Structural Steel Fabrication Checklist — IS 800 and IS 7215

A structural steel fabrication checklist is a phase-by-phase quality control document that a fabrication shop uses to verify every stage of production — from incoming material inspection through to dispatch — against the tolerances and requirements of IS:800:2007 and IS:7215:1973. Without a checklist referenced to these IS standards, QC sign-offs are subjective and non-auditable. This guide gives you the complete checklist in sequence, with exact IS standard clause references for each check item.

Why Reference IS:800 and IS:7215 — Not Generic Checklists

IS:800:2007 is the Indian code of practice for general construction in steel — its Clause 12 covers fabrication tolerances, workmanship requirements, and erection tolerances that are legally binding on all structural steel work in India governed by this standard. IS:7215:1973 is a dedicated tolerance standard for fabricated steel structures, providing dimensional tolerance tables for members, connections, and assembled frames.

IS 800 ke anusar tolerance values are not guidelines — they are acceptance criteria. A member outside these tolerances is a non-conforming item and must be corrected or formally accepted via a deviation note before dispatch. Every check item in this checklist ties back to a specific clause so your QC record is audit-ready for client inspection, third-party inspection, and IS certification audits.

Phase 1 — Incoming Material Inspection

No fabrication begins until incoming steel is accepted. Check every incoming batch against these items:

• Mill Test Certificate (MTC): Verify heat number on MTC matches heat number stamped or stencilled on steel. Grade must match purchase order — e.g. IS:2062 E250A for general structural work. See the IS:2062 E250 grade guide for full material property reference.
• Visual surface condition: Check for laminations, deep pits, scale build-up, or corrosion beyond IS:2062 surface quality limits. Any lamination visible at cut ends is a rejection criterion.
• Section dimensions: Spot-check OD/width/thickness with vernier caliper on minimum 10% of pieces. Verify against IS:808 (for angles, channels, beams) or IS:4923 (for hollow sections). Mass per metre must be within ±2.5% of IS tabulated value for the consignment.
• Straightness: Check with straight edge and feeler gauge. Maximum bow ≤ 1 mm per metre of length as per IS:7215 Table 1.
• Length: Random length material must be within agreed tolerance — typically +100 mm / −0 mm for cut-to-length supply.

Phase 2 — Marking and Cutting

Marking errors propagate through every downstream phase. Control them here:

• Cutting list verification: Confirm cutting list against approved fabrication drawings before any marking. Use our Pipe and Bar Cut List Optimizer to generate an optimised cut plan that minimises waste and documents every piece.
• Mark-out accuracy: All dimensions marked with scriber on steel surface, not chalk alone. Chalk marks are acceptable only for non-critical reference lines. Dimension tolerance on marked length: ±1 mm.
• Kerf allowance: Gas cutting kerf = 2–3 mm; plasma cutting kerf = 1–2 mm. Add the correct allowance to each piece before cutting. See the kerf allowance guide for standard values by cutting method and plate thickness.
• Cut face quality: Gas-cut faces must be smooth, free of deep drag lines, and within squareness tolerance of 1° from perpendicular to the plate surface for thickness up to 50 mm, per IS:7215.
• Hole marking: Bolt-hole centres marked with centre punch, minimum 3 mm depth. Verify centre distances from datum, not from edge, to prevent accumulation of error.

Phase 3 — Fitting and Assembly

Fitting is where dimensional errors become locked in. Check before any weld tacks are applied:

• Overall length of member: Tolerance ±3 mm on overall fabricated length for members up to 6 m; ±5 mm for members 6–12 m. Per IS:7215 Table 1.
• Squareness of ends: Base plates and end plates must be square to the member axis within 1 mm per 300 mm of cross-section depth. Check with engineer's square and feeler gauge.
• Camber: For beams and columns, maximum permitted bow (camber) = L/1000, where L is the member length in mm. For a 6-metre column: maximum camber = 6000/1000 = 6 mm. Measure with piano wire or laser level over the full length.
• Joint fit-up gap: Root gap for butt welds as per WPS (Welding Procedure Specification). Typical root gap 2–4 mm for manual metal arc. Gaps exceeding WPS tolerance require QC approval before welding.
• Bolt-hole diameter: Standard clearance hole = nominal bolt diameter + 2 mm for M12–M24 bolts, per IS:800:2007 Clause 12.8. Maximum oversizing by drilling: +1.5 mm / −0 mm. Holes outside this range are rejectable without approval.
• Stiffener position: Web stiffener position tolerance ±2 mm from drawing dimension. Out-of-plane deviation of stiffener plate ≤ 3 mm per IS:7215.

Phase 4 — Welding

Welding is the highest-risk phase for quality failures. Every weld must be traceable to a qualified welder and an approved WPS:

• Welder qualification: All welders must hold a valid qualification test certificate per IS:7318 for the weld process and position. Verify before assigning weld joints.
• Pre-heat: For plate thickness above 25 mm or carbon equivalent (CE) above 0.43, pre-heat temperature must be maintained as per IS:9595:1996 or the project WPS. Measure with contact thermometer or temp-stick crayons.
• Visual weld inspection (VT): Every weld seam inspected per IS:9595:1996. Check for undercut (maximum 0.5 mm depth for structural welds), porosity, surface cracks, incomplete fusion at toes, and crater cracks at weld ends. All visible defects are rejectable.
• Weld size: Fillet weld leg length must meet drawing requirement ±1 mm. Use weld gauge (Hi-Lo gauge) to check. Undersized fillet welds are structurally deficient and must be repaired by additional passes.
• Distortion control: Post-weld distortion checked against Phase 3 camber limits. Angular distortion of plated members ≤ 1° per IS:7215. Flame straightening permitted only with QC approval and controlled temperature (maximum 650°C for structural steels).

Phase 5 — Surface Treatment

• Surface preparation: Blasting standard specified in contract — typically Sa 2.5 (near-white metal blast) per ISO 8501-1 for primer application. Verify with visual comparator plates.
• Dry Film Thickness (DFT): Primer DFT minimum 75 µm unless project specification states otherwise. Measure with DFT gauge on minimum 5 random readings per member. No single reading below 60 µm (80% rule).
• Paint coverage: All edges, bolt holes, and weld toes must be coated — these are the first corrosion initiation points. Stripe coat applied to edges before full coat.
• Holiday (pinhole) check: For immersed or buried members, holiday detection test required per project specification. Not mandatory for standard atmospheric exposure.

Phase 6 — Pre-Dispatch Inspection and Sign-Off

• Member identity: Each fabricated member must carry a permanent, legible piece mark matching the erection drawing. Mark in paint stick or stencilled paint — not chalk.
• Dimensional final check: Repeat key dimensions from Phase 3 on 100% of dispatch members. Any member outside tolerance goes back for correction before dispatch documentation is signed.
• MTC and test records file: Dispatch package must include originals or certified copies of: incoming material MTCs, welder qualification records, WPS documents, dimensional check records, and DFT readings.
• Loading plan: Members loaded with piece marks visible. Heavy members at bottom. Base plates and connection plates protected with timber packing. No stacking that creates bending stress on slender members in transit.

IS:800 and IS:7215 Tolerance Quick Reference Table

Tolerance values as per IS:800:2007 (Third Revision) Clause 12, IS:7215:1973 Table 1, and IS:9595:1996. Project specifications may impose tighter tolerances — always apply the more stringent requirement. IS 800 ke anusar tolerance values are acceptance criteria, not guidelines; members outside tolerance require formal deviation approval before dispatch.

Worked Example — 40-Tonne Column Assembly Dispatch, Surat

A fabrication shop in Surat is preparing dispatch documentation for a structural column assembly: twenty 6-metre-long 200×200×8 mm SHS columns in IS:2062 E300B, total weight approximately 40 tonnes. The QC engineer runs through five critical check items before signing the dispatch certificate.

Check 1 — Camber:
IS:7215 limit for 6-metre member: L/1000 = 6000/1000 = 6 mm maximum
Method: piano wire stretched tight along column length, measure maximum deviation with steel rule.
All 20 columns measured: maximum recorded camber = 4.2 mm. PASS.

Check 2 — Base plate squareness:
IS:7215 limit: ≤ 1 mm per 300 mm of cross-section dimension.
Column size 200×200 mm — maximum permitted out-of-square = 200/300 × 1 = 0.67 mm
Checked with precision engineer's square and feeler gauge on all four faces of every base plate.
Two columns showed 0.8 mm — outside tolerance. Returned for flame straightening and re-check. FAIL → corrected → PASS.

Check 3 — Bolt-hole diameter:
Drawing specifies M20 bolts → nominal hole diameter = 22 mm (nominal + 2 mm per IS:800 Clause 12.8).
Maximum permitted hole = 22 + 1.5 = 23.5 mm
Random check with go/no-go plug gauge: all holes within range. PASS.

Check 4 — Weld visual inspection per IS:9595:
Each base plate fillet weld (8 mm leg) inspected with weld gauge and torch. Three welds showed undercut of 0.6 mm — exceeds 0.5 mm IS:9595 limit. Welds marked, repaired by grinding and rewelding, re-inspected. FAIL → corrected → PASS.

Check 5 — Paint DFT:
Primer specification: 75 µm minimum. Five DFT readings per column taken at random.
All 100 readings ranged 72–94 µm. Four readings between 60–75 µm (within 80% rule). Average: 81 µm. PASS.
Dispatch certificate signed. MTCs, welder records, and dimensional check sheets filed with dispatch documentation.