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Legionella Risk at Work: Re-inspection Management

Survey Safe™ can check for Legionella bacteria during an asbestos re-inspection

If you are an employer, or someone in control of premises, including landlords, you must understand the health risks associated with Legionella.

Duties under the Health and Safety at Work Act 1974 extend to risks from Legionella bacteria, which may arise from work activities.

As an employer, or a person in control of the premises, you are responsible for health and safety and need to take the right precautions to reduce the risks of exposure to Legionella. You must understand how to:

• identify and assess sources of risk
• manage any risks
• prevent or control any risks
• keep and maintain the correct records
• carry out any other duties you may have

Let Survey Safe™ manage this for you

Legionella is such a serious issue, why would you want to leave anything to chance? Survey Safe™ are able to factor in your Legionella management as part of a holistic service.

What is Legionella?

The genus Legionella is a pathogenic group of Gram-negative bacteria that includes the species L. pneumophila that causes Legionellosis. Legionella also causes a pneumonia like illness called Legionnaires' disease and a mild flu like illness called Pontiac fever.

Pontiac Fever

Pontiac fever is best described as an acute, but non-fatal respiratory disease that is caused by various species of Gram-negative bacteria in the genus Legionella. Pontiac fever was named after Pontiac, Michigan USA, where the first case was discovered. The illness causes a mild upper respiratory infection that resembles acute influenza. Pontiac fever sufferers usually recover quickly and the illness often goes undiagnosed. Both Pontiac fever and the very severe Legionnaire' disease are caused by the same bacteria, however Pontiac fever does not include the pneumonia element.

Sources of Legionella

Some documented sources of Legionella include industrial cooling towers, public and private swimming baths and showers facilities, domestic and commercial water systems, ice machines, refrigerated cabinets, whirlpool spas, decorative water fountains, vehicle windscreen washer fluid and some industrial coolants.

The largest and most common source of Legionnaires' disease outbreaks come from cooling towers, air conditioning and industrial cooling water systems. This is because of the risk of widespread circulation.

Recent authoritative research has shown evidence that Legionella pneumophila, which is the cause of Legionnaires' disease, can travel about 3.7 miles from its original source by means of airborne spread. An epidemic of Legionnaires' disease in northern France caused 86 people to be diagnosed with the disease, 18 of which sadly died. The source of this infection was a cooling tower in an industrial plant that was approximately 3 - 4 miles away.

Chlorination is an effective method of dealing with Legionella

Chlorine gas is known to kill almost all kinds of bacteria, as well as viruses and protozoa. It should be added to water at night as it is most effective as sunlight the hypochlorite ion breaks up very quickly, reducing its efficacy. Also, it leaves behind no contaminants in the water, except the harmless chloride ion. Chlorination is an effective and relatively cheap method of treating large volumes of water, which is why it is frequently used in swimming pools.

Treatment for Legionellosis

There is no vaccine for Legionellosis, and antibiotic prophylaxis is not effective. Any licensed vaccine for humans in the United States is still probably quite a few years away. This is why it is vital to ensure you and your staff are not exposed to this deadly bacteria.

Legionella control

The control of Legionella growth can occur through chemical or thermal methods. The more expensive of these two options is that of temperature control. In other words, keeping all cold water below 25 °C (78 °F) and all hot water above 51 °C (124 °F). The high cost incurred with this method arises from the extensive retrofitting required for existing complex distribution systems in large facilities and the energy cost of chilling or heating the water and maintaining the required temperatures at all times and at all distal points within the system.

According to the World Health Organisation, temperature affects the survival of Legionella as follows:

• Above 70 °C (158 °F) - Legionella will die almost instantly
• At 60 °C (140 °F) - 90% die in 2 minutes (Decimal reduction time (D) = 2)
• At 50 °C (122 °F) - 90% die in 80–124 minutes, depending on strain (Decimal reduction time (D) = 80-124)
• 48 to 50 °C (118 to 122 °F) - Can survive but do not multiply
• 32 to 42 °C (90 to 108 °F) - Ideal growth range
• 25 to 45 °C (77 to 113 °F) - Growth range
• Below 20 °C (68 °F) - Can survive but are dormant, even below freezing

Legionella is common in many environments, including soil and aquatic systems, with at least 50 species and 70 serogroups identified. Below is a table listing them.

Further Information

If you would like to know more or are interested in a quote we would be happy to help. Phone us on 07730 446 224, email us at info@survey-safe.com or fill in our enquiry form and we will be in touch as soon as possible.