According to standard building services practice, what is the recommended installation height of a wash basin (sink) rim above the finished floor level?

Introduction / Context:
Ergonomic placement of plumbing fixtures affects user comfort, accessibility, and maintenance. The wash basin (also called a lavatory basin) height is standardized within a narrow band so that most users can comfortably wash hands without strain, and to coordinate with mirror heights and trap clearances.

Given Data / Assumptions:

• The basin is wall-hung or pedestal-supported, with normal adult usage.
• Finished floor level (FFL) is the reference.
• Standardized height range is sought for general buildings.

Concept / Approach:
Most codes of practice and design handbooks recommend placing the rim of the wash basin at a height of approximately 0.75 m to 0.80 m above FFL. This range accommodates typical trap geometry, mixer fitting clearances, and user ergonomics. Special cases (children’s facilities, barrier-free design) involve different heights, but the general rule remains 75–80 cm for standard adult facilities.

Step-by-Step Solution:
Identify typical ergonomic band for adult-use basins.Select the option that provides the recommended range.Confirm coordination with mirror and accessory positioning.

Verification / Alternative check:
Handbooks on building services and public health engineering commonly cite the 0.75–0.80 m range; accessibility standards prescribe different values for barrier-free installations.

Why Other Options Are Wrong:

• 60 cm or 70 cm: Too low for general adult use.
• 80 cm as a single value: Acceptable but lacks the common range; the preferred answer is the band 75–80 cm.

Common Pitfalls:
Not accounting for counter-top basins (where counter height matters); ignoring trap and bottle-siphon clearances.

Final Answer:
75 cm to 80 cm