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IS 15690:2006 is the Indian Standard (BIS) for flood resistant design and construction of buildings - guidelines. This standard provides guidelines for the planning, design, and construction of new buildings to resist damage from floods. It covers site selection, determination of flood levels, design for hydrostatic and hydrodynamic loads, and specifies materials and construction techniques for enhanced flood resilience.
Provides guidelines for the design and construction of buildings to resist flood effects.
Overview
Status
Current
Usage level
Specialized
Domain
Structural Engineering — Disaster Resilience and Retrofitting
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Crucial to establish the correct Design Flood Level (DFL) from local authorities or hydrological studies before starting design.
! Pay close attention to providing adequate flood vents in foundations and enclosed spaces below the DFL to equalize hydrostatic pressure and prevent wall/foundation failure.
! Ensure all electrical and mechanical equipment is elevated above the DFL or is designed to be submersible.
Coastal Construction Manual: Principles and Practices of Planning, Siting, Designing, Constructing, and Maintaining Residential Buildings in Coastal Areas
Provides detailed guidance for residential construction in coastal flood zones, including wave action and high winds.
CIRIA C790 (2020)Construction Industry Research and Information Association (UK)
MediumCurrent
Code of practice for flood resilience for buildings – Part 1: Assessing and managing flood risk
Offers a framework for assessing flood risk and selecting appropriate property-level flood resilience measures (resistance and recoverability).
ABCB Flood Resilient Building Handbook (2021)Australian Building Codes Board (Australia)
HighCurrent
Flood Resilient Building Handbook
Provides non-mandatory guidance for designers, builders and planners to improve the flood resilience of buildings.
Key Differences
≠IS 15690 is a set of 'Guidelines' offering recommendations, whereas ASCE 24 is a mandatory standard referenced by the International Building Code (IBC) in the US, making it legally enforceable.
≠ASCE 24 defines specific flood zones (e.g., A Zone, V Zone) with distinct requirements for each, a level of prescriptive detail not present in the broader classification of IS 15690.
≠US standards (ASCE 24, FEMA) provide highly detailed, prescriptive requirements for 'dry floodproofing' (making structures watertight) and 'wet floodproofing' (using flood-damage resistant materials and vents). IS 15690 discusses these concepts but in more general, qualitative terms.
≠The concept of 'freeboard' (an additional height margin above the base flood level) is a mandatory, quantifiable requirement in ASCE 24, often determined by local ordinance, while IS 15690 provides a fixed recommendation for plinth height (0.3m-0.6m) above a design or highest flood level.
Key Similarities
≈Both IS 15690 and its international counterparts identify elevation of the building's occupied spaces and critical equipment as the primary and most effective method of flood protection.
≈All standards recognize the need to design the foundation and lower portions of a building to resist hydrostatic (from standing water), hydrodynamic (from flowing water), and debris impact loads during a flood event.
≈There is a common emphasis across all standards on protecting critical utilities (electrical systems, HVAC, plumbing) by elevating them or constructing protective barriers to prevent damage and ensure rapid re-occupancy.
≈All documents strongly advocate for proper site selection and planning, recommending that construction in high-risk floodplains be avoided as the first and most important line of defense against flood damage.
≈Both IS 15690 and international guides recommend the use of flood-damage resistant materials (e.g., concrete, steel, closed-cell insulation) for structural and non-structural components located below the design flood level.
Parameter Comparison
Parameter
IS Value
International
Source
Minimum Building Elevation
Plinth level at least 0.6m above Highest Flood Level (HFL) or 0.3m above Design Flood Level (DFL), whichever is higher.
Lowest floor elevated to or above the Base Flood Elevation (BFE) plus a required freeboard (e.g., 1-3 feet).
ASCE/SEI 24-14
Wet Floodproofing Vents
Recommends openings or pipes for pressure equalization but does not specify a formula for sizing or number.
Requires a minimum of two openings on different walls with a total net area of at least 1 sq. inch per 1 sq. foot of enclosed area below BFE.
ASCE/SEI 24-14
Material Durability Requirement
Recommends water-resistant materials like cement mortar, stone, concrete and avoiding soil-based mortars and untreated wood.
Mandates use of specific 'Flood Damage-Resistant Materials' (as defined in FEMA Technical Bulletin 2) for any building component below the BFE.
ASCE/SEI 24-14
Anchorage against Flotation
States the building should be 'properly anchored to the ground so that it is not lifted up by the surrounding water'.
Requires specific engineering calculations to show that the structure securely resists flotation, collapse, and lateral movement from all flood-related loads.
ASCE/SEI 24-14
Electrical System Protection
All electrical lines, switches, and outlets should be 'at least 0.6m above the HFL'.
All electrical service equipment, including panelboards, switches and outlets, must be located above the Design Flood Elevation (DFE).
ASCE/SEI 24-14
⚠ Verify details from original standards before use
Key Values3
Quick Reference Values
Minimum freeboard above Design Flood Level (DFL)300 mm
Required net area of flood openings (vents)1 sq inch per 1 sq foot of enclosed area below DFL
Minimum finished floor levelDFL + 300 mm
Key Formulas
Hydrostatic Force (Standing Water): Force increases linearly with water depth.
Hydrodynamic Force (Flowing Water): Force is proportional to the square of water velocity.
Buoyancy Force (Uplift): Uplift force is equal to the weight of water displaced by the submerged portion of the building.
Tables & Referenced Sections
Key Tables
No tables data
Key Clauses
Clause 4 - General Planning and Layout Considerations
The finished floor level of the lowest floor should be at least 300mm above the Design Flood Level (DFL). (Clause 4.3)
What are flood vents and why are they needed?+
Flood vents are openings in foundation walls that allow floodwaters to enter and exit, equalizing hydrostatic pressure on both sides of the wall to prevent its collapse. (Clause 7.2.1)
What types of loads does a building in a flood zone need to resist?+
It must resist hydrostatic (standing water), hydrodynamic (moving water), buoyancy (uplift), and impact loads from debris. (Clause 5)