Vitreous Sanitary Appliances (Vitreous China) -, Part 16: Specific Requirements of Wash Down Wall Mounted Water Closets
2002 Edition

The standard outlines two main design variants: Pattern 1 comprises water closets secured using frame rag bolts with a concealed outlet as depicted in Figure 1, whereas Pattern 2 involves water closets mounted atop brackets shown in Figure 2. Installation requires fixing on a smooth wall surface with a mortar or facing layer behind the unit. Load testing mandates applying a 400 ± 15 kg load for one hour via a 100x100 mm wooden beam over the top opening. Fixing bolts differ by pattern, with diameters of 14 ± 2 mm for Pattern 1 and 10 ± 1 mm for Pattern 2. Additionally, a minimum clearance of 40 mm between the lowest part of the water closet and the finished floor must be maintained.

Manufacturers are required to follow specific dimensional limits for inlet and outlet connections to ensure proper installation and interchangeability. For Pattern 1, the internal inlet diameter is 55 mm with a tolerance of +3/-1 mm, and for Pattern 2, it is 50 mm ± 3 mm. The minimum socket depth is 25 mm for both patterns. The internal outlet diameter must be at least 80 mm, with an external outlet diameter of 102 mm ± 5 mm. Space around the outlet center must be no less than 75 mm. The distance from the supporting plane to the outlet face is at least 15 mm horizontally and vertically. Fixing hole center distances are 230 mm ± 5 mm for Pattern 1 and 180 mm ± 5 mm for Pattern 2. Fixing hole sizes vary between circular and oval forms depending on pattern, and seat bolt hole diameters are 15 mm ± 2 mm. Outlet angles are 90° ± 3° for Pattern 1 and 104° ± 3° for Pattern 2. Ovality within these tolerances is permitted.

Performance testing includes the Toilet Paper Test, where the water closet is filled to the normal water seal level and loaded with six loosely crumpled pieces of toilet paper or polyethylene sheets (0.05 mm thick, sized approximately 150 x 115 mm). The unit is flushed four times, and it must successfully clear the paper at least three times to pass. The Holding Capacity Test requires the outlet to be sealed watertight, and the unit must retain a minimum of 10 litres of water between the normal and maximum water levels without leakage. These tests verify the flushing efficiency and discharge capabilities as mandated by the standard.

Installation stipulations require the water closet to be constructed as a single piece featuring an integral flushing rim (which can be a box rim, open rim, or a combination) with a self-draining flushing inlet that includes a weep-hole to prevent water stagnation. Fixing must utilize at least two corrosion-resistant bolts and nuts, paired with a concealed, independent support frame such as a metal hanger or carrier anchored securely to structural components to avoid strain on plumbing connections. The fixture must be mounted against a smooth wall with a mortar or facing layer behind it. The assembly must endure a load of 400 ± 15 kg, applied continuously for one hour via a 100 mm by 100 mm wooden beam across the top opening, without incurring damage or instability.

The interior surface of the water closet, extending up to 40 mm below the flushing rim, should be treated with quartz powder smudging using a contrasting color powder that passes through a 1.18 mm IS sieve, followed by careful flushing to ensure no residual smudge remains. The internal surfaces and traps must be smooth and uniform to facilitate efficient flushing. The outlet surface must be glazed if it lacks serrations; serrated outlets may remain unglazed. The flushing rim must be an integral part of the unit—either box rim, open rim, or a combination—with adequate holes or slots for uniform water distribution. Additionally, the flushing rim and inlet need to be self-draining, incorporating a weep-hole at the flushing inlet to prevent water accumulation.