oSIST prEN ISO 6781-1:2022

SLOVENSKI STANDARD
oSIST prEN ISO 6781-1:2020
01-december-2020
Toplotne značilnosti stavb - Kvalitativno zaznavanje toplotnih nepravilnosti v
ovoju zgradbe - Infrardeča metoda (ISO/DIS 6781:2020)
Thermal performance of buildings - Qualitative detection of thermal irregularities in
building envelopes - Infrared method (ISO/DIS 6781:2020)
Wärmetechnisches Verhalten von Gebäuden - Qualitativer von Gebäuden - Qualitativer
Nachweis von Wärmebrücken in Gebäudehüllen - Infrarot-Verfahren (ISO/DIS
6781:2020)
Performance thermique des bâtiments - Détection qualitative des irrégularités
thermiques sur les enveloppes de bâtiments - Méthode infrarouge (ISO/DIS 6781:2020)
Ta slovenski standard je istoveten z: prEN ISO 6781-1
ICS:
91.120.10 Toplotna izolacija stavb Thermal insulation of
buildings
oSIST prEN ISO 6781-1:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN ISO 6781-1:2020
oSIST prEN ISO 6781-1:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 6781-1
ISO/TC 163/SC 1 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-09-11 2020-12-04
Performance of buildings — Detection of heat, air and
moisture irregularities in buildings by infrared methods —
Part 1:
General procedures
ICS: 91.120.10
IMPORTANT — Please use this updated version dated 2020-09-18,
and discard any previous version of this DIS. Note that the project is
now being processed as ISO/CEN parallel processing.
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
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WHICH REFERENCE MAY BE MADE IN
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ISO/DIS 6781-1:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
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PROVIDE SUPPORTING DOCUMENTATION. ISO 2020

oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
© ISO 2020
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oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General terms . 2
3.2 Thermography terms. 4
3.3 Definitions used in thermography . 6
4 Symbols (and abbreviated terms) . 7
5 Example applications of use of thermography in building assessments .7
6 Customer preparation . 8
7 Qualification of personnel . 9
7.1 Personnel – General Guidance . 9
7.2 Application specific requirements .10
7.2.1 Residential and small buildings - qualification requirements .10
7.2.2 Commercial buildings - qualification requirements .10
7.2.3 Institutional / industrial buildings - qualification requirements .10
8 Equipment requirements for thermographic examination of residential,
commercial and institutional buildings .11
8.1 Equipment – General Requirements' .11
8.2 Equipment – Specific Requirements .11
8.3 Calibration and checking of equipment . .11
9 Safety .12
10 Thermography techniques .12
10.1 Comparative thermography . .12
10.1.1 General.12
10.1.2 Technique .13
10.2 Comparative qualitative thermography .13
10.3 Comparative quantitative thermography.13
10.3.1 Comparative quantitative thermography - Limitations .14
11 Non-contact infrared radiometry (spot radiometry) using infrared thermography
cameras .14
12 Air Leakage and mass transfer .14
12.1 Air leakage .14
12.2 Mass Transfer - Moisture .15
13  .15
13.1 Conductivity test method - Moisture detection .15
13.2 Capacitance test method - Moisture detection .15
13.3 Phase change test method - Moisture detection .16
14 Baseline measurements for building maintenance and condition monitoring .16
15 Data collection .16
16 Field measurements of reflected temperature and emissivity, and attenuating media .17
17 Comparative assessment criteria – severity .17
18 Diagnosis and prognosis .18
18.1 Survey intervals .18
18.2 Image interpretation .18
oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
18.3 Fault identification process .18
19 Test report .18
19.1 General information .18
19.2 Building-specific information .19
19.3 Qualitative Inspections .20
19.4 Quantitative Inspections .21
19.5 Reporting of unsafe conditions .21
Annex A (informative) Pro-forma safety rules and guidelines .22
Annex B (normative) Field measurements of reflected apparent temperature and emissivity .23
Annex C (informative) Examples of buildings heat, air and moisture faults, failures and
anomalies detected by infrared thermography (IRT) .27
iv © ISO 2020 – All rights reserved

oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO's adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is Technical Committee ISO/TC 163, Thermal Performance
and Energy Use in the Built Environment, Subcommittee SC1, Test and measurement methods, Working
Group 15, Thermography of buildings and industrial installations.
ISO 6781-1 cancels and replaces the first edition of ISO 6781:1983 which was a single-part document.
ISO 6781 consists of the following parts, (some of which are presently in development as indicated)
under the general title Performance of buildings — Detection of heat, air and moisture irregularities in
buildings by infrared methods:
— Part 1: General procedures
— Part 2: Equipment requirements (Under development)
— Part 3: Qualifications of equipment operators, data analysts and report writers (Under development)
— Part 4: Conducting Thermographic Inspections and Reporting of Results - Residential and small
buildings (Under development)
— Part 5: Conducting Thermographic Inspections and Reporting of Results – Commercial Buildings (Under
development)
— Part 6: Conducting Thermographic Inspections and Reporting of Results – Institutional and special
purpose buildings (Under development)
oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
Introduction
Infrared building thermography provides a tool to qualitatively identify the presence of energy-
wasting defects and anomalies within building structures. These defects and anomalies can include,
for example, thermal insulation defects, moisture content, and / or unwanted air movement or leakage
within the building enclosure.
Building thermography is carried out by means of an infrared thermography camera, which produces
an image based on the apparent radiance temperature of the target surface area. The thermal radiation
(infrared radiation density) from the target area is converted by the infrared thermography camera to
produce a thermal image (thermogram). This image (thermogram) represents the relative intensity of
thermal radiation from different parts of the surface. The radiation intensity indicated by the image is
related directly to (i) the surface temperature and distribution, (ii) the characteristics of the surface,
(iii) the ambient conditions, and (iv) the sensor itself.
As a result, surface temperature distribution can be a key parameter for monitoring the performance of
building components, building enclosure and the diagnostics of problems. In use, via analysis of surface
temperature distributions, irregularities in the heat and moisture properties of building enclosures and
components, and air movement within the building enclosure, can be indicated. These irregularities
can be due to, for example, thermal insulation defects, moisture content, air leakage within components
or through assemblies, or incorrect installation of components which comprise the construction of the
building.
To realize its full utility as an initial qualitative screening technique, or in-depth diagnostic technique,
thermography must often be supported and/or validated by other methods. These methods include, but
are not limited to, infrared photosensitive tracer gas methods, fan pressurization of the building enclosure,
heat-flow meters, smoke diffusion, anemometry, moisture metres, relative humidity sensors, etc.
Infrared building thermography inspection methodologies can be used for either new-construction
quality control applications, or in existing buildings as ongoing condition monitoring for periodic or
specific building-condition reporting. The latter applications may be accompanied with visual fault
symptoms, while the former may not necessarily present symptoms via visual faults.
vi © ISO 2020 – All rights reserved

oSIST prEN ISO 6781-1:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 6781-1:2020(E)
Performance of buildings — Detection of heat, air and
moisture irregularities in buildings by infrared methods —
Part 1:
General procedures
1 Scope
This document specifies requirements and methodologies for infrared thermographic services for
detection of heat, air and moisture irregularities in buildings that help users to specify and understand
(i) the extent of thermographic services required, (ii) the type and condition of equipment that must
be used, (iii) the qualifications of equipment operators, image analysts, and report authors and
those making recommendations (iv) the requirements for reporting results, and (v) have a guide to
understanding and utilizing the final results stemming from provision of the thermographic services
This part of ISO 6781 is applicable to the general procedures for infrared thermographic methods as
may be applied to residential, commercial, and institutional & special use buildings.
2 Normative references
The following documents, in whole or part, are indispensable for the application of this international
standard. For dated references, only the edition cited applies. For undated references, the latest
edition of the referenced document (including any amendments) applies. Member Bodies of ISO and IEC
maintain registers of currently valid International Standards.
ISO 6781-3, Performance of buildings — Detection of heat, air and moisture irregularities in buildings by
infrared methods — Part 3: Qualifications of equipment operators, data analysts and report writers
ISO/DIS 9972, Thermal performance of buildings — Determination of air permeability of buildings — Fan
pressurization method
ISO/FDIS 10878, Nondestructive testing – Infrared thermography – Vocabulary
ISO/FDIS 12569, Thermal performance of buildings and materials — Determination of specific airflow rate
in buildings — Tracer gas dilution method
ISO 9869-1, Thermal insulation — Building elements — In-situ measurement of thermal resistance and
thermal transmittance — Part 1: Heat flow meter method
ISO 7345, Thermal performance of buildings and building components — Physical quantities and definitions
ISO 9288, Thermal insulation — Heat transfer by radiation — Physical quantities and definitions
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 9288 and the following apply:
oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
3.1 General terms
3.1.1
system
regularly interacting or interdependent group of associated entities (components, factors, members,
parts, etc) forming an integrated whole and delineated by its spatial and temporal boundaries
Note 1 to entry: One or more of the associated entities define the boundary of the system.
3.1.2
analysis
careful scrutiny of constituent parts of a system (3.1.1) in order to thoroughly understand the whole
3.1.3
function
functional purpose of the building, building component or building system (3.1.1)
Note 1 to entry: The function is the activity assigned to, required of, or expected of the system.
3.1.4
small / residential building
building meeting the parameters defined in local building codes as small / residential building and as
agreed with customer receiving thermographic services
3.1.5
parameter
numerical or other measurable factor forming one of a set that sets the conditions for measurement, or
defines the system and its operation
3.1.6
performance
behaviour, characteristics and efficiency of a building, building component or building system (3.1.1)
3.1.7
sign
characteristic parameter of a signal, which shows information about a state
3.1.8
symptom
perception, made by means of human observations and measurements (descriptors), which may
indicate the presence of one or more faults (3.1.12) with a certain probability
3.1.9
syndrome
group of signs (3.1.7) or symptoms (3.1.8) that collectively indicate or characterize an abnormal
condition
3.1.10
anomaly
something that deviates from what is standard, normal or expected, and irregularity or abnormality
(3.1.11) in a system (3.1.1)
3.1.11
abnormality
deviation from a standard condition
3.1.12
Irregularity
a condition which significantly departs from the operational norm
2 © ISO 2020 – All rights reserved

oSIST prEN ISO 6781-1:2020
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3.1.13
fault
a condition that occurs when a building or one of its components or assemblies degrades or exhibits
abnormal behaviour, which may lead to the failure (3.1.14) to perform in accordance with its design intent.
Note 1 to entry: A fault may be the result of a failure, but can exist without a failure.
Note 2 to entry: Planned actions or lack of external resources are not a fault.
3.1.14
fault progression
characterization of the change in severity of a fault (3.1.12) over time
3.1.15
failure
termination of the ability of an item to perform a required function (3.1.4)
Note 1 to entry: Failure is an event as distinguished from fault (3.1.12), which is a state.
3.1.16
failure mode
effect by which a failure (3.1.14) is observed
3.1.17
diagnostics
examination of symptoms (3.1.8) and syndromes (3.1.9) to determine the nature of faults (3.1.12) or
failures (3.1.14) (i.e.: kind, situation, extent)
3.1.18
root cause
set of conditions and/or actions that occur at the beginning of a sequence of events and result in the
initiation of a failure mode (3.1.15)
3.1.19
root cause failure analysis - RCFA
after a failure, the logical systematic examination of an item, its construction, application and
documentation in order to identify the failure mode (3.1.15) and determine the failure mechanism and
its basic cause
Note 1 to entry: Root cause failure analysis is often used to provide a solution to chronic problems.
3.1.20
risk assessment
process of balancing risk with cost, schedule and other management considerations
Note 1 to entry: Risk assessment consists of identifying risks, assessing those risks, determining a course of
action and tracking the effectiveness of the decision.
3.1.21
prognostics
analysis of the symptoms of faults (3.1.12) to predict a future condition and remaining useful life
3.1.22
prognosis
result of the prognostics process
3.1.23
qualitative
relating to measuring, or measured by the quality of something, rather than its quantity
oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
3.1.24
quantitative
relating to measuring, or measured by the quantity of something, rather than its general qualities
3.2 Thermography terms
3.2.1
Infrared
IR
that portion of the electromagnetic spectrum extending from the red visible wavelength, 0,75 μm to 1 mm
Note 1 to entry: Because of instrument design and infrared transmission characteristics of the atmosphere, most
infrared measurements are made between 0,75 μm and 15 μm wavelengths.
3.2.2
thermography
representation of the temperature distribution of a surface , in a thermal image
3.2.3
Thermographic analysis
interpretation and determination of the casual mechanisms producing variations and irregularities in
the thermal image
3.2.4
quantitative thermographic examination
examination of whole buildings, structures or components using thermographic methods with the
objective of providing quantitative (3.1.22) output
Note 1 to entry: Reporting requirements for both qualitative and quantitative examinations are specified in
clause 19 of this document.
3.2.5
infrared thermography camera
IRT camera
instrument that collects the infrared radiant energy from a target surface and produces a monochrome
(black and white) or colour image, where the grey shades (monochrome) or colour hues are related to
the target surface apparent temperature
3.2.6
thermal image
image which is produced by an infrared thermography camera and which represents the apparent
radiance temperature distribution over the target surfaces
Note 1 to entry: Such images are sometimes called infrared thermograms.
3.2.7
Isotherm
enhancement feature applied to an image, which marks an interval of equal apparent
temperature
3.2.8
Isotherm
region on an IR display consisting of points, lines or areas having the same infrared
radiation density
3.2.9
isotherm image
output from a infrared thermography camera showing isotherms (3.2.7 & 3.2.8)
4 © ISO 2020 – All rights reserved

oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
3.2.10
ironbow image
image comprising a colour palette running from black through blue, magenta, orange, yellow to white
that creates best contrast, in particular in regard to edges and shapes
3.2.11
image processing
converting an image to digital form and enhancing the image to prepare it for computer or visual
analysis
Note 1 to entry: In the case of a thermal image or thermogram this could include temperature scaling, spot
temperature measurements, thermal profiles, image manipulation, subtraction and storage.
3.2.12
apparent temperature
uncompensated reading from an infrared thermography camera containing all radiation incident on
the detector, regardless of its source
3.2.13
attenuating media
windows, filters, atmospheres, external optics, materials or other media that attenuate the infrared
radiation emitted from a source
3.2.14
black body
ideal perfect emitter and absorber of thermal radiation at all wavelengths. The emissivity 3.2.14 of a
black body is 1… ε = 1
Note 1 to entry: This is described by Planck's law.
3.2.15
emissivity
ε
ratio of a target surface’s radiance to that of a black body at the same temperature and over the same
spectral Interval
3.2.16
total radiance
radiant heat flow rate divided by the solid angle around the direction ∆ and the projected area normal
to this direction.
Note 1 to entry: Radiance includes emitted radiation from a surface as well as reflected and transmitted radiation.
3.2.17
apparent radiance temperature
temperature determined from the measured total radiance
Note 1 to entry: This temperature is the equivalent black body temperature which would produce the same total
radiance.
3.2.18
reflectivity
ρ − the ratio of the total reflected energy from a surface to total incident energy on that surface
Note 1 to entry: ρ = 1 – ε - τ ; for a mirror, reflectivity approaches 1.0; for a black body, ρ = 0.
Note 2 to entry: Technically, reflectivity is the ratio of the intensity of the reflected radiation to the total
radiation; reflectance is the ratio of the reflected flux to the incident flux. In IRT, the two terms are often used
interchangeably.
oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
3.2.19
reflected apparent temperature
Trefl
apparent temperature of other objects that are reflected by the target into the thermography camera
3.2.20
repeatability
capability of an instrument to repeat exactly a reading on a fixed target over a short or long-term
interval
Note 1 to entry: Repeatability is expressed in ± degrees or a percentage of full scale.
3.2.21
signal processing
manipulation of a temperature signal or image data for the purposes of enhancing or controlling a process
EXAMPLE 1 For infrared radiation thermometers: peak hold, valley hold, sample hold and averaging.
EXAMPLE 2 For scanners, cameras and imagers: isotherm enhancement, image averaging, alignment, image
subtraction and image filtering.
3.2.22
spatial measurement resolution – instantaneous field of view
IFOV
measurement-spot size in terms of working distance
Note 1 to entry: In an infrared radiation thermometer this is expressed in milliradians or as a ratio of the
target-spot size (containing 95 % of the radiant energy, according to common usage) to the working distance. In
scanners, cameras and imagers it is most often expressed in milliradian.
3.2.23
target
object surface to be measured
3.2.24
working distance
distance from the target to the instrument, usually to the primary optic
3.2.25
diffuse surface
a surface from which light or other electromagnetic radiation is scattered, rather than reflected
3.2.26
specular surface
a surface from which light or other electromagnetic radiation is strongly reflected, rather than
randomly scattered
3.3 Definitions used in thermography
3.3.1
transmissivity / transmittance
τ
proportion of infrared radiant energy impinging on an object surface, for any given spectral interval,
that is transmitted through the object
Note 1 to entry: Transmissivity: τ = 1 - ε - ρ,  where:
τ is transmissivity;
ε is emissivity;
ρ is reflectivity.
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oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
Note 2 to entry: For a black body, τ = 0. Transmissivity is that fraction of incident radiation transmitted by matter.
3.3.2
thermal index (TI)
the ratio of temperature drop across the building enclosure, to the total temperature drop between
inside and outside environmental temperatures
Note 1 to entry: Thermal index is calculated as follows: TI= [(T -T ) / (T -T )] x 100%, where:
surface out in out
T surface = The surface temperature of a part of the building enclosure.
Tout = The localized outside air temperature measured by the user.
Tin = The air temperature inside the structure measured by the user.
o o o
Note 2 to entry: Example: Tsurface=60 C; Tin=70 C; Tout=30 C; Therefore TI = [(60 - 30) / (70-30)] x 100 = 75%.
4 Symbols (and abbreviated terms)
FOV Field of view
Hz Hertz
IFOV Instantaneous field of view for detection (Note: thermographic terms 3.2.22)
IRT Infrared Thermography
MDT Minimum detectable temperature
MRTD Minimum resolvable temperature difference
NETD Noise equivalent temperature difference
NUC Non-uniformity correction
MIFOV Instantaneous field of view for measurement
Mrad milliradian
TI Temperature index
L Radiance
e
ε(λ) Spectral emissivity
ρ(λ) Spectral reflectivity
τ(λ) Spectral transmissivity
α(λ) Spectral absorptivity
ΔT Differential temperature
5 Example applications of use of thermography in building assessments
The following list gives examples of where thermography may be applied as a screening or initial
analysis too in the context of building examinations. These examinations can be conducted from inside
or outside of the building. The list given below is not limiting:
a) surface temperature variations
oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
b) uniformity of building component installation
c) thermal anomalies… bridges, insulation deficiencies or variances, misfits
d) locations of air movement
e) extent of air movement through (i) wall (ii) single component (iii) inter component (iv) interstitial
and determination of volumes when pressure differentials are known
f) moisture transport due to temperature or pressure differentials
g) moisture ingress and egress
h) extent and phase of moisture present during inspection
i) thermal comfort
j) delaminating of coatings or renderings
k) as a standard for training personnel
l) provide a basis / set a performance standard / level of qualification for certifying Thermographers
m) energy efficient renovation of buildings
n) location of under-floor heating
o) building condition assessments of existing structures"
p) quality control assessments of renovations to existing buildings.
q) quality control assessments of new construction, part of Building Enclosure Commissioning
r) quality control assessment of repairs to new construction,
s) re-commissioning of building enclosure.
t) detection of structural components within masonry wall assemblies.
u) detection of structural reinforcing in poured concrete assemblies.
v) location of roof leaks, severity of leak and path of drainage through structural components.
i) moulds and fungus, The presence of moisture in materials that can lead to formation of either
surface or interstitial mould and fungus growth.
6 Customer preparation
The customer of Infrared Thermography (IRT) service shall, as applicable:
a) provide access to the building / facility to be inspected;
b) provide the thermographer with details of any potential safety hazards related to the building /
facility use;
c) disclose the history of any prior problems;
d) provide or help develop an inventory of building enclosure, architectural & structural assemblies,
building components, etc., to be inspected, in a logical and efficient route with "line of sight"
viewing;
e) make available any building, architectural and structural shop drawings;
f) make available any building equipment operating manuals and building "as built" drawings;
8 © ISO 2020 – All rights reserved

oSIST prEN ISO 6781-1:2020
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g) identify fire zones;
h) provide qualified guide(s) knowledgeable in the operation and maintenance history of the building
/ facility to be inspected. This person(s) shall accompany the infrared thermographer during the
examination and shall be qualified and authorized to:
— gain access to the inner outer parts of the buildings to be inspected and to notify the building
owner, occupants, operating and maintenance personnel, etc. of the IRT examination activities;
— open and make accessible any requested areas immediately before examination by the infrared
thermographer;
— close and/or secure these areas immediately after examination by the infrared thermographer;
— operate, as possible, any building architectural, structural, mechanical and/or electrical
equipment;
— assure that building systems are operating normally, or placed in a state as requested by the
infrared thermographer and allow sufficient time for stable thermal patterns to be attained
— take full responsibility for consequences resulting from actions taken, or not taken, as a result
of information provided by an infrared examination;
— provide information on the results of follow up examination and repair activities.
7 Qualification of personnel
7.1 Personnel – General Guidance
The requirements for operator competence and qualificationsvaries with the type of structure being
investigated and methodologies employed. The building thermographer's qualification classification
shall be agreed upon by the customer and service provider. The thermographer shall provide
evidence of qualification to that classification prior to the commencement of any work. Building
Thermographers shall be possess knowledge, skills and abilities assessed in accordance with the
classification requirements of ISO/FDIS 6781-3, Performance of buildings – Detection of heat, air and
moisture irregularities in buildings by infrared methods – Part 3 - Qualifications of equipment operators,
data analysts and report writers.
The following provides an outline summary of classification levels:
Class 1: Conversant and capable in knowledge, skills and abilities regarding camera operation, heat
transfer basics, infrared basics, applications basics, baseline imaging, thermal signatures, problem
identification, recognition of special (atypical) problems, fundamental analysis and reporting, safety
considerations, and the ability to think and conceptualize ‘thermally’.
Class 2: All Class 1 requirements plus knowledge, skills, abilities, baseline experience in building
physics and technology, building materials and construction methods, thermographic methodologies,
building thermographic procedures, infrared radiometrics, diagnostic imaging, thermographic infrared
measurement, and basic Infrared thermography program management.
Class 3: All Class 2 requirements plus knowledge, skills, abilities, experience and advanced knowledge
in building physics, building technology, materials and construction methods plus advanced
thermographic methodologies in thermographic program management, cost / benefit accounting,
specialized diagnostics, advanced radiometric, technology planning, and training & certification.
oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
7.2 Application specific requirements
7.2.1 Residential and small buildings - qualification requirements
Thermographic Inspections - Personnel operating equipment performing thermographic inspections
/ investigations on small and residential buildings, where standard construction is employed, shall be
qualified to building-thermography qualification Class 1 or higher in accordance with international
standard ISO/FDIS 6781-3.
Report author / Data analyst - Personnel analyzing thermographic data / results, or writing reports
of thermographic inspections / investigations on residential buildings, where standard construction
is employed, shall be qualified to building-thermography qualification Class 1 or higher in accordance
with international standard ISO/FDIS 6781-3.
7.2.2 Commercial buildings - qualification requirements
Inspections – Wall assemblies - Personnel supervising or operating equipment performing
thermographic inspections / investigations of wall assemblies, of conventional construction, on
commercial buildings, shall be:
i) qualified to building-thermography qualification Class II (or higher) in accordance with
international standard ISO/FDIS 6781-3.
ii) Alternatively, a Class I thermographer may be the field investigator, but shall either be under
the direct supervision of a Class II thermographer, or follow a written procedural methodology
prepared by a Class II thermographer. The procedural methodology for the field investigation
developed by the Class II thermographer shall be for the specific structure being investigated.
Inspections – Roof assemblies - Personnel operating equipment performing thermographic
inspections / investigations of low-slope roof assemblies, of conventional construction, on commercial
buildings, shall be qualified to building-thermography qualification Class I (or higher) in accordance
with international standard ISO/FDIS 6781-3.
Report author / Data analyst – Wall Assemblies - Personnel analyzing thermographic data / results,
or writing reports of thermographic inspections / investigations on wall assemblies, of conventional
construction of commercial buildings, shall be qualified to building-thermography qualification Class II
(or higher) in accordance with international standard ISO/FDIS 6781-3
Report author / Data analyst – Roof Assemblies - Personnel analyzing thermographic data / results,
or writing reports of thermographic inspections / investigations on roof assemblies, of conventional
construction, of commercial buildings, shall be qualified to building-thermography qualification Class I
(or higher) in accordance with international standard ISO/FDIS 6781-3
7.2.3 Institutional / industrial buildings - qualification requirements
Inspections – Wall assemblies - Personnel supervising or operating equipment performing
thermographic inspections / investigations of wall assemblies, of conventional construction, on
institutional / industrial buildings, shall be qualified to building-thermography qualification Class II
(or higher) in accordance with Clause 7.0 of this international standard.
NOTE A Class I thermographer may be the field investigator in this case, but must either be under the
direct supervision of a Class II thermographer, or follow a written procedural methodology. The procedural
methodology for the field investigation shall be developed by a Class II thermographer for the specific structure
being investigated.
Inspections – Roof assemblies - Personnel operating equipment performing thermographic
inspections / investigations of low-slope roof assemblies, of conventional construction, on institutional
/ industrial buildings, shall be qualified to building-thermography qualification Class I (or higher) in
accordance with Clause 7.0 of this international standard
10 © ISO 2020 – All rights reserved

oSIST prEN ISO 6781-1:2020
ISO/DIS 6781-1:2020(E)
Report author / Data analyst – Wall Assemblies - Personnel analyzing thermographic data / results,
or writing reports of thermographic inspections / investigations on wall assemblies, of conventional
construction, of on institutional / industrial buildings, shall be qualified to building-thermography
qualification Class II (or higher) in accordance with Clause 7.0 of this international standard
Report author / Data analyst – Roof Assemblies - Personnel analyzing thermographic data / results,
or writing reports of thermographic inspections / investigations on roof assemblies, of conventional
construction, of on institutional / industrial buildings, shall be qualified to building-thermography
qualification Class I (or higher) in accordance with Clause 7.0 of this international standard
8 Equipment requirements for thermographic examination of residential,
commercial and institutional buildings
8.1 Equipment – General Requirements'
Infrared cameras vary widely. Performance factors to be considered shall include variance in thermal
perfo
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