Considering the current COVID-19 pandemic, buildings of various types have found themselves completely or partially inactive for extended periods of time. Given this condition, building owners, operators and managers should take precautions when restoring building occupancy as it relates to domestic water systems.
Responsible plumbing design and various plumbing codes dictate the avoidance of ‘dead-end’ piping in domestic water distribution systems to avoid stagnant water. Stagnant domestic water creates the potential for growth of pathogens and other potentially harmful conditions. Buildings that have been unoccupied for any significant period of time can create a condition in which portions of the domestic water piping distribution system may contain stagnant water.
Common measures that can be taken to assist in delivering fresh water to the points of use throughout a facility are provided below:
- Check with your local public health department for reopening requirements that may apply to domestic water in your facility type.
- Survey the domestic water piping system and equipment to identify any leaks that may have developed during the period of extended inactivity. This is of particular importance for facilities with vintage galvanized piping.
- Independently flush the domestic cold water equipment and piping system. All domestic water equipment and points of use should be flushed thoroughly and may require a review of the domestic water piping distribution system in the facility. Flushing should progress from the water service entry point towards the last point of use to ensure that all piping is adequately flushed with fresh water. . All strainers in the system should be repeatedly cleaned during flushing.
- Drain and clean water storage tanks along with other potentially sensitive equipment throughout the domestic water system such as decorative fountains. Follow manufacturer recommendations and utilize cleaning products appropriate for domestic water equipment. Adequately flush the water storage tanks and other equipment after cleaning with fresh water. Refer to manufacturer recommendations for additional measures for specific equipment or points of use.
- Independently flush the domestic hot water equipment and piping system utilizing a similar approach to the cold water.
- Check the functionality of all domestic water equipment and components (i.e. pumps, heaters, storage tanks, water treatment, etc.). Change all filters utilized in the domestic water system. Exercise valves throughout the system and pro-actively replace valves that do not seat fully closed.
- Perform water quality testing for areas of concern to identify if contaminants have developed during the period of inactivity. The confirmation of contaminants in the domestic water systems may require cleaning of the domestic water piping and the consultation of an industrial hygienist, engineer and contractor.
- Maintain domestic hot water storage tanks at safe temperatures without creating a potential scalding hazard for building occupants.
- Refill p-traps in floor drains, open site drains, etc.
- Document all measures taken to create a facility standard for future reference.
- Refer to resources such as the Environmental Protection Agency’s (EPA’s) “Maintaining or Restoring Water Quality in Buildings with Low or No Use” for more information.
Generally speaking, domestic water quality measures may not only be limited to significant periods of low or no usage. Normal facility operations can still include areas of stagnant water which should be managed as part of a regular maintenance plan. A water management plan for the facility should be created and updated on a regular basis.
Additional resources related to this topic include ASHRAE Standard 188, the CDC’s Water Management Plan Guidance, the American Industrial Hygiene Association Guideline, and the EPA’s WaterSense at Work.
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