IS 1893:2015 Part 4 is the Indian Standard (BIS) for criteria for earthquake resistant design of structures - industrial structures including stack-like structures. This code establishes the criteria for the earthquake-resistant design of industrial structures, encompassing plant buildings, elevated structures, and stack-like structures such as chimneys, silos, and cooling towers. It provides specialized design parameters including importance factors, response reduction factors, and damping ratios tailored to the unique dynamic characteristics and hazard levels of industrial facilities.
Specifies criteria for earthquake resistant design of various industrial structures and stack-like structures.
Quick Reference — IS 1893 Part 4:2015 Industrial Structures
Importance factor by category, R-values, drift limits and equipment anchorage for industrial / process plant.
| Reference | Value | Clause |
|---|
| Scope | Industrial structures (incl. stack-like, large RCC silos, frames supporting equipment) | Cl. 1 |
| Importance factor I — minimum (industrial general) | 1.0 | Cl. 6.2.6 (Table 1) |
| Importance factor I — hazardous / Cat 1 | 1.75 | Cl. 6.2.6 (Table 1) |
| Importance factor I — Category 2 (high process) | 1.50 | Cl. 6.2.6 (Table 1) |
| Importance factor I — Category 3 (moderate) | 1.25 | Cl. 6.2.6 (Table 1) |
| Response reduction R — RC frame (SMRF) | 5.0 | Cl. 6.2.7 (Table 2) |
| Response reduction R — Steel SMRF | 5.0 | Cl. 6.2.7 (Table 2) |
| Response reduction R — Steel braced (CBF) | 4.0 | Cl. 6.2.7 (Table 2) |
| Response reduction R — Stack / chimney (cantilever) | 1.5–2.0 | Cl. 6.2.7 (Table 2) |
| Damping — bolted steel structures | 5 % (typical) — but lower for OWSJ / equipment skids | Cl. 7.5 |
| Sloshing / liquid in vessel — refer Part 2 | Use IS 1893 Part 2 (liquid retaining) | Cl. 1.3 / 7 |
| Time period — stack/chimney | Ta = CT · h^(3/4) (use Annex) | Annex C / E |
| Drift limit — industrial frame | 0.004 × storey height (general); 0.0025 for crane frames | Cl. 7.11.1 |
| Ductile detailing | Per IS 13920 (RC) / IS 800 ductile clauses | Cl. 7.2.4 |
| Vertical seismic — required when | Long span, cantilever, prestressed, equipment | Cl. 6.4.5 |
| Equipment anchorage forces | Per Annex F (rigid 0.6 g for Z=0.36) | Annex F |
⚠ Part 4 cross-references Part 1 (general spectra) and Part 2 (liquid). Use latest amendments and project-specific seismic risk assessment.
Overview
- Status
- Current
- Usage level
- Specialized
- Domain
- Structural Engineering — Structural Design and Loading
- Type
- Code of Practice
Also on InfraLens for IS 1893
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Must be used in conjunction with IS 1893 (Part 1) for general seismic parameters like the Zone Factor (Z) and basic response spectra.
! Response Reduction Factors (R) for industrial structures are typically lower than those for standard commercial buildings due to a lack of structural redundancy.
! Carefully classify the industrial structure into Categories 1 to 4 based on toxicity, flammability, and post-earthquake functional requirements to determine the correct Importance Factor (I).
Frequently referenced clauses
reinforced concretesteelmasonry
International Equivalents
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International Comparison — Coming Soon
We're adding equivalent international standards for this code.
Key Values6
Quick Reference Values
Importance Factor for Hazardous Structures (Category 1)1.5
Importance Factor for Lifeline/Important Structures (Category 2)1.5
Importance Factor for General Industrial Structures (Category 3)1.0
Damping ratio for welded steel structures2%
Damping ratio for bolted steel structures5%
Damping ratio for reinforced concrete structures5%
Key Formulas
Ah = (Z/2) * (I/R) * (Sa/g) — Design horizontal seismic coefficient
VB = Ah * W — Design seismic base shear
T = C * sqrt(W * h / (E * A * g)) — Fundamental natural period of uniform stack-like structures
Tables & Referenced Sections
Key Tables
Table 1 - Importance Factor (I) for Industrial Structures
Table 2 - Response Reduction Factor (R) for Industrial Structures
Table 3 - Damping Percentages for Different Industrial Structures
Key Clauses
Clause 4 - Categorization of Structures
Clause 6 - Industrial Structures (Plant and Building)
Clause 7 - Stack-Like Structures
Clause 8 - Elevated Structures
Frequently Asked Questions4
Should I use IS 1893 Part 1 or Part 4 for a factory building?+
Part 4 is used for process and industrial plant structures, whereas standard administrative buildings within the same facility follow Part 1.
What is the Importance Factor (I) for a hazardous chemical storage tank?+
1.5, as it falls under Category 1 (Hazardous structures) per Table 1.
What is the response reduction factor (R) for an unlined steel chimney?+
The factor varies based on the detailed structural system, but stack-like structures generally have lower R values (often 2.0 or 2.5) as given in Table 2.
What is the recommended damping for an RC cooling tower?+
5% for reinforced concrete structures as per Table 3.
QA/QC Inspection Templates
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QA/QC templates coming soon for this code.