Applying quota items to civil-defence duct airtight sleeves (airtight wall-penetrating spools with sealing flange rings) under the Beijing 2024 consumption quota standard: select Type I / III by the wall-penetration form, band by diameter within d300 / d600 / d1000, measured per "piece"; fabrication and installation of the sealing rib and the spool body are included in the item and not charged separately

Topic Positioning

This card gives the quota-application position for civil-defence (ventilation) duct airtight sleeves - airtight wall-penetrating spools with sealing flange rings (sealing ribs) and embedded duct sections cast directly into the wall - under the Beijing 2024 consumption quota standard (DB11/T 2382-2024): which table and items apply, how they are measured, and whether the sealing rib and spool body are charged separately (the main-material conversion question).

Core Conclusions

1. Item description (selection rule, original wording): "Pipes through airtight walls divide by the pipe wall-penetration form into Types I, II and III. Type I applies where a plain steel-plate duct is cast directly into a reinforced concrete wall; Type II applies where pressure-measuring or sampling pipes pass through a wall; Type III applies where the duct does not pass directly into the reinforced concrete wall." Work content: "lofting, cutting, cropping, welding, positioning, installation, packing with filler". The unit of measurement is the "piece" (one per penetration), not steel-plate mass or duct developed area.

2. Item assignment

• Type I (at protective airtight walls, where what is embedded is the protective airtight duct itself and the later duct is welded directly to the embedded pipe) -> C7-11-68 (within d300) / C7-11-69 (within d600) / C7-11-70 (within d1000), in table C.7.59-3 "civil-defence components and others";
• Type III (at airtight partition walls, where a spool with a sealing flange ring is embedded, the duct connected after, sealed with filler) -> C7-11-72 (within d300) / C7-11-73 (within d600) / C7-11-74 (within d1000), in table C.7.60 "pipes through airtight walls";
• Type II is for pressure-measuring and sampling pipes through walls - keep it distinct from duct sleeves.

3. The sealing rib and spool body are included in the item, not charged separately: the item materials contain two bands of plain steel plate - 2.6 mm to 3.2 mm (for rolling the spool body) and 4.1 mm to 7 mm (for making the sealing flange ring); the work content includes cutting, cropping and welding, and the plant includes a 6.3 x 2000 mm guillotine shear and a 2 x 1600 mm plate-rolling machine. That is: no separate "sealing rib / flange-ring fabrication and installation" or steel-piece item, and no duplicate charging or conversion of the spool or sealing rib as main material. Type III also contains round-bar d10 anchor bars (0.588 / 1.486 / 3.141 kg) and bitumen-mastic filler (1.575 / 3.675 / 7.875 m3), likewise item content.

4. Content of the six items, quick reference (per "piece"; labour is all-in labour Grade II; plate is plain steel plate):

Item	Type / diameter	Labour (workdays)	Plate 2.6-3.2 mm (kg)	Plate 4.1-7 mm (kg)
C7-11-68	Type I, within d300	1.499	14.353	3.226
C7-11-69	Type I, within d600	2.225	30.731	8.512
C7-11-70	Type I, within d1000	3.302	50.296	17.793
C7-11-72	Type III, within d300	3.987	10.613	2.245
C7-11-73	Type III, within d600	4.117	21.410	6.600
C7-11-74	Type III, within d1000	5.727	34.453	14.720

5. Consistency with design and acceptance requirements (selection can be checked against the clauses)

• DB11 994-2021 clause 5.2.20: "ventilation ducts through protective airtight walls shall take reliable protective airtight measures and shall be embedded in place in one pass during civil construction"; the clause commentary: what is embedded is the protective airtight duct, not a sleeve; at later installation the duct is welded directly to the embedded pipe, so the embedded duct diameter must equal the connecting duct diameter - this corresponds to the Type I practice.
• DB11/T 1832.15-2022 clause 6.4.19: "where a duct passes through an airtight partition wall, an airtight wall-penetrating spool with a sealing flange ring shall be embedded; the sealing flange ring shall be made of steel plate thicker than 3 mm ... with a flange height of 30 mm to 50 mm; the joint between the sealing flange ring and the spool shall be fully welded; the ring shall sit at the middle of the wall thickness and be welded to the surrounding structural rebar"; "the airtight duct spool shall be welded from 3 mm steel plate with full, even, tight welds ... and shall project beyond both wall faces by more than 100 mm" - this corresponds to the Type III practice.
• DB11/T 1490-2017 clause 5.13.4: "where pipes pass through protective airtight partition walls, an airtight wall-penetrating sleeve or spool with sealing flange ring and blast-resistance plate shall be embedded; where pipes pass through airtight partition walls, an airtight wall-penetrating sleeve or spool with sealing flange ring shall be embedded"; "the airtight duct spool shall be welded from steel plate 2 mm to 3 mm thick"; "the sleeve sealing flange ring shall be made of steel plate not thinner than 10 mm; the spool sealing flange ring shall be made of steel plate not thinner than 3 mm"; "the sealing flange ring shall sit at the centre of the wall thickness and be welded to the surrounding structural rebar"; the filler length shall be 3 to 5 times the pipe diameter and not less than 100 mm.

6. Water / electrical side comparison: airtight wall-penetrating sleeves for water supply, drainage, cables and wires take table C.4.99-2 "civil-defence wall-penetrating airtight sleeves" (e.g. C4-11-412 galvanised steel pipe within DN50, unit "piece", work content including sealing-rib fabrication and installation, packing with airtight material, fitting blast-resistance plates and bolts etc.) - a different table from the ventilation duct sleeves (unit "piece" as counted here), and the two must not be mixed.

Applicability Boundaries

• Region and edition: this card rests on Beijing DB11/T 2382-2024, Annex C general building services works; other provinces have different item codes, contents and measurement positions and must not be applied directly.
• Selection premise: Type I for ducts (embedded duct sections) cast directly into reinforced concrete walls (protective airtight walls, one-pass civil embedding); Type III for airtight partition wall cases with an embedded spool and the duct connected after. Selection follows the wall-penetration detail on the design drawings; picking the wrong type changes the content markedly (at equal diameter, Type III labour is about 1.7 to 2.7 times Type I).
• Measurement position: per "piece" (one per penetration), not by steel-plate mass, duct developed area or sleeve length.
• This card covers only ventilation duct airtight sleeves (C7-11-68 to 70, C7-11-72 to 74); water, cable and wire side sleeves are priced separately under the civil-defence wall-penetrating airtight sleeve tables of the C.4 volume (e.g. C4-11-412), with different units and positions, and must not be mixed with this table.
• Material price-difference adjustment, design-change conversions and other unfinished matters follow the general notes of the standard and its companion pricing documents; DB11/T 1490-2017, DB11/T 1832.15-2022 and DB11 994-2021 are acceptance and design requirements, usable to check the practice and the type selection, but not directly as a pricing basis.

Further Reading

• DB11/T 2382-2024 Construction Works Consumption Quota Standard, Annex C general building services works: table C.7.59-3 "civil-defence components and others" (C7-11-68 to 70, Type I); table C.7.60 "pipes through airtight walls" (C7-11-72 to 74, Type III); table C.4.99-2 "civil-defence wall-penetrating airtight sleeves" (C4-11-412 etc.).
• DB11/T 1490-2017 Technical Specification for Acceptance of Protective Equipment Installation in Civil Air Defence Works, clause 5.13.4 (installation acceptance of airtight sleeves and spools: materials, ring dimensions, filler length, inspection method).
• DB11/T 1832.15-2022 Construction Technology Code for Building Works, Part 15: ventilation and air-conditioning installation, clause 6.4.19 (duct system installation in civil-defence zones).
• DB11 994-2021 Design Code for Civil Air Defence Works Combining Peacetime and Wartime Use, clause 5.2.20 and its commentary (ducts through protective airtight walls; the national standard drawing collection Ventilation Design for Civil Air Defence Basements 07FK02 also carries three protective airtight wall-penetration pipe details).
• Beijing Municipal Housing and Urban-Rural Development Commission website, engineering cost section (the publication channel for the consumption standard and other local standards): https://zjw.beijing.gov.cn/bjjs/gczj14/xhlbz/index.shtml https://zjw.beijing.gov.cn/bjjs/gczj14/zjzbbz/index.shtml