Compliance
VDI 2047-2 and 42. BImSchV: operator duties at a glance.
Germany’s 42. BImSchV governs operation, monitoring and records for systems within its scope. VDI 2047 Part 2 provides technical guidance for hygienic operation of evaporative cooling systems. These duties apply regardless of the treatment method used.
Operator duties in practice.
Applicable duties and testing intervals depend on the statutory system category and operating circumstances. The following points provide an overview; the current requirements and any conditions imposed by the competent authority govern the individual case.
Legionella values: evaporative coolers and wet scrubbers.
| Test value 1 (Prüfwert 1) | 100 CFU/100 ml |
|---|---|
| Test value 2 (Prüfwert 2) | 1,000 CFU/100 ml |
| Action value (Maßnahmenwert) | 10,000 CFU/100 ml |
Values for Legionella spp. from Annex 1 of 42. BImSchV, for the two named system categories. Responses to exceedances follow the applicable provisions; an individual reading is not a general demonstration of compliance.
System categories and intervals
Cooling towers in the specific sense of § 2 no. 5 (natural draught, more than 200 MW per air outlet) have different Legionella values: test value 1 = 500, test value 2 = 5,000, action value = 50,000 CFU/100 ml.
Routine laboratory testing for Legionella is required at least every three months under § 4, or monthly for cooling towers under § 7. Both categories require internal checks at least every two weeks. Statutory conditions can change these intervals.
For evaporative coolers and wet scrubbers, the general colony count is assessed against a system-specific reference value under § 4. 10,000 CFU/ml is not a universal limit for every system.
Integrate system care with the hygiene programme.
Biofilm and deposits are relevant factors in system hygiene. Probiotic treatment must be assessed alongside water quality, operation, cleaning and required control measures. It replaces neither statutory testing nor responses to concerning findings.
System condition
Assess deposits and operating conditions alongside microbiological findings.
Monitoring over time
Document sampling, test methods and operating conditions clearly.
Auditable records
Bring treatment and testing records together within the operating documentation programme.
Safety assessment
Review product information, chemical and biological-agent requirements and necessary protective measures.