Borewell Cluster
IS 4270 Borewell Casing Pipe — sizes, threading, depth ratings
Buyer guidance for MS steel water-well casing, threaded joints, slots, wall thickness, and safe depth selection.
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IS 4270 casing pipe is mild-steel water-well casing used to hold a drilled bore open, protect the pump chamber, and screen the aquifer. Buy it by OD, wall thickness, plain or slotted length, square-threaded couplings, coating, MTC, and expected planned depth safely.
Which IS 4270 casing size should procurement specify for a new borewell?
Specify casing by drilled bore diameter, pump outside diameter, expected yield, and depth. Most farm wells use 150-200 mm casing; commercial bores may use 250-300 mm. Keep enough annular clearance for gravel packing, straightness, and pump removal during maintenance later.
IS 4270 is the steel casing standard buyers should cite when the well design calls for mild-steel tubes instead of PVC. The purchase line should not say only “6 inch bore pipe”; it should state OD in millimetres, wall thickness, length, threaded-and-coupled ends, and whether each piece is plain, slotted, or blank casing. Nominal Bore is only a shorthand. For fitment, outside diameter and coupling OD decide whether the assembly passes through the drilled hole without binding.
The Central Ground Water Board drilling guidance separates the well into blank casing above the water-bearing formation and screened or slotted pipe across the aquifer. Procurement should therefore split the order into blank lengths and slotted lengths instead of asking the fabricator to slot everything. Over-slotting weakens the string and lets fines enter the pump. Under-slotting restricts inflow and can burn the submersible motor during summer drawdown.
For RP Sales RFQs, include the drilling contractor’s bore log or at least the target depth band. Shallow alluvial wells can often use lighter casing, while rocky or caving formations require heavier wall and better thread condition. IS 4270 gives the manufacturing basis; final selection still depends on local hydrogeology and the contractor’s responsibility for well design.
How much wall thickness is enough for shallow, medium, and deep borewells?
Wall thickness rises with collapse load, handling abuse, and joint stress. Use lighter 4-5 mm sections only for shallow stable formations. Medium and deep wells normally justify 5-8 mm casing, especially where gravel packing, hammering, or crooked bores are expected.
Depth rating is not a single catalogue number because groundwater wells fail from a combination of external formation pressure, installation damage, corrosion, and poor joint make-up. A 150 mm pipe that survives at 80 m in stable alluvium may deform in a collapsing clay lens or a crooked hard-rock bore. That is why the RFQ should carry a depth band rather than a generic “standard wall” request.
As a procurement rule, choose wall thickness for the worst operation the pipe will see, not just static service. Casing is lifted, clamped, lowered, sometimes hammered, and rotated. Threaded ends take concentrated stress. Heavier wall gives more thread engagement and more forgiveness if the bore is slightly out of line. It also adds weight, freight, and lowering effort, so do not overspecify deep-well wall for a shallow seasonal irrigation bore.
Ask for the MTC, heat number traceability, and straightness check. For saline zones, specify galvanised or coated casing separately; zinc or coating improves corrosion life but does not compensate for inadequate wall thickness. The CGWB manual’s construction logic—proper diameter, correct screen placement, and sanitary sealing—matters as much as pipe mass per metre.
Should IS 4270 casing be plain end, bevel end, or threaded and coupled?
Threaded-and-coupled casing is usually safest for field installation because joints can be assembled quickly without site welding. Plain or bevel ends suit welded strings but increase leak, alignment, and coating-repair responsibility. Confirm thread and coupling supply before dispatch approval.
Most water-well steel casing is ordered threaded and coupled because drilling crews can make up the string with chain wrenches and lower it progressively. Square-shoulder threads are common in the Indian borewell market. The purchase order should state that one coupling per length is included, threads are protected during transit, and damaged male ends will be rejected before loading.
Bevel end is a welding preparation, not a borewell thread. It may make sense when a contractor insists on welded joints, but site welding introduces fit-up variation, weld-quality risk, and bare-metal heat-affected zones that need coating repair onsite welding. Welded joints are also harder to dismantle if the top section has to be modified later repair.
Threaded joints reduce site time but only if dimensions are compatible across the full lot. Avoid mixing mills unless coupling interchangeability is checked. A small thread mismatch can leak fines, seize during make-up, or leave the casing string crooked. For critical wells, ask the supplier to trial-fit sample pieces before dispatch and photograph the thread protection.
What inspections should be checked before accepting IS 4270 casing pipe?
Check OD, wall, length, straightness, slot pattern, thread engagement, coupling quantity, coating condition, heat number, and MTC. Reject crushed ends, incomplete slots, visibly oval pipe, damaged threads, and mixed lots without traceability because installation failures are expensive underground later today.
Incoming inspection should start on the truck. Measure a sample of OD and wall thickness, count pieces and couplings, and compare heat numbers with the MTC. Confirm that slotted pieces match the marked water-bearing zone lengths. If slots are cut too close to the threaded end, the joint becomes a weak point precisely where the casing sees handling stress.
Thread inspection is practical: make a coupling up by hand for a few turns, then with the proper wrench. It should not cross-thread, wobble, or bottom out immediately. Keep thread protectors until the pipe reaches the bore site. Transport damage is common on long steel lengths, and a crushed male end can stop drilling work even if the pipe body is correct.
Documentation matters because borewell failures are buried. If a casing collapses or corrodes early, heat-level traceability, MTC chemistry, and visible dimensions are the buyer’s evidence. RP Sales therefore quotes IS 4270 casing with MTC by default and can coordinate third-party inspection for tenders or institutional groundwater works.
Specifications
| Entity | IS 4270 mild-steel borewell casing pipe |
|---|---|
| Size range | 100-300 mm OD typical; 150, 180, 200, 250 and 300 mm common |
| Wall / pressure attribute | 4-8 mm typical; selected for depth, collapse risk, and handling load |
| Threading attribute | Square-threaded and coupled; plain or bevel end only when welding is specified |
| Screen attribute | Blank casing above formation; slotted lengths across aquifer per bore log |
| Documentation | MTC, heat number, dimensional check, coupling count, coating note |
Standards cited for IS 4270 Borewell Casing Pipe
Reference standards cited on this page
- IS 4270 — Steel tubes used for water wells — specification (Bureau of Indian Standards)
- IS 12818 — Unplasticized PVC screen and casing pipes for bore/tube wells (Bureau of Indian Standards)
- CGWB Drilling Manual — Manual on construction and maintenance of tube wells (Central Ground Water Board)
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