To prevent sewer backup in a culinary sink, which installation is required?

To prevent sewer backup in a culinary sink, the required installation is an air break. An air break is a physical separation between the end of a drainpipe and the top of the receiving fixture, such as a sink, which helps to prevent any potential backflow of wastewater into the kitchen sink.

The air break allows wastewater to drain freely while ensuring that the water cannot siphon back into the plumbing system, thereby reducing the risk of contamination from sewer systems. This is particularly important in commercial kitchens where food safety is paramount, as preventing sewer backups can help to maintain a clean and sanitary environment.

In contrast, while a backflow valve is designed to prevent reverse flow of water in general plumbing systems, it may not be suitable for all culinary applications. An air gap, which is a more significant physical separation than an air break, is also effective at preventing backflow but may not always be practical in the limited space of a culinary sink. A grease trap is essential for managing fats, oils, and grease in wastewater but does not specifically prevent sewer backups.