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IS 9394:1979 is the Indian Standard (BIS) for stone lintels. This standard specifies the requirements for materials, dimensions, finish, and physical properties for stone lintels made from natural stones like sandstone, limestone, and granite. It provides criteria for workmanship and sets minimum physical requirements like compressive strength and water absorption to ensure durability and performance.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Crucially, the natural bedding plane of the stone must be placed vertically and perpendicular to the span to maximize its load-bearing capacity, as specified in Clause 5.3.
! Stone lintels are best suited for relatively small spans. For larger openings, consider composite (e.g., stone-faced RCC) or alternative structural lintels.
! Ensure the minimum bearing of the lintel on the supporting masonry is provided to prevent local crushing or shear failure at the supports.
BS EN 845-2:2013+A1:2016BSI / CEN (British Standards Institution / European Committee for Standardization), UK/Europe
HighCurrent
Specification for ancillary components for masonry - Part 2: Lintels
Covers performance requirements for lintels, including those of manufactured/natural stone, but is performance-based unlike the prescriptive IS code.
TMS 402/602-16The Masonry Society (TMS), USA
MediumCurrent
Building Code Requirements and Specification for Masonry Structures
Provides engineering design requirements for masonry lintels (including stone) rather than a prescriptive product specification.
ASTM C616 / C616M - 15(2020)ASTM International, USA
MediumCurrent
Standard Specification for Quartz-Based Dimension Stone
Specifies material properties for sandstone, a common stone for lintels, but does not cover lintel dimensions or installation.
BS 5642-1:1978BSI (British Standards Institution), UK
LowWithdrawn
Sills and copings. Specification for window sills of precast concrete, cast stone, clayware, slate and natural stone
While withdrawn and for sills, it is a rare example of a prescriptive British standard that explicitly covered finished natural stone components.
Key Differences
≠IS 9394 is a prescriptive standard, providing fixed dimensional rules (e.g., depth = Span/12), whereas BS EN 845-2 is performance-based, requiring manufacturers to declare performance characteristics like load-bearing capacity for a designer to verify.
≠The Indian standard is exclusively for natural stone lintels. In contrast, BS EN 845-2 covers a wide array of materials including steel, reinforced concrete, autoclaved aerated concrete, and manufactured stone.
≠Quality assurance in IS 9394 is based on lot-by-lot acceptance testing. Modern standards like BS EN 845-2 mandate a system of Initial Type Testing (ITT) and continuous Factory Production Control (FPC), leading to a formal Declaration of Performance (DoP).
≠IS 9394 provides simple 'rules of thumb' for sizing. In contrast, US codes like TMS 402/602 require a full engineering design for stone lintels based on allowable stress or strength design principles, considering specific loads and material properties.
Key Similarities
≈All related standards acknowledge the fundamental purpose of a lintel to span an opening and safely support the vertical loads from the structure above it.
≈Both IS 9394 and comparable material standards (like ASTM C616) place critical importance on the stone's flexural strength (termed Transverse Strength or Modulus of Rupture) as the key performance indicator for bending.
≈The concept of providing adequate bearing area on the supporting wall at each end of the lintel is a common requirement across all standards to ensure proper load transfer and prevent localized crushing.
≈All standards emphasize the need for specified tolerances on finished dimensions (length, width, depth) to ensure the lintel fits correctly within the masonry course and performs as intended.
Parameter Comparison
Parameter
IS Value
International
Source
Minimum Bearing Length
200 mm or Span/10, whichever is greater.
150 mm is a common minimum recommendation, but the manufacturer must declare the required length.
BS EN 845-2:2013
Depth Sizing Rule
Prescribed as Span/12, with a minimum of 100 mm.
No rule of thumb; depth is determined by engineering calculation based on span, load, and the material's allowable flexural stress.
TMS 402/602-16
Key Strength Test
Transverse Strength Test (as per IS 1121 Part 2)
Flexural Strength / Modulus of Rupture Test (as per ASTM C99 or EN 12372)
ASTM C616 / BS EN 845-2
Min. Strength (Typical Sandstone)
3.5 N/mm² (3.5 MPa) for certain sandstones.
2.8 MPa (400 psi) for Type I Sandstone.
ASTM C616 / C616M
Water Absorption (Sandstone)
Max 5% by weight (as per IS 1706).
Max 8% by weight for Type I Sandstone.
ASTM C616 / C616M
Quality Assurance Framework
Lot-based acceptance sampling and testing.
Mandatory Factory Production Control (FPC) and Initial Type Testing (ITT).
BS EN 845-2:2013
⚠ Verify details from original standards before use
Key Values7
Quick Reference Values
Minimum thickness of lintel7.5 cm
Minimum bearing length10 cm (or thickness of lintel, whichever is more)
Minimum compressive strength for Sandstone35 N/mm²
Minimum modulus of rupture for Sandstone3.5 N/mm²
Maximum water absorption for Sandstone (by weight)5%
Dimensional tolerance in length± 5 mm
Dimensional tolerance in width/thickness± 2 mm
Tables & Referenced Sections
Key Tables
Table 1 - Physical Requirements for Stone for Lintels