1

Thermography of Buildings

Stacey Ward

- BSRIA Instrument Solutions -

- Sales Manager -

2

Benefits of thermography

Quick inspection Results clearly shown in pictures Shows precise location of fault Shows severity of fault Shows compliance with

regulations Improves build quality

3

Limitations

Needs temperature difference Needs clear view of surface Building surveys limited by

Wind Rain Past temperatures Not an accurate heat loss assessment

Cameras are not cheap They are more affordable than they were And you can hire by the week

4

Typical applications

Building insulation and air leakage Building energy efficiency Building moisture surveys Pipework Electrical installations

5

Building insulation and air leakage

Meet requirements of Building Regulations Part L ‘reasonably continuous thermal insulation’

Show air leakage paths to help re-sealing

6

Air tightness testing

7

Testing to include effect of leakage through the floor

Can include smoke testing

Can include both pressurisation and depressurisation tests

8

Locating air leakage

4.6°C

13.4°C

6

8

10

12

SP01

9

10

Understand how thermography is affected by:

features of buildings, surface properties acceptable temperatures, understanding the environment you are

working in, obtaining a good image, differentiating between anomalies faults and normal temperature variations.

Thermal Imaging

11

10oC temperature difference for at least 4 hours.

Dry, no sun, wind speed < 8m/s.

320 x 240 pixels minimum infrared resolution.

12

Features of buildings important for Thermography

Masonry or framed construction Glass Rainscreen cladding Air outlets Light fittings Heaters

13

Framed construction - roof

14

Framed Construction - walls

15

Glass not transparent

10.0°C

14.5°C

10

11

12

13

14AR01: 11.6°C

SP01: 15.8°C

16

Heat sources under windows

7.0°C

13.0°C

8

10

12

17

Acceptable temperatures

Need to have sufficient temperature difference to detect defects

Normally means at least 10°C between inside and out

18

Understand the environment

Heat exchange by radiation and convection Sky can be –50°C Sunshine can raise surface temperature to

+70°C in the UK Set the ‘ambient temperature’ in your camera Wind can eliminate surface temperature

difference in external surveys

19

Effects of cold sky

-18.0°C

-3.1°C

-15

-10

-5

SP01: <-20.0°CSP02: -14.1°C

SP03: -3.9°C

SP04: <-20.0°C

20

In buildings with no heating

21

Solar gain can be used to an advantage

22

Obtain a good image

At survey time: Subject Distance/resolution Focus Broad temperature range

In analysis Correct temperature range Correct environmental settings

23

Zoom in to focus

7.0°C

13.0°C

8

10

12

24

Zoom out for full image

7.0°C

13.0°C

8

10

12

25

Benefits of high resolution

26

Defect, anomaly or feature

30.0°C

36.0°C

30

32

34

36

27

Cold bridges - steelwork

21.2°C

26.5°C

22

23

24

25

26SP01

SP02 SP03

SP04

28

Thermography locates air leakage

behind plasterboard

29

Thermography locates air leakage

25.5°C

31.0°C

26

27

28

29

30

31

behind plasterboard

30

Extract from the thermographic

report

Note: this is inside of building but outside was warmer so the poorly insulated areas show up as warm

31

Case study 1

retail building, 130x75 metres and 6-9 m high interface detail left a 73mm strip uninsulated =30 square metres of cladding with a U value

of 3.5W/m²K instead of 0.35W/m²K. would require an extra 2kW of heating nearly 8000 kWh a year extra heating cost of over £600 a year generating nearly 4000kg of additional CO2.

32

Building fabric thermography

Construction defects

33

Building fabric thermography

Construction defects

Remedial action

34

Case study 2

Traditional brick - cavity - block wall Note surface temperature variations Effect of missing cavity bat Effect of mortar joint Condensation Mould growth

35

Mortar in poor structure U value 1.41

36

Mortar in poor structure U value 1.41

37

Energy surveys

Temperature differences between similar areas

Hidden features

Buried services

-18.2°C

-3.3°C

-15

-10

-5

SP01SP02

SP03

38Wasted Energy ?

39

Roof Moisture

Warm area shows moisture in roof structure

40

Roof moisture survey

Relies on change in temperature Survey after sunset on a sunny day Avoid surface water or debris Moist insulation has high thermal capacity Stays warm for some time after sunset Sharp contrast with dry insulation

41

Underfloor heating

Warm areas shows underfloor heating pipes

42

Underfloor heating

What can go wrong?

13.7°C

31.0°C

15

20

25

30

12.4°C

21.2°C

14

16

18

20

9.7°C

17.0°C

10

12

14

16

11.9°C

16.4°C

12

13

14

15

16

43

Chilled ceilings

Cold areas are working, warm are not

44

Busbars

65.0°C

120.0°C

70

80

90

100

110

120

SP01

SP02

45

What to inspect

Critical items Where no other method

– don’t forget conventional test & inspection

Consider failure modes Cost / benefit Access / safety

46UPS Battery Systems

47

Electrical thermography to avoid fires

48

Commissioning lighting panel

12.0°C

74.0°C

20

40

60

AR01: 13.1°C

12.0°C

74.0°C

20

40

60

AR01: 26.2°C

12.0°C

74.0°C

20

40

60

AR01: 36.9°C

12.0°C

74.0°C

20

40

60

AR01: 44.6°C

12.0°C

74.0°C

20

40

60

AR01: 54.0°C

12.0°C

74.0°C

20

40

60

AR01: 61.0°C

12.0°C

74.0°C

20

40

60

AR01: 68.8°C

12.0°C

74.0°C

20

40

60

AR01: 72.8°C

12.0°C

74.0°C

20

40

60

AR01: 79.3°C

12.0°C

74.0°C

20

40

60

AR01: 81.7°C

49

Summary

Thermography has almost limitless applications Quick and easy way of checking quality and

condition New regulations will increase use Standards are being established Training and Certification essential BSRIA at the centre of development

50

Thanks! Any questions?

stacey.ward@bsria.co.uk www.bis.fm Anne.king@bsria.co.uk www.bsria.co.uk 01344 465545