Legionnaires’ Disease – How To Stop A Serial Killer


There is a serial killer at large in the HVAC sector. It has attacked more than 3,000 people and killed almost 250 since it was first identified in Pennsylvania, USA in the 1970s.

The bacterium that causes what became known as Legionnaires’ disease was finally isolated on January 18, 1977. Much research followed and the hvac industry eventually came up with strategies to minimise the risks associated with this vicious, opportunistic infection.

Legionella can grow in any workplace if the conditions are right. The way to prevent it is, of course, to ensure that the conditions are not right. And that means keeping hvac systems clean and in good order. But the preventive measures don’t stop there.

Legionella requires a particular set of conditions in order to survive. For example, it needs to live in a temperature range of between 20 and 50˚C. Its optimum temperature for growth is 37˚C – coincidentally, the body core temperature of people – making it particularly efficient at attacking the human body once it gets into the system.

It also requires nutrition and can survive off other bacteria, algae, scale wood, rust or other organic nutrients present in a water system.

There are accepted practices for mitigating the effects of the bacteria and these include removing storage where the mains supply can match demand, decommissioning and removing redundant tanks and pipework, lining tanks with hand-laid GRP for a smooth surface to prevent dirt adhesion and bacterial growth, and general maintenance, repair and refurbishment of tanks.

ECEX’s skilled engineers can offer all these, plus other mechanical services that help save water, including:

But there are also other important precautions that can be taken against legionella. ECEX Air Intake Screens – simple, retrofitted mesh pre-filters that stop airborne debris from entering an air intake system without negatively impacting airflow – help prevent bacterial proliferation in cooling towers and other air conditioning plant by reducing the bio loads that provide bacterial growth, which increases water treatment chemical effectiveness.

For more information about ECEX’s legionella prevention services, click here.