Dental Operatory Function Notes

Commonly accepted minimums

Minimum clear length: 11 feet (≈3.35 m)
Preferred / more functional length: 12 feet (≈3.65 m)
Typical width: 9–10 feet (≈2.7–3.0 m)

This gives:

Minimum functional size: ~10′ × 11′ (110 sq ft)
Preferred size: 10′ × 12′ (120 sq ft)

Why rear delivery needs more length

Rear delivery requires:
Space behind the patient chair for cabinets and delivery units
Assistant circulation behind the headrest
Clearances for doors, carts, and equipment swing

Code & guideline notes
FGI Guidelines (used by many jurisdictions) commonly reference 120 sq ft for a dental operatory, which aligns well with rear-delivery layouts
ADA guidelines and dental equipment manufacturers typically recommend 12 ft length for optimal ergonomics
Local building codes, accessibility rules, and equipment specs can override these minimums