Measurement rules for the matching flanges of flanged valves: in water supply/drainage, heating and gas works the flanges are not applied separately, while in industrial-pipeline works the valve and its matching flanges are calculated separately (DB11/T 2382-2024)

Topic Positioning

This card answers a high-frequency dispute in applying consumption standards: when a flanged valve is installed, must the matching flanges connecting it to the pipe be applied under separate flange-installation sub-items? The basis is the Beijing local standard DB11/T 2382-2024 "Construction Consumption Standard", general installation works - the rules of the water-supply/drainage/heating/gas system and the industrial-pipeline system are exactly opposite; the card serves to prevent omissions and duplicate pricing in budget compilation.

Core Conclusions

1. Water supply and drainage, heating and gas works: no separate flange application.

• 6.10.49: "The construction consumptions of flanged valves may be compiled assuming flange connections on both sides; where only one side is flanged, the flange and bolt quantities shall be halved." The flanged-valve sub-items are thus compiled on the both-side flange-connection basis; the pipe-side matching flanges and bolts are included in the valve installation sub-item; with only one flanged side, the "halving" adjusts the flange and bolt contents inside the sub-item and is not a separate flange-installation sub-item.
• 6.10.48: "The construction consumptions of valve installation shall include the sampling-inspection work of strength and tightness tests before valve installation."
• 6.10.52: "Medium- and high-pressure valve installation shall be executed under the corresponding items of industrial-pipeline works." - medium/high-pressure valves within the water-supply-and-drainage volume revert to the industrial-pipeline "calculate separately" basis.

2. Industrial-pipeline works: flange-installation sub-items must be applied separately.

• 6.8.54: "The installation of all flanged valves and the installation of the matching flanges shall have their quantities calculated separately." The valve and the matching (pipe-side) flange are two independent sub-items, measured separately.
• The valve sub-item does not include installation of the flange body: the work content of low-pressure flanged-valve sub-item C8-7-13 is "preparation, valve shell pressure test and seal test, valve installation, bolting with molybdenum disulfide coating", with the note "flanged-valve installation includes the installation of one gasket and one set of flange bolts; the gasket material shall be determined by the design; the bolt material consumption is charged separately".
• Consumption basis of the flange-installation sub-items (6.8.67): "The construction consumptions of low-pressure flange installation shall include the installation of one gasket, one set of flange bolts and blank plates (blinds), and shall not include cold/hot re-tightening during system commissioning after installation."
• Adjustment rules, 6.8.68 (original text): "For stub-end lapped flanges of stainless steel and non-ferrous metals, the corresponding lapped-flange installation items apply; for fully heated jacketed flanges, the items for the inner-pipe flange diameter apply with the construction consumptions multiplied by 2.00; for single-flange installation, the corresponding flange-installation items apply with the consumptions multiplied by 0.61, the bolt quantity unchanged; throttle (flow-restriction) devices execute the flange-installation items with the consumptions multiplied by 0.70; welded blank plates (heads) execute the pipe-fitting connection items with the consumptions multiplied by 0.60."
• 6.8.69: "Quantities of all flange installations shall be calculated by the numbers shown on the design drawings." 6.8.70: "For pipes connected by flanges, the pipe and the flange shall have their quantities calculated separately."
• Bolts: 6.8.55 "the bolt specification and quantity shall be determined by the design"; 6.8.71 directs bolt calculation to Clause 6.8.55.
• Medium and high pressure, same basis: 6.8.73 and 6.8.77 - the medium- and high-pressure flange-installation consumptions likewise "shall include the installation of one gasket, one set of flange bolts and blank plates"; 6.8.74 - "for single-flange installation the corresponding flange-installation items apply with the consumptions multiplied by 0.61, the bolt quantity unchanged; ... medium-pressure threaded flanges execute the low-pressure threaded-flange items with the consumptions multiplied by 1.20; medium-pressure slip-on welded flanges execute the low-pressure slip-on items with the consumptions multiplied by 1.20"; 6.8.79 refers execution to Clauses 6.8.69 and 6.8.70.

3. Omission/duplication checks.

• The flanges shipped on the valve body: priced with the valve material; installation not counted in either system.
• The pipe-side matching flanges (including the flanges on both sides of wafer-type valves): in the water-supply/drainage/heating/gas system they are included in the valve-installation sub-item - do not re-apply; in the industrial-pipeline system they must be applied under separate flange-installation sub-items.
• Common errors: in industrial pipelines applying only the valve and omitting the matching flanges = omission; in the water-supply system re-applying flange installation for a flanged valve = duplicate pricing.

Applicable Boundaries

• These rules come from Chapter 6 of the Beijing local standard DB11/T 2382-2024 (general installation works); the volume-note bases of other provinces'/cities' standards or the national unified quota may differ - verify the volume/chapter notes and sub-item work content of the applicable standard before cross-region use.
• "No separate flange application" is limited to flanged-valve items of the water-supply/drainage/heating/gas system; the industrial-pipeline system (including medium/high-pressure valves within the water volume) requires the valve and the matching flanges to be measured separately.
• Content halving and the coefficient adjustments (0.61, 1.20, 2.00, 0.70, 0.60 etc.) are consumption-adjustment rules, not new sub-items; apply coefficients per the original text of the standard.
• Wafer-type valves (wafer butterfly valves, wafer check valves etc. whose bodies carry no flange): in the industrial-pipeline system both pipe-side connections are matching flanges, counted under flange-installation sub-items; in the water system they are covered by the two-side flange content of the valve sub-item.
• Flange and bolt materials are quantified per the design; bolt specification and quantity per Clause 6.8.55.

Further Reading

• DB11/T 2382-2024 Chapter 6 "General Installation Works", 6.10 water supply/drainage, heating and gas works, VI "Valves and pipe accessories", 6.10.47 to 6.10.60 (esp. 6.10.49 and 6.10.52).
• The same standard, 6.8 industrial-pipeline works: VIII "Low-pressure valve installation" 6.8.48-6.8.55; XI "Low-pressure flange installation" 6.8.66-6.8.71; XII "Medium-pressure flange installation" 6.8.72-6.8.75; "High-pressure flange installation" 6.8.76-6.8.79.
• Appendix C, general installation works, Table C.8.49 "Low-pressure flanged valves", sub-item C8-7-13 (example of work content and consumption composition, incl. the gasket-included / bolts-charged-separately basis).
• Related extensions: 6.8.50 (valve shell pressure and seal tests - where no test is done, the consumptions of the corresponding items are multiplied by 0.60); 6.10.51 (solenoid valves, filters, steam traps and pressure-reducing valves execute the valve-installation items, with their labor coefficient provisions).