Hot Water Systems – Designing for Safe Water
There are an estimated 8,000 to 18,000 cases a year of Legionella Disease in the United States. Legionella bacteria, the cause of Legionnaires’ Disease, is commonly found in water. If your hotel’s domestic hot water system is not properly designed and maintained, Legionella can find a way to multiply and colonize in the system. Any outbreak of Legionella leaves your hotel vulnerable to serious liability and potential legal retribution.
While Legionella grows in water temperatures ranging from 95 to 113°F, the bacteria can survive within a larger temperature range between 68 to 122°F.
Below are some design steps you can take to protect your hotel’s water from Legionella:
- Avoid “Dead Legs” in Piping Design – “Dead Legs” pool hot water in one place, providing a protective environment for Legionella to survive and multiply. It’s important your plumbing design avoids these types of areas.
- Use Recirculation Pumps – Recirculation pumps continuously provide hot water flow to the plumbing fixtures in a matter of seconds. This continuous movement minimizes the potential for Legionella growth.
- Use Backflow Preventers – Backflow preventers ensure water flow goes in the intended direction and closes when there is pressure pushing back on the system. Having a properly designed and operating backflow preventer is vital to prevent cross-contamination of domestic hot water.
- Consider Tankless Water Heaters – Tankless water heaters remove many of the concerns of Legionella as hot water is no longer stored in the system.
- Consider TMV (Thermostatic Mixing Valves) – In hotels, domestic water should be delivered at 120°F. A TMV is a temperature setting valve that blends hot water with cold water to maintain the desired water temperature and prevent Legionella.
Next week, I focus on tankless water heater systems and how these are best utilized in hotel applications. In the meantime, if you have any questions about designing hot water system in your hotel, please contact me by phone or email.
Blair Hildahl
Base4 Principal
608.304.5228
