Issue link: https://hi.iaq.net/i/692160
8 DEVELOPING A LEGIONELLA WATER MANAGEMENT PROGRAM 2 Describe Your Building Water Systems Using Text EXAMPLE: BUILDING A You will need to write a simple description of your building water system and devices you answered YES to on page 2. This description should include details like where the building connects to the municipal water supply, how water is distributed, and where pools, hot tubs, cooling towers, and water heaters or boilers are located. An existing as-built diagram of the plumbing system and fixtures may be useful in developing this description. Below is a description of the water systems for an example building (Building A). You will see how this text gets turned into a diagram in the next section (page 10). 1. Water enters the basement of the property via a 4-inch main from the municipal water line at Maple Street. Water is immediately drawn off to charge the fire suppression system. The rest of the water is sent through cold water distribution. There is backflow prevention throughout the system, including between the cold water distribution and the city water main and between the cold water distribution and the fire suppression system. Note: Problems with entering water are usually beyond the building manager's control, such as main breaks or construction that disrupts water service. However, an essential part of a water management program is monitoring water and responding to changes coming in from the municipal water line. You can contact your drinking water provider to report any changes you notice in the quality of water being delivered to your building. 2. Cold water is distributed directly to the lit decorative fountain in the lobby, the cooling tower on the roof, the hot tub and pool on the first floor, ice machines on floors 2, 4, 6, 8, and 10, and shower and faucet fixtures in rooms on all 12 floors. All internal plumbing consists of 2-inch copper and polyvinyl chloride (PVC) piping. There is backflow prevention between cold water distribution and the utility lines that serve the cooling tower and hot tub/pool room. Note: In warm climates, water in pipes that typically carry cold water may reach a temperature that allows for growth of Legionella. Detectable residual disinfectant added by your water provider helps to limit growth of Legionella and other germs. Additionally, decorative fountains with submerged lighting and devices such as cooling towers and ice machines may contain areas where cold water can be heated to temperatures that allow Legionella to grow. Swimming pools and toilets do not usually generate hazardous conditions because they rarely reach adequate temperature for growth or generate water droplets small enough to be inhaled. 3. Cold water is heated to 140°F by two joined 120-gallon water heaters. The heaters supply a 500-gallon storage tank. Cold water is also delivered to an 80-gallon water heater in the basement that serves the kitchen and staff break room. Note: Even water heaters set to the correct temperature may contain zones of lower temperature water where cold and hot water mix or where excessive sediment blocks heating elements. Most residual disinfectants are reduced by heating the water. Healthcare Facilities Be sure to include descriptions of water sources relevant to: • • • Patient care areas Clinical support areas Components and devices that can expose patients to contaminated water You should also develop an ongoing dialogue with your drinking water provider so that you are aware of changes that may affect your building's water supply. Disclaimer: Example content is provided for illustrative purposes only and is not intended to be relevant to all buildings. Reference: ASHRAE 188: Legionellosis: Risk Management for Building Water Systems June 26, 2015. ASHRAE: Atlanta. www.ashrae.org