IS 800:2007 is the Indian Standard (BIS) for general construction in steel - code of practice. IS 800:2007 is the fundamental code of practice for general structural steel design in India. It mandates the Limit State Method (LSM) for designing steel tension members, compression members, flexural members, and connections, ensuring safety, stability, and durability of steel structures under various loads.
Provides guidelines for design, fabrication, and erection of steel structures.
Partial safety factors, slenderness limits, section classification, bolt/weld and serviceability limits used in steel design.
| Reference | Value | Clause |
|---|---|---|
| Partial safety factor — material (yielding) γm0 | 1.10 | Cl. 5.4.1 (Table 5) |
| Partial safety factor — material (ultimate/rupture) γm1 | 1.25 | Cl. 5.4.1 (Table 5) |
| Partial safety factor — bolt (shop fabricated) γmb | 1.25 | Cl. 5.4.1 (Table 5) |
| Partial safety factor — weld (shop) γmw | 1.25 (shop) / 1.50 (site) | Cl. 5.4.1 (Table 5) |
| Partial safety factor — DL | 1.5 (1.0 if relieving) | Cl. 5.3.3 (Table 4) |
| Partial safety factor — LL leading | 1.5 | Cl. 5.3.3 (Table 4) |
| Steel grade — Fe410 yield (E250) | fy = 250 MPa, fu = 410 MPa | Cl. 2.2.4 / IS 2062 |
| Modulus of elasticity (E) for steel | 2.0 × 10⁵ MPa | Cl. 2.2.4.1 |
| Poisson's ratio (elastic) | 0.30 | Cl. 2.2.4.1 |
| Slenderness limit — compression member (general) | 180 | Cl. 3.8 (Table 3) |
| Slenderness limit — tension member (main) | 400 (180 if reversal) | Cl. 3.8 (Table 3) |
| Slenderness limit — bracing / member subjected to wind only | 250 | Cl. 3.8 (Table 3) |
| Plastic section limit — b/t outstand of compression flange | ≤ 9.4 ε | Cl. 3.7 (Table 2) |
| Compact / semi-compact / slender — outstand limits | 9.4ε / 10.5ε / 15.7ε | Cl. 3.7 (Table 2) |
| ε (epsilon) factor for Fe410 | 1.0 (= √(250/fy)) | Cl. 3.7.2 |
| Bolt grade 4.6 — fub | 400 MPa (proof 240 MPa) | Cl. 10.3 / IS 1367 |
| Bolt grade 8.8 — fub | 800 MPa (proof 640 MPa) | Cl. 10.3 / IS 1367 |
| HSFG bolt — slip factor μf (clean mill scale) | 0.50 (typical) | Cl. 10.4.3 (Table 20) |
| Min weld size — fillet (max parent ≤10 mm) | 3 mm | Cl. 10.5.2.3 (Table 21) |
| Min weld size — fillet (parent 32–50 mm) | 8 mm | Cl. 10.5.2.3 (Table 21) |
| Vertical deflection limit — floor beam (LL) | Span / 300 | Cl. 5.6.1 (Table 6) |
| Vertical deflection limit — cantilever (LL) | Span / 150 | Cl. 5.6.1 (Table 6) |
| Lateral sway limit — multi-storey (wind) | Height / 500 | Cl. 5.6.1 (Table 6) |
| Effective length factor (K) — fixed-fixed | 0.65 | Cl. 7.2.2 (Table 11) |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
IS 800:2007 is the default code for any steel structure designed in India — industrial sheds, multi-storey steel frames, warehouses, communication towers, crane girders, and composite slabs. If the member resists axial, flexural, shear, or combined loads through steel primarily, start here.
Two situations where IS 800 alone is insufficient:
The code allows both Limit State Method (LSM) and Working Stress Method (WSM), but WSM is a legacy carryover — it's retained in Annex F only for projects that specifically demand it (typically old government tenders). For any modern project, use LSM. If a tender insists on WSM in 2026, raise an RFI requesting LSM consent — the request is professionally defensible and usually accepted.
Problem: 6 m simply-supported beam carrying factored UDL of 30 kN/m. Fe 250 steel, floor beam in a building. Select the lightest rolled ISMB.
Step 1 — Factored bending moment: M_u = wL² / 8 = 30 × 6² / 8 = 135 kNm
Step 2 — Required plastic section modulus per IS 800 Clause 8.2.1.2: M_d = β_b × Z_p × f_y / γ_m0, with β_b = 1 for plastic sections Rearranged: Z_p ≥ M_u × γ_m0 / f_y = 135 × 10⁶ × 1.10 / 250 = 594 cm³
Step 3 — Trial from IS 808: - ISMB 300 → Z_p = 651 cm³ ≥ 594 ✓ (44.2 kg/m) - ISMB 250 → Z_p = 465 cm³ < 594 ✗
Step 4 — Shear check per Clause 8.4: V_u = wL/2 = 90 kN V_d = d × t_w × f_y / (√3 × γ_m0) = 300 × 7.7 × 250 / (1.732 × 1.10) = 303 kN ≥ 90 ✓
Step 5 — Deflection check per Clause 5.6.1 (SLS, unfactored load): Allowable (L/300 for floor beam) = 6000/300 = 20 mm Actual with w_service ≈ 20 kN/m and I_xx = 8,603 cm⁴: δ = 5wL⁴ / (384EI) = 19.6 mm — marginal
ISMB 300 passes at the limit. For comfort margin, ISMB 350 (I = 13,630 cm⁴ → δ = 12.4 mm) adds ~13% weight but halves the deflection.
1. Wrong γ_m0 factor. Use 1.10 for yielding of members. Use 1.25 for rupture or ultimate strength of cross-section. Confusing these gives 14% error in either direction.
2. Forgetting β_b. For plastic sections (most rolled sections), β_b = 1 — but semi-compact sections have β_b = Z_e / Z_p < 1. Check Table 2 first before assuming β_b = 1.
3. Using Fe 250 for all beams. Fe 350 (E350 per IS 2062) gives 40% more moment capacity for 0-5% price premium — worth specifying for spans above 8 m.
4. Ignoring lateral-torsional buckling. Clause 8.2.2 applies whenever the compression flange is not continuously restrained. A beam with lateral bracing only at midspan and ends needs the LTB check — commonly missed on industrial shed roof beams.
5. Treating bolt bearing as the governing limit. For standard hole clearances, bolt shear usually governs before bearing. Check both per Clauses 10.3.3 and 10.3.4, but don't over-engineer bearing.
IS 800:2007 is well-written but is now 18 years old. The 2007 revision introducing LSM was a major step forward, but seismic provisions (Clause 12, ~12 pages) are thin compared to AISC 341 (~120 pages) and EN 1998-1. For seismically critical buildings — hospitals, fire stations, schools designated as shelters, tall buildings in Zone IV/V — supplement IS 800 with AISC 341 provisions for moment frames, braced frames, and plastic hinge detailing. Note the supplementation in your design basis report. Most private clients and engineering PMCs accept this; state PWDs occasionally question it but rarely reject on well-reasoned DBRs. A 2026 revision of IS 800 has been rumoured for several years but no draft has been circulated publicly.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Partial Safety Factor for Material (Yielding, γm0) | 1.10 | 1.0 (γM0) | EN 1993-1-1:2005 |
| Partial Safety Factor for Material (Ultimate, γm1) | 1.25 | 1.25 (γM2, for connections) | EN 1993-1-1:2005 |
| Resistance Factor (φ) for Flexure | Implicitly ~0.90 (1/1.10) | 0.90 | AISC 360-22 |
| Resistance Factor (φ) for Compression Members | Implicitly ~0.90 (1/1.10) | 0.90 | AISC 360-22 |
| Resistance Factor (φ) for Bolts (Shear) | Implicitly 0.80 (1/1.25) | 0.75 | AISC 360-22 |
| Modulus of Elasticity of Steel (E) | 200,000 N/mm² | 200,000 N/mm² | EN 1993-1-1:2005 |
| Maximum Vertical Deflection for Live Load (Floors) | Span / 360 (for elements susceptible to cracking) | L / 360 (common recommendation) | AISC 360-22 (Appendix L) |
| Maximum Slenderness Ratio (Compression Members) | 180 (carrying dead & imposed loads) | 200 (recommended limit) | AISC 360-22 (Chapter E) |