We draw samples from your drinking water installations "state of the art". Each sample will be marked with a distinct bar code label that cannot be lost or be confused with other samples until the legionella test is completed. We work with own samplers and cooperate nationwide with laboratories accredited for microbiological water analysis.
The sampling process is based on the German technical Rule W 551, Drinking water heating and drinking water piping systems; technical measures to reduce Legionella growth; design, construction, operation and rehabilitation of drinking water installations, issued by the German Association for Gas and Water (DVGW).Additionally in terms of storage and transport, we abide by the international standard for water sampling for microbiological analysis ISO 19458:2006.
To fulfill the legal requirements of the so called orienteering examination of drinking water two samples have to be drawn from suitable sampling valves directly at the storage tank and at least one sample is collected at the fartherst point (in flow direction) from the boiler in the entire piping system. That is usually a sampling point in top floor apartments of residential buildings., for instance the water tap in the bathroom.The points chosen should generally yield samples that are representative of the system as a whole and of its main components.
Before a sample can be taken the tap or sampling valve needs to be disinfected either thermally (by flaming, which is favorable) or chemically (which is advisable if heat would damage the fitting)
Perlators or other beam regulators have to be removed from the tap before sampling to avoid influence of the fitting to the results.
One liter flows from the tap before the sample is collected in a sterile glas or plastic container. The sampler needs to wear gloves and should not touch the inner rim of the cover when sealing the sample container to avoid false results.
The hot water samples are immediately put in a steel box called passive cooling device filled with cold destilled water cooling them down to ambient temperature within 30 minutes. Once the sample set is completed all samples taken are cooled down to temperatures from 2 to 8 ° C, a range ISO 19458:2006 stipulates for microbiological sampling if the period of time from sample taking to incubation in the lab exceeds 8 hours.
Samples stored and transported have to arrive in the lab within 24 hours, for particular microbiological parameters 48 hours is tolerated.
We work with own experienced and certified samplers who are integrated in the quality management system of the laboratory we cooperate with for analysis. Having contact with many tenants, house owners, janitors and plant operators every day good manners and communications skills of our field staff are essential to do a good job. We care for you and your customers!
Steps of sampling
Preparing sampling point:
Remove beam regulator and desinfect water tap (outlet)
Purging sampling fitting:
Open water-tap and let at least one liter (max. 3 liters) drain in a measuring beaker, dispose the water
Filling sampling container:
Immediately (without closing and re-opening the tap) fill water from the jet in a sterile sample container and seal it.
Taking water temperature after collection:
Directly afterwards, fill 250 ml of water in measuring beaker and record water temperature.
Taking maximum water temperature:
After that let water flow in a measuring beaker. Monitor temperature. If the temperatures does not rise anymore, record it (maximum temperature).