GB 25502-2024Minimum Allowable Values of Water Efficiency and Water Efficiency Grades for Water Closets (English PDF)

5.3 Flushing function

5.3.1 Cleaning function

The average total length of the accumulated residual ink line after each flushing shall not exceed 50 mm, and the length of each residual ink line shall not exceed 13 mm.

5.3.2 Water seal recovery function

The water seal recovery shall not be less than 50 mm. For a siphonic water closet, there shall be siphon every time.

5.3.3 Sewage replacement function

For a single-flush water closet, the dilution rate shall not be less than 100; for a dualflush water closet, only a half-flush sewage replacement test is performed, and the dilution rate shall not be less than 25.

5.3.4 Discharge function

5.3.4.2 Particle discharge function

Carry out the test three times in succession, and the average number of visible polyethylene (HDPE) particles remaining in the water closet trap shall not be greater than 125, and the average number of visible nylon balls shall not be greater than 5.

5.3.4.3 Mixed media discharge function

The number of mixed media flushed out of the water closet the first time shall be no less than 22 (The number of mixed media flushed out of the infant-type water closet the first time shall be no less than 11). Residual media, if any, shall be all flushed out the second time.

5.3.6 Drainage pipeline transmission characteristics

The average transmission distance of balls shall not be less than 12 m.

5.4 Trap seal

The trap seal of water closets shall not be less than 50 mm.

5.5 Water seal surface dimensions

The water seal surface dimensions of water closets shall not be less than 100 mm × 85 mm.

5.6 Minimum diameter of the trap

The water channel of the water closet trap shall be able to pass a solid ball with a diameter of 41 mm.

5.7 Performance of flush valve for water closets that is not sold as a set Connect a flush valve for water closets that is not sold as a set to a standard water closet that has obtained a national standard sample certificate, and test it according to the method described in Chapter 6. The combined performance shall comply with the requirements of Chapter 4, 5.1 ~ 5.6.

6.1 Flushing water consumption test

6.1.2 Test procedure

Carry out the water closet flushing water consumption test according to the following steps.

a) Install the water closet on the test device specified in A.1 of Appendix A. The flushing device equipped to the water closet shall be kept in the factory state. There shall be no leakage at all interfaces after connection. Clean the washable surface and trap, and start flushing once or pre-flush according to the requirements of the instructions.

specified in Table 2. If the manufacturer has special requirements for the product test pressure, the test shall be carried out according to the test pressure explicitly stated.

device in the normal way (press it to the bottom within 1 second and release it immediately). If the manufacturer has clearly stated the time to start the flushing device, start the flushing device at the specified time, and record the flushing water consumption (including overflow water) of one flushing cycle. For water closets whose water seal cannot be recovered to the full trap seal during the test, the water in the water seal shall not be replenished. Record the test pressure and flushing water consumption for each flush.

For a dual-flush water closet, measure the full-flush water consumption three times continuously under each test pressure specified in Table 2; then, measure the half-flush water consumption three times continuously; record the test pressure and flushing water consumption for each flush.

6.1.3 Result calculation

6.1.3.1 Single-flush water closet

Calculate the average flushing water consumption of the single-flush water closet according to Formula (1), and round off the result according to the requirements of GB/T 8170 (retain one decimal place):

(gravity) water closet, n=3; for pressure water closet, n=2];

the specified ith test pressure, in liters (L).

6.1.3.2 Dual-flush water closet

Calculate the average flushing water consumption of the dual-flush water closet according to Formula (2) ~ Formula (4), and round off the result according to the requirements of GB/T 8170 (retain one decimal place):

V1 – full-flush water consumption of dual-flush water closet, in liters (L);

the specified ith test pressure, in liters (L);

V2 – semi-flush water consumption of dual-flush water closet, in liters (L);

under the specified ith test pressure, in liters (L);

Vdual – average flushing water consumption of dual-flush water closet, in liters (L).

6.2 Flushing function test

6.2.1 Test pressure

The test pressure for the flushing function of water tank (gravity) water closet is 0.14 MPa as static pressure, and the test pressure for the flushing function of pressure water closet is 0.24 MPa as static pressure.

6.2.5 Discharge function test

6.2.5.1 Ball discharge function test

6.2.5.1.2 Test procedure

Gently place the solid ball into the trap of the water closet; start the flushing device to perform a full-flush test; […]

6.2.5.2 Particle discharge function test

6.2.5.3 Mixed media discharge function test

6.2.6 Toilet tissue paper discharge test

6.2.7 Drainage pipeline transmission characteristics test

A.2 Drainage pipeline transmission characteristics test device

The schematic diagrams of the water closet drainage pipeline transmission characteristics test device are shown in Figures A.2 and A.3.

B.1 Test medium

The discharge function test media include ball discharge function test media solid balls, particle discharge function test media cylindrical polyethylene particles and nylon balls, mixed media discharge function test media sponge strips and typing paper.

B.2 Acceptance steps

B.2.1 Solid balls

The number of solid balls shall be 100 and meet the following acceptance requirements:

a) Use a vernier caliper or other suitable measuring tool to measure the diameter of the solid ball. The diameter of each solid ball shall be (19±0.1) mm;

b) Use the immersion method or other applicable methods to measure the density of the solid ball. The density shall be (850±15) kg/m³;

c) There is no special requirement for the color of the solid ball. To facilitate test observation, use colors other than white and transparent.

B.2.2 Polyethylene particles

The number of polyethylene particles shall be (2 500 ± 50) and meet the following acceptance requirements:

a) Polyethylene particles shall be regular cylinders;

b) Use the immersion method or other applicable methods to randomly

measure the density of 125 particles, and the density shall be (935±10) kg/m³;

c) There is no special requirement for the color of polyethylene particles. To facilitate test observation, use colors other than white and transparent.

B.2.3 Nylon balls

The number of nylon balls shall be 100 and meet the following acceptance requirements: a) Use a vernier caliper or other suitable measuring tool to measure the diameter of the nylon ball. The diameter of each solid ball shall be (6.35±0.25) mm; […]

B.2.4 Sponge strips

The number of sponge strips shall be 20 and meet the following acceptance requirements:

a) Use a steel ruler or other suitable measuring tool to check the size of the sponge strips. The size of each sponge strip shall be (20±1) mm × (20±1) mm × (28±3) mm;

b) Use weighing method or other applicable methods to test the dry density of the sponge strip, and its density shall be (17.5±1.7) kg/m3.