The limits of risk-based maintenance in water law
In global competition, German companies face increasing cost pressure, making creative cost-saving solutions appear attractive. A corresponding approach in German industry has long been the shift from preventive maintenance (PM) according to DIN EN 13306 to risk-based maintenance (RBI) according to DIN EN 16991.
PM vs. RBM
If the maintenance technician relies on fixed time intervals for the preventive variant, the risk-based approach uses the combination of probability of failure and the associated extent of damage as the fixed point for the intensity of the respective maintenance of the system component. The aim is to save costs for less critical areas of the plant. And with the multitude of different plants and hazardous substances, a specific consideration also seems more sensible at first glance than a rigid deadline concept.
No risk, no fun?
Anyone who now imagines themselves in a world of unlimited savings opportunities will be severely restricted by German water law. Starting with the overriding principle of concern according to § 62 of the Water Resources Act (WHG): This dictates to the plant operator that he must operate (and thus also maintain) his plant for handling water-endangering fluids in such a way that an adverse change in the properties of water bodies is not a concern. The mere concern that water pollution could occur is sufficient to move the operator to take appropriate countermeasures. As a result, the risk assessment should no longer only be based on a possible damage event, but must already be based on a worrying preliminary stage of it. This significantly expands the range of scenarios to be considered. A “just good enough” as the basis for the maintenance concept can affect, if not exceed, the principle of concern in some areas.
What the type approval requires
The following § 63 WHG in turn sets narrow limits to the possibilities of the maintenance technician. Paragraph 4 defines the suitability of system components for systems for storing, filling or transferring water-endangering substances. These are suitable, among other things, if a proof of usability has been issued for mass-produced components in accordance with building regulations, which guarantees compliance with water law requirements. Compliance with the test cycles specified by the manufacturer is stipulated in the respective “general building authority approval” (abZ) or the “general building type approval” (aBG). For the classic safety devices such as overfill protection devices or leak detectors, a test interval of 12 months is the maximum limit value across all manufacturers for the expert inspection. This “at least once a year” approach can also be found outside of water law, for example in flame arresters.
Above-ground pipelines
But even for the “banal” above-ground pipeline, water law sets the benchmarks for the operator. For this purpose, the Technical Rule for Water-Hazardous Substances TRwS 780 contains clear specifications regarding the recurring tests as well as the content design of the maintenance plan. Analogously, TRwS 779 extends the requirements for maintenance and monitoring plans for the entire system.
Don't do the math without the auditor
An all too creative interpretation of the maintenance scope as well as an overextension of the maximum deadlines will therefore fall on the operator’s feet at the latest during the next recurring system inspection in accordance with § 46 of the Ordinance on Installations Requiring Supervision (AwSV). As a remedy, a maintenance concept coordinated with an expert organization could be created, based on the Industrial Safety Ordinance. However, the assessments regarding the risks would have to be supported by both parties in agreement.
When the revolution devours its own children
In summary, maintenance personnel of facilities handling water-hazardous substances face strict limits for a risk-based maintenance concept. Therefore, potential savings may be realized primarily with regard to supply security. And that’s exactly when “the revolution devours its own children.” The closer cost savings bring you to a “production failure” scenario, the more expensive the consequences can ultimately become.
