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IS 6165:1992 is the Indian Standard (BIS) for dimensions for unique shapes of clay bricks. This standard specifies the dimensions, shapes, and tolerances for special types of burnt clay bricks used in construction. It covers shapes such as bullnose, cant, plinth, and squint bricks, providing standardized geometry for architectural and structural detailing based on the modular brick size.
Dimensions for unique shapes of clay bricks
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Clay and Stabilized Soil Products
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! These special shapes are dimensionally based on the standard modular brick size (190x90x90 mm) from IS 1077; ensure coordination with the base bricks being used on site.
! The availability of these special shapes can be limited and may require custom orders. Plan procurement well in advance with brick manufacturers.
! Achieving a clean aesthetic in exposed brickwork heavily depends on adhering to the dimensional tolerances specified in this standard. It is advisable to check batches upon delivery.
BS 4729:2005BSI - British Standards Institution, UK
HighCurrent
Specification for dimensions of bricks of special shapes and sizes
Defines a standard range and dimensions for special shaped bricks, similar to the catalogue approach of IS 6165.
BS EN 771-1:2011+A1:2015CEN - European Committee for Standardization (adopted by BSI)
MediumCurrent
Specification for masonry units - Part 1: Clay masonry units
Sets performance criteria for all clay bricks, including special shapes, but requires manufacturers to declare dimensions rather than prescribing them.
BIA Technical Note 10BIA - Brick Industry Association, USA
LowCurrent
Dimensioning and Estimating Brick Masonry
Provides guidance on dimensions for common brick shapes in the US, but is an industry guide, not a mandatory standard.
Key Differences
≠IS 6165 is prescriptive, defining exact dimensions for specific shapes. In contrast, BS EN 771-1 is performance-based, requiring manufacturers to declare the dimensions and tolerances of the shapes they produce.
≠The fundamental brick sizes differ. IS 6165 is based on Indian modular (190x90x90 mm) and non-modular bricks, while BS 4729 is based on the UK standard work size (215 x 102.5 x 65 mm), affecting all derived special shape dimensions.
≠Dimensional tolerance specification is different. IS 6165 provides absolute values (e.g., ±3 mm for length), whereas BS EN 771-1 uses tolerance categories (T1, T2, Tm) which the manufacturer must declare and adhere to.
≠BS 4729 provides a more extensive and numerically coded catalogue of special shapes compared to the list in IS 6165, reflecting different architectural practices.
Key Similarities
≈Both IS 6165 and its international counterparts (like BS 4729) aim to standardize special shaped bricks to simplify architectural design and avoid inefficient on-site cutting of standard bricks.
≈Core geometric shapes such as bullnose (for rounded corners), cant (for splayed corners), and squint (for non-orthogonal corners) are common to both the Indian and British standards.
≈The dimensions of special shapes in all standards are derived from the standard rectangular brick of their respective regions to ensure compatibility and proper bonding in masonry work.
≈The primary material specified or implied in all compared standards is burnt clay, focusing on traditional masonry units.
Parameter Comparison
Parameter
IS Value
International
Source
Underlying Brick Size (Modular/Work)
190 x 90 x 90 mm (Modular)
215 x 102.5 x 65 mm (Work Size)
BS 4729:2005
Single Bullnose Brick Radius
45 mm
51 mm
BS 4729:2005 (Type BN.1)
Double Bullnose Brick Radius
45 mm (on a 90mm width)
51 mm (on a 102.5mm width)
BS 4729:2005 (Type BN.2)
Single Cant Brick Angle
45°
45° (common type)
BS 4729:2005 (Type AN.5)
Squint Quoin Brick Angle
45° (Acute) and 135° (Obtuse)
Typically 30°, 45°, 60° (Acute) and 120°, 135°, 150° (Obtuse)
BS 4729:2005 (Type AN.1-4)
Length Tolerance
± 3 mm (for 190 mm length)
Declared by manufacturer based on categories, e.g., T2, Tm
BS EN 771-1:2011+A1:2015
Width Tolerance
± 2 mm (for 90 mm width)
Declared by manufacturer based on categories, e.g., T2, Tm
BS EN 771-1:2011+A1:2015
⚠ Verify details from original standards before use
Key Values8
Quick Reference Values
Base modular brick length190 mm
Base modular brick width90 mm
Base modular brick height90 mm or 40 mm
Radius of Single Bullnose Brick (Type A)40 mm
Length of splay on a Cant Brick65 mm
Angle of internal/external Squint Quoin Brick45°
Dimensional tolerance for length± 6 mm
Dimensional tolerance for width/height± 3 mm
Tables & Referenced Sections
Key Tables
Table 1: Dimensions of Common Burnt Clay Building Bricks (as per IS 1077)