ISO 26842-1:2020

Overview

ISO 26842-1:2020 - "Adhesives - Test methods for the evaluation and selection of adhesives for indoor wood products - Part 1: Resistance to delamination in non-severe environments" provides test guidelines to select and evaluate adhesive/wood combinations for indoor wood products that are not exposed to extreme temperature or humidity swings. The standard defines exposure cycles, apparatus, specimen preparation and an assessment method to verify resistance to delamination for non‑severe indoor environments.

Key topics and technical requirements

• Purpose: Select and evaluate adhesives and adhesively bonded wood products for low- to medium-delamination indoor use; not intended for structural qualification.
• Specimens: Parallel two‑ply laminates, typically 300 × 300 × 7.5 mm; prepared per ISO 6238, ISO 9424 and ISO 16999. Minimum 10 specimens per test condition.
• Conditioning: Standard conditioning at 23 ± 2 °C and 50 ± 5 % RH for at least 7 days (or agreed period) prior to testing.
• Apparatus: Conditioning, dry‑heat (40 ± 2 °C), cold (−5 ± 3 °C) and humidity chambers (30 °C at 30 % RH and 85 % RH) with specified measurement tolerances and air circulation.
• Delamination‑resistance grades:
  • Grade 1 - low resistance (e.g., coasters, pencil boxes)
  • Grade 2 - medium resistance (e.g., panels, cabinets, doors)
• Test types (used to verify grades):
  • Test A - cyclic hot/cold (−5 °C 4 h / 40 °C 4 h)
  • Test B - cyclic humid/dry (30 °C 85 % RH for 2 days / 30 °C 30 % RH for 5 days)
  • Test C - hot & humid (30 °C, 85 % RH)
  • Test D - hot & dry (30 °C, 30 % RH)
• Test durations: Grade 1 (A:1 cycle, B:1 cycle, C/D:7 days); Grade 2 (A:5 cycles, B:2 cycles, C/D:14 days).
• Pass criterion: Measure delamination within 1 hour of testing using ~10× magnification. Total delamination must be ≤ 10 % of total bond line length to meet the selected grade.
• Reporting: Test report must reference ISO 26842-1:2020 and include adhesive identification, wood type, application/curing details, specimen numbers, conditioning, tests performed, % delamination and dates.

Applications and users

• Adhesive manufacturers - product development, quality control and formulation validation.
• Wood product and furniture makers - adhesive selection for indoor panels, cabinets, doors and consumer wood goods used in non‑severe climates.
• Independent test labs and QA teams - comparative testing, supplier verification and batch acceptance.
• Specifiers and procurement - defining performance requirements for indoor wood products.

Practical benefits include objective delamination resistance verification, consistent selection criteria for adhesives in indoor applications, and standardized test reporting for supplier communication.

Related standards

• ISO 6238 - shear strength of wood-to-wood adhesive bonds
• ISO 9424 - dimensions of test pieces for wood-based panels
• ISO 16999 - sampling and cutting of test pieces

Keywords: ISO 26842-1:2020, adhesives, delamination resistance, indoor wood products, test methods, humidity chambers, climate cycling, adhesive selection.