Tag: Legionnaires’ disease

News headlines about Legionnaires’ disease outbreaks are a stark reminder of a critical public health challenge that often originates within the very water systems of our commercial, institutional, and residential buildings.

Legionnaires’ disease, a severe form of pneumonia, is caused by Legionella bacteria, which thrive in specific conditions found in complex plumbing systems.

When cold water flow is minimal or stopped altogether, disinfectant levels evaporate, and temperatures gradually rise to the Legionella growth range (77–113°F, 25–42°C), leading to bacterial colonization and uneven free chlorine distribution throughout the system.

Understanding how these bacteria flourish in various parts of a building’s water infrastructure and how to prevent their growth proactively is crucial for safeguarding public health and ensuring compliance.

Understanding the Threat of Legionnaires’ Disease

Legionnaires’ disease is a severe lung infection contracted by inhaling small droplets of water (aerosols) contaminated with Legionella bacteria. Various building water systems, including showers and faucets, can generate these aerosols. It’s important to note that Legionnaires’ disease is not spread person-to-person.

Symptoms can range from mild to severe, including cough, shortness of breath, high fever, muscle aches, and headaches. While some individuals recover, Legionnaires’ disease can be fatal, particularly for those with weakened immune systems or chronic lung conditions. The severity and public impact of outbreaks underscore the critical need for effective and proactive prevention strategies.

The Critical Role of Balanced Recirculation

Recirculating cold water eliminates stagnation, which promotes harmful bacteria growth, and provides consistent distribution of residual chlorine throughout domestic cold-water systems:

• Keeps water moving
• Maintains water quality to reduce stagnation
• Ensures residual chlorine is distributed throughout the cold-water system
• Keeps water temperature in branches and risers evenly distributed, minimizing heat gain

How Thermostatic Technology Changes the Game

Implementing effective recirculation, particularly in large and complex plumbing systems, requires precision to ensure adequate flow to all branches without creating significant water waste or manual balancing. This is where self-actuating thermostatic valve technology comes into play.

How the CircuitSolver^® CSU-CW Valve Works

The CircuitSolver^® Union Cold Water valve, using innovative automatic thermal balancing technology, offers a robust solution for optimizing cold water recirculation loops, ensuring optimal conditions for Legionella control.

The CSU-CW valve utilizes the same reliable and precise thermal actuator technology as the original CircuitSolver^®. It addresses critical issues related to Legionella mitigation in cold water recirculation systems by maintaining a stable temperature. It accomplishes this by continuously monitoring the water temperature and modulating flow to maintain a set temperature at the end of each branch or riser.

The valve operates over a 10°F temperature range. For example, a valve specified for a desired return temperature of 60°F will open at 70°F (10°F above the desired return temperature). At 60°F, the valve is in its closed position. A bypass in the design always allows water to flow back to the pump so that the pump is never dead-headed.

The CircuitSolver^® Difference

Simplified Design & Operation

Unlike manual balancing valves that require extensive, often inexact, commissioning and re-balancing, automatic valves like CircuitSolver^® provide continuous, dynamic balancing. This eliminates the need for manual adjustments, saving time and labor while ensuring optimal, ongoing system performance.

_{Enhanced Efficiency}

By intelligently directing flow only where needed, CircuitSolver^® thermostatic balancing valves maximize the effectiveness of the recirculation system, leading to both safety and cost savings.

_{Mitigate Legionella with Thermostatic Technology}

By taking a proactive, comprehensive approach to Legionella control and utilizing advanced technology like CircuitSolver’s automatic thermal balancing valves, you can transform your building’s water system from a potential risk into a safe, reliable, and compliant resource, mitigating Legionella bacteria.

Find more information about our thermostatic balancing valves here.

Legionnaires’ disease is arguably the hottest topic in the plumbing industry today.

First identified after an outbreak in 1976, this potentially fatal form of pneumonia is contracted by aspirating Legionella bacteria and presents with coughing, shortness of breath, fever, and pain.

Since its initial discovery, the bacteria has been found to be pervasive in large-scale water systems, leading offices, hospitals, hotels, and other sizeable buildings to double down on their sanitization, identification, and prevention efforts.

Legionella bacteria can be found in many domestic hot and cold water systems in trace amounts but does not present a health concern until it colonizes, and the bacteria are atomized and aspirated.

In warm, stagnant water, the bacteria can grow and multiply to high concentrations, which is when it becomes dangerous.

Organizations differ on the specific temperature at which the bacteria will grow, but the most common range stated for Legionella bacteria survival is 68°-122°F (20°-50°C). The bacteria are dormant below 68° (20° C) and does not survive above 140° (60° C).

The key to preventing disease Legionnaires’ disease is to make sure that building owners and managers follow a water management program. Unfortunately, there is no one guideline to follow on how to reduce the risk of Legionella growth and spread. Go to any ASPE meeting and ask the members what the best way is to prevent Legionella and you are likely to get as many different answers as there are attendees.

Organizations that mandate domestic hot water systems design guidelines and recommendations are similarly scattered and contradictory in their requirements, torn between the need for energy conservation and Legionella prevention.

ASHRAE, which touts energy conservation practices, suggests that temperature maintenance systems should be automatically switched off “during extended periods when hot water is not required,” whereas OSHA states that in the interest of Legionella prevention, DHWS should be excluded from energy conservation measures and run continuously.

The Uniform Plumbing Code and International Plumbing Code set minimum guidelines for plumbing system and component safety, but do not provide concrete “how to” documents and checklists for Legionella prevention.

The Center for Disease Control simply suggests periodically culturing potable water samples to test for bacteria growth.

Which codes and guidelines dictate your DHWS design typically falls to your local jurisdictions and personal or corporate preferences. However, it still leaves the question of just how can plumbing engineers best design their systems to prevent, or at the very least discourage Legionella bacteria from growing while still adhering to the necessary requirements so as not to find themselves on an inspector’s infraction list?

Read the full article at pmengineer.com.