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HEALTH AND SANITATION
Where a management programme is implemented , it is typical for a water management team to be formed to provide a description of the water system and identify potential areas of Legionella growth with temperature ranges . A water management programme may be established when required by the authority having jurisdiction .
Cooling Towers Cooling towers , evaporative condensers and indirect evaporative aircooling equipment are standard components used in large building air conditioning systems and have been the source of numerous Legionella outbreaks . These systems use the natural cooling process of evaporation to remove heat from water or to directly cool the air . may be accomplished by sampling the water . Testing should be done regularly .
Routine monitoring can help to evaluate the effectiveness of the water management programme . Interpreting Legionella monitoring data must also include how to respond to certain Legionella levels . If high Legionella levels are found , the water treatment programme should be adjusted as needed . Although there is no established Legionella concentration necessary to cause an outbreak , levels above 10 CFU / mL ( Colony Forming Units per milliliter ) are commonly considered a cause for concern . Remediation actions may include additional chemical treatment and maintenance procedures .
The warm and wet environment of cooling towers provides an ideal environment for Legionella to grow . Legionella control in cooling towers should start early , preferably during the design and commissioning phases . Chapter 11 Part II of the UMC addresses the installation and construction of cooling towers . Section 1122.0 ( Chemical Treatment Systems ) has been a useful resource for developing a water treatment plan using chemical disinfectant .
Codes and Standards . These days , there is no lack of safety guidance documents , standards , regulations , and policies intended to assist building owners and managers in controlling Legionella in buildings . No list would be complete without mentioning ASHRAE 188 and ASHRAE Guideline 12 . These documents have proven to be industry standards for Legionella risk management and have gained the reputation of being reliable sources for Legionella control .
Section 1126.0 ( Drift Eliminators ) requires drift eliminators to be installed in cooling towers to reduce the quantity of mist or water droplets that is carried away from the cooling tower . Drift eliminators can assist with reducing the spread of waterborne pathogens into the airstream . Compliance with these code requirements will ensure a safer and more efficient cooling tower . The Legionella Task Group will look into expanding these safety provisions for cooling towers .
Regular monitoring and testing of the water quality are some of the most common steps used to control Legionella growth . It has been recommended to check cooling water chemistry , pH levels and total bacteria count a minimum of twice a week . Monitoring and testing
The goal of all such guidelines should always be to ensure the health and safety of the public . The UMC Legionella Task Group is an extensive and diverse group with knowledge and experience in mechanical and plumbing systems . The recommendations from the UMC Legionella Task Group will provide recommendations to the UMC Technical Committee for consideration to the 2024 edition of the UMC . The UMC continues to address the most important issues to serve the industry and to include all major industry standards within its contents to ensure public health and safety . The UMC , along with the other IAPMO codes , strives to keep up with the times in which we are living to address the most significant areas of concern within building mechanical systems in our ever-changing world . PA
www . plumbingafrica . co . za @ plumbingonline @ plumbingonline @ PlumbingAfricaOnline January 2022 Volume 27 I Number 11