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IS 4879:1968 is the Indian Standard (BIS) for method of sub-division of a gross sample of powder used for determination of particle size. This standard provides uniform procedures for accurately sub-dividing a gross bulk sample of powder into smaller, representative test portions for particle size determination, minimizing size segregation and operator bias.
Method of sub-division of a gross sample of powder used for determination of particle size
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Sieves, Sieving and Other Sizing Methods
Standard Practice for Reducing Samples of Aggregate to Testing Size
Describes identical methods (coning/quartering, riffle splitting) for a different primary material (aggregate).
BS EN 932-2:1999British Standards Institution / European Committee for Standardization, UK/EU
HighCurrent
Tests for general properties of aggregates - Part 2: Methods for reducing laboratory samples
Covers the same sample reduction techniques, specifically for aggregates, but the principles are universal.
ISO 3082:2017International Organization for Standardization, International
MediumCurrent
Iron ores — Sampling and sample preparation procedures
Details highly specified sample division procedures (riffle, etc.) within a material-specific context (iron ore).
ASTM B215 - 15(2020)ASTM International, USA
MediumCurrent
Standard Practices for Sampling Metal Powders
Focuses on metal powders and includes more modern methods like rotary sample division alongside riffle splitting.
Key Differences
≠IS 4879 is a general, concise guide from 1968, whereas modern international standards (e.g., ISO 3082) provide highly detailed, statistically-validated procedures with stricter tolerances and quality checks.
≠Modern standards like ASTM B215 and ASTM D7953 explicitly describe and recommend rotary sample division (spinning riffler), considered the most accurate method, which is not mentioned in IS 4879:1968.
≠International standards often have more precise specifications for apparatus. For example, ASTM C702 specifies chute widths and numbers based on aggregate size (coarse vs. fine), while IS 4879 provides a single minimum recommendation.
≠IS 4879 mandates repeating the coning process three times, whereas standards like ASTM C702 specify repeating the process as many times as necessary to reach the target sample size, which is a more flexible approach.
Key Similarities
≈Both IS 4879 and its international counterparts describe the same two fundamental manual methods for sample reduction: Coning and Quartering, and Mechanical Splitting (Riffle Splitting).
≈The underlying objective across all standards is identical: to obtain a smaller, representative test portion from a larger gross sample while minimizing sampling bias.
≈The principle of the riffle splitter—dividing a stream of material into numerous smaller streams and collecting alternate ones—is a common technique described in all compared standards.
≈All standards implicitly or explicitly reject simple scoop sampling from a bulk container for obtaining a representative test sample due to its high susceptibility to segregation errors.
What is the primary purpose of sub-dividing powder samples?+
To obtain a small, manageable test aliquot that accurately represents the true particle size distribution of the entire bulk gross sample without segregation.
How wide should the chutes be on a sample splitter?+
The chute width should be at least three times the maximum particle size of the powder to prevent blockage and bridging.
Which sub-division method is considered the most accurate?+
A rotary sample divider (spinning riffler) generally provides the most statistically representative sub-samples by taking many small increments over time.