A few months after the “reopening” of the economy, understandably, business owners and government officials welcomed a return to normalcy. However, new and different risks are faced when reopening dormant buildings with stagnant water systems.
Several weeks of zero flow, low flow, and tempered water can result in microbiological growth, leeching heavy metals, and corrosion within our plumbing systems.
让我们来仔细看步建立设备管理人员，以保持在管道系统水质安全应该考虑未使用或使用略微建筑(as defined by industry organizations including NSF International, Centers for Disease Control and Prevention (CDC), and the International Association of Plumbing & Mechanical Officials (IAPMO).
Begin by documenting protection measures for staff and visitors. Consider working with a water quality expert or consultant. And, ask the local water utility the following questions:
If one isn’t already in place, create a map of the building’s plumbing system.
Establish or reestablish a flushing and cleaning regimen. Flushing is important because it clears out the low-quality water that accumulated during low use and replaces it with high-quality water from the municipal supply. The fresh water helps mitigate loss of protective scale as well as biofilm growth that emerged while the water was stagnant.
- Kitchen sink sprayers
- 所有的每个都应该被删除。如果继续使用我s planned, clean or replace the screens prior to reinstalling the aerators
- Showerheads and faucets should be disinfected and sterilized. Consider replacing outlets if vulnerable populations have access
As part of the flush, all locations where water is stored should be identified, drained, and flushed with clean cold water. Examples include humidifiers, ice machines, and dishwashers. Most buildings have some form of water treatment in their plumbing system such as filters and water softeners. These should run as normal, be included in the flush, and should not be bypassed.
Once flow has returned after this initial flush, all hot water tanks should be drained. Temperature should be maintained, and the heater should not be turned off. Continual operation is important to prevent microorganisms from growing. Make sure that water heat storage temperature are sufficient to kill bacteria (131 to 140°F).
After the initial flush, ongoing flushes should be scheduled; continual flushes help to repair destabilized scale and minimize biofilm growth. The American Water Works Association (AWWA) recommends continued flushing for a minimum of 12 weeks. This allows the protective scale to re-stabilize and for harmful lead particles to be washed through the plumbing system.
Recommendations for ongoing flushes include:
- Open each point-of-use tap at least once per day
- Flush the entire building once per week during ongoing flushing
- It is not necessary to drain water storage during ongoing flushing
Monitoring and testing
Monitoring and testing should start for Legionella, other bacteria growth, and disinfectant levels prior to the initial flush, throughout the ongoing flushing, and on a predetermined schedule going forward. Monitoring and testing are the only ways to know the health of the plumbing system.
At the end of the initial flush, disinfectant levels should be checked. The concentration level of chlorine, the most commonly used disinfectant, should be measured at the point-of-entry and in the cold water of the most distant tap of each zone after the tap is flushed. Comparison of the point-of-entry concentration to the distal tap concentration will give an indication of the protection being provided to the entire plumbing system.
如果测试证明军团菌的不可接受的水平Hyperchlorination或休克消毒应进行。这是高于正常水平的氯通过管道系统冲洗特定的时间长度，并且水温度上升快速杀灭。冷水系统应该从点进入被刷新到点对点的使用，包括所有的灯具。水应该达到不低于3000 mg。分钟/ L的CT。“CT”值的消毒剂和接触时间的浓度与水被消毒。
Systems that have high levels of Legionella, or are known to have heavy biofilm, may require even higher CT targets. Higher chlorine dosage may allow for shorter disinfection contact times. Always take proper precautions to ensure there is no inadvertent exposure to occupants. Strict access controls should be in place. Conduct testing to ensure chlorine levels are in normal ranges at the conclusion of treatment. When hyperchlorination is complete, the system should go through an additional thermal flushing.
Following, adjusting, and creating a water management plan
A facility management team should record all monitoring and testing practices including the frequency, locations, and results. If there is a water management plan, those findings should be integrated into the record keeping portion of the plan. If a water management plan does not exist, we strongly encouraged the creation of one. Most healthcare facilities are required under the Centers for Medicare & Medicaid (CMS) mandate to have a water management plan. Failing to do so can cause a facility to lose Medicaid and Medicare reimbursements.
Implementing a water management plan as outlined in ASHRAE 188 will help maintain a high-quality level in a building. The Centers for Disease Control (CDC) has developed a water management plan toolkit based on ASHRAE 188. The toolkit aids in the understanding of risk levels of different building types and devices and walks step by step through the requirements of a healthy water management plan.
As part of the process of reopening a building, all mechanical equipment should be inspected. Examples include cooling towers, boilers, pumps, backflow preventers and digital mixing stations. Essentially, the water systems and equipment should be recommissioned as if it were a new building. Make sure any scheduled maintenance that may have been missed during building closings are completed and recorded in accordance with normal practices.
Digital thermostatic mixing
- Drain the piping system prior to closing if planning for a long-term building closure
- Conduct a periodic purge of all dead legs to keep the system reasonably clean
- Generally, calibration of mixing valves is not needed
- Conduct a visual inspection
- If the water supply was completely shut off and the pressure decreased, all reduced pressure zone units need to be repressurized correctly, and the relief valve should be closed
- Assuming equipment has been turned off, a device such as FloPro™-MD can assist with a startup check to ensure each piece is operating at manufacturer’s specification
- 验证适当的气体供应的气体燃烧器具与325,000 BTU的或更少的BTU的评价，无论是在商业厨房或不
- For general drains, there are no special requirements. However, a visual inspection should be part of the reopening plan
- Other than the absence of water in the traps from either back siphonage or evaporation, stainless steel piping systems require no special considerations when being returned to full service after periods of non-use
- Stainless steel pipe and fittings are resistant to corrosion caused by decomposition of organic matter and the subsequent formation of hydrogen sulfide gas or microbiologically-influenced corrosion
- Purge the system via the hose bibs or flush out the system by opening the flush valves to create a steady flow of water
- Check the tanks to ensure the aerator is functioning and the inlet pre-filter is in service
- Inspect to ensure the light is working correctly
- Check to make sure any scheduled maintenance wasn’t missed
- Visually inspect
- Visually inspect
- Check to make sure any scheduled maintenance wasn’t missed
- In measuring instruments such as the CIX Instrument from HF scientific (chlorine measurement), there is a potential for reagents to crystallize in the tubes if there is a sudden loss of power or power is off for an extended time
- During inspection, in the rare event that crystallization has occurred, the unit needs to be primed and reagents replaced
- Inspect the control display to ensure there are no error messages due to faulty sensors
- Make sure the water heater is set to at least 122°F and consider higher temperatures (131°F -140°F) for a quicker kill
- Ensure that measures are taken to prevent scalding if the water heater is set to >130°F
- Conduct a significant blowdown of all components
Hot tubs, spas, therapy pools
- Visually inspect for slime and biofilm prior to refilling
- Perform a hot tub/spa disinfection procedure before use per CDC guidance
- Revisit startup and shutdown procedures
- Follow manufacturer guidelines and industry best practices
- Assuming the cooling tower has been well maintained, proceed with disinfection procedures. Guidance can be found from the Cooling Technology Institute:https://www.cti.org/downloads/WTP-148.pdf
Planned and detail cleaning should be part of the reopening process. This includes proper maintenance of all equipment and fixtures, and the replacement of filters from point-of-entry to point-of-use. Be sure to follow manufacturer guidelines and contact the proper authorities when necessary.
前24小时开放,我t’s recommended to conduct a round of checks. Bring the hot water system back up to 140° F. Open all outlets and flush until they reach a minimum of 131° F. After flushing, conduct a final round of sampling to ensure there is no contamination.
一旦已经恢复正常运行the water system is back to standard function, the main priority will be maintaining water system quality and safety. If there is no water management plan prior to the disruption, create one immediately. This should include a schedule for monitoring and testing disinfectants, bacteria levels, and water temperature. Follow the plan, document activities, and adjust as needed. If an issue arises, promptly address it and notify authorities if deemed necessary.
- Conduct weekly visual inspections
- Initiate operation of moving parts such as pumps for at least 10 minutes per week to prevent seizure and failure
- Increase water temperature to 140° F for at least 1 hour per week to reduce bacteria growth
- If equipment such as a water heater has a thermal sterilization cycle, utilize it per manufacturer recommendations
- Ensure all storage maintains proper disinfectant levels
- Document all activity, monitoring, and testing
If the decision has been made to not heat water within the plumbing system during closure, then consider the following:
- Close the building and do not drain the system
- Turn off storage tanks, drain, and the water supply
- Flush cold water systems on a regular schedule to maintain temperature and disinfectant. Free chlorine residual should be at or above .2 mg/L
- Restrict access to any unused portions of the building
- Document all monitoring, testing, and maintenance
There are a multitude of tools and guidance to assist in maximizing water safety and minimizing water risks when preparing to reopen an unused or slightly used building:
- From Plumbing to Patients:https://www.cdc.gov/hai/prevent/environment/water.html
- ASHRAE Standard 188: Legionellosis Risk Management for Building Water Systems
- Cooling Technology Institute Legionellosis Guideline 2008 (WTP-148)
- 制冷技术研究所军团准则2019（GLD 159）
Learn more about ensuring safety in commercial buildings by mitigating the risk of Legionella and other waterborne bacteria atwww.legionella-strategies.com。
Jana Summey, MBA, Watts Healthcare Vertical Market Manager, has nearly 20 years’ experience in the MEP (mechanical/electrical/plumbing) design and architectural design industries. She is a popular speaker on mitigating Legionella through a multi-barrier approach in on-premise plumbing systems – from point of source to tap. Recently Jana navigated her mother through the experience of being exposed to Legionnaires’ as a hospital patient, gaining valuable insight into the serious threat Legionella poses for at-risk populations.