resistance to Legionnaires’ disease. However, somepeople naturally have a lower resistance to the disease and would be at high riskfor infection. The following factors result in greater risk for contractingLegionnaires’ disease.• Age ( Very young and those middle aged and older are most susceptible)• Gender (males are twice as likely to contract the disease)• Heavy Smokers and Drinkers• Individuals with weakened immune systems• Individuals with chronic medical problemsSymptomsAlthough Legionnaires disease can be fatal, it can be successfully treated withantibiotics. Early symptoms of the illness resemble that of influenza at the onset,
  • during the first two days of illness. These include slight fever, headache, joint soreness, muscle cramps, lack of energy, feeling lethargic, loss of appetite, and diarrhea. As the disease progresses symptoms of pneumonia become more prevalent such as high fever, a cough that starts out dry and later produces phlegm, breathing difficulty or shortness of breath, chills and chest pains. Legionnaires’ disease (LD) cannot be transmitted from person to person through physical contact. LD is not contagious. If numerous individuals contract LD it is due to contact with the contaminated water aerosol, not with each other.Legionella are widespread organisms which can be found in natural and man-made watersystems such as cooling towers and humidifier sumps. There is presently no treatmentprogram that can completely or permanently eliminate this organism.POLICYA.C.M.L. staff must follow ASHRAE guidelines and the recommendations of the watertreatment providers that we work with in order to minimize microbial growth, as well asthe scaling, corrosion and sediment deposition which can harbor the bacteria. Thisproactive approach to minimize colonization of Legionella in a water system includes thefollowing measures: • Each site that has cooling towers, humidifiers and decorative fountains will utilize the services of a qualified water treatment specialist to define and oversee the water treatment program. o The water treatment specialist will provide each site with a written water treatment program that includes all test procedures. o The water treatment specialist, at a frequency not to exceed monthly, will check on-site that the water treatment program is being carried out as defined. o The water treatment specialist will train all new site maintenance/operating staff to ensure new site employees fully understand the water treatment program. • A maintenance service program to regularly drain, clean and disinfect the system. o Have in place scheduled maintenance tasks to drain and clean cooling tower and humidifier sumps, at a minimum frequency of 6 months. • The addition of corrosion and scale inhibitors to minimize deposition. o Have in place a scheduled maintenance task to analyze and replace the corrosion & scale coupons at a minimum frequency of 3 months. • Regular visual inspections. o Visual check cooling tower and humidifier sumps, at a minimum weekly basis for the growth of algae, slime or the build up of deposits. • A water treatment program that includes the use of alternate biocides that have a proven ability to effectively control the growth of Legionella. o Discuss with the water treatment specialist the effective use of biocides.
  • • Keeping detailed records of water treatment and maintenance programs. o Each site will maintain detailed daily water treatment records for cooling towers. • Monitoring of bleed off and make up rates. o On a daily basis each site will check & record bleed off and make up rates. • At a minimum, quarterly monitoring and recording of general bacteria levels. o Bacteria levels will be verified by the use of cultural slides and the results recorded. The bacteria levels should be checked prior to adding biocide and 8 hours after adding the biocide; this will indicate if the biocide added was effective.Each Project Manager is to provide confirmation that the above measures areimplemented at their facility utilizing the form in Appendix A. This form is to besubmitted to your respective site senior management representative on May 1 st andNovember 1st of each and every year. You are to create a Preventive Maintenance cardon your Maintenance Management system to serve as a reminder to complete this task.Regular testing for Legionella has not been mandated by any government agency and isnot recommended on a routine basis because of the difficulty of interpreting test results.In addition, accurate Legionella testing requires a 10 to 14 day turnaround time. This istoo long a period to allow Legionella monitoring to serve as a useful control tool. Thereis presently no official test standard; however a Legionella count of greater than 1000CFU (Colony Forming Units) has been debated as the level where the potential forLegionnaires’ disease is more likely to occur.The A.C.M.L. site senior management representative will discuss chemical watertreatment issues that arise from time-to-time with the A.C.M.L. Site Manager.For further information regarding Legionella, please refer to the attached documents fromASHRAE, The Cooling Technology Institute, and Ashland Chemical.
  • ANGUS CONSULTING MANAGEMENT LIMITED 1129 Leslie Street, Toronto, Ontario, M3C 2J6, Tel: (416) 443-8300, Fax: (416) 443-8323JOB SITEPROJECT MANAGERDATE PROGRAM IN PLACE AT PROGRAM TO BE POLICY DIRECTIVE SITE IMPLEMENTED BY YES NO1. Water Treatment Program with Qualified Water Treatment Specialist for all Cooling Towers, Humidifier Sumps, Decorative Fountains.2. Maintenance service program to regularly drain, clean, and disinfect cooling tower sumps, humidifier sumps and decorative fountains etc.3. Water treatment program incorporates the use of corrosion and scale inhibitors.4. Conduct regular (weekly) inspections of cooling tower sumps, humidifier sumps and decorative fountains, etc.5. Biocides are alternated in Cooling Towers, applicable humidifiers, decorative fountains, etc.6. Detailed water treatment records are maintained on site.7. Bleed off and make up meter readings are recorded daily.8. At a minimum quarterly monitoring and recording of general bacteria levels utilizing cultural dip slides in cooling tower sumps, applicable humidifier sumps, decorative fountains etc.Project Manager’s Signature: ____________________________________________ Date: __________________________ APPENDIX A