VDI / DVGW 6023
The hygiene-conscious planning, construction and operation of drinking water installations was first taken up in 1999 by the VDI ( Association of German Engineers ) in the VDI 6023 guideline . The VDI 6022 guideline was partly the model . The status of recognized rules of technology is assigned to the guidelines of the VDI . As such, they have the character of recommendations under private law without legal character. However, they act as "anticipated expert reports" and can develop an exculpatory effect in the event of a dispute due to their presumptive effect.
The second revision of the guideline, published in April 2013, was issued as a joint VDI / DVGW guideline.
scope of application
The guideline applies to all drinking water installations on land, in buildings and on merchant ships (including inland waterways). It can be used analogously for all other water supply systems according to § 3 of the Drinking Water Ordinance .
General requirements
“Water has to flow.” The biggest problem with drinking water hygiene is the lack of water exchange. Since drinking water is not sterile, germs that are present in stagnant water, especially at temperatures between 20 and 50 ° C, can multiply and lead to the formation of biofilms and stubborn contamination. In addition, the water quality can change adversely due to prolonged interaction with the pipe materials.
Drinking water installations should therefore be as large as necessary to satisfy the water requirement, but still as tight as possible. Unnecessarily large pipe diameters, pipes "in stock" for taps to be connected later or installation sections, dead pipes and taps where the water cannot be replaced within 72 hours are not permitted.
When a drinking water installation is filled for the first time, the constant exchange of water must be ensured through (possibly simulated) normal operation.
At no time and at any point should there be an unsecured ("direct") connection between the drinking water installation and a system for other waters, e.g. B. fire water systems, heating systems or rainwater harvesting systems. (VDI 2070 contains detailed information on service water systems.) Installations for other types of water must always be separated from the drinking water installation by a safety device in accordance with EN 1717 .
Initial hygiene inspection
The purpose of the initial hygiene inspection is to determine whether the requirements for proper operation, i. H. proper planning and execution are given.
operation and maintenance
The basis of the intended operation is the use specified in the room book .
Business interruption, restart
Proper operation requires a water exchange within 72 hours. If it is foreseeable that this water exchange cannot be ensured through normal use, then suitable organizational (flushing instructions) or technical (time-controlled flushing devices) measures must be taken to ensure the necessary water exchange.
If the intended operation is interrupted for more than four weeks, the lines must be shut off beforehand and flushed in a specified manner before restarting.
In the case of interruptions of use of more than six months, in addition to the flushing, microbiological examinations and, if necessary, further measures to restore the hygienically harmless condition are required before restarting.
maintenance
Maintenance of drinking water installations should be carried out by trained specialists. VDI / DVGW 6023 describes suitable training courses in Appendix D.
The time grid for inspections of systems and system parts as well as the deadline for rectifying identified defects are based on the severity of the possible effects. Restrictions on comfort are less urgent than restrictions on use, and these in turn are less critical than health hazards.
Responsibilities
According to the Drinking Water Ordinance, the entrepreneur and other owners are responsible for maintaining the health safety of the drinking water provided within the scope of their duty to maintain safety. Initially, this is the owner of the installation; if the installation is made available within the framework of usage contracts, the user is next to him. The responsibility extends z. B. in rental apartments up to the private area of the tenant.
Drinking water hygiene training
The VDI / DVGW 6023 guideline distinguishes between the following qualifications:
- Category A: planner, responsible installer, auditor
- Category B: Executor, maintenance engineer
- Category C: User (only own system)
Water supply companies (WVUs) keep lists of contractors who are authorized to carry out certain activities on drinking water installations. The drinking water hygiene training courses in accordance with VDI / DVGW 6023 do not automatically qualify for entry in these directories, as the determination of the qualifications required for this is the responsibility of the WVUs.