Use of beverage dispensing systems DGUV Regulation 110-007 (excerpt)
Beverage dispensing systems are systems from which, with or without operating overpressure, beverages are dispensed for final consumption, ... e.g. beer, wine, hot beverages containing wine, non-alcoholic soft drinks, water, smoothies and spirits.

Gas warning systems in accordance with DIN 6653-2 "Beverage dispensing systems - Equipment - Part 2: Requirements for the operating behavior and test methods of carbon dioxide warning systems" must be used to ensure adequate personal protection.
Gas warning systems must be equipped with at least two alarm thresholds. The pre-alarm is triggered at a carbon dioxide concentration from
1.5% by volume, the main alarm at 3% by volume and above. The pre-alarm and main alarm must be visually and acoustically distinct from each other.