Final answer:
The shower opening should be a minimum of 22 inches wide to ensure safe and comfortable access, although ADA standards recommend a wider opening of 36 inches for accessibility.
Step-by-step explanation:
The shower opening (or access and egress opening) should be at least 22 inches of clear and unobstructed finish width. This measurement ensures that the shower can be accessed comfortably and safely by most users.
The width standard provides enough space for an individual to enter and exit the shower without safety hazards, which can be particularly important for those with mobility issues. Building codes may vary, so it's essential to refer to local regulations for the exact requirements. However, the Americans with Disabilities Act (ADA) sets forth accessibility standards for newly constructed and altered state and local government facilities, public accommodations, and commercial facilities to be usable by people with disabilities, which recommend a minimum opening of 36 inches to accommodate users with disabilities.