| # | Code | Description | Unit | Qty | Rate (₹) | Amount (₹) |
|---|---|---|---|---|---|---|
| 1 | 2.8.1 | ExcavationEarth work in excavation by mechanical means (Hydraulic excavator) / manual means in foundation trenches or drains (not exceeding 1.5 m in width or 10 sqm on plan), including dressing of sides and ramming of bottoms, for all lift, including getting out the excavated soil and disposal of surplus excavated soil as directed, within a lead of 50 m. — All kinds of soil. | Cum | 3.08 | 260.30 | 801.72 |
| 2 | 4.1.10 | Pcc BedProviding and laying in position cement concrete of specified grade excluding the cost of centering and shuttering - All work up to plinth level : — 1:5:10 (1 cement : 5 coarse sand (zone-III) derived from natural sources : 10 graded stone aggregate 40 mm nominal size derived from natural sources) | Cum | 0.16 | 6,518.60 | 1,042.98 |
| 3 | 6.4.2 | Brick WallsBrick work with common burnt clay F.P.S. (non modular) bricks of class designation 7.5 in superstructure above plinth level up to floor V level in all shapes and sizes in : — Cement mortar 1:6 (1 cement : 6 coarse sand) | Cum | 1.08 | 9,105.95 | 9,834.43 |
| 4 | 4.10 | DpcProviding and laying damp-proof course 40 mm thick with cement concrete 1:2:4 (1 cement : 2 coarse sand (zone-III) derived from natural sources : 4 graded stone aggregate 12.5 mm nominal size derived from natural sources) | Sqm | 0.83 | 410.85 | 341.01 |
| 5 | 5.3 | Rcc Cover SlabReinforced cement concrete work in beams, suspended floors, roofs having slope up to 15° landings, balconies, shelves, chajjas, lintels, bands, plain window sills, staircases and spiral stair cases above plinth level up to floor five level, excluding the cost of centering, shuttering, finishing and reinforcement with 1:1.5:3 (1 cement : 1.5 coarse sand(zone-III) derived from natural sources : 3 graded stone aggregate 20 mm nominal size derived from natural sources). | Cum | 0.13 | 11,505.50 | 1,495.72 |
| 6 | 5.9.3 | Centering SlabCentering and shuttering including strutting, propping etc. and removal of form for — Suspended floors, roofs, landings, balconies and access platform | Sqm | 1.28 | 927.25 | 1,186.88 |
| 7 | 5.22.6 | SteelSteel reinforcement for R.C.C. work including straightening, cutting, bending, placing in position and binding all complete upto plinth level. — Thermo-Mechanically Treated bars of grade Fe-500D or more. | Kg | 12.83 | 107.85 | 1,383.72 |
| 8 | 13.1.2 | Plaster Int12 mm cement plaster of mix : — 1:6 (1 cement: 6 fine sand) | Sqm | 3.96 | 333.35 | 1,320.07 |
| 9 | 7132 | Manhole CoverCircular shape 450 mm dia precast R.C.C. manhole cover with frame - L.D. - 2.5 | Each | 1.00 | 610.00 | 610.00 |
| 10 | HDPE.AIR.VL | Air Valve SmallAir valve 50 mm + chamber. | Each | 1.00 | 14,500.00 | 14,500.00 |
| Your inputsAir valve ⌀ 50 mm · Orifice type Double-orifice · Chamber depth 1 m · chambers 1 | TOTAL | ₹32,517 | ||||
- Air valve sizing rule: **valve dia = main pipe dia / 8 to 1/12** (per CPHEEO Manual Chapter 9). 200 mm main → 25-50 mm air valve; 500 mm main → 65-100 mm air valve. The dropdown defaults to typical pairings.
- Place air valves at every high point of the longitudinal profile + every change of slope > 1 in 200 + every 500 m on long horizontal runs. A 5-km transmission main typically needs 5-8 AVCs.
- Single-orifice valves release trapped air bubbles during normal operation only. Double-orifice valves additionally admit air during emptying (preventing dangerous vacuum that can collapse thin-wall pipe). **Always use double-orifice on transmission mains ≥ 250 mm** — single-orifice is acceptable on small distribution mains where shutdown for repair is brief.
- MJP SSR rates: 50 mm single-orifice flanged PN-1 air valve = ₹1,669 + chamber estimate (HDPE.AIR.VL all-in @ ₹14,500); 80 mm double-orifice = ₹9,355 + chamber (DI.AIR.VALVE all-in @ ₹28,000). For 100 mm — interpolate from MJP SSR p175 items 5a/6a/7a tables.
- Chamber dimensions are smaller than sluice-valve chambers — air valves are vertical-axis components with smaller footprint. Default 0.65 × 0.50 m inside is adequate for 50 mm valve; 0.85 × 0.65 m for 80 mm.
- Excludes: bypass nipple (50 mm dia, 300 mm long, connecting main pipe to AV body — typically supplied with valve, included in MJP rate); air-relief vent pipe above ground (some specifications require a 50 mm GI pipe extending 1 m above NGL); cathodic protection in salt-spray coastal areas.
An **Air Valve Chamber (AVC)** is a small brick-masonry chamber housing the air-release / air-admission valve at every high point on a water-supply main. **Air trapped at high points** restricts flow + causes pressure surges + accelerates corrosion; **vacuum during emptying** can collapse thin-wall pipe like a soft-drink can. The air valve solves both problems automatically: a float opens the orifice when air accumulates, and (in double-orifice designs) admits air when negative pressure develops. **Standard JJM practice** places AVCs at every high point and every 500 m on long horizontal runs per **IS 14845 + CPHEEO Manual Chapter 9**. This Builder generates the per-chamber BOQ — multiply by chamber count across your scheme.
Single-orifice vs double-orifice — which to use
**Single-orifice air valve** (small orifice, typically 12-25 mm) releases small pockets of dissolved air that accumulate during normal operation. Float drops as water enters → ball opens → air escapes → ball seats again. Adequate for distribution mains where occasional shutdown for repair is brief + small. **Double-orifice air valve** has both a small orifice (continuous air release during operation) AND a large orifice (50-100 mm, admits air during emptying). When pipeline is drained for repair, pressure drops below atmospheric → large orifice opens → air rushes in → pipe stays at atmospheric pressure (no collapse). **Always specify double-orifice on transmission mains ≥ 250 mm** — IS 14845 mandate. Single-orifice is acceptable on small distribution mains (≤ 150 mm) where drainage events are brief + supervised.
Where to place AVCs
**Rule 1 — every high point.** Walk the longitudinal profile; air collects at every local maximum, no matter how small. Skipping one high point means a flow restriction that the operator can't diagnose. **Rule 2 — every change of slope > 1 in 200.** Even on a downhill run, a change from steeper to flatter slope creates a 'soft' high point that traps air. **Rule 3 — every 500 m on long horizontal runs.** Theoretically you don't need AVCs on flat sections, but pipe-laying tolerance creates micro-undulations; periodic AVCs flush these. **Rule 4 — at every dead end** (gives a controlled flushing point). A typical 10-km transmission main has 12-20 AVCs; a typical JJM village distribution network 40-60 AVCs depending on terrain.