Performance of buildings -- Detection of heat, air and moisture irregularities in buildings by infrared methods

Performance des bâtiments -- Détection d'irrégularités de chaleur, air et humidité dans les bâtiments par des méthodes infrarouges

General Information

Status

Published

ICS

91.120.10 - Thermal insulation of buildings

Technical Committee

ISO/TC 163/SC 1 - Test and measurement methods

Drafting Committee

ISO/TC 163/SC 1 - Test and measurement methods

Current Stage

4020 - DIS ballot initiated: 5 months

Start Date

11-Sep-2020

Completion Date

11-Sep-2020

Ref Project

RELATIONS

Revised

ISO 6781:1983 - Thermal insulation -- Qualitative detection of thermal irregularities in building envelopes -- Infrared method

Effective Date

23-Apr-2020

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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
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
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
---------------------- Page: 1 ----------------------
ISO/DIS 6781-1:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
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

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
---------------------- Page: 4 ----------------------
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)
© ISO 2020 – All rights reserved v
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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
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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:

© ISO 2020 – All rights reserved 1
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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
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ISO/DIS 6781-1:2020(E)
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

© ISO 2020 – All rights reserved 3
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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

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
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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

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.
© ISO 2020 – All rights reserved 5
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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

tar
...

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
THIS DOCUMENT IS A DRAFT CIRCULATED
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
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 6781-1:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
---------------------- Page: 1 ----------------------
ISO/DIS 6781-1:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020