Sieve Mesh Number: Translating Screens to Particle Size
Sieve mesh number identifies how many openings per linear inch exist in a woven wire screen. Because wire diameter reduces the effective aperture, mesh numbers correspond to specific nominal opening sizes defined by standards bodies such as ASTM E11 and ISO 3310, enabling consistent particle size classification.
Materials laboratories pair sieve analyses with specific surface area measurements to verify grinding efficiency, hydration rates, and filtration performance.
Definition and Notation
A sieve labelled “No. 200” contains 200 openings per linear inch, yielding a nominal aperture of 75 micrometres after accounting for wire thickness. Standard series include the American (ASTM) and ISO metric designations, with conversion tables linking mesh numbers to micrometre sizes for compatibility with laser diffraction and sedimentation methods.
Reporting sieve analysis results typically involves cumulative percent passing and percent retained for each screen. These values inform gradation curves used in concrete, asphalt, pharmaceutical powders, and soil classification.
Historical Background
Wire cloth sieving dates back to mining and milling operations of the 18th and 19th centuries, where ore processors needed reproducible particle cuts. The U.S. Bureau of Standards (now NIST) codified sieve dimensions in the early 1900s, allowing interchangeable sieves across labs.
ASTM Committee E29 and ISO technical committees continue to maintain tolerances for wire diameter, aperture size, and frame dimensions, ensuring that test results remain comparable worldwide.
Conducting a Sieve Analysis
Sample Preparation
Representative sampling is essential. Coning and quartering or riffle splitting ensures the test portion reflects the entire batch. Dry samples to constant mass when required and break up agglomerates without crushing individual particles.
Stack Assembly and Shaking
Sieves are stacked with the coarsest at the top and finest at the bottom, capped above and supported by a pan below. Mechanical shakers provide consistent vibration and tapping, while wet sieving aids fine powders that tend to agglomerate.
Data Reduction
After sieving, each fraction is weighed. Percent retained equals the mass on each sieve divided by the total sample mass; cumulative percent passing is computed from the bottom up. Plotting these results generates gradation curves used to verify compliance with specifications, such as ASTM C33 for concrete aggregates.
Applications
Construction materials. Aggregate gradation influences workability, strength, and durability of concrete and asphalt. Consistent mesh-based specifications help balance void content and binder demand, complementing volumetric analyses performed with the concrete slab volume calculator.
Pharmaceuticals. Tablet dissolution and content uniformity depend on powder fineness. Sieve certification documents ensure active ingredients meet USP and EP requirements before blending.
Agriculture and soils. Soil texture classification uses sieve splits alongside hydrometer analysis to estimate sand, silt, and clay fractions. These results feed into agronomic tools such as the ppm-to-pounds calculator when translating lab results into field recommendations.
Quality Assurance and Reporting
Record sieve serial numbers, calibration certificates, and time since last inspection to maintain traceability. Note any deviations such as broken wires or out-of-tolerance openings. When correlating sieve data with alternative sizing methods, cite the relevant standard (ASTM E11, ISO 3310) and include conversion tables for mesh-to-micrometre relationships.
Sharing gradation plots and descriptive statistics alongside related properties—bulk density, specific surface area, or turbidity—provides stakeholders with a holistic view of particle behaviour. Image-analysis campaigns that report Feret diameter statistics offer an additional check on sieve performance, capturing shape effects that mesh openings alone cannot describe. These cross-checks support process control, regulatory compliance, and product development across industries.