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IS 4844:1968 is the Indian Standard (BIS) for method of sampling and preparation of asbestos fibre for laboratory test purposes. This standard prescribes the methods for drawing representative samples of asbestos fibres from a consignment and their preparation for laboratory testing. It ensures the drawn samples accurately represent the physical and chemical characteristics of the bulk material for subsequent quality evaluation.
Method of sampling and preparation of asbestos fibre for laboratory test purposes
! Handling asbestos fibres requires stringent health and safety protocols, including appropriate respirators and dust control measures, which are outside the scope of this standard.
! To prevent moisture loss or gain, immediately place the prepared laboratory sample into clean, dry, and airtight containers.
! Thorough mixing and quartering (or using a riffle divider) is essential to avoid segregation of different fibre lengths during sample reduction.
ISO 3995:1981ISO (International Organization for Standardization)
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Asbestos — Sampling of fibres for laboratory testing
Specifies methods for obtaining a representative bulk sample from a consignment of asbestos fibre in bags.
ASTM D2590-06(2011)ASTM International (USA)
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Standard Test Method for Sampling Chrysotile Asbestos
Covers the procedure for taking a composite sample from a lot of chrysotile asbestos for evaluation.
ASTM D3879-90(2011)ASTM International (USA)
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Standard Test Method for Sampling Amphibole Asbestos
Details procedures for obtaining representative samples of amphibole asbestos for laboratory analysis.
Key Differences
≠IS 4844 specifies 'coning and quartering' as the primary method for sample reduction, which is a manual process prone to operator variability.
≠International standards like ASTM D2590 are more prescriptive about equipment, mandating the use of a 'riffle splitter' for sample reduction to ensure better representativeness and repeatability.
≠ASTM standards differentiate sampling methods based on the type of asbestos (D2590 for Chrysotile, D3879 for Amphibole), whereas IS 4844 provides a single, general procedure for all asbestos fibre types.
≠The formula for determining the number of bags to sample from a lot can differ. For very large lots, IS 4844 uses a simple square root formula, while ISO 3995 provides a tiered table with different sampling numbers for various lot sizes.
Key Similarities
≈All standards are based on the fundamental principle of obtaining a representative laboratory sample from a much larger lot or consignment.
≈They all employ a statistical approach for selecting the primary units (bags) to be sampled from a lot, often based on the square root of the lot size.
≈The process is multi-staged in all standards, involving: drawing increments from multiple bags, combining them into a gross or composite sample, and then systematically reducing this sample to a final laboratory size.
≈All standards emphasize the importance of using clean sampling tools and procedures to prevent contamination and the loss of fine fibres during handling.
Parameter Comparison
Parameter
IS Value
International
Source
Primary Sample Reduction Method
Coning and quartering
Mechanical riffle splitter
ASTM D2590-06(2011)
Number of bags to sample (Lot size N > 100)
Square root of N, rounded to the next whole number
Varies by table; e.g., 20 bags for a lot of 401-800 bags
ISO 3995:1981
Designated Sampling Tool
Sampling spear or trier
Thief sampler
ASTM D2590-06(2011)
Initial increment mass per sampled bag
Approximately 500 g
At least 500 g
ISO 3995:1981
Final mass of laboratory sample (composite)
Approximately 2 kg
Not less than 1.14 kg
ASTM D2590-06(2011)
Standard Applicability
General (Asbestos Fibre)
Specific (Chrysotile Asbestos)
ASTM D2590-06(2011)
⚠ Verify details from original standards before use
Key Values2
Quick Reference Values
Minimum number of containers to sample (lot size up to 50)3