Drainage-pipe testing caliber and pricing inclusion boundary: gravity pipes take leakage-tightness tests (water/air) not pressure tests/disinfection-flushing; tests are included in the pipe BOQ item, norm items listed separately != separate BOQ items, with a four-step omitted-item test for settlement

Topic Positioning

The engineering caliber and pricing boundary of drainage-pipe functional testing: drainage pipes are gravity pipes — the applicable test is leakage tightness (water/air), not "pressure test", and water-supply "disinfection flushing" does not apply. This card gives the mandatory test scope and the "included in BOQ, norm may itemize separately" boundary, plus a four-step test for settlement disputes of the "drainage disinfection/pressure test" type.

Core Conclusions

1. Caliber: drainage = gravity pipe; tightness test, not "pressure test" or "disinfection flushing" GB 50268-2008, 9.1.1: after installation, pipes are functionally tested — "(1) pressure pipes per 9.2 by hydrostatic test, in pre- and main-test stages, judged by allowable pressure drop or allowable infiltration per design, or both; (2) gravity pipes per 9.3 and 9.4 by leakage-tightness test — water test or air test per design, or per actual conditions where silent; (3) where actual infiltration of pressure pipes is measured, the water-filling method of Annex C is preferred." Hence: drainage (gravity) pipes take tightness tests (water/air); "drainage pressure test" in settlement is a caliber error; "disinfection flushing" is a potable-water pre-commissioning process — "drainage disinfection flushing" is a wrong item, strike it.

2. Mandatory tightness-test scope (whether it should occur)

• GB 50268-2008, 9.1.11 (mandatory): "Sewage and combined pipes, and storm pipes in collapsible soil, expansive soil, and quicksand areas, must pass leakage-tightness tests before being put into service."
• GB 55027-2022, 4.2.12: "Sewage pipes and their appurtenances shall pass leakage-tightness tests before use."
• GB 50014-2021, 5.1.12: "Sewage and combined pipes and appurtenances in collapsible/expansive/quicksand areas shall be watertight and tightness-tested."
• DB11/T 1835-2021, 9.6.1: "Sewage, combined, inverted-siphon, and other drainage pipes with water-test requirements shall be water-tested." — ordinary storm pipes may skip it (unless designed).
• DB11/T 1835-2021, 9.6.5 sampling: DN700-2400 per Table 9.6.5; fewer than 3 well-spaces still sample 1; on failure, test the whole line; DN2500-3000 double sampling, then whole line; water shortage with ID <= 700mm: sample 1/3 of well-spaces (confirmed by employer/design/supervision); with genuine water shortage, single-mouth pressure testing (material confirmed per design); water test per Annex A; concrete trenched drains below 1200mm may use the air test (9.7 and Annex B).

3. BOQ level: tests included in pipe items, not itemized separately

• Building installation: GB/T 50856-2024 Table K.1.1 note 9: "All pipe items' work content includes pressure testing and purging/cleaning — pressure testing covers hydrostatic, pneumatic, leakage, water-fill, ball-passing, vacuum tests etc. per design; purging/cleaning covers water flushing and air blowing per design." (Note 6: drainage work content includes riser cleanouts and vent caps.)
• Municipal: GB/T 50857-2024 Annex E pipe laying (040501) sets characteristics incl. testing requirements; E.5.3: "describe pipe blowing, flushing/disinfection, strength, tightness, and water-fill tests per the discipline's acceptance codes and design"; 4.1.2: "...deemed to include all work necessary to complete the item... construction processes in the work content shall not be split into separate items unless specially stated."
• Conclusion: under the 2024 national caliber, tightness tests are inside the pipe BOQ item (unit rate) — no separate chargeable item.

4. Norm level and settlement omissions test

• Norm structures differ: some systems itemize tests for pricing — SJG 181.4-2024, 1.3.8 has water tests (channel/pipe), pipe pressure tests (air/hydraulic), disinfection flushing, and well leakage items; 1.1.12: "new-old connections, functional testing, disinfection flushing, and well leakage tests do not include dewatering — dewatering is computed separately per the approved method statement"; SJG 84-2020, 2.1.13: water-test source is tap water (adjust for others); pressure test assumes ordinary water, one test incl. blind-plate/cam amortization; well full-water tests include pump install/remove; dewatering excluded (per approved statement); heating of test water priced separately.
• Key distinction: a separate norm item does not equal a separate BOQ item. Norm test items go into the pipe item's unit rate; whether itemized and the item boundary (water source/plugging/dewatering/heating) follow the norm volume/chapter notes.
• Four-step omission test: (1) caliber — "disinfection flushing/pressure test" on drainage is struck; (2) scope — tightness testing per the mandatory scope (sewage, combined, inverted siphons, special-soil storm) and design; (3) inclusion — per 2024 national calibers tests are/should be in the unit rate, not recharged; (4) norm and contract — local itemization affects pricing mode only; genuine BOQ omissions not due to the contractor follow the contract and the standard's defect/omission adjustment rules.

Applicable Boundaries

• Pressure/gravity calibers per GB 50268-2008, 9.1.1: supply (pressure) -> hydrostatic; drainage (gravity) -> tightness (water/air); terms not interchangeable.
• The mandatory scope is the floor; stricter design governs. Ordinary storm pipes may skip water tests, but storm pipes in collapsible/expansive/quicksand soils must test.
• Norm structures differ (Shenzhen SJG itemizes vs merged elsewhere); whether applicable and item boundaries follow the norm notes — this card does not replace norm verification.
• Local details (DB11 sampling, single-mouth testing, air-test substitution) apply regionally; elsewhere follow local rules.
• Norm itemization does not equal separate BOQ items; pricing and itemization are two layers — do not confuse.

Further Reading

• GB 50268-2008: 9.1.1, 9.2, 9.3-9.4, Annex C; supply-pipe flushing/disinfection has separate provisions.
• GB 55027-2022, 4.2.12; GB 50014-2021, 5.1.12.
• GB/T 50856-2024 Table K.1.1 note 9; GB/T 50857-2024 Annex E Table E.1.1 (040501), E.5.3, 4.1.2.
• DB11/T 1835-2021, 9.6.1, 9.6.5, Annex A, 9.7 and Annex B.
• SJG 181.4-2024, 1.3.8, 1.1.12; SJG 84-2020, 2.1.13.