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IS 10790:2000 (Part 2) is the Indian Standard (BIS) for methods of sampling of steel for prestressed and reinforced concrete, part 2: reinforcing steel. This standard specifies the methods for sampling reinforcing steel from a given lot or batch for conducting quality control tests. It defines the lot size, the number of samples to be drawn based on the lot size, and the acceptance criteria for the lot based on test results. It is the primary standard used for quality assurance of reinforcement steel at manufacturing plants and construction sites.
Methods of sampling of steel for prestressed and reinforced concrete, Part 2: Reinforcing steel
! This code tells you 'how many' samples to take and 'acceptance criteria'. The actual test procedures are in other codes like IS 1608 (for tensile testing) and IS 1599 (for bend tests).
! The acceptance criteria in Table 1 is '0' defectives for most sample sizes, meaning a single sample failure leads to the rejection of the entire lot, subject to retest provisions in Clause 6.
! Ensure proper tagging and identification of samples from the point of collection to the laboratory to maintain traceability to the original lot.
ISO 15630-3:2019ISO (International Organization for Standardization)
HighCurrent
Steel for the reinforcement and prestressing of concrete — Test methods — Part 3: Prestressing steel
Directly specifies test methods, including sampling and test piece preparation, for prestressing steel.
ASTM A370-23ASTM International (USA)
MediumCurrent
Standard Test Methods and Definitions for Mechanical Testing of Steel Products
Broad standard for all steel, with specific annexes (A7) covering sampling and testing of prestressing strand.
EN ISO 15630-3:2019CEN (European Committee for Standardization)
HighCurrent
Steel for the reinforcement and prestressing of concrete - Test methods - Part 3: Prestressing steel
European adoption of the ISO standard, ensuring harmonized test methods including sampling across Europe.
AS/NZS 4672.2:2007Standards Australia / Standards New Zealand
HighCurrent
Steel prestressing materials - Part 2: Testing requirements
Specifies testing requirements, which inherently includes sampling procedures and frequency for prestressing materials.
Key Differences
≠IS 10790 is a dedicated *sampling* standard, whereas ISO 15630-3 and ASTM A370 are comprehensive *test method* standards where sampling procedures are an integral part but not the sole focus.
≠IS 10790 specifies sampling frequency directly within the standard (e.g., 1 sample per 25 tonnes). International standards like ISO 15630-3 are modular and instruct the user to find the sampling frequency in the relevant product standard (e.g., EN 10138), which defines a 'test unit'.
≠IS 10790 defines a sampling plan for selecting coils from a lot based on the number of coils (e.g., select 2 coils from a lot of 3-15). The international approach typically defines a 'test unit' by mass (e.g., 30 tonnes), and every test unit is sampled, bypassing the need for a coil selection plan.
≠ISO 15630-3 and ASTM A370 provide more detailed and stringent requirements for test piece preparation, such as specifying minimum free lengths between grips and giving explicit warnings against heat-cutting, which are less detailed in IS 10790.
Key Similarities
≈All standards share the fundamental purpose of ensuring a representative sample is taken from a production lot/cast to verify its specified mechanical properties.
≈All standards mandate that the sampling procedure must not alter the mechanical properties of the material, implicitly or explicitly discouraging methods like flame cutting that induce heat.
≈A common principle is to discard a certain length from the end of the coil before taking the test sample to avoid non-representative material from the very end, though the specified lengths may differ.
≈All systems require robust marking and traceability, ensuring that each sample taken for testing can be unequivocally linked back to its specific cast/heat and production lot.
Parameter Comparison
Parameter
IS Value
International
Source
Sampling Frequency (Mass Basis)
One sample per 25 tonnes or part thereof from the same cast.
One series of tests per 'test unit', which is typically defined as a mass not exceeding 30-40 tonnes in product standards.
EN 10138-3 (referencing ISO 15630-3)
Sample Discard Length from Coil End
A length of at least 3 m shall be discarded.
At least 1 m of material from each end of a coil shall be discarded.
AS/NZS 4672.2:2007
Primary Scope
Methods of sampling.
Test methods (which includes sampling).
ISO 15630-3:2019
Lot/Batch Definition for Sampling
Based on number of coils to be selected from a larger lot (e.g. select 3 from a lot of 16-50 coils).
Based on a 'test unit' of a defined maximum mass from a single cast; every test unit is tested.
ISO 15630-3 / EN 10138-3
Tensile Test Piece Free Length (Strand)
Not specified; refers to test method standard IS 1521.
The free length between the grips shall be at least 600 mm.
ISO 15630-3:2019
Reference to Test Methods
Refers to other IS codes for specific test procedures (e.g., IS 1521 for tensile tests).
Contains the detailed test procedures directly within the standard itself.
ASTM A370-23
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Maximum Lot Size100 tonnes
Sample Size (Lot ≤ 100 t)2 samples per 25 tonnes or part thereof
Sample Size (Lot 101-300 t)3 samples per 50 tonnes or part thereof
How many TMT bar samples do I need to test for a 40-tonne truck?+
For a lot up to 100 tonnes, you need 2 samples per 25 tonnes. For 40 tonnes, this means taking 4 samples (2 for the first 25t, 2 for the remaining 15t). Refer to Table 1 for details.
What is considered a 'lot' of steel?+
A lot is a collection of bars of the same size, grade, and from the same cast/heat, submitted for inspection at one time. As per Clause 3.1, the maximum mass of a lot is 100 tonnes.
What happens if one sample fails its strength test?+
If a test piece fails, the sample is considered defective. Since Table 1 typically allows for 0 defective samples, the lot is considered non-conforming. However, Clause 6.2 provides a re-test procedure where additional tests can be done to potentially accept the lot.