In 2013, mysterious waves of illness with flu-like effects and in some cases severe pneumonia were reported in 165 persons in Warstein. Three of those affected ultimately died of their severe illnesses. After detailed investigations into the sources of infection, the authorities and local companies found that so-called re-cooling plants as well as waste water pre-treatment and post-treatment tanks were the cause of the disease. Highly elevated levels of the pathogen Legionella pneumophila were found, also known as Legionnaires' disease. There had been a similar incident in Ulm in 2009, with 6 fatalities. In that case, a recooling system for a large building had been the cause of a large number of sick people.
These special incidents prompted the competent federal authority to issue a new Ordinance on evaporative cooling systems, cooling towers and wet separators in 2017 - the 42nd BlmSchV. This Ordinance regulates the legal requirements for the hygienic operation of evaporative cooling systems, cooling towers and wet separators throughout Germany.
How long has the 42nd BlmSchV been enforced?
In March 2017, the Federal Ministry for the Environment, Nature Conservation, Construction and Nuclear Safety (BMUB) published the 42nd Ordinance on Evaporative Cooling Systems, Wet Separators and Cooling Towers (42nd BImSchV.) in the Federal Gazette. It officially took effect on August 19, 2017 and contains new obligations and requirements for plant operators. VDI 2047, Part 2, served as the content basis for the ordinance; it is part of the Federal Immission Control Act and must therefore be implemented by plant operators.
Since 20 July 2018, pursuant to §13 - Obligations for notification, every operator has been obliged to notify a competent authority of a plant covered by this Ordinance. Accordingly, operators have to or had to report as follows:
- New installations no later than one month after initial filling with service water
- Existing installations - installations commissioned before the Ordinance took legal effect - by 19 August 2018 or at the latest 6 months after the Ordinance took legal effect
- Changes to a plant and plant shutdowns
With the help of the web application KaVKA-42.BV, created by the federal authority, every operator can efficiently comply with this duty of notification and information.
Which plants are affected by the 42nd BlmSchV?
Evaporative cooling systems, cooling towers and wet separators are generally used to dissipate heat generated in the production process into the ambient air.
Such systems can be found in large industrial plants as well as in large buildings (e.g. exhibition halls, hospitals, hotels, etc.). All installations where water comes into contact with air currents have a tendency to form aerosols. Evaporative cooling systems, cooling towers and wet separators have therefore long been suspected of being sources of aerosols containing legionella. The associated risk of legionella disease has contributed to the inclusion of these plant types in the 42nd BlmSchV.
An evaporative cooling system is a system in which heat is dissipated to the ambient air by evaporation of water. It consists of a sprinkler or sprinkler system for the cooling water and a heat exchanger. The cooling tower differs essentially from the evaporative cooling system in that the air is conveyed by the natural draft in the cooling tower and has a considerably higher cooling capacity >200 MW. The function of the wet separator is to remove solid, liquid and gaseous impurities from an exhaust gas with the aid of washing liquids. The washing liquid binds the impurities within the exhaust gas flow and is separated accordingly.
What are the demands the 42nd BlmSchV puts on operators?
The formation of bacteria and in particular of Legionella cannot be excluded with regard to the planning, design and manufacture of the above-mentioned plants. Therefore, the operators of such plants are obliged by law to guarantee the requirements for construction, condition and operation.
It is therefore essential for every operator to deal with the contents of the 42nd BlmSchV and to recognize the requirements and tasks, to organize them within the company, to carry them out and to document them.
The requirements of the Ordinance include:
- Before (re)commissioning a plant, a risk assessment must be carried out, which must be accompanied by a hygienically competent person.
- Possible hazards must be identified and the remaining risk assessed in order to derive the necessary measures.
- 4 weeks after (re)commissioning of a plant, the process water must be fed to a laboratory test. For plants which are in operation for less than 90 consecutive days per year, the laboratory test must be carried out within 2 weeks of (re)commissioning.
- In the case of evaporative cooling systems, wet separators and cooling towers, the hygienic condition of the service water must be determined by the operator at least every two weeks within the plant.
- Regular sampling and subsequent laboratory testing of the service water for Legionella must be carried out every 3 months for evaporative cooling systems and wet separators and every month for cooling towers.
- Sampling and laboratory testing of process water must be carried out and documented by an accredited testing laboratory.
- Operators must ensure that additional water supplied to the service water also meets the hygienic requirements.
- For each plant, operators shall keep an operating log, in which, in addition to the general operator and plant data, the results of the laboratory analyses of the process water, the operating and downtimes of the plant, any exceedances of the test values and information on the measures taken and the dates of the inspections are recorded. In addition, the operating log also contains the risk assessment carried out by the operator.
- After commissioning, each plant must be inspected every 5 years by a publicly appointed and sworn expert or an accredited inspection body with regard to proper operation.
- If the values for the concentration of Legionella in industrial water specified in the Ordinance are exceeded, the operator must immediately report the results of the laboratory tests to the competent authority.
With the help of a checklist listed in the Ordinance, the operator can ensure proper operation during (re)commissioning of a plant and document this accordingly.
How do the manufacturers of plants deal with this?
Of course, the new Ordinance not only concerns the operators, but also, to the same extent, the manufacturers of the equipment, including those in the foundry sector. Here, recooling systems for induction and melting furnaces are used, which have to cool down the required cooling water from > 70 °C to up to 25 °C for a reliable process operation. Foundry Service GmbH, a plant manufacturer in Hemer, Sauerland, is one such manufacturer of recooling plants covered by this Ordinance. The delivered plants are technically mature and tailored to customer requirements. With regard to the documentation accompanying the product, further efforts had to be made with regard to customer-oriented documentation, after the Ordinance had taken effect.
The aging recooling plant of the melting furnaces of the traditional family business Gontermann-Peipers - one of the oldest foundries in Siegerland - was replaced in 2017 after a thorough analysis by Foundry Service GmbH. It had become necessar to replace the existing freecoolers, because the existing system could no longer guarantee constant temperatures, especially in midsummer. Also there had to be a noise reduction to make the complete cooling installation more neighbor-friendly. In addition, corrosion was found in the old equipment, which caused leaks. In view of the Ordinance, this condition was a further motivation to start planning and implementing a new recooling system.
The new system installed on the hall roof is operated without antifreeze additives. In order to avoid the risk of frost in winter during standstill, the coolers were installed in such a way that they can be emptied automatically and completely into the existing intermediate basin. The use of glycol could thus be avoided.
Vibration dampers were used to decouple the vibrations of the radiators from the console. The use of EC fans, which are electronically controlled compared to conventional squirrel cage motors and achieve savings of up to 80 %, had a cost-saving effect. An increase in the service life of the coolers was achieved by coating the aluminum fins.
Upon completion of the project, the customer received a detailed, legally compliant documentation, which also deals with the requirements of the Ordinance with regard to maintenance and servicing.
It should be noted that Legionella is an issue for foundries. The disease must be fought vigorously - for the health of employees and for the environment. Both plant manufacturers with their technical possibilities and expertise and operators with their everyday experience are called upon to meet the requirements of the Ordinance.
The Ordinance and the requirements it contains are still too fresh for scientific evidence to be available at this stage to report on changes and improvements.
OLIVER VON COLSON, VON COLSON TECHNICAL DOCUMENTATION, ISERLOHN
IRAKLIS PAPADOPOULOS, FOUNDRY SERVICE GMBH, HEMER
References: 42. BlmSchV, Bundesanzeiger Verlag GmbH, Köln