Abstract
Thousands of preventable injuries and deaths are annually caused by microbial, chemical and physical hazards from building water systems. Water is processed in buildings before use; this can degrade the quality of the water. Processing steps undertaken on-site in buildings often include conditioning, filtering, storing, heating, cooling, pressure regulation and distribution through fixtures that restrict flow and temperature. Therefore, prevention of disease and injury requires process management. A process management framework for buildings is the hazard analysis and critical control point (HACCP) adaptation of failure mode effects analysis (FMEA). It has been proven effective for building water system management. Validation is proof that hazards have been controlled under operating conditions and may include many kinds of evidence including cultures of building water samples to detect and enumerate potentially pathogenic microorganisms. However, results from culture tests are often inappropriately used because the accuracy and precision are not sufficient to support specifications for control limit or action triggers. A reliable negative screen is based on genus-level Polymerase Chain Reaction (PCR) for Legionella in building water systems; however, building water samples with positive results from this test require further analysis by culture methods.
Highlights
Every year, tens of thousands of preventable injuries and deaths are caused by exposure to microbial, chemical and physical hazards from building water systems [1,2,3,4,5,6,7,8]
The control of microbial hazards associated with building water systems is challenging, made all the more difficult by practical limits on hot water temperatures owing to scalding risks
Acinetobacter, Elizabethkingia (Flavobacterium), Escherichia coli, Klebsiella, Legionella, non-tuberculous Mycobacteria (NTM), Pseudomonas, and Stenotrophomonas are known to cause significant disease associated with building water systems
Summary
Tens of thousands of preventable injuries and deaths are caused by exposure to microbial, chemical and physical hazards from building water systems [1,2,3,4,5,6,7,8]. Microorganisms in high-quality, SDWA-compliant drinking water can enter plumbing systems in small numbers, attach to the inside surfaces of pipes and equipment, form biofilms and amplify to very large, potentially-dangerous numbers [12,25]. Pathogenic biofilms established on interior surfaces of plumbing infrastructure may shed or be dislodged, be broadcast as respirable droplets in infectious bio-aerosol from the plumbing into the environment, for example through showerheads, faucet fixtures and ornamental fountains. They may be released from non-potable water in cooling towers in the HVAC system of the building [1,7,12,25]. The physical-chemical parameters that are conducive to biofilm development and microbial amplification—temperature, pH, water age—are reasonably well known for prominent plumbing-associated pathogens, such as Legionella, as are the parameters that inhibit or prevent such amplification [19]
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