Comfort classes
VDI guideline 6003 introduces comfort classes for the assessment of hot water tapping points. The comfort class must be determined in consultation with the user or client for each tap according to its use. The comfort classes depend on the type of fitting, the PWH discharge time and the tapping volume flow of the fitting in question.
The relevant assessment criteria are
For a tapping valve to be categorised in the highest comfort class III, a high tapping valve flow rate must be available in addition to a low discharge time. The reference taps in DIN 1988-300 are often unable to provide the required high flow rates. This is also the case if the flow rate at resting pressure is used for categorisation. In these cases, only comfort class II is achieved despite a short discharge time. In order to ensure comfort class III, a tapping valve with a larger calculated flow rate may need to be used, using manufacturer data.
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