ISO 15927-1:2003

Overview

ISO 15927-1:2003, "Hygrothermal performance of buildings - Calculation and presentation of climatic data - Part 1: Monthly means of single meteorological elements," defines procedures for calculating and presenting monthly mean climatic parameters needed to assess aspects of a building’s thermal and moisture behaviour. It covers single meteorological variables such as air temperature, atmospheric humidity, wind speed, precipitation, solar radiation, and longwave (terrestrial) radiation. Instrumentation and observation methods are outside its scope (see WMO guidance); numerical data should be obtained from the relevant national meteorological service.

Key topics and technical requirements

• Scope and definitions: standardized terms (mixing ratio, vapour pressure, global/direct/diffuse solar irradiance, etc.) and symbols/units for hygrothermal analysis.
• Calculation procedures: methods to compute monthly means, daily statistics, and standard deviations for relevant variables.
• Periods and representation: guidance on the periods over which parameters are calculated and how results should be expressed.
• Variable-specific methods:
  • Air temperature: monthly mean, daily mean deviations, annual aggregates.
  • Atmospheric humidity: relationships between temperature and humidity parameters and monthly averaging.
  • Wind: mean wind speed and direction, environmental corrections, statistical elements.
  • Precipitation: monthly totals (including melted solid precipitation equivalents).
  • Solar radiation: procedures for monthly total irradiation and methods to estimate unmeasured irradiances (Annex A).
  • Longwave radiation: estimating monthly atmospheric longwave irradiation and sky temperature (Annex B).
• Normative references: aligns observational/instrumentation practices with the World Meteorological Organization (WMO) guidance.

Practical applications and users

Who uses ISO 15927-1:2003:

• Building designers and architects - for climate inputs when assessing hygrothermal performance and moisture risk.
• HVAC and energy modelers - to derive monthly climate inputs for thermal simulations and energy calculations.
• Researchers and consultants - for consistent climatic datasets in studies of building performance, condensation risk, and durability.
• Standards bodies and regulators - to harmonize climatic data presentation for compliance and comparative analyses.

Practical uses:

• Generating reliable monthly climatic input files for hygrothermal and energy simulation tools.
• Producing standardized climate summaries for building performance assessments and design decisions.
• Supporting risk assessments for condensation, moisture accumulation and thermal comfort analyses.

Related standards

• Other parts of the ISO 15927 series: Part 2 (cooling loads/overheating), Part 3 (driving rain index), Part 4 (data for annual energy demand), Part 5 (winter design temperatures), Part 6 (accumulated temperature differences).
• World Meteorological Organization (WMO) Guide to meteorological instruments and methods of observation for measurement/observation standards.

Keywords: ISO 15927-1:2003, hygrothermal performance, climatic data, monthly means, air temperature, humidity, wind speed, solar radiation, longwave radiation, WMO, building simulation.