EXISTING CANAL 16'-0"EXISTING CANAL 16'-0"KITCHEN / BACK OF HOUSEBETHLEHEM HALLCHURCHCOURTYARDHEALTH WINGS · 7 × DN200 · 42.1 mN · 8 × DN200 · 40.5 mC · 5 × DN200 · 35 mTSTNTCOH-SOH-NOH-CENTRYENTRYSITE 380'-0" × 94'-0" / 115.8 × 28.65 m94'-0" / 28.65 m
HERITAGE COMMUNITY CENTER · KARAMCHEDU, CHIRALA
COVER · SUMMARY · VERDICT
CONCEPT DESIGN — NOT FOR CONSTRUCTION · 09 NOVEMBER 2026 · REV A
Canadian well (earth–air tunnel) · Option 1 · health wing, Bethlehem Hall, church
SCALE
NTS
DRAWING
CW-00
OPTION 1 · HEALTH WING · BETHLEHEM HALL · CHURCH
CANADIAN WELL
Earth–air tunnel cooling
Three buried pipe banks, two shaded strips and a west garden. No refrigerant, no water, no sealed building — filtered fresh air cooled by the ground at 2.4–3.0 m, delivered low where people sit.
THE VERDICT, HONESTLY
At this latitude the ground at 2.7 m sits at 28.4–30.8 °C all year. The banks deliver air at 31.3–33.0 °C when it is 39.8 °C outside — a 6.8–8.4 K drop at the hours heat stress peaks — on 646 W of fan power. In the monsoon the ground and the air converge, so the system is sealed and off. This is pre-cooling and fresh air, not air-conditioning.
10.7
kW sensible at the May peak
8.4
K below ambient, largest drop
4,290
m³/h of filtered fresh air
646
W of EC fan power, all three
THREE BANKS, ONE SYSTEM
Zone
Pipes
Length
Sensible
Fan
S
Health wing
7 × DN200
42.1 m
3.9 kW
220 W
N
Bethlehem Hall
8 × DN200
40.5 m
4.2 kW
266 W
C
Church
5 × DN200
35.0 m
2.6 kW
160 W
Go / no-go
The scheme stands or falls on groundwater. Pipes must sit at least 0.5 m above the highest water table. Two test pits — late May and late November — before tender. If the post-monsoon table is below 2.9 m, the pipes are not built and the design switches to a closed water loop in a borehole.
KEY PLAN · THREE BANKS · DIAGRAMMATIC
Blue: pipe banks · brown: intake towers TS/TN/TC and header chambers · green: supply ducts. Not to scale; set out from the architect's grid.
SHEET INDEX
CW-00
Cover, summary & verdict
CW-01
Climate & ground basis
CW-02
Site layout — banks, towers, chambers
CW-03
Long section & trench sections
CW-04
Intake tower, outlet chamber, diffuser
CW-05
Distribution — health, hall, church
CW-06
Sizing calculations & performance
CW-07
Controls, O&M, risks & cost
CW-08
Church bank — plan, section, cost
Basis: IMD 1991–2020 normals for Ongole; ground-wave model for moist sandy-clay loam; Option 1 room schedule dated 10 August 2026. Concept accuracy ±1–1.5 K.
2025303540JanMarMayJulSepNovambient max10–17 hsoil 2.7 mN outS outC out
HERITAGE COMMUNITY CENTER · KARAMCHEDU, CHIRALA
CLIMATE · GROUND · GO / NO-GO
CLIMATE & GROUND BASIS
IMD Ongole 1991–2020 · annual-wave ground model
CONCEPT DESIGN — NOT FOR CONSTRUCTION · 09 NOVEMBER 2026 · REV A
Canadian well (earth–air tunnel) · Option 1 · health wing, Bethlehem Hall, church
SCALE
NTS
DRAWING
CW-01
Twelve months
Ambient, dew point and ground temperature at three depths. Shaded columns are months the system runs.
T max
T min
10–17
RH
Dew
Soil 2.0
Soil 2.7
Soil 4.0
S out
N out
C out
Jan
30.5
19.5
27.0
70
24.4
30.9
30.4
29.6
—
—
—
Feb
32.5
21.8
28.8
60
23.7
30.3
30.0
29.6
30.8
31.0
30.6
Mar
35.5
24.5
31.6
55
25.1
29.4
29.4
29.5
31.3
31.8
31.0
Apr
37.8
26.5
33.9
50
25.6
28.3
28.7
29.5
31.5
32.3
31.1
May
39.8
28.0
35.7
45
25.6
27.5
28.4
29.4
31.9
33.0
31.4
Jun
37.5
27.5
34.0
50
25.3
27.8
28.6
29.5
31.4
32.2
30.9
Jul
34.5
26.5
31.4
65
27.0
28.6
29.0
29.5
30.7
31.2
30.4
Aug
33.5
26.0
30.6
70
27.3
29.4
29.5
29.5
30.7
31.1
30.5
Sep
33.0
25.5
30.2
75
28.0
30.3
30.0
29.6
30.9
31.2
30.8
Oct
32.0
24.0
29.3
75
27.0
31.1
30.5
29.6
—
—
—
Nov
30.5
21.5
27.7
70
24.4
31.6
30.8
29.6
—
—
—
Dec
29.5
19.5
26.8
70
23.5
31.4
30.7
29.6
—
—
—
All temperatures °C. Soil at 2.7 m is the design source; 2.0 m and 4.0 m bracket it. Outlet temperatures are daytime design values with daytime-only running.
Ambient vs ground vs outlet
Groundwater — the go / no-go test
Post-monsoon table
Decision
> 3.5 m
Build as drawn. Inverts −3.00 to −1.90 m.
2.9–3.5 m
Raise inverts to 1.9–2.4 m, add 15 % pipe, outlet +0.8 K.
< 2.9 m
Do not bury pipes. Closed loop in a borehole / sump feeding a fan-coil.
Canal-irrigated coastal plain: water commonly at 2–5 m and it rises after the NE monsoon. Measure late May and late November. Pipes must stay 0.5 m above the highest table.
How the ground behaves here
—
Annual mean air 29.6 °C; first-harmonic amplitude ±3.5 K.
—
Damping depth of moist soil 2.45 m. At 2.7 m the annual swing is only ±1.2 K and arrives ~2.1 months late — so May, the hottest month, is close to the coolest ground (28.4 °C).
—
Below 4 m nothing is gained: the ground is ~29.5 °C all year.
—
Shade matters. Under sun-baked paving the mean is ~1 K higher. The south bank sits under tree canopy; the north bank under the cobble drive and Kanuga avenue (+0.8 K allowed).
—
Moist soil conducts roughly twice as well as dry. Drip-irrigate the groundcover over the banks March–June from the RWH sump.
—
Dew point at the afternoon peak stays at least 1 K below soil temperature in the run months, so the pipes cool the air sensibly and stay dry. October–December the margin collapses: off.
OPERATING RULE
Run when the outlet is at least 3 K cooler than ambient at the afternoon peak, the outdoor dew point is at least 1 K below the pipe-soil temperature, and the zone is scheduled. Night and Sunday: off, so the soil recovers. October–January: sealed.
DESIGN VALUES ADOPTED
Ground at 2.7 m, May
28.4 °C
Ground at 2.7 m, annual mean
29.6 °C
Design ambient, May peak
39.8 °C
May dew point
25.6 °C
Soil conductivity (assumed)
1.5 W/m·K
EXISTING CANAL 16'-0"EXISTING CANAL 16'-0"KITCHEN / BACK OF HOUSEBETHLEHEM HALLCHURCHCOURTYARDHEALTH WINGS · 7 × DN200 · 42.1 mN · 8 × DN200 · 40.5 mC · 5 × DN200 · 35 mTSTNTCOH-SOH-NOH-CENTRYENTRYSITE 380'-0" × 94'-0" / 115.8 × 28.65 m94'-0" / 28.65 mN05101520 m5 × DN200 @ 600 c/c35.0 m · invert −2.30 → −1.90 · fall 1.5 % to sumpTCOH-C
HERITAGE COMMUNITY CENTER · KARAMCHEDU, CHIRALA
LAYOUT · OPTION 1 · DIAGRAMMATIC SET-OUT
SITE LAYOUT
Banks, intake towers, header chambers & supply routes
CONCEPT DESIGN — NOT FOR CONSTRUCTION · 09 NOVEMBER 2026 · REV A
Canadian well (earth–air tunnel) · Option 1 · health wing, Bethlehem Hall, church
SCALE
1:400 @ A3
DRAWING
CW-02
Three banks, two shaded strips, one west garden
Pipe bundles are drawn to scale in width and length; the 224' × 51' ground-floor band leaves a 6.5 m strip on each long side. Exact position follows the architect's grid.
LEGEND
Pipe bank — S (health)
Pipe bank — N (hall)
Pipe bank — C (church)
Intake tower / header chamber
Supply duct in plinth
SET-OUT NOTES
·
Banks 1.5 m clear of footings — lay pipes first. Keep 3.0 m from the canal bank; the 10' widening is outside the site line.
·
Excavate February–May, the low-water window. Wellpoint dewatering as contingency.
·
Inverts must stay 0.5 m above the highest recorded water table.
·
Trees at least 1.0 m off the outer pipe, with root barrier on the avenue side.
·
Do not pave the south strip in dark stone. Keep the canopy and groundcover.
·
North bank: SN8 pipe, 2.0 m cover under the drive, D400 covers.
CHURCH BANK — SET-OUT 1:250 (DIAGRAM)
BILL OF GROUND, ALL THREE BANKS
Trench length
117.6 m
DN200 pipe
475 m
Pipes
20
Intake towers
3
Header chambers
6
Excavation
≈ 1,120 m³
Why here
South bank under the only long run of permanent canopy. North bank under the cobble drive, clear of the RWH sump and recharge pits. Church bank in the west garden — the only 35 m run that reaches the church without crossing the health wing — 27 m of plinth duct to the church, checked for static in CW-06.
A · SOUTH BANK — HEALTH WING7 × DN200 · 42.1 m · 414 L/shighest water table (assumed, to be tested)INTAKEOH3.0 m2.4 m0m10m20m30m40mB · NORTH BANK — BETHLEHEM HALL8 × DN200 · 40.5 m · 516 L/shighest water table (assumed, to be tested)INTAKEOH2.7 m2.1 m0m10m20m30m40mS — HEALTH3.4 m4.4 m · 7 × DN200 @ 600 c/cN — HALL3.0 m4.9 m · 8 × DN200 @ 600 c/cC — CHURCH2.6 m3.2 m · 5 × DN200 @ 600 c/c
HERITAGE COMMUNITY CENTER · KARAMCHEDU, CHIRALA
SECTIONS · BANKS & TRENCHES
LONG SECTION & TRENCH SECTIONS
Horizontal 1:150 · vertical 1:100 (1.5× exaggerated)
CONCEPT DESIGN — NOT FOR CONSTRUCTION · 09 NOVEMBER 2026 · REV A
Canadian well (earth–air tunnel) · Option 1 · health wing, Bethlehem Hall, church
SCALE
1:150 / 1:100 / 1:75
DRAWING
CW-03
How the pipes sit in the ground
Vertical scale is exaggerated 1.5× to read the fall and cover. All three banks fall continuously to the intake sump — no sags, no trapped water.
The church bank (C) is drawn in full on CW-08: 5 × DN200, 35.0 m, invert −2.30 → −1.90.
Trench sections
1:75 · seven, eight and five pipes
SPECIFICATION NOTES
·
Pipe: DN200 PE100 SDR26 or antimicrobial-lined PP earth-air pipe, smooth bore, butt- or electro-fusion welded — watertight, root-proof, no joints below the water table.
·
Fall: 1.5 % continuous to the intake sump, laser-levelled. A sag holds water and grows mould.
·
Bedding: 150 mm sand bed, sand haunching, 300 mm over the crown, compacted by hand around the pipe — air gaps kill heat transfer.
·
Cover: ≥ 2.0 m under the drive (SN8), ≥ 1.5 m elsewhere. Warning tape 300 mm above the crown.
·
Test: air-pressure each pipe to 500 Pa for 15 minutes before backfill; CCTV after backfill; record as-built inverts.
·
Dewatering: excavate February–May; wellpoint set as contingency. Do not open trenches in the monsoon.
MANGALORE-TILE CAPRAIN LOUVRES + 2 mm SS MESHG4 SLIDE-OUT FILTEREC PLUG FAN →600+4.0 mSILL +0.45ALGAE-RESISTANT LOUVRELOCKABLE DOORF7DAMPERSUMP600 × 600 × 400 · float pump → recharge pitHEAVY-DUTY COVERHEADERF7floor falls to sumpSWIRL PLATEØ200 BRANCHPLINTH FILLsupply at 21.5 L/s
HERITAGE COMMUNITY CENTER · KARAMCHEDU, CHIRALA
DETAILS · AIR IN, AIR OUT
INTAKE, CHAMBER & DIFFUSER
Tower 1:50 · chamber 1:50 · diffuser 1:20
CONCEPT DESIGN — NOT FOR CONSTRUCTION · 09 NOVEMBER 2026 · REV A
Canadian well (earth–air tunnel) · Option 1 · health wing, Bethlehem Hall, church
SCALE
1:50 / 1:20
DRAWING
CW-04
Four metres of tower, one accessible chamber
INTAKE TOWER TS / TN / TC
section 1:50
OUTLET HEADER CHAMBER OH
plan 1:50 · 1.2 × 3.4 m
section 1:50
FLOOR SWIRL DIFFUSER
1:20 · 600 nominal
WHY THE DETAILS ARE LIKE THIS
Fan in the tower, pushing
Pipes run at slight positive pressure. If a joint leaks, air leaks out — groundwater, soil gas and insects cannot be drawn in. Fan heat is shed before the air reaches anyone.
4 m intake
Above dust, splash and flood, out of reach. G4 pre-filter keeps the pipes clean; F7 at the building end is the last line of defence for clinical rooms.
Storm shutter + damper
Both ends close for cyclone warnings and the Oct–Jan off season, so humid air cannot sit in the pipes.
Sump at the low end
Any condensate or ingress collects in one visible place and is pumped to a recharge pit — never left standing.
Low supply, high exhaust
Floor diffusers release cool air at the feet; it rises as it warms and leaves through the lantern and clerestory jaalis.
Materials
Tower: laterite / CSEB in lime, tiled cap, teak shutter. Chambers: RCC, bitumen tanked. All metalwork SS 316 for coastal salt air.
CORRIDOR 2000 mmREC52 L/sC0152 L/sC0252 L/sC0352 L/sC0452 L/sPHARM52 L/sNURSE52 L/sFEED52 L/sØ355 MAIN IN PLINTH12 TABLES · 2 DIFFUSERS EACH · 21.5 L/sØ400 AISLE12345678PEW ROWS · LOW GRILLES IN PLINTH · 32.5 L/s EACH
HERITAGE COMMUNITY CENTER · KARAMCHEDU, CHIRALA
SUPPLY · OUTLETS · AIRFLOW SCHEDULE
DISTRIBUTION
Health wing · Bethlehem Hall · church
CONCEPT DESIGN — NOT FOR CONSTRUCTION · 09 NOVEMBER 2026 · REV A
Canadian well (earth–air tunnel) · Option 1 · health wing, Bethlehem Hall, church
SCALE
1:150 key plans
DRAWING
CW-05
Low outlets, high exhaust, positive rooms
Every zone is supplied below the window line or at the floor, and exhausted through the building's own stack — courtyard, lantern, clerestory jaalis.
HEALTH WING — 8 OUTLETS · 415 L/s
BETHLEHEM HALL — 24 DIFFUSERS · 516 L/s
CHURCH — 8 GRILLES · 260 L/s
Return: the courtyard and the clerestory. The church sits at slight positive pressure; the sacristy and toilets exhaust separately.
AIRFLOW SCHEDULE
Zone
No.
Type
L/s
Total
L/s/pp
Supply °C
Health wing
8
grille
52
415
4.2
31.9
Bethlehem Hall
24
swirl
21.5
516
3.7
33.0
Church
8
grille
32.5
260
3.7
31.4
TOTAL
40
—
—
1,191
—
—
Fresh-air rates are ventilation-led: 3.7 L/s per seated person in the hall and church, roughly the outdoor-air rate a mechanical system would give these rooms. Health rooms are pressurised with filtered air; toilets keep their own exhaust.
COMFORT, HONESTLY
Supply at 31.4–33.0 °C plus ceiling-fan air movement of ~1 m/s feels like 27–29 °C still air for a seated person in May. Not air-conditioning — but the building stays open.
DUCTS IN THE PLINTH
PVC SN4 ducts in the 600 mm plinth fill, sand-surrounded, laid to fall back to the outlet chamber, cleaning eye at every branch. No insulation — the plinth is already at ground temperature.
HERITAGE COMMUNITY CENTER · KARAMCHEDU, CHIRALA
CALCULATIONS · PERFORMANCE · ENERGY
SIZING & PERFORMANCE
Effectiveness–NTU per bank · May design peak
CONCEPT DESIGN — NOT FOR CONSTRUCTION · 09 NOVEMBER 2026 · REV A
Canadian well (earth–air tunnel) · Option 1 · health wing, Bethlehem Hall, church
SCALE
NTS
DRAWING
CW-06
The numbers behind the three banks
Effectiveness–NTU with a soil-side resistance fitted to the measured behaviour of moist sandy-clay loam at 600 mm spacing.
Parameter
S — health
N — hall
C — church
Pipes
7
8
5
Bore / area
185 mm · 171 m²
185 mm · 188 m²
185 mm · 102 m²
Length
42.1 m
40.5 m
35.0 m
Flow
414 L/s
516 L/s
260 L/s
Velocity
2.2 m/s
2.2 m/s
1.9 m/s
Reynolds
25,400
25,400
22,000
Nusselt / h
60 · 8.5
60 · 8.5
53 · 7.9
U overall
3.44 W/m²K
3.00 W/m²K
4.12 W/m²K
UA
589 W/K
564 W/K
419 W/K
Air capacity
499 W/K
622 W/K
314 W/K
NTU / ε
1.18 / 0.69
0.91 / 0.60
1.34 / 0.74
Outlet, May
31.9 °C
33.0 °C
31.4 °C
Sensible
3.9 kW
4.2 kW
2.6 kW
Fan, EC
220 W
266 W
160 W
Sensitivity
What moves the outlet temperature, in order of influence.
Driver
Effect
Soil temperature
+1 K ground → +0.7 K supply
Pipe length
−20 % → +0.9 K supply
Velocity
1.5 → 2.5 m/s → +0.6 K
Shade / moisture
dry, paved ground → +1.0 K
Spacing
600 → 900 c/c → +0.4 K
ANNUAL ENERGY, DESIGN-CAPACITY METHOD
1,666 scheduled run-hours, Feb–Sep, at an average part-load of 0.7.
Cooling delivered
≈ 7,400 kWh
Fan energy
≈ 1,080 kWh
Seasonal COP
≈ 6.9
Running cost at ₹8/kWh
≈ ₹8,600
Equivalent split AC (COP 3)
≈ 2,470 kWh
CHURCH DUCT — 27 m IN PLINTH
Ø355 at 260 L/s = 2.6 m/s · 0.8 Pa/m · 22 Pa friction + 45 Pa fittings + 30 Pa grilles ≈ 100 Pa. Outlet fan selected at 260 L/s / 350 Pa, 200 W absorbed.
Month by month
Month
T max
Soil
S out
N out
C out
kW
h/day
kWh
Jan
30.5
30.4
—
—
—
—
0
—
Feb
32.5
30.0
30.8
31.0
30.6
2.4
6
279
Mar
35.5
29.4
31.3
31.8
31.0
5.8
8
1,008
Apr
37.8
28.7
31.5
32.3
31.1
8.7
8
1,456
May
39.8
28.4
31.9
33.0
31.4
10.8
8
1,876
Jun
37.5
28.6
31.4
32.2
30.9
8.4
7
1,236
Jul
34.5
29.0
30.7
31.2
30.4
5.2
6
681
Aug
33.5
29.5
30.7
31.1
30.5
3.8
6
498
Sep
33.0
30.0
30.9
31.2
30.8
2.9
6
360
Oct
32.0
30.5
—
—
—
—
0
—
Nov
30.5
30.8
—
—
—
—
0
—
Dec
29.5
30.7
—
—
—
—
0
—
Design-capacity values. kW is the sum of the three banks at that month's ambient and ground temperature; kWh applies the scheduled hours, days and 0.7 part-load. Annual total ≈ 7,398 kWh.
Assumptions and limits
·
Soil conductivity 1.5 W/m·K, diffusivity 0.6 × 10⁻⁶ m²/s — to be confirmed by thermal-needle test.
·
600 mm spacing ≈ 3 D: close enough to fit the strips, wide enough that neighbouring pipes do not share the same soil heat within a season.
·
Daytime-only running lets the soil recover at night. Continuous running would warm the ground and cut output by 20–30 %.
·
Concept accuracy ±1–1.5 K. Verify with a transient ground-tube model once the tests are in.
HERITAGE COMMUNITY CENTER · KARAMCHEDU, CHIRALA
OPERATION · RISK · BUDGET
CONTROLS, O&M, RISKS & COST
One caretaker · three modes · monthly checklist
CONCEPT DESIGN — NOT FOR CONSTRUCTION · 09 NOVEMBER 2026 · REV A
Canadian well (earth–air tunnel) · Option 1 · health wing, Bethlehem Hall, church
SCALE
NTS
DRAWING
CW-07
Simple enough that it actually gets run
Control logic
Condition
Action
Schedule on
Health 09–17 Mon–Sat; hall 11–16 daily; church 07:30–12:30 Sun + override
T amb − T outlet ≥ 2 K
Damper open, fan on; EC speed modulates to hold outlet ≤ 32 °C at ≤ 2.4 m/s
ΔT < 1 K for 30 min
Off, damper closed — natural ventilation only
Outlet RH > 85 % for 10 min
Off + alarm (condensation risk)
Sump high level
Pump on; if still high after 30 min, system off + alarm
Cyclone warning, Oct–Jan
STORM-OFF: fans off, dampers and shutters closed
Dry sunny day, Nov–Jan
30-min purge at midday with low-RH air to dry the pipes
Night & Sunday
Off — soil recovery
Operating calendar
Month
S
N
C
Note
Jan
OFF
OFF
OFF
sealed
Feb
auto
auto
auto
weak
Mar
auto
auto
auto
—
Apr
auto
auto
auto
—
May
FULL
FULL
auto
peak
Jun
auto
auto
auto
—
Jul
auto
auto
auto
—
Aug
auto
auto
auto
—
Sep
auto
auto
auto
—
Oct
OFF
OFF
OFF
sealed
Nov
OFF
OFF
OFF
sealed
Dec
OFF
OFF
OFF
sealed
Risks & mitigation
Risk
Mitigation
High water table
Go / no-go test; welded pipes; sump + pump; build in dry season
Mould / bacteria
Fall to sump, no sags, positive pressure, G4/F7, dry seasonal shutdown, annual CCTV
Humid-season condensation
Dew-point interlock; off Oct–Jan; purge before restart
Cyclone & flood
Intake 4 m high, storm shutters, sealed chambers, sill +0.45, float pumps
Insects / rodents / snakes
2 mm SS mesh, closed dampers when off, sealed chambers
Radon / soil gas
Positive-pressure pipes; leak test at commissioning
Tree roots
Welded joints, root barrier, trees ≥ 1 m off the outer pipe
Under-performance
Daytime-only running, moist shaded surface, data logging, commissioning targets
Indicative cost — 2026, AP, ex-GST
Item
Qty
₹ lakh
Excavation 1.5–3.3 m, shoring, dewatering
≈ 1,120 m³
6.8–9.6
DN200 PE100 / PP pipe, welded, laid & tested
≈ 475 m
10.3–15.0
Sand bedding, backfill, root barrier, tape
item
2.4–3.2
Intake towers, laterite + louvres
3 nos
4.5–6.0
Header chambers, RCC + sumps + pumps
6 nos
6.8–9.0
EC fan + F7 filter + damper set
3 sets
3.8–5.3
Plinth ducts, 40 outlets, diffusers
item
5.0–7.2
Controls, sensors, logging, wiring
item
1.6–2.6
Reinstatement of cobbles & planting
item
1.3–2.0
TOTAL
43–60
Running cost ≈ ₹8,600/yr of fan energy for ≈ 7,400 kWh of delivered cooling. Excavation and dewatering are the swing items — get quotes after the soil tests. Phase S + C first if the budget is tight.
COMMISSIONING TARGETS — MAY
·
Flow within ±10 % of design per bank.
·
Outlet ≤ 33.0 °C (S), ≤ 34.0 °C (N), ≤ 33.0 °C (C) at ≥ 38 °C ambient.
·
Outlet RH ≤ 75 %; no water in the pipes after two weeks of running.
·
Record as-built inverts, flows and temperatures; log the first season.
WHO RUNS IT
The caretaker. A simple controller with three modes — AUTO, OFF, STORM-OFF — and a monthly checklist on a plant-room door. No BMS, no specialist.
Monthly Feb–Sep: G4 filters, both sumps, pump floats.
Quarterly: F7 filters, diffuser baskets, data log (ΔT, RH).
December: CCTV all banks; brush / pig from the chambers; mild disinfectant; dry by purge; service fans.
After any flood or cyclone: inspect chambers, pump out, CCTV before restart.
5 × DN200 @ 600 c/c · 1.5 % fall35.0 m · invert −2.30 → −1.90TCOH-Chighest water tableTCOH-C2.3 m → 1.9 m · 35.0 m5 × DN2003.2 m trench · 2.65 m deep12345678LOW GRILLES IN PEW PLINTH · 32.5 L/s EACH · ≤ 2 m/s FACE50'-10" × 24'-1" · 113.7 m² · 70 seats
HERITAGE COMMUNITY CENTER · KARAMCHEDU, CHIRALA
NEW BANK · CHURCH · OPTION 1
CHURCH BANK
5 × DN200 · 35 m · 260 L/s · 2.6 kW
CONCEPT DESIGN — NOT FOR CONSTRUCTION · 09 NOVEMBER 2026 · REV A
Canadian well (earth–air tunnel) · Option 1 · health wing, Bethlehem Hall, church
SCALE
1:200 / 1:150 / 1:100
DRAWING
CW-08
The room the old package missed
Church 50'-10" × 24'-1", 70 seats, ground floor. A dedicated bank and chamber, 27 m of plinth duct, eight low grilles.
BANK PLAN 1:200
LONG SECTION 1:150 · VERTICAL 1:75
TRENCH 1:50
CHURCH — GRILLE LAYOUT 1:100 · 8 × 32.5 L/s
Church bank — cost delta
Item
₹ lakh
5 × DN200, 35 m, welded
2.6–3.8
Excavation / dewatering
1.2–1.8
Sand, backfill, root barrier
0.6–0.9
Intake tower TC
1.5–2.0
2 header chambers
2.3–3.0
Fan + F7 + damper
1.3–1.8
Ducts, 8 grilles
0.7–1.0
Controls / reinstatement
0.5–0.7
TOTAL ₹10.7–15.0 lakh
PERFORMANCE
Flow
260 L/s
Velocity
1.9 m/s
Outlet, May
31.4 °C
Sensible
2.6 kW
Fan
160 W
Duct
27 m Ø355
Static
≈ 100 Pa
If the 27 m duct exceeds 120 Pa in the final route, add an inline EC fan (200 W) at the chamber — do not upsize the bank.