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IS 14900:2018 is the Indian Standard (BIS) for transparent float glass. This standard specifies the requirements, dimensional tolerances, and test methods for transparent float glass. It serves as the primary quality benchmark for unprocessed float glass used in architecture, furniture, and automotive applications, covering aspects like optical clarity, visual defects, and physical dimensions.
Specifies requirements for transparent float glass for general applications, including building glazing.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! The standard differentiates between defect acceptance criteria for the central zone (main viewing area) and the edge zone of a glass sheet, as detailed in Annex A.
! Always account for the specified thickness tolerances (Table 2) in the design of glazing channels, frames, and gaskets to ensure a proper fit.
! This code is for the base float glass. Any further processing like tempering, heat-strengthening, or laminating must conform to other relevant standards like IS 2553 (Safety Glass) or IS 16700 (Laminated Glass).
EN 572-2:2012CEN (European Committee for Standardization), Europe
HighCurrent
Glass in building - Basic soda lime silicate glass products - Part 2: Float glass
Directly corresponds to the specification of monolithic clear and tinted float glass.
ASTM C1036 - 16(2021)ASTM International, USA
HighCurrent
Standard Specification for Flat Glass
Covers multiple flat glass types; Type I (Transparent), Class 1 (Clear), Quality Q3 is the standard equivalent.
JIS R 3202:2022JSA (Japanese Standards Association), Japan
HighCurrent
Float glass and polished plate glass
Specifies requirements for float glass, serving as a direct Japanese equivalent.
GB 11614-2022SAC (Standardization Administration of China), China
HighCurrent
Flat glass
Chinese national standard that includes detailed specifications for float glass.
Key Differences
≠IS 14900 mandates the ISI Standard Mark for conformity, a national certification requirement not present in international standards like EN or ASTM.
≠ASTM C1036 uses a different defect evaluation methodology, classifying 'blemishes' based on size, intensity, and separation for a given quality level (e.g., Q3), whereas IS 14900 quantifies spot and linear defects per square meter.
≠The scope of ASTM C1036 is broader, covering various flat glasses including patterned and wired glass, while IS 14900 is exclusively for transparent float glass, similar to EN 572-2.
≠IS 14900 specifies a prescriptive optical distortion test using a zebra board at a 60° angle, while EN 572-2 is less specific on the angle, and ASTM C1036 treats distortion as a general characteristic to be agreed upon.
Key Similarities
≈All standards are based on soda-lime silicate glass, with very similar chemical composition requirements for SiO₂, Na₂O, CaO, and other oxides, defining the fundamental material properties.
≈Dimensional tolerances for common nominal thicknesses are nearly identical. For example, the tolerance for 4 mm glass is ±0.2 mm in both IS 14900 and EN 572-2.
≈The fundamental performance characteristic of high visible light transmittance for clear glass is a common requirement across all standards, forming the basis for 'standard' float glass.
≈The method for determining squareness by comparing the lengths of the two diagonals and the acceptable deviation limits are conceptually and often numerically similar.
Parameter Comparison
Parameter
IS Value
International
Source
Thickness Tolerance (4 mm glass)
± 0.2 mm
± 0.2 mm
EN 572-2:2012
Visible Light Transmittance (4 mm clear glass)
≥ 85 %
89% (typical value, normative values from manufacturer)
EN 572-2:2012
Standard Nominal Thickness Range
2 mm to 19 mm
2 mm to 25 mm
EN 572-2:2012
Chemical Composition (SiO₂ Content)
68 - 75 %
70 - 74 %
EN 572-1:2012
Squareness Tolerance (per 1000 mm of length)
≤ 2 mm
≤ 2 mm (for stock sizes)
EN 572-2:2012
Defect Evaluation Method
Number/size of defects per unit area (m²)
Blemish size/separation based on quality (Q1-Q4)
ASTM C1036-16
⚠ Verify details from original standards before use
Key Values5
Quick Reference Values
Visible light transmittance for 4mm clear glassNot less than 87 percent
Tolerance on nominal thickness for 4mm glass± 0.2 mm
Tolerance on nominal thickness for 12mm glass± 0.3 mm
Maximum bow for cut size glass0.3 percent of the length of the edge
Standard nominal thicknesses available2, 3, 3.5, 4, 5, 6, 8, 10, 12, 15, 19 mm
Tables & Referenced Sections
Key Tables
Table 1 - Visual and Optical Defects
Table 2 - Dimensional Tolerances for Nominal Thickness
Table 3 - Tolerances on Length and Width (Cut Size Glass)
What are the standard available thicknesses of float glass under IS 14900?+
The standard nominal thicknesses are 2, 3, 3.5, 4, 5, 6, 8, 10, 12, 15, and 19 mm (Clause 5.1).
What is the permitted thickness variation for a 6 mm sheet of glass?+
The tolerance is ± 0.2 mm, meaning the actual thickness can range from 5.8 mm to 6.2 mm (Table 2).
How is the quality of float glass checked for visual defects?+
Glass is checked for defects like bubbles, scratches, and deposits, which are classified and limited based on their size, quantity, and location (central vs. edge zone) as per Table 1 and Annex A.
Does this standard cover tinted or coated glass?+
No, this standard is specifically for transparent (clear) float glass. Tinted and coated glass are covered by separate standards.