EN ISO 7231:2023 PDF

Overview

EN ISO 7231:2023 (adopted by CEN as EN ISO 7231:2023) defines standardized laboratory methods for determining the air flow value at a constant pressure-drop across flexible cellular polymeric materials (flexible foams). The standard specifies two main routes:

• Method A - for conventional flexible cellular polymeric materials (those not intended for sealing), and
• Method B - for all types, with special focus on low-air-permeability materials; Method B is split into B1 (manual measurement) and B2 (automatic measurement).

The core principle is to impose a specified constant pressure differential across a foam specimen and measure the volumetric air flow required to maintain that pressure.

Key Topics and Requirements

• Test principle: Maintain a constant pressure drop across a standard specimen and measure the air flow value (volume flow rate).
• Specimen and mounting: Standard test cavity dimensions and a specified specimen support (minimum 70% open area). Example chamber geometries in the standard include 140 mm diameter × 150 mm depth or 75 mm diameter × 1000 mm length; specimen cavity 50 × 50 × 25 mm (±0.05 mm).
• Apparatus accuracy: Flow meters with low pressure drop and an accuracy up to ±2%; manometers graduated 0 Pa to 250 Pa with ±2% accuracy. Provision for air supply or vacuum to produce positive or negative pressure.
• Methods:
  • A: Suited to conventional flexible foams.
  • B1: Manual measurement for low-permeability and sensitive materials.
  • B2: Automated measurement for higher repeatability and throughput.
• Reporting and precision: Procedures include conditioning, leak checks, test sequence and reporting items. An annex provides precision data for methods B1/B2.

Applications and Users

EN ISO 7231:2023 is used to:

• Evaluate foam air permeability and compare effects of formulation or process changes on cellular structure.
• Provide quality control criteria in foam production and R&D.
• Characterize materials for end-use suitability (e.g., cushioning, insulation-not sealing applications). Primary users:
• Foam manufacturers and compounders, R&D teams, and production quality laboratories.
• Independent test laboratories and material certification bodies.
• Product designers and specifiers assessing foam performance related to breathability and air flow.

Related Standards

• ISO 7231:2023 supersedes ISO 7231:2010 (third edition published 2023).
• Adopted as EN ISO 7231:2023 by CEN. For conformity and implementation, consult national standards bodies and related test standards for cellular polymeric materials and foam characterization.

Keywords: EN ISO 7231:2023, ISO 7231:2023, air flow value, constant pressure-drop, flexible cellular polymeric materials, foam testing, method A, method B1, method B2, air permeability, CEN.