| S.No. | Checkpoint | IS Requirement | Status |
|---|---|---|---|
| A. PIPE MATERIAL & CERTIFICATION | |||
| A1 | Pipe material is certified (ISI mark or equivalent); invoice/certificate matches pipe specifications Acceptance: ISI mark visible on pipe, test certificate provided, material type matches design drawings, diameter/pressure verified | Cl. 3.1 — Material certification | OK NC NA HOLD |
| A2 | Pipe is not dented, cracked, or deformed; no visible damage or defects Acceptance: Pipe surface smooth, no dents > 2mm depth, no cracks or discoloration, ISI mark intact | Cl. 4.1 — Physical condition | OK NC NA HOLD |
| A3 | Pipe coating/interior lining intact and free from corrosion (for GI/MS pipes) Acceptance: GI coating continuous, no rust/pitting visible, internal coating applied if required, no bare metal exposed | Cl. 5.2 — Coating protection | OK NC NA HOLD |
| B. TRENCH PREPARATION & LAYING | |||
| B1 | Trench bottom is firm, leveled, and free from sharp objects; minimum cushioning layer 100 mm sand/gravel provided Acceptance: Trench bottom compacted (soft spots removed), 100 mm sand cushion layer installed, no sharp stones | Cl. 6.1 — Trench preparation | OK NC NA HOLD |
| B2 | Pipe is laid on sand cushion; gradient/slope is as per design (typically 1:100 to 1:200 for horizontal runs) Acceptance: Pipe gradient checked with level/theodolite, slope within design range, documented on as-laid drawing | Cl. 6.2 — Gradient design | OK NC NA HOLD |
| B3 | Pipe depth is minimum 0.75 m below finished ground level (to avoid freeze-thaw and surface damage) Acceptance: Measured depth ≥ 0.75 m from FGL, documented with depths at key points, recorded on as-laid drawing | Cl. 6.3 — Burial depth | OK NC NA HOLD |
| B4 | Pipe spacing from parallel lines maintained: min. 0.3 m from sewerage, 0.5 m from electrical/gas underground Acceptance: Clearances verified on site with measuring tape, non-crossing layout confirmed, parallel routing ≥ 0.3 m apart | Cl. 7.1 — Service co-ordination | OK NC NA HOLD |
| B5 | Pipe is not laid under/over structures or in corrosive soils without protection (chemical analysis if required) Acceptance: Layout avoids structures, corrosive soils analyzed if suspected, wrapping/coating applied per requirement | Cl. 7.2 — Environmental protection | OK NC NA HOLD |
| C. PIPE SUPPORT & PROTECTION | |||
| C1 | Support layer (sand + fine gravel) placed over pipe, minimum 150 mm thickness before backfill Acceptance: Support layer 150 mm thick, compacted properly, free from large stones, even distribution along pipe | Cl. 6.4 — Support layer | OK NC NA HOLD |
| C2 | Backfill material is suitable (soil without stones >50 mm); compacted in layers of 200 mm maximum Acceptance: Backfill material free from large stones/debris, compacted in 200 mm layers, compaction degree 90% standard Proctor | Cl. 6.5 — Backfill and compaction | OK NC NA HOLD |
| C3 | Above-ground pipe runs protected with insulation jacket (if exposed to sun/temperature); support brackets at 1.5-2.0 m intervals Acceptance: Insulation jacket applied on exposed runs, UV protection provided, support brackets bolted securely at ≤ 2.0 m spacing | Cl. 8.1 — Above-ground protection | OK NC NA HOLD |
| C4 | In freeze-prone areas, pipe is buried below frost line or insulated (consult local frost depth) Acceptance: Pipe depth ≥ frost line depth (if applicable), OR thermal insulation applied with R-value per design, documented | Cl. 9.1 — Freeze protection | OK NC NA HOLD |