Premier Control Technologies Logo
Premier Control Technologies Fluid Solutions

Safeguarding Against Legionella: A story of Industrial Water Safety

Wednesday, 24th January 2024

The Issue

In the landscapes of industrial buildings, the growth of legionella bacteria slowly develops becoming an ever-increasing issue, even more so now, as a noticeable amount are vacant structures - where the stillness of stagnant water raises the spectre of contamination. To thwart the potential health hazards posed by the bacteria, vigilant facility and building managers are turning to skid-mounted water treatment systems.

The Bacteria Legionella is known to infect people with legionellosis, a dangerous respiratory illness also known as Legionnaires’ disease which has been described as a stronger version of Pneumonia. This can be caught by ingestion or inhalation of the bacteria.

According to previous records from the Mayo Clinic, it has caused infections in lungs and other key organs as well as wounds, and in extreme causes death. The origins of Legionella trace back to an outbreak in 1976, Philadelphia. This date marks the beginning of a steady rise in cases, in 2018 approximately 10,000 documented cases were reported.

Even in Modern day systems stagnant and slightly elevated temperatures provide an excellent breading area for legionella bacteria. The bacteria is even known to survive Chlorine treatment, which is used for drinking water and Pools which makes it imperative that continuous treatment and testing is carried out.

In order to reduce risk and exposure there are rules and regulations to follow from when the building is designed to being finished and even when servicing and maintenance needs carrying out which is outlined on the ASHRAE website.

The Solution

As we understand how we can possibly encounter the bacteria we also need a way to determine how much cleaning chemicals (including silver and copper) is required to be introduced to the possibly infectious water, which is where the Dynasonic TFX-5000 ultra sonic clamp on flow meter comes in.

By using Non-invasive ultrasonic technology, the transmitters connect to the outside of the pipe work and transmit a signal to and from each other. The ultrasonic sound signal is received more quickly when it is transmitted in the flow direction compared to it being received more slowly in the opposite direction against the flow. This sound signal is converted into a velocity of the fluid which in turn is calculated into a volumetric flow rate based on the programming of the flow meter and the pipe diameter.

The transmitters which are connected to the transducer feature a local display which can display the flow rate and accumulated total whilst also offering a +/- 0.5% accuracy. The TFX 5000 is also able to output the flow rate via an analogue or digital output. It is vital to have accurate readings of the flow rate so that the correct amount of chemical maybe dosed into the water to prevent Legionella. This reduces exposer to the dangerous bacteria along with giving us the required information to treat it.

Due to how the device is designed, it can be programmed, fitted and operational in less than 1 hour. The meter is also designed to be suitable for pipe work between DN20 up to DN2000. If the flowrate or requirement changes, the device can be disconnected, reprogrammed, and reinstalled without interfering with process media.

In this application, the key benefits of the device is being non-invasive therefore reducing any exposure to a minimum allowing the previously empty industrial site to be reopened and safe for use once again.

Related article

Monitoring the flow of drinking water at a football stadium