Link points to Internet Archive / others. Not hosted by InfraLens. Details
IS 6508:1988 is the Indian Standard (BIS) for glossary of terms relating to building lime. This standard provides a glossary of terms related to building lime. It defines the terminology for different types of lime (quicklime, hydrated lime), related materials like limestone, manufacturing processes (calcination, slaking), and properties used in the construction industry, particularly in mortars and plasters.
Glossary of terms relating to building lime
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Building Limes and Gypsum Products
! Crucial for interpreting specifications for heritage conservation and restoration projects where lime mortar is predominantly used.
! Helps differentiate between hydraulic lime (sets with water) and non-hydraulic/fat lime (sets by air carbonation), which is critical for mortar design.
! Should be used as a companion document to IS 712, which covers the specifications for building limes.
Standard Terminology Relating to Lime and Limestone (as Used by the Industry)
Provides definitions for terms used in the lime and limestone industries, directly mirroring the glossary function of IS 6508.
EN 459-1:2015CEN (European Committee for Standardization), Europe
MediumCurrent
Building lime - Part 1: Definitions, specifications and conformity criteria
Includes a comprehensive definitions section, but is much broader, also covering specifications and conformity.
BS 890:1995BSI (British Standards Institution), UK
LowWithdrawn
Building Limes
A former national standard that provided definitions and classifications before harmonization with European standards.
Key Differences
≠IS 6508 is a pure glossary, whereas EN 459-1 is a comprehensive standard that also includes chemical/physical specifications, performance requirements, and conformity assessment.
≠The Indian Standard defines region-specific terms like 'Kankar Lime', which is derived from calcareous nodules found in India and has no direct equivalent term in ASTM or EN standards.
≠The classification system is different. IS 6508 supports the IS 712 classification (Class A, B, C, etc.), which is based on hydraulic properties and purity. EN 459-1 uses a system based on composition and strength (e.g., CL 90, NHL 3.5, NHL 5).
≠EN 459-1 provides a more granular and quantitative classification for natural hydraulic limes (NHL 2, NHL 3.5, NHL 5) based directly on 28-day compressive strength, a practice not found in the IS definitions.
Key Similarities
≈All standards provide fundamental definitions for 'quicklime' (calcium oxide) and 'hydrated lime' (calcium hydroxide), which are universally consistent.
≈A core similarity is the fundamental distinction between non-hydraulic (air-hardening) limes and hydraulic (water-setting) limes, although the sub-classifications differ.
≈All standards recognize and provide definitions for limes derived from dolomitic or magnesian limestone, distinguishing them from high-calcium limes.
≈The primary purpose of the definitional sections in all compared standards is to establish a common and unambiguous technical vocabulary for the specification and use of building lime.
Parameter Comparison
Parameter
IS Value
International
Source
Basis for High-Purity Lime Definition
Defines 'Fat Lime' (Class C), which in the associated IS 712 standard requires >90% (CaO + MgO).
Classified as CL 90, CL 80, CL 70 based on (CaO + MgO) content being ≥90%, ≥80%, and ≥70% respectively.
EN 459-1:2015
28-Day Compressive Strength of Hydraulic Lime
For Class A (Eminently Hydraulic Lime), IS 712 specifies a range of 1.75 to 2.8 N/mm².
Categorized by minimum strength: NHL 5 (≥5 N/mm²), NHL 3.5 (≥3.5 N/mm²), NHL 2 (≥2 N/mm²).
EN 459-1:2015
MgO Content for Dolomitic Lime
Defines Class D (Dolomitic Lime) as typically containing 5% to 20% magnesium oxide.
Dolomitic Lime (DL) is defined as having an MgO content >5%.
EN 459-1:2015
Soundness (Le Chatelier Expansion)
The referenced specification IS 712 requires a maximum expansion of 10 mm for all classes of lime.
≤ 10 mm for Natural Hydraulic Lime (NHL); ≤ 2 mm for Hydraulic Lime (HL).
EN 459-1:2015
Initial Setting Time for Hydraulic Lime
IS 712 specifies a minimum of 2 hours for Class A and B hydraulic limes.
≥ 1 hour for all Natural Hydraulic Lime (NHL) and Hydraulic Lime (HL) types.
EN 459-1:2015
Sulphate (SO₃) Content
IS 712 specifies a maximum of 3% for Class A and 2% for Class B hydraulic limes.
≤ 2% for all Natural Hydraulic Lime (NHL) types.
EN 459-1:2015
⚠ Verify details from original standards before use
Key Values0
No quick reference values available for this code yet.
A calcined material, primarily calcium oxide or calcium oxide with magnesium oxide, which is capable of slaking with water (Clause 3.1).
What is the definition of 'slaking'?+
The process of chemically combining quicklime with water (Clause 4.3).
How does the code define 'fat lime'?+
It is a type of white lime, also known as non-hydraulic lime, which sets slowly by reaction with atmospheric carbon dioxide. It is typically derived from high-purity limestone (Clause 3.4).
What is 'hydraulic lime'?+
A lime containing silica or alumina which combines with it during burning, giving it the property of setting and hardening under water (Clause 3.5).