Overview
ISO 7806:1983 - "Industrial plate screens - Codification for designating perforations" defines a concise, machine-readable code for describing perforated plates used in sieving, screening and sizing applications. The standard codifies the key attributes of a perforation in a fixed sequence so buyers, manufacturers and engineers can unambiguously specify hole geometry and arrangement regardless of plate material.
Key topics and technical requirements
- Codification sequence: The perforation designation expresses, in order, shape of holes, aperture size, mutual arrangement of holes, pitch, and orientation relative to the plate edges.
- Hole shape symbols: Standard symbols are used for shapes:
- R = circular (round)
- C = square (sides parallel to edges)
- CD = square (diagonals parallel to edges)
- H = hexagonal
- LR = slot with round ends
- LC = slot with square ends
- Aperture size format: Sizes are stated in millimetres following the shape symbol. For slots the width and length are combined with an “x” (e.g., LR3x10).
- Arrangement codes:
- U = vertices of rectangles
- Z = rectangle vertices and diagonal intersections
- M = square vertices and diagonals (optional)
- T = vertices of equilateral triangles
- Pitch specification: Pitches p1 and p2 (in mm) are stated after the arrangement. For many layouts the shorter pitch is listed first (e.g., U15x20). Use of the “x” sign has no spaces.
- Orientation: Orientation 1 or 2 indicates how the perforation grid aligns with the plate edges (e.g., with the longer or shorter edge). Specific orientation rules are given for T, U/Z and slot arrangements.
- Scope and applicability: Applies to perforated plates regardless of material. Purchasers should additionally specify plate thickness and material for manufacturing and performance considerations.
- Reference vocabulary: ISO 2395 is referenced for sieving terminology.
Applications and users
ISO 7806 is valuable for:
- Perforated plate manufacturers and pattern-makers for consistent production and tooling.
- Screening and sieve equipment designers to define screen decks and liners.
- Procurement and quality control teams to create unambiguous purchase orders and inspection criteria.
- Materials engineers and process engineers who select perforated media for separation, filtration, grading or acoustic panels.
- CAD/CAM libraries and technical documentation where compact, standardized codes (e.g., R10 U15x20) help automate part selection.
Practical benefits include improved supplier-buyer communication, reduced errors in specification, easier documentation of perforated metal products, and compatibility across international markets.
Related standards
- ISO 2395 - Test sieves and test sieving: vocabulary (referenced for definitions used in ISO 7806).
