ASTM International Committee E29 on Particle and Spray Characterization has approved an extensive revision of ASTM standard E11, Specification for Wire Cloth and Sieves for Testing Purposes. The revision will lead to better control of the quality of sieve cloths and test sieves. 
  
ASTM E11 is under the jurisdiction of Subcommittee E29.01 on Sieves, Sieving Methods and Screening Media. With the revised standard, users will be able to purchase test sieves that conform to both E11 and ISO 3310-1, Test Sieves — Technical Requirements and Testing.
  
According to Richard Campbell, president, Newark Wire Cloth Co., and an E29 member, the revised ASTM E11 includes standard deviation as one of the parameters for sieve cloth and test sieve evaluation. “By including the standard deviation, the minimum acceptable aperture size is controlled by distribution of aperture size rather than just considering the overall average opening size and only limiting the maximum individual opening size of the sieve cloth,” says Campbell.
  
Campbell notes that ASTM E11 now provides for test sieves that can be supplied in three different grades -- compliance, inspection, and calibration -- with each grade being based on the confidence level of the sieve cloth/test sieve. Table 1 in the revised standard includes nominal dimensions and permissible variations for the sieve cloth itself and inspection criteria for the compliance, inspection, and calibration grade test sieves. The following criteria are specified for each grade:
 
* Compliance grade is supplied with basic documentation — a certificate of conformance.
* Inspection grade is supplied with documentation having limited inspection data.
* Calibration grade is supplied with documentation showing more detailed inspection data.
  
The calibration grade test sieve has twice as many apertures measured during the inspection process, thus providing a greater confidence level for the user.
  
While this revision to ASTM E11 is complete, interested parties are welcome to join in the standards developing activities of Subcommittee E29.01. The subcommittee is currently working on a proposed new standard, WK23197, Guide for Industrial Woven Wire Filter Cloth. Those with a technical knowledge of or users of filter cloth are particularly encouraged to join the subcommittee.
 
ASTM International standards are available for purchase at 610-832-9585, [email protected], or at www.astm.org.