Overview
ISO 14857:2014 - "Thermal performance in the built environment - Determination of air permeance of building materials" specifies a laboratory test method to measure the air permeance of building materials independent of a substrate. The standard defines equipment, specimen preparation and conditioning, test procedures at various pressure differentials, and the assignment of an air permeance rate referenced to ΔP = 75 Pa. Results are used to assess whether a material qualifies as an air barrier material in building envelope applications.
Key Topics
- Scope and purpose: Evaluates air leakage through standalone building material specimens (intended to inform air barrier performance).
- Specimen requirements: Nominal specimen size 1,2 m × 1,2 m (test opening 1 m × 1 m); five specimens are required for testing.
- Conditioning: Specimens conditioned (typical: 23 ± 2 °C and 50 ± 10 % RH or specified alternatives) prior to testing.
- Apparatus essentials:
- Test chamber with 1 m × 1 m opening and 400 mm depth, compression frames and observation panels.
- Airtight piping, filters and flow-control devices.
- Airflow measurement devices and static pressure transducers with defined accuracy tolerances.
- Variable pressure differential equipment able to produce positive and negative pressures; over‑pressure protection at 1 000 Pa.
- Installation procedures: Detailed methods for self-supporting and non-self-supporting materials (including use of rigid support meshes and air‑impermeable wrapping).
- Calibration and accuracy: Calibration using a defined orifice plate (interior square-edge diameter 25,4 ± 0,1 mm) and procedures to quantify extraneous leakage and measurement errors.
- Reporting and precision: Guidance on calculation of air permeance, normalization to standard temperature/pressure, and reporting requirements.
Applications
ISO 14857:2014 is intended for:
- Manufacturers of membranes, coatings, vapor/air barrier materials who need documented air permeance values for product data sheets.
- Independent test laboratories performing compliance or certification testing of building materials.
- Architects, façade consultants and building envelope specialists specifying air barrier performance for energy efficiency, moisture control and indoor air quality.
- Regulators and certification schemes that reference laboratory air-permeance values for building code compliance or product classification.
Practical benefits include standardized, comparable air permeance data to support material selection, quality control, and performance-based specification of air barrier systems.
Related Standards
- ISO 7345 - Thermal insulation: physical quantities and definitions
- ISO 9229 - Thermal insulation: vocabulary
- ISO 12576-1 - Conformity control systems for factory-made insulating materials
Keywords: ISO 14857:2014, air permeance, air barrier material, building materials, test method, thermal performance, specimen conditioning, pressure differential (75 Pa).