🌡️ Building Thermography

Construction PN-EN 13187

Overview

STATUS (as of 06.11.2026). PN-EN 13187:2001 “Właściwości cieplne budynków — Jakościowa detekcja wad cieplnych w obudowie budynku — Metoda podczerwieni” (Thermal performance of buildings — Qualitative detection of thermal irregularities in building envelopes — Infrared method) — Polish version, published 13.06.2001, implements EN 13187:1998 [IDT] and ISO 6781:1983 [MOD]; WITHDRAWN on 08.02.2024 and replaced by PN-EN ISO 6781-1:2024-02 (English version, published 08.02.2024, implements EN ISO 6781-1:2023 and ISO 6781-1:2023 [IDT]). EN 13187:1998 was based on ISO 6781:1983 (modified — the main change being the addition of “simplified testing with an IR camera”); according to the iTeh catalogue, the Slovenian adoption of this standard was withdrawn on 26.09.2023 and replaced by EN ISO 6781-1:2023. ISO 6781-1:2023 “Performance of buildings — Detection of heat, air and moisture irregularities in buildings by infrared methods — Part 1: General procedures” (first edition, 04.08.2023) replaced ISO 6781:1983. The procedure below comes from the text of EN 13187:1998; the new standard is described in a separate paragraph.

SCOPE (EN 13187, clause 1). The standard specifies a qualitative method for detecting thermal irregularities in building envelopes by thermographic examination — primarily to identify wide variations in the thermal properties of the external envelope components, including their airtightness. It specifies two forms: testing with an IR camera — mainly for inspecting new buildings or the result of rebuilding — and simplified testing with an IR camera, suitable for audits, e.g. on a construction site, in production control and routine inspections; the two differ mainly in reporting and presentation of results. The results are to be interpreted and assessed by persons specially trained for this purpose. The method is used to locate thermal irregularities and air leakage paths; it is not used to determine the degree of thermal insulation and airtightness — other methods are needed for that.

PRINCIPLE (clause 4). The examination comprises: determination of the surface temperature distribution over a part of the envelope from the apparent radiance temperature distribution recorded by an infrared system; ascertaining whether the distribution is “abnormal”, i.e. due, for example, to insulation defects, moisture content or air leakage; assessment of the type and extent of defects. The thermograms are compared with the temperature distribution expected for the given element, determined from drawings, calculations, reference thermograms or other investigations.

MEASURING SYSTEM (clause 5). An infrared sensor operating at wavelengths between 2 µm and 12 µm with sufficient temperature resolution (according to a footnote of the standard, field experience shows that a minimum resolvable temperature difference of 0.3 °C at a surface temperature of 20 °C is sufficient); a device displaying the thermal image; a device recording the image and data; a means of establishing temperature levels on the examined surface. No significant drift of the system may occur during the test.

TEST CONDITIONS (6.1). When defining the conditions — including the side of the envelope (outdoors or indoors) — the equipment capabilities, the construction of the envelope, the radiative properties of the surface, climatic factors, accessibility and environmental influences are considered. The temperature difference across the envelope shall be large enough for irregularities to be detected; the examination should preferably be carried out with constant temperature and pressure differences — not when the outside or inside air temperature is liable to vary considerably, when the envelope is exposed to direct solar radiation or when the wind varies markedly. The actual requirements may be adapted to the envelope, the equipment and the climate; they are recorded in the report. An example of a set of requirements for Scandinavian conditions is given in Annex D of the standard.

PROCEDURE (6.2). Drawings and documents of the envelope are consulted, the emissivity of the materials is estimated from tables, and the outside air temperature, cloudiness, precipitation, moisture on the outside surface, wind and orientation of the building are recorded. If the examination is to locate air leakage, a pressure difference is produced across the envelope — at least 5 Pa at the location of the inspection — and the envelope is examined from the low pressure side. The effects of ventilated air layers and heat sources are estimated (heat sources are shut off before the test where possible) and furniture obstructing the test areas is removed. Immediately before the test, the inside and outside air temperatures are measured to an accuracy of ± 1 °C; the pressure difference is recommended to be measured to ± 2 Pa on the leeward and windward side of each storey. Variations of apparent temperature in the image are measured to ± 10 % or ± 0.5 °C (whichever is greater), and the reference surface temperature is recommended to be determined to ± 0.5 °C. The examination starts with a preliminary survey of the whole surface; thermograms are taken of parts without defects and of suspect parts; reflections are recognised by viewing the surface from different positions; the positions of the thermograms are marked on a plan; emissivity and reflections must be taken into account when converting to surface temperature. Air leakage indicated by a thermogram is verified, where possible, by measuring air velocity.

EVALUATION (6.3). The expected temperature distribution is determined from drawings and documents of the envelope, heating and ventilation — by calculations, experience, laboratory tests or reference thermograms of envelopes without defects. An irregularity that cannot be explained by the design of the envelope, heat sources, differences in emissivity or in the heat transfer coefficient is stated as a defect.

NEW STANDARD — ISO 6781-1:2023 (foreword, introduction, clauses 1–2). It covers general requirements for building thermography: the extent of thermographic services, the type and condition of equipment, the qualifications of operators, analysts and report writers (according to ISO 6781-3) and the reporting of results; it applies to residential, commercial, institutional and special-use buildings. Compared with ISO 6781:1983 it also covers the detection of air leakage and moisture, updates the requirements to technological progress and distinguishes qualitative and quantitative thermography. Among its normative references are ISO 9972 (fan pressurization method) and ISO 9869-1 (in-situ measurement of thermal resistance with a heat flow meter).

WHAT WE DO NOT GIVE HERE. Clause 7 (thermographic report) and Annexes A–D of EN 13187 (reference thermograms, example requirements for Scandinavian conditions) — they are outside the available preview; therefore we do not give a numerical minimum temperature difference across the envelope or a time without sunshine. We do not know the requirements of ISO 6781-1:2023 beyond clauses 1–3. We do not give camera parameters (resolution, sensitivity), emissivity values of materials or a permissible wind speed — the available texts do not give them.

Method principle

A thermal imaging camera (sensor operating between 2 µm and 12 µm) records the distribution of apparent radiance temperature over the surface of the building envelope. After taking emissivity and reflections into account, the surface temperature distribution is determined and compared with the distribution expected for the given element (from drawings, calculations or reference thermograms).

An irregularity not explained by the design of the element, a heat source or differences in emissivity or heat transfer is stated as a defect — e.g. an insulation defect, moisture or air leakage. For locating air leakage a pressure difference of at least 5 Pa is produced and the examination is made from the low pressure side.

Applications

• Testing with an IR camera of new buildings or buildings after rebuilding — assessment of the envelope as a whole (EN 13187, clause 1)
• Simplified testing with an IR camera for audits, e.g. on a construction site, in production control and routine inspections (EN 13187, clause 1)
• Locating thermal irregularities and air leakage paths through the envelope — without determining the degree of insulation and airtightness
• Detection of heat, air leakage and moisture irregularities in residential, commercial, institutional and special-use buildings (ISO 6781-1:2023)

Key parameters

Standard

Standard number

PN-EN 13187:2001 → PN-EN ISO 6781-1:2024-02

Title (PL)

Właściwości cieplne budynków — Jakościowa detekcja wad cieplnych w obudowie budynku — Metoda podczerwieni

Title (EN)

Thermal performance of buildings — Qualitative detection of thermal irregularities in building envelopes — Infrared method

Step-by-step procedure

1. Defining the conditions

   Consider the equipment, the envelope construction, the radiative properties of the surface, climate, accessibility and environment; choose the side of the examination (outdoors or indoors). Do not test with considerable changes of air temperature, direct sunshine on the envelope or markedly varying wind (6.1).

2. Documents and external conditions

   Consult the drawings and documents of the envelope, estimate the emissivity of materials from tables; record the outside air temperature, cloudiness, precipitation, surface moisture, wind and orientation of the building (6.2).

3. Preparation

   When testing for air leakage, produce a pressure difference of at least 5 Pa and examine from the low pressure side. Where possible, shut off heat sources and remove furniture obstructing the test areas. Immediately before the test, measure the inside and outside air temperatures (± 1 °C) (6.2).

4. Camera setting and preliminary survey

   Set the system according to its instructions (sensitivity, range, aperture); carry out a preliminary survey of the whole surface, and examine suspect parts and selected parts without defects in detail (6.2).

5. Thermograms

   Take thermograms; recognise reflections by viewing the surface from different positions; mark the positions of the thermograms on a plan; take emissivity and reflections into account when converting to surface temperature (6.2).

6. Evaluation and report

   Compare the temperature distribution with the expected one; state an irregularity not explained by the envelope design, heat sources, emissivity or heat transfer as a defect; verify air leakage, where possible, by measuring air velocity; record the test conditions in the report (6.1–6.3).

Required equipment and apparatus

Health and safety (OHS)

• The available texts of the standards give no safety requirements — the rules of work (e.g. at height and at a building in use) are set by the contractor on the basis of a risk assessment

Frequently asked questions