When it comes to water, movement keeps our systems healthy. Exercise! Exercise!
Typically in spring and fall heating and cooling systems are not operating 24/7 because of outside temperatures and low heating/cooling loads on a building or facility. COVID-19 has also impacted facilities; many will need to address potable water concerns as they begin to reopen. Whether you are in an industrial or commercial setting, low water use poses problems that need to be addressed. This article highlights how to protect your systems and safely return to operation after periods of limited use.
INDUSTRIAL WATER SYSTEMS
The biggest need for protecting your system is the operation of mechanical pumps, steam boilers, tower pumps, recirculation pumps, etc. These mechanical devices need to operate so they can move the water and various chemistries around in your system. Stagnant water (with or without chemistries) will lead to corrosion in short periods of time. Water that is not moving in your system is NOT protecting your system.
The inhibitor chemistries in closed loops, towers, and boiler systems need to constantly be moving and coming in contact with the different metal surfaces. Circulation assures these surfaces are protected. Without this water movement, your system will be in jeopardy of premature corrosion or even failure.
Keeping Your Boiler Healthy
Boilers should be rotated a couple of times a week or heated up to keep the boiler chemistry moving. This practice will help to ensure your boiler is protected and the chemistry is coming in contact with the metal surfaces. Your oxygen scavenger or (sulfite) levels should be 2-3 times above the normal operating range to prevent pitting. A cool/cold wet steam boiler will pit very quickly. Adequate sulfite residuals and moving the water around in the boiler is key.
Keeping Your Cooling Tower Healthy
Stagnant water in cooling towers can cause just as many issues. If the water is not moving, the system is not being protected. The tower water should be operated for 4-6 hours every 2-3 days. A good tower controller program should also allow biocides to be added when the system is operating. This should prevent biological growth/fouling AND should protect the welfare and health of the public and employees.
POTABLE WATER SYSTEMS
Keeping Your Domestic Water Healthy
Stagnant water in a complex plumbing system will drastically increase the potential for growth of Legionella and other water borne pathogens. According to the Department of Safety and Professional Services, water that is stagnant for 3 weeks or more is considered “old water.” When flows are decreased or stopped completely as we have seen during this COVID-19 induced shut down, disinfectant levels evaporate and temperatures change leading to the build-up of pathogens and heavy metals. Below are some tips on ways to help minimize exposure and potential to contract Legionnaires’ disease after an extended shut down.
Steps to safely reopen closed buildings:
- Risk Assessment: If you have a Water Management Plan in place, it will identify all risk areas that need to be addressed. If not, perform an assessment to identify risk areas, including creating a water flow diagram and identifying areas with slow or stagnant water.
- Flush System: Flush your buildings water system at all outlets (showers, sinks, drinking fountains, water coolers, hoppers, mop sinks, backflows, ice machines, water heaters, water softeners and toilets). When working with stagnant water use the recommended Personal Protective Equipment (PPE) including an NIOSH-approved N95 facemask, safety goggles and rubber gloves. Open outlets slowly to avoid splashing and generating aerosols, and watch drains closely so they do not overflow while flushing. Please note that flushing the system before a disinfection may cause planktonic bacteria to break loose from the biofilm.
- Chlorination: Consider potable water chlorination and/or bacteria filtration (≤ 0.2 micron) to disinfect systems and reduce the risk of waterborne disease.
- Legionella Testing: After completing the steps above, test for Legionella prior to reopening the building. A Legionella culture test takes 10-14 days to for results.
- Inspect System Components: Inspect backflows, pumps, air handlers, drains and heaters to ensure they are in good working order.
- Inspect Devices: Inspect aerators, filters, showerheads, drinking fountain spouts and other devices. Clean or replace items as needed.
- Cooling Tower Maintenance: If cooling towers are turned on, make sure they are cleaned and maintained to manufacturers guidelines prior to operation. Ensure proper treatment is being adding continuously during this time. If your tower has been shut down, refer to the Cooling Tower Start-up resource in our Knowledge Center.
- Decorative Water Features: If your site contains decorative water features, it is best to fully drain and clean by following manufacturer guidelines. After refilling, test disinfectant levels to ensure safe operation.
- Floor Drains: To prevent sewer gases from entering the building, pour water down floor drains.
- Water Management Plan: Once the building is open and operating then follow your Water Management Program to maintain the water systems in each building as you would in any other building.
A stagnant system poses both industrial and potable water challenges and creates an ideal environment for premature failure of components and opportunistic waterborne pathogens to amplify. Water needs to be moving through a system to keep all components healthy and protected and in the case of potable water to minimize health concerns.
For more detailed information on exercising, protecting and starting up your buildings, please contact us at email@example.com or 414-425-3339.
Tom Koeppen, PE
Territory Manager, Watertech of America, Inc.
Tom holds a Bachelor of Science in Engineering from UW-Platteville and is a licensed Professional Engineer. He has over 25 years of experience including water, wastewater, and environmental compliance. He has been with Watertech over 11 years helping customers manage their systems.
Director of Water Safety, Watertech of America, Inc.
Kyle Pachowitz has worked in the process chemical industry for 7 years with experience in consulting and laboratory services. Holds a Bachelor of Science in Biochemistry from UW-Milwaukee. Current role at Watertech is the Director of Water Safety, focusing on Legionella control for healthcare and industrial customers.