Terminology

• Shower receptor / pan: floor of the shower, prefabricated or site-built
• Pan liner: waterproof membrane under a tiled shower floor
• Bonded waterproofing membrane: sheet or liquid membrane under tile
• Pressure-balancing / thermostatic valve: anti-scald shower valves
• Transfer shower: 36 in. by 36 in. accessible shower with a seat
• Roll-in shower: curbless accessible shower
• Alcove / drop-in / freestanding tub: bathtub installation types
• Whirlpool bathtub: tub with circulation pump

Standards

Ratings

• Showerheads 2.0 gpm maximum
• Shower and tub valves limit outlet temperature to 120°F
• Shower compartments at least 900 sq in. with a least dimension of 30 in. (or 25 in. with at least 1,300 sq in.)
• Shower walls waterproof to at least 72 in. above the floor and 70 in. above the drain
• Pan liners turn up at least 2 in. above the threshold and slope 1/4 in. per ft to the drain
• Shower waste outlets at least 1-1/2 in.
• Accessible transfer showers 36 in. by 36 in.; standard roll-in 30 in. by 60 in.; alternate roll-in 36 in. by 60 in.; thresholds 1/2 in. maximum
• Accessible showers have a hand shower on a hose at least 59 in. long

Test standards

• ASME A112.19.1/CSA B45.2: enameled cast iron and steel fixtures
• CSA B45.5/IAPMO Z124: plastic plumbing fixtures
• ASSE 1016/ASME A112.1016: individual shower control valves
• ANSI A118.10: bonded waterproof membranes
• ASME A112.19.7/CSA B45.10: whirlpool bathtubs

Components

• Receptor or tub: acrylic, fiberglass, enameled cast iron or steel, or tile over mortar bed
• Waterproofing: pan liner or bonded membrane
• Valve and trim: pressure-balancing or thermostatic valve, showerhead, hand shower
• Drain: point drain or linear drain
• Enclosure: safety-glazed door or curtain
• Grab bars and seats: for accessible showers

Detailing

• Depress slabs or framing for curbless and roll-in showers
• Slope floors to the drain; coordinate linear drains with tile layout
• Flood test pan liners before tile
• Use safety glazing for shower doors and enclosures
• Provide blocking for grab bars, seats, and valve supports

Uses

Specific uses

• Residential baths
• Hotel guest rooms, including accessible rooms
• Locker rooms and gyms
• Dormitories and healthcare

Pros and cons

Pros

• One-piece units install quickly and resist leaks
• Tiled showers allow custom sizes and curbless entries
• Anti-scald valves improve safety

Cons

• Site-built pans depend on careful waterproofing
• Curbless showers need structural depressions
• Large one-piece units may not fit through doors in renovations

Manufacturing and cost

Construction

• Acrylic and fiberglass units molded in factories; cast iron tubs cast and enameled; tiled showers built on site over membranes

Main manufacturers and suppliers

• Kohler
• American Standard
• Moen
• Delta
• Bradley

Trade associations: [[Plumbing|[Plumbing]] Manufacturers International and IAPMO.

Sources

• UpCodes: 2024 IPC Chapter 4 fixtures, faucets, and fixture fittings (GSA adoption without amendments), https://up.codes/viewer/general-services-administration/ipc-2024/chapter/4/fixtures-faucets-and-fixture-fittings
• UpCodes: 2024 IPC Chapter 6 water supply and distribution (showerhead flow), https://up.codes/viewer/general-services-administration/ipc-2024/chapter/6/water-supply-and-distribution
• Corada: 2010 ADA Standards Section 608 shower compartments, https://www.corada.com/documents/2010ADAStandards/608
• Wikimedia Commons: Diagrams showing space required to set 'Imperial' baths (NYPL b15260162-487336).jpg, by New York Public Library (Public domain), https://commons.wikimedia.org/wiki/File:Diagrams_showing_space_required_to_set_'Imperial'_baths_(NYPL_b15260162-487336).jpg