Overview
ISO/TR 21136:2017 - Timber structures: Vibration performance criteria for timber floors reviews three decades of research on human acceptability criteria for timber floor vibrations induced by walking. The Technical Report provides guidance and reviewed methods to establish both design criteria (using calculated response parameters) and performance criteria (using measured parameters). It covers lightweight joist-and-subfloor systems, heavy timber floors, and mass timber slabs including CLT, NLT, and glulam.
Key topics
- Scope and purpose: Methods to define human acceptability criteria for walking‑induced timber floor vibration and guidance for designers and researchers.
- Response parameters: Parameters correlated with human perception - fundamental natural frequency, static deflection (e.g., 1 kN static deflection used historically), peak velocity/acceleration, root‑mean‑square acceleration and damping.
- Mechanisms of response: Characteristics of footstep forces and typical timber floor dynamic response.
- Procedures to derive criteria:
- Comprehensive procedure: Uses large databases, subjective evaluation questionnaires (lab and field), and statistical analysis to derive criteria. Recommends discriminant analysis for multi‑level ratings and logistic regression for binary acceptability.
- Simplified procedure: For smaller datasets; examples provided (e.g., CLT design criteria).
- Annexed tools and examples: Informative annexes include sample questionnaires, application examples for Canadian floors, calculation methods (Eurocode 5 and Hamm et al.), and worked examples for CLT floors.
- Measurement and verification: Links to field/laboratory testing procedures and validation approaches.
Applications and users
ISO/TR 21136:2017 is practical for:
- Structural engineers and floor designers developing vibration‑sensitive timber floor systems
- Architects specifying mass timber and light timber floor performance
- Code writers and regulatory bodies establishing regional acceptability criteria
- Manufacturers of engineered timber products (CLT, NLT, glulam) validating design guidance
- Researchers conducting subjective evaluations and floor vibration studies
Practical uses include establishing national/regional human acceptability criteria, deriving design limits from calculated parameters at the design stage, and evaluating in‑field performance via measured parameters.
Related standards
- ISO 18324 (floor testing procedures) - referenced for test/measurement context
- Eurocode 5 (EC5) - design criteria and calculation formulae summarized in Annex D
- Research criteria (e.g., Hamm et al.) - summarized in Annex E
- Canadian National Building Code examples and applications are discussed in the report
ISO/TR 21136:2017 is a resource for anyone seeking evidence‑based, statistically derived methods to predict and control timber floor vibration performance with an emphasis on human acceptability and practical design application.
