Septic tank pricing by applying quota line items (Beijing DB11/T 2382-2024 structures works): line-item selection along the three construction routes of cast-in-place concrete / masonry / GRP factory-made tanks, work content already included, and measurement adjustment rules

Topic Positioning

This card sets out how to apply the quota line items for septic tank works under the structures works volume of the Beijing local standard "Construction Consumption Standard" DB11/T 2382-2024: selecting line items along the three construction routes (cast-in-place concrete, masonry, GRP factory-made), identifying the work content already included in each item to prevent double counting, and giving the measurement treatment of associated items such as covers and seats, vent pipes and riser-height adjustments.

Core Conclusions

1. Three construction routes and line-item ranges (all measured per tank)

Route	Quota table	Line-item range	Selection factors
Cast-in-place concrete (standard-atlas tanks)	F.1.5-2.4 standard concrete septic tanks	F-1-57 to F-1-79	size number (1# to 9#), effective volume (4 to 100 m3), with/without groundwater, H+h earth cover condition
Masonry (standard brick tanks)	F.2.3-2.1 standard masonry septic tanks	F-2-10 to F-2-23	size number (3# to 9#), effective volume (12 to 100 m3), with/without groundwater
GRP factory-made	F.3.2-1 BZHC-A / F.3.2-2 BZHC-B / F.3.2-3 YJBH (prefabricated-product structures)	from F-3-107	size number, effective volume (2 to 100 m3), with/without groundwater, trafficable / non-trafficable

2. Work content already included (preventing double counting)

• Standard concrete septic tank (item F-1-58, original work-content wording): "excavation and backfill of earthworks; rebar fabrication and fixing; concrete placing, vibrating and curing; waterproof rendering; damp-proof course; cover installation etc." -> earthworks, rebar, waterproofing and covers are already included in the per-tank price and must not be double counted; its consumptions include concrete modules, ready-mixed concrete and rebar (corresponding to the "concrete modules + grouted core" construction); formwork for cast-in-place concrete is not within the item and is billed separately under the preliminary (measures) items by the contact area of formwork against the concrete member.
• Standard masonry septic tank (item F-2-18, original wording): "excavation, backfilling and hauling of earthworks; laying of bedding; mortar mixing; bricklaying, pointing and rendering; damp-proof rendering; rebar fabrication and fixing; concrete placing and curing etc."
• GRP factory-made tank (item F-3-107, original wording): "excavation and backfill of earthworks, on-site handling; sand bedding; gravel bedding; installation of the factory-made unit; riser; cover; vent pipe etc." -> riser, cover and vent pipe are already included and must not be applied separately; the GRP tank body enters the rate build-up as the principal material, per tank.

3. Treatment of associated items

• Covers and seats: where already included in the tank item, they are not listed again; for separate purchase / replacement or non-standard cases, apply Table F.2.4 "covers, trench cover slabs, factory-made treads" - factory-made covers F-2-38 (per set) / F-2-39 (m3) / F-2-40 (piece), the work content being installation of factory-made covers, trench cover slabs and treads etc.
• Vent pipe: already included for GRP factory-made tanks; not listed in the work content of concrete / masonry tanks - verify against the selected construction atlas, and where separate accounting is genuinely required, follow the corresponding pipe installation items, avoiding double counting.
• Grouted core / prefabricated assembly: for the "concrete modules + grouted core" construction, first attempt a match against F.1.5-2.4; integral precast concrete tanks delivered and installed on site are work items not covered by the quota manuals, to be handled by preparing supplementary quota items or by conversion.

4. Measurement and adjustment rules (original wording)

• 9.2.5 "Quantities of standard chambers and tanks shall be calculated as the design-shown number of units."
• 9.2.6 "Quantities of septic-tank risers, for each 0.10 m increase or decrease, shall be calculated as the design-shown number of risers."
• 9.3.3 "Quantities of standard tanks shall be calculated as the design-shown number of units."
• 9.3.4 "Quantities of septic-tank riser height, for each 0.10 m increase or decrease, shall be calculated as the design-shown number of risers."
• 9.3.5 "Non-standard tanks shall be calculated by volume from the design-shown dimensions"; "factory-made covers shall be calculated as the design-shown number of pieces"; "precast covers, trench cover slabs and chamber rings shall be calculated by volume from the design-shown dimensions".

Applicable Boundaries

• Applies only to the current Beijing "Construction Consumption Standard" DB11/T 2382-2024 structures works volume (septic tanks fall under structures works in that system and are not included in the building works volume); other provinces and cities differ in volume division and line-item numbering, and cross-region application is not permitted.
• The riser-height increase/decrease items are used only where the riser height differs from the standard atlas, quantities being calculated by the number of risers.
• The consumptions are resource-consumption standards for labour, materials and plant; unit rates for labour, materials and plant are built up from market prices or published price information at the time of preparation; this card does not involve specific prices.
• Specific works shall be governed by the design drawings, the contractual pricing agreement and the pricing rules in force at the time of preparation.

Further Reading

• DB11/T 2382-2024 "Construction Consumption Standard", Chapter 9 structures works: 9.2 concrete structures (9.2.5, 9.2.6), 9.3 masonry structures (9.3.3, 9.3.4, 9.3.5).
• Appendix F structures works: F.1.5-2.4 standard concrete septic tanks (F-1-57 to F-1-79, see e.g. the item details of F-1-58, F-1-79); F.2.3-2.1 standard masonry septic tanks (F-2-10 to F-2-23, see F-2-18); F.3.2-1/2/3 prefabricated-product structures (see F-3-107, F-3-245); F.2.4 covers, trench cover slabs, factory-made treads (F-2-38 to F-2-40).
• Preliminary (measures) items: concrete formwork measured by contact area.