“Safety First, Always First” is about more than the equipment we wear and the precautions we take on jobsites. Preventative maintenance goes a long way in protecting the health and safety of all from hazards that aren’t always visible. An example of this is water system flushing to eliminate Legionella bacteria or other contaminants in schools during summer break.
Legionella is known to survive and colonize in building water systems due to its presence in source waters. Hot water and water passing through older and lower volume systems are particularly susceptible because warm temperatures and thicker biofilm buildups are risk factors for Legionella colonization.
In general, concentrations of the bacteria in building water supplies are very low. However, when the conditions are right – for example, an older school experiencing an abrupt and steep reduction in water usage while on summer break – the chance for colonization exists.
Methods of Water System Flushing
Routine and systematic monitoring serves as an alarm to determine whether there is contamination and if remediation is necessary. The most common remediation techniques to eliminate Legionella in building water systems include:
- Super-chlorination – introducing free chlorine (Cl) gas to increase Cl levels system-wide for a few hours to achieve a concentration greater than 5 parts per million (ppm) and flushing the entire system
- Super-heating – raising the water temperature to 160ºF (70ºC) or higher for one hour for every ten years of water system age and flushing the entire system
- Drying and flushing – disconnecting the entire water system, draining all the water and blowing hot, dry air through the pipes, and then reconnecting the water to flush the system
With every water system installed, TP Mechanical trains owners and maintenance personnel on preventing these types of water quality issues. We provide third party documentation showing we have met code requirements and are turning over a clean, safe water system.
With children everywhere heading back to school after a long summer off, it’s important to remember the words of Benjamin Franklin: “An ounce of prevention is worth a pound of cure.”