ISO 15265:2004

Overview

ISO 15265:2004 - Ergonomics of the thermal environment defines a practical, prevention‑oriented risk assessment strategy for identifying and controlling stress or discomfort in thermal working conditions. Rather than prescribing a single measurement procedure, the standard sets out a three‑stage strategy (Observation → Analysis → Expertise) to progressively collect only the information needed to prevent heat or cold disorders and improve working conditions. It applies to steady or varying climates, metabolic rates and clothing ensembles, and complements other thermal‑environment standards (for example, ISO 13731).

Key topics and technical requirements

• Three‑stage strategy
  • Stage 1 - Observation: qualitative, low‑cost workplace scoring of six parameters to identify problems and simple corrective actions. Uses simple scoring scales (air temperature, humidity, thermal radiation, air movement, physical workload, clothing and worker opinions) to decide if further analysis is needed.
  • Stage 2 - Analysis: targeted quantitative assessment for representative periods. Includes activity sequencing, measurements (mean/max values) and calculation of standard thermal indices.
  • Stage 3 - Expertise: specialized investigations and advanced measurements for complex cases, carried out with expert support.
• Parameters assessed
  • Air temperature, relative humidity, globe/thermal radiation, air velocity, metabolic rate (workload), clothing insulation.
• Common indices referenced
  • IREQ (Required Clothing Insulation), PMV/PPD (Predicted Mean Vote / Predicted Percentage Dissatisfied), WBGT (Wet Bulb Globe Temperature), PHS/DLE (Predicted Heat Strain / Duration Limit of Exposure).
• Prevention focus
  • Emphasis on identifying control measures (engineering, organizational, clothing, work/rest regimes) and estimating residual risk; Annex A provides examples of prevention measures.
• Population considerations
  • Strategy targets an average subject; interindividual differences are addressed through medical supervision and surveillance as needed.

Applications and who uses it

• Practical for occupational health & safety professionals, ergonomists, industrial hygienists, facility and HVAC designers, plant managers, and safety regulators.
• Use cases include: assessing heat or cold stress in manufacturing, outdoors work, food processing, foundries, cleanrooms, emergency response, and any workplace with thermal extremes or variable conditions.
• Helps justify interventions, prioritize mitigation (engineering controls, work organization, PPE), and decide when specialist expertise or further measurement is required.

Related standards and context

• References ISO 13731 (vocabulary and symbols) and forms part of a series of ISO standards on thermal environments developed from the BIOMED II "HEAT STRESS" research. ISO 15265:2004 should be used alongside standards that define measurement methods and interpretation of thermal indices (e.g., WBGT, PMV/PPD, PHS).