Codes referenced
Cl 5 materials, Cl 10 production of concrete, Cl 11 formwork and falsework, Cl 12 assembly of reinforcement, Cl 13 placing / compaction / curing, Cl 14 concreting under special conditions, Cl 15 sampling and strength, Cl 16 acceptance criteria, Cl 17 inspection and testing of the structure.
Line, level, plumb tolerances; propping and bracing; release agent.
IS 2502 bar-bending schedule; IS 1786 Fe500/Fe550 mechanical properties.
IS 516 cube compression; IS 1199 sampling and slump.
Seismic zone detailing for rebar spacing, anchorage, and confinement.
ITP structure — columns of an ITP table
A complete ITP table has seven columns per row. Each row is one checkpoint within one activity:
| Column | What it captures |
|---|---|
| Activity | Earthwork, Rebar, Formwork, Concreting, Curing, Stripping |
| Checkpoint | Specific observation — e.g. "cover to rebar", "slump test", "cube cast" |
| Spec / IS clause | Reference — IS 456 Cl 13.2, IS 1199, drawing ref XYZ |
| H / W / R | Hold, Witness, Review designation (see FAQ below for definitions) |
| Acceptance criterion | Quantitative threshold — slump 100 ± 25 mm, cover ≥ 40 mm, cube mean of 4 ≥ 30 + 0.825σ, every cube ≥ 27 |
| Records | Form / register / photograph — delivery ticket, cube register, cover meter log |
| Frequency | Every pour / every 5 m³ / every delivery / per activity |
The ITP is signed by the contractor's QA manager, the consultant's QA engineer, and the client's project manager before the first activity starts. Any change to scope, design, or material triggers an ITP revision with the same approval chain.
Activity 1 — Earthwork and excavation
- Excavation level (H) — check reduced level matches drawing ± 25 mm; verify against benchmark.
- Slope stability (W) — verify batter slope ≤ 1:1 in cohesive soil; side protection in deep excavations.
- Dewatering (W) — confirm pumping rate and disposal; verify no standing water in footing pit.
- Bearing capacity (H) — soil test report from geotech (SBC ≥ design value); plate load test if specified.
- PCC base (W) — blinding concrete 75-100 mm thick M10/M15; level surface for rebar cage.
Activity 2 — Reinforcement (BBS, cutting, bending, fixing)
- Material receipt (R) — IS 1786 test certificate per batch; manufacturer mark rolled on bar.
- BBS per IS 2502 (R) — bar-bending schedule matches drawing; cutting length accounts for hooks and bends per IS 1786.
- Cover blocks (H) — concrete cover blocks (not plastic) of specified thickness; tied with binding wire.
- Spacing and lap (H) — main bar spacing ± 10 mm; lap length per IS 456 Cl 26.2.5.1 — Ld or 30φ, whichever is greater, for flexural tension, 2Ld or 30φ for direct tension, with a straight length of not less than 15φ or 200 mm; staggered splices at centres not less than 1.3 × the lap length.
- Ductile detailing (H) — for seismic zones, IS 13920 Cl 6 / 7 / 8 — 135° hooks, hoop spacing, anchorage.
- Pre-pour rebar approval (H) — full inspection, photographs, sign-off before formwork closure.
Activity 3 — Formwork (per IS 14687)
- Material (R) — plywood / steel / aluminium; release agent type approved.
- Line and level (H) — plumb within 1.5° of vertical and level within IS 14687 Cl 9.7; verify with total station.
- Propping and bracing (W) — props at specified centres; bracing for lateral loads; sole boards on soft ground.
- Tightness and release agent (W) — gaps sealed to prevent grout loss; release agent applied evenly.
- Openings and embedments (W) — sleeves, dovetail slots, inserts positioned and fixed.
Activity 4 — Concreting
- Pre-pour checklist (H) — forms clean, rebar cover verified, waterstops placed, dewatering operational, equipment standby.
- Delivery ticket check (W) — IS 4926 Cl 7.1 compliance; transit time ≤ 90 min.
- Slump per IS 1199 (W) — every delivery or every 5 m³; target slump ± 25 mm.
- Temperature check (W) — fresh concrete ≤ 40°C at placement per IS 7861 (Part 1) Cl 7.1, which IS 456 Cl 14.1 invokes.
- Placing and vibration (W) — lift ≤ 1.5 m, vibrator pattern 100% per IS 456 Cl 13.2.
- Cube cast per IS 516 (Part 1/Sec 1) (H) — 3 specimens per sample, all tested at 28 days; sample frequency per the IS 456 Cl 15.2.2 volume bands.
Activity 5 — Curing (per IS 456 Cl 13.5)
- Curing initiation (H) — within 1 h of finishing; ponding / wet hessian / membrane as specified.
- Curing duration (W) — 7 days for OPC and 10 days for mineral admixtures or blended cements per IS 456 Cl 13.5.1, and 10 days for concrete exposed to dry and hot weather.
- Temperature control (W) — avoid temperature drop > 5°C/h on mass concrete; insulation blankets if needed.
- Curing log (R) — daily log of method, duration, ambient temperature.
Activity 6 — Stripping and finishing (per IS 456 Cl 11.3.1)
- Stripping time (H) — minimum per IS 456 Cl 11.3.1: 16–24 h for vertical formwork to columns, walls and beams; 3 days for the soffit of a slab; 7 days for the soffit of a beam; props to slabs 7 days and to beams 14 days.
- Stripping sequence (W) — remove props symmetrically; no sudden release of load.
- Defect inspection (W) — honeycombing, cold joints, cracks; mark for repair.
- Surface finish (R) — record finish class; carry out repair as per project specification.
The standard ITP map
Each row is one checkpoint with H / W / R designation and IS clause. Six activities × 4-6 checkpoints = 24-36 rows per structural element. Hold points are the contractually binding stops: the contractor cannot proceed without the client's QA engineer signing off. Typical hard hold points on a structural pour: rebar fixation approval, formwork line/level approval, pre-pour checklist sign-off, cube/strength acceptance. Witness points require 24 h notice; if the client does not attend, the contractor proceeds. Review points are documentation only.
Source: IS 456:2000 Cl 10–14; IS 14687:1999 falsework; IS 2502:1963 BBS; IS 1786:2008 rebar; IS 516 hardened concrete; IS 1199 fresh concrete.
Worked example — ITP for an M30 raft pour (200 m³)
| Activity | Checkpoint | H/W/R | Acceptance criterion |
|---|---|---|---|
| Earthwork | Reduced level at formation | H | ± 25 mm of design RL; PCC base 75 mm |
| Earthwork | Bearing capacity | H | SBC ≥ 200 kN/m² per geotech report |
| Reinforcement | Material certificate per batch | R | IS 1786 Fe500D; manufacturer test cert filed |
| Reinforcement | Cover blocks & spacing | H | Cover ≥ 50 mm bottom / 40 mm sides; spacing ± 10 mm |
| Reinforcement | Lap & anchorage length | H | Ld or 30φ, whichever is greater, per IS 456 Cl 26.2.5.1; staggered laps |
| Formwork | Line, level, plumb | H | plumb to 1.5° of vertical (25 mm over 1 m) for adjustable steel props, per IS 14687 Cl 9.7 |
| Formwork | Propping & bracing | W | Props at 600 mm centres; bracing at 1.2 m centres |
| Concreting | Pre-pour checklist | H | All prior hold points signed; standby vibrator on site |
| Concreting | Slump per IS 1199 | W | 100 ± 25 mm at point of placement |
| Concreting | Temperature of fresh concrete | W | ≤ 40°C at placement per IS 7861 (Part 1) Cl 7.1 |
| Concreting | Cube cast per IS 516 | H | 1 sample per 50 m³ · 3 specimens, all at 28 days |
| Curing | Curing initiation | H | Within 1 h of finishing; ponding method |
| Curing | Curing duration | W | 7 days minimum (OPC) per IS 456 Cl 13.5 |
| Stripping | Side formwork removal | W | After 24-48 h; no damage to edges or arris |
| Stripping | 28-day cube strength | R | mean of 4 ≥ fck + 0.825σ per IS 456 Cl 16.1 and Table 11; every cube ≥ fck − 3 |
Critical hold points (H) on this pour: rebar fixation approval, formwork line/level approval, pre-pour sign-off, cube/strength acceptance. Skipping any one of these voids the QA chain.
Common deviations seen on Indian sites
An unsigned ITP has no legal standing in a dispute. Work that proceeds without a signed ITP leaves the contractor exposed to rework at their cost. Fix: require all three signatures (contractor, consultant, client) before mobilisation.
A contractor pours without waiting for the rebar approval because the client engineer is travelling. Fix: 24 h advance notice with a contractual hold-point register; any bypass triggers an automatic NCR.
A "witness" call at 06:00 for a 09:00 pour is not 24 h notice. The activity should be rescheduled or the witness can refuse to attend, with the contractor's right to proceed dependent on the contract. Fix: pre-pour schedule frozen 48 h in advance.
Cubes cast, signed, but the register entry is missing. At the 28-day audit the cube cannot be traced to the pour location. Fix: log every cube in the cube register within 24 h, with delivery ticket reference.
Field-checklist blocks
A short questionnaire, an inspector's checklist, and three worked examples that show how a signed ITP resolves into a signature at a hold point on the day of the pour.
Questionnaire — asked when the ITP is submitted for signature, before the first activity starts
- Are all three approvals in place, from the contractor's QA manager, the consultant's QA engineer and the client's project manager? An unsigned ITP has no standing in a dispute.
- Does every row carry all seven columns: activity, checkpoint, spec or IS clause, H/W/R designation, acceptance criterion, record and frequency? A row without a clause reference or a record is not a checkpoint.
- Which checkpoints are hold points, and are they the right ones? A major structural pour carries three to four hard hold points: rebar fixation approval, formwork line and level approval, pre-pour checklist sign-off and cube/strength acceptance.
- Is every acceptance criterion a number you can measure, not a description? Reduced level at ± 25 mm, cover at ≥ 50 mm bottom and 40 mm sides, bar spacing at ± 10 mm, slump at 100 ± 25 mm, fresh concrete at ≤ 40 °C, transit time at ≤ 90 min, propping at 600 mm centres.
- Does each hold point name who signs and what happens if they do not come, and does each witness point carry the 24 hour notice period with a frozen pre-pour schedule 48 hours ahead?
- Is the cube sampling tied to the pour volume under IS 456 Cl 15.2.2, with three specimens per sample and all of them tested at 28 days?
- Are the stripping times written against IS 456 Cl 11.3.1, with the propping times stated separately from the soffit removal times?
- What triggers a revision: a change of scope, design, mix design, specification, material source, formwork system, or a regulatory or audit update? Each revision takes a new number and the same approval chain.
Inspector's checklist — what to verify on site
- Signature and revision block: three approvals dated before the first activity, the current revision number, and the document register entry.
- Row count against scope: six activities with four to six checkpoints each, giving 24 to 36 rows per structural element, with no activity left without a checkpoint.
- Hold-point register listing every hold point with its approver, and the 24 hour advance-notice record against each one.
- Earthwork: reduced level against the benchmark at ± 25 mm, batter at ≤ 1:1 in cohesive soil with side protection, dewatering confirmed, bearing capacity against the geotechnical report, and PCC blinding at 75 to 100 mm in M10/M15.
- Reinforcement: IS 1786 test certificate per batch with the manufacturer mark rolled on the bar, BBS per IS 2502, cover blocks in concrete rather than plastic tied with binding wire, spacing at ± 10 mm, lap per IS 456 Cl 26.2.5.1, and IS 13920 detailing where the structure is in a seismic zone.
- Formwork: plumb within 1.5° of vertical and level per IS 14687 Cl 9.7 verified with a total station, props at the specified centres, bracing for lateral loads, gaps sealed, release agent applied evenly, and openings and embedments fixed.
- Concreting: pre-pour checklist signed, delivery ticket per IS 4926 Cl 7.1, transit time ≤ 90 min, slump per IS 1199, temperature per IS 7861 (Part 1) Cl 7.1, lift height ≤ 1.5 m with full vibrator coverage per IS 456 Cl 13.2, and cubes cast per IS 516.
- Curing and stripping: curing started within 1 h of finishing, duration per IS 456 Cl 13.5.1, a daily curing log, and stripping only after the times in IS 456 Cl 11.3.1 with the props removed symmetrically.
What happens if… three worked examples
What happens. The ITP row for this pour sets cube sampling at one sample per 50 m³, three specimens per sample, all tested at 28 days. For 200 m³ that is 200 ÷ 50 = 4 samples, and 4 × 3 = 12 cubes. Each of the four samples has to be tied to a delivery ticket and a location in the raft.
Likely outcome. Twelve cubes, and each one logged in the cube register within 24 hours with its delivery ticket reference. Miss the register entry and the cube cannot be traced back to the pour at the 28-day audit, which is a records failure on top of a strength record. Under IS 456 Cl 16.1 and Table 11 the acceptance decision runs on the mean of four and on every cube individually, so the sample count has to hold across the whole pour, not just at the end of it.
What happens. A witness point needs 24 hours of notice. A call at 06:00 for a 09:00 pour gives 09:00 − 06:00 = 3 hours, so the notice is 21 hours short of what the ITP requires.
Likely outcome. The witness can refuse to attend, and whether the contractor may proceed depends on the contract. Either way the activity is not witnessed as the ITP intended, and the record has to show what actually happened. The cure is procedural and cheap: freeze the pre-pour schedule 48 hours ahead, so every witness call is inside the 24-hour window without anyone chasing anyone on the morning of the pour.
What happens. The checkpoint is written as a description rather than a criterion, so on site the inspector is asked to judge whether propping is adequate. There is nothing to measure and nothing to fail. Compare the same ITP's other formwork rows: plumb to 1.5° of vertical, which is 25 mm over 1 m, level per IS 14687 Cl 9.7 verified with a total station, props at 600 mm centres and bracing at 1.2 m centres.
Likely outcome. The row passes because nobody can mark it wrong, which is the worst outcome an acceptance criterion can have. Rewrite it as the number and the tool that verifies it, and the same checkpoint becomes enforceable. This is where most ITPs fail: not in the activities listed, but in the criteria that are adjectives.
Frequently Asked Questions
What is the difference between a Hold point and a Witness point?
Who approves the ITP before construction starts?
When should an ITP be revised?
Related articles
Amit Haridas
Founder & Proprietor, ConcreteInfo. 25+ years experience in construction QA/QC, ITP drafting and approval, hold-point management and CAPA across Indian projects. For an ITP draft or a hold-point register for your next pour, contact amit@concreteinfo.in.
Technical updates, not sales emails
One email when a new article goes out on concrete technology, QA/QC and construction quality. No promotions, and your address is never sold or passed to advertising networks. Subscribing is separate from making an enquiry.