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Building Operating Management

Facility Managers' Responsibilities for Legionella Prevention Under ASHRAE 188

Determining responsibility for water safety in buildings has historically been murky. It typically falls somewhere among the building owner, the facility manager and a water treatment company. ASHRAE 188 lays the responsibility for water safety squarely at the feet of those responsible for the water systems. That means everyone associated with design, construction, installation, ownership, operation, management, and maintenance are required to ensure building water systems are designed, maintained and operated in a manner that minimizes the risk of Legionellosis. There is no question that the new standard puts facility managers on the front line of Legionellosis prevention.

ASHRAE Standard 188 applies to water systems in human-occupied buildings — new and existing. Single-family residential homes are exempt. To comply with the standard, facility owners and managers will be required to do an annual survey of their buildings, on a building-by-building basis, to determine risk characterization. If a building possesses one or more of the risk characteristics set out in the standard, it will be necessary to develop a risk management plan for Legionella control. This includes conducting an evaluation using Hazard Analysis Critical Control Point (HACCP) methodology, documenting water system operation and maintenance, and verifying monitoring and control.

ASHRAE Standard 188 also requires validating that Legionella is under control in all water systems. These include: potable and utility water systems for water used for drinking, cooking, washing, bathing, and also water emitted from plumbing fixtures, cooling towers, boilers and other HVAC-related equipment.

Annual Survey to Determine Risk Characteristics

There are specific building characteristics that allow Legionella to colonize building water systems. Facilities at high risk for Legionella include healthcare facilities, such as hospitals and nursing homes. An increasing number of cases have been reported from assisted-living and long-term care facilities.

Under the new standard, facility managers are charged with conducting an annual survey to determine what risk is present in their buildings. Specific risk factors called out in the standard are:

  • multiple housing units with one or more centralized water heaters
  • more than 10 stories (including levels below grade)
  • cooling tower or evaporative condenser
  • one or more whirlpools or spas within or adjacent to building
  • devices that release aerosols (e.g., ornamental fountains, misters, air washers or humidifiers)
  • incoming potable water containing less than 0.5 ppm residual halogen such as chlorine
  • inpatient health care facility
  • occupants primarily older than age 65
  • occupants receiving chemotherapy for cancer or bone marrow transplantation.

If a facility manager identifies the presence of one or more risk factors after conducting the survey, then a risk management team must be assembled to prepare and implement a HACCP plan to prevent the threat posed by Legionella bacteria.

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  posted on 2/3/2012   Article Use Policy

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