What exactly is the Legionella Regulation – and does it apply to my system?

In Germany, too, there are repeated outbreaks of Legionella, particularly caused by the bacterial species Legionella pneumophila, which can colonise technical water systems. To minimise risks, the 42nd Ordinance Implementing the Federal Immission Control Act (42nd BImSchV) came into force in 2017. This primarily affects businesses that work with water at elevated temperatures – such as electroplating plants or paint shops, particularly those using wet scrubbers. 

The regulation requires operators to regularly check whether the water used is free from harmful bacteria. The results must be recorded in the government database KaVKA (Register of Evaporative Cooling Systems). 

Key questions regarding the 42nd BImSchV

What exactly are Legionella bacteria?

Legionella are aerobic bacteria that thrive in warm water (< 60 °). They often form biofilms with other microorganisms, enabling them to survive in tanks or pipework.

Why are Legionella bacteria dangerous?

They are the cause of legionellosis (“Legionnaires” disease’), a severe form of pneumonia. Infection occurs through the inhalation of respirable aerosols (< 5 µm). Swallowing contaminated water or human-to-human transmission, on the other hand, does not result in infection.

Where do Legionella bacteria occur?

Typical sources include drinking water systems (e.g. water pipes, such as those leading to showers where water stagnates) or sprinkler systems (e.g. nurseries, car washes). Particular attention is now also being paid to recooling plants, evaporative coolers, wet scrubbers, droplet separators and water walls in paint shops.

What exactly is the 42nd BImSchV?

The 42nd Ordinance implementing the Federal Clean Air Act is legally binding. It sets out reporting obligations, analytical procedures and the powers of the authorities to carry out inspections, and provides for criminal penalties in the event of breaches.

Areas of application

The Regulation applies to installations in which water is dripped, sprayed or comes into contact with the atmosphere, for example:

• Evaporative cooling systems 
• Cooling towers (> 200 MW) 
• Wet separator

Exceptions apply to:

• Systems with a water temperature that remains at ≥ 60 °C 
• Wet separators with a pH that is consistently ≤ 4 or ≥ 10
• Wet separator with fresh water flow only 
• Installations that emit only within enclosed halls 

It is precisely the pH value (≤ 4 or ≥ 10) that can, in some cases, mean operators fall outside the scope of application – it is therefore important to assess each case individually.

Obligations for operators

1. Self-monitoring: In-house monitoring of chemical, physical and microbiological parameters every 14 days (e.g. pH value, dip-slide test) 
2. External sampling: every three months by an accredited laboratory 
3. Notification to KaVKA: mandatory for all relevant installations 
4. External examination: every five years by a publicly appointed and sworn expert or an accredited Type A inspection body.

Measures to be taken when limit values are exceeded

Action to be taken if values rise or are exceeded

Practical application and examples of implementation

In approximately 70 % of electroplating plants, the pH value is deliberately adjusted ( 10) so that the plant does not fall within the scope of the regulation. This can be done manually, through organisational measures or automatically using probes and dosing pumps. 

The remaining businesses are additional measures including, amongst other things: 

1. Keeping an operating log in accordance with Section 42 of the BImSchV 
2. Selection of suitable internal sampling methods (dip slides are not strictly necessary and are often time-consuming)
3. Comparison of laboratory providers for external samples (price differences are significant) 
4. Ensure that biocides and, where necessary, system cleaners are dosed correctly 
5. Use of biocides or system cleaners; where appropriate, silver-filament fabric (as yet not widely tested in practice) 
6. Avoid downtime of more than 7 days, as otherwise an inspection by a person with expertise in hygiene is required 

It is advisable for every business to keep track of necessary deadlines, notifications, inspections and documentation.

The following applies to new installations:

• Avoid areas of stagnant water
• Provide dosing options
• Ensure ease of cleaning (large inspection hatches)
• timely notification to the KaVKA (within 4 weeks)

Conclusion