AFE March/April 2012 : Page 16THE IMPACT OF IMPENDING STANDARDS ON BUILDING WATER TREATMENT PRACTICES Th e team’s job is to identify the critical control points in the building. A critical control point is any place or situ-ation where a person might be exposed to water containing the bacteria. Th ese could include decorative fountains, outdoor mist cooling systems, drink-ing fountains or cooling towers. Once the critical control points have been identifi ed, the team needs to develop a plan to deal with minimizing the risk of exposure at each of these points. Th is plan will contain: 1. Names and titles of the HACCP team members 2. Process fl ow diagrams of both potable and utility water systems 3. Hazard analysis summaries 4. A monitoring schedule 5. An equipment device maintenance procedure 6. A validation summary 7. A verifi cation schedule 8. Planned responses to disruptions in water service In practical terms this means that for every HACCP the team must decide four things: 1. Th e critical control limits 2. Th e hazard control monitoring method 3. Th e hazard control frequency of monitoring 4. Th e corrective actions to be taken if the critical control limit is violated For example, if your building has one or more cooling towers, these will be critical control points. Th e critical control limit may be non-detectable levels of Legionella bacteria in the water. Th e monitoring method might be regular water sampling with bacteria culturing. Th e corrective action might be increasing or modifying your biocide feed program until non-detectable levels are reached (see CTI-159 below). Section 8 of Stan-dard 188P provides suggested monitor-ing methods and corrective actions. When this process is completed by the team, they can move to the last steps: 1. Deciding how the team will confirm the plan is being imple-mented (verification). 2. Determining what evidence will be necessary to prove the plan’s eff ec-tiveness (validation). 3. Preparing the planned responses to disruption of service. Th e HACCP plan is now complete and implementation can begin. CTI Stan-dard 159 is titled “ Legionellosis Related Practices for Evaporative Cooling Water Systems.” Its stated purpose is to provide the practices for the control of Legionella from evaporative cooling systems, spe-cifi cally evaporative condensers, closed circuit cooling towers and open circuit cooling towers. Th e striking diff erence between the two standards is the scope of water systems covered. While ASHRAE 188P applies to all water systems in a building or facility, the CTI standard only applies to evapora-tive cooling water systems. Th is consider-ably narrows the fi eld of facilities impacted. 16 March | April 2012 Q  Facilities Engineering Journal Q  www.AFE.org Publication List Using a screen reader? Click Here |
