ISO 19993:2020

Overview

ISO 19993:2020 - "Timber structures - Glued laminated timber - Face and edge joint cleavage test" specifies a factory quality‑assurance test method for evaluating the effectiveness of glued laminated timber (glulam) face and edge bonds. The standard defines how to cleave the glue line in both dry and wet conditions and assess the percentage of wood failure, confirming whether the bond is stronger than the substrate’s perpendicular‑to‑grain tension strength. It is intended for production batch testing, not for initial type testing where cyclic delamination or block shear methods are preferred.

Key topics and requirements

• Scope & principle
  • Cleavage of full cross‑section specimens to determine wood failure at bond lines; high wood failure indicates the adhesive is not the weak element.
• Specimen preparation
  • Specimens taken from off‑cut ends, include full cross‑section, 50 mm long along the grain, with saw kerfs cut to 10 mm depth across each bond line.
• Apparatus
  • Chisel (blade not touching bottom of saw kerf), hammer/mallet (≥1 kg), saw equipment, autoclave/vessel with vacuum pump (≥65 kPa vacuum) and pressure capability (≥500 kPa).
• Wet conditioning
  • Vacuum of at least 65 kPa held for 1.5 h, release then (500 ± 30) kPa pressure for 1.5 h; repeat the vacuum‑pressure cycle once. Specimens fully immersed between 10 °C and 27 °C.
• Cleaving & assessment
  • Cleave each bond line using a chisel and hammer; assess wood failure to the nearest 5% and compute the average wood failure across all bond lines.
• Advisory acceptance criteria (Annex A)
  • Average wood failure ≥ 60% to be acceptable; any individual bond line < 30% is a fail.
• Test report
  • Must record ISO reference, production date/time, specimen ID, species, adhesive type, individual and average wood failure, treatment status, and tester signature.

Applications

• Factory quality assurance for structural glulam production to monitor inter‑laminar face and edge bond integrity.
• Useful for routine batch verification after normal production (not for establishing type approval after major process changes).
• Can be applied to non‑structural glulam where bond verification is required.

Who should use this standard

• Glulam manufacturers, production quality managers, plant testing technicians, timber engineers, and third‑party inspectors responsible for in‑factory bond quality control.

Related standards

• ISO 19993:2020 is maintained by ISO/TC 165 (Timber structures). For initial type testing or changes to adhesive/process, consider cyclic delamination and block shear test methods referenced in broader timber testing guidance.