EN ISO 15758:2014 PDF

Overview

EN ISO 15758:2014 - Hygrothermal performance of building equipment and industrial installations specifies a calculation method for water vapour diffusion into cold pipe insulation systems. The standard defines how to calculate the density of water vapour flow within the insulation and the total moisture uptake per linear metre of pipe over time. It applies to pipes with medium temperatures above 0 °C, both inside buildings and exposed outdoors, and assumes vapour migration occurs by diffusion only (no airflow) and through homogeneous, isotropic insulation materials.

Key topics and requirements

• Scope and assumptions: Diffusion-only transport; temperature of pipe medium > 0 °C; isotropic, homogeneous insulation where vapour partial pressure is constant at equal radial distances.
• Calculation formulae: Methods for single-layer and multi-layer insulation, and systems with drying capacity; includes definitions of variables such as water vapour permeability, diffusion equivalent air layer thickness, and moisture uptake (kg/m).
• Boundary conditions and procedure: Prescribed boundary conditions and a stepwise calculation procedure to estimate condensation rate and cumulative moisture.
• Special systems: Treatment of systems with vapour retarders, capillary-active fabrics and designs that allow drying (see informative Annex B).
• Performance outputs: Water vapour flow rate (kg/(m·s)), rate of condensation/evaporation, and total accumulated moisture per metre of pipe for specified periods (months/years).
• Informative examples: Worked examples and guidance (Annex A) to help apply the method in practice.

Practical applications and users

EN ISO 15758:2014 is used to assess and manage moisture risks in cold piping systems. Typical applications:

• Estimating interstitial condensation and accumulated moisture in insulation.
• Selecting vapour retarders and low-permeability insulation materials.
• Designing insulation for refrigeration, chilled water and process lines to avoid corrosion and material deterioration.
• Predicting service life and maintenance intervals based on a maximum acceptable moisture content.
• Evaluating retrofit options and compliance in building services and industrial installations.

Who uses it:

• Mechanical/building services engineers and designers
• Thermal and hygrothermal consultants
• Insulation manufacturers and specifiers
• Facility managers, maintenance teams and corrosion protection specialists
• Energy auditors and compliance assessors

Related standards

Normative references cited include ISO 9346, ISO 12241, ISO 12572, and ISO 13788, which cover hygrothermal vocabulary, calculation rules, vapour transmission testing, and surface condensation criteria respectively.

Keywords: EN ISO 15758:2014, water vapour diffusion, cold pipe insulation, hygrothermal, condensation calculation, vapour retarder, insulation materials, moisture uptake.