What must separate the barbershop facilities from the living quarters?

The requirement for a permanently installed wall to separate barbershop facilities from living quarters ensures a clear and effective barrier between the two areas. This is crucial for maintaining health and safety standards in the barbershop, as it helps to prevent cross-contamination and upholds a professional environment.

A permanently installed wall not only serves as a physical barrier but also meets regulatory standards that govern the operation of barbershops and salons. These regulations are designed to protect both the clients and the professionals working in the space by ensuring that the hygiene and safety levels are maintained at all times.

In contrast, options like a temporary partition, opaque curtain, or folding screen do not provide the same level of security and may not comply with health codes. They can be easily moved or are not designed to be permanent, thus failing to create a consistent and reliable separation required in barbershop operations.