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IS 2469:1976 is the Indian Standard (BIS) for glossary of terms relating to gypsum. This standard provides a comprehensive glossary of terms relating to gypsum, its processing, and gypsum-based building products. It serves to standardize the terminology used across the Indian construction and materials industry for clarity in specifications, manufacturing, and contracts.
Glossary of terms relating to gypsum
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Building Limes and Gypsum Products
! Use this code strictly for resolving ambiguities in material definitions in tender documents or architectural specifications.
! Do not use this code for physical, chemical, or performance requirements; refer to specific gypsum product codes (like IS 2095 for boards or IS 8273 for plaster) instead.
Standard Terminology Relating to Gypsum and Related Building Materials and Systems
Both are dedicated standalone standards providing definitions of terms used in the gypsum industry.
EN 13279-1:2008CEN (European Committee for Standardization), Europe
MediumCurrent
Gypsum binders and gypsum plasters - Part 1: Definitions and requirements
Contains a dedicated and comprehensive 'Definitions' section covering similar terms, but is part of a larger product specification standard.
BS 1191-1:1973BSI (British Standards Institution), UK
MediumWithdrawn
Specification for gypsum building plasters. Part 1: Excluding premixed lightweight plasters
As a near-contemporary UK standard, its definitions section reflected similar terminology and technology to the IS code.
Key Differences
≠IS 2469 is a standalone glossary, whereas modern international standards like EN 13279-1 typically integrate the terminology section within a broader product specification and requirements standard.
≠International standards like ASTM C11 are regularly updated and include definitions for modern materials and systems (e.g., synthetic gypsum, glass-mat gypsum sheathing, alpha/beta hemihydrates) not conceived of or included in the 1976 Indian standard.
≠There are regional variations in preferred terminology. IS 2469 prominently defines 'Plaster of Paris', a common term in India and the UK. ASTM C11 defines the primary term as 'calcined gypsum' and lists 'plaster of Paris' as a historical synonym, often referring specifically to beta hemihydrate.
≠The IS code provides general definitions, while international standards often offer more technical nuance, such as differentiating between 'alpha-hemihydrate' and 'beta-hemihydrate' based on manufacturing process and physical properties.
Key Similarities
≈The fundamental scientific definitions of core materials like 'Gypsum' (hydrated calcium sulfate, CaSO₄·2H₂O) and 'Anhydrite' (anhydrous calcium sulfate, CaSO₄) are identical across all standards.
≈All standards share the primary purpose of creating a common, unambiguous vocabulary to facilitate clear communication in specifications, contracts, and on-site practices within the construction industry.
≈Key process-related terms have consistent meanings. For instance, 'Gauging' is universally understood as the act of mixing plaster with water, and 'Setting' refers to the chemical process of hardening.
≈The concepts of 'Initial Set' and 'Final Set' as critical time-based properties of plaster are defined and recognized in both the IS code and international standards, forming a basis for quality control.
Parameter Comparison
Parameter
IS Value
International
Source
Primary Term for Calcined Gypsum
Plaster of Paris
Calcined Gypsum (CaSO₄·½H₂O)
ASTM C11
Chemical Formula for Gypsum Mineral
CaSO₄·2H₂O
CaSO₄·2H₂O
ASTM C11
Definition for Mixing Plaster with Water
Gauging: The process of mixing plaster... with water to a plastic state.
Gauging is also a defined term, though 'mixing' is used more generally. Gauging Plaster is a specific product type.
ASTM C11
Definition of Anhydrite
Anhydrous calcium sulphate (CaSO₄).
The mineral, anhydrous calcium sulfate (CaSO₄).
ASTM C11
Term for Uncalcined Gypsum Rock
Gypsum Rock
Gypsum Rock; also Crude Gypsum.
ASTM C11
Differentiation of Hemihydrate Types
Not explicitly defined.
Explicitly defines 'alpha-hemihydrate' and 'beta-hemihydrate' with different properties.
ASTM C11
Term for Gypsum from Industrial By-products
Not defined.
Synthetic Gypsum: 'a chemical product... having the same chemical composition as natural gypsum.'
ASTM C11
⚠ Verify details from original standards before use
Key Values0
No quick reference values available for this code yet.
To provide standard definitions for terms related to raw gypsum, calcined gypsum, and gypsum products to ensure uniform understanding across the industry.
Does this standard contain testing methods or material specifications?+
No, it is purely a terminology standard. Testing methods are covered in codes like IS 2542.
How does the code differentiate between raw and calcined gypsum?+
Raw gypsum is the naturally occurring dihydrate form, whereas calcined gypsum has been partially dehydrated by heating to form calcium sulphate hemihydrate (commonly known as Plaster of Paris).