Anderson Mechanical Services Thermal Imaging In Association with - PowerPoint PPT Presentation

Anderson Mechanical Services Thermal Imaging In Association with Anderson Mechanical Services Loughgall, Armagh BT61 8HZ www.andersonmechanical.net Email: info@andersonmechanical.net By Colin Pearson Head of Condition Monitoring – BSRIA

Anderson Mechanical Services My background  Head of Condition Monitoring at Research and Specialist Consultants, BSRIA.  PCN Level III thermographer  Chairman of the UK Thermography Association  Fellow of BINDT  Member of CIBSE  Associate Member Institute of Acoustics  14 years experience in building thermography  5 years experience in acoustic testing  Chairman Thermography Training and Certification Working Group  BSI and ISO CM & NDT committees.  10 years in research & consultancy for farm buildings  BSc Environmental Engineering  5 years with mechanical and electrical contractor 4 years with lighting manufacturer 

Anderson Mechanical Services Today’s Presentation  Current Building Regulations  Testing vs. Assured Design  Thermal Imaging Basics  Buildings  Benefits   Acoustic Testing Basics  Benefits   Training and certification  The future

Anderson Mechanical Services Current Building Standards (Regulations)  The Building Control Act 2007 Ireland (Building Standards)  Technical Guidance Documents (Approved Documents)  Parts A to M (L: Conservation of Fuel & Energy, E: Sound)  Specifies the minimum acceptable standards  No testing specified  Are these providing the right quality of buildings?

Anderson Mechanical Services Testing vs. Assured Design  No matter how good the design and the Building Inspector, there is no way to be sure of thermal insulation or noise isolation without testing!

Anderson Mechanical Services Pre-Completion Testing  Thermal insulation problems don’t show until it gets cold  Acoustic problems don’t show until the neighbours are noisy  The only way to be sure is to test!  Testing provides quality assurance

Anderson Mechanical Services Thermal Imaging - Basics  Infrared  Material properties  Imaging systems  Benefits  Common faults  Survey method  Understanding results

Anderson Mechanical Services Infrared radiation  Discovered in 1800 by William Herschel  “There is a heating effect from solar radiation beyond the red zone of the visible spectrum”  Detection improved by thermoelectric thermometer (Nobili – 1830)  The radiated energy is due to molecular vibration (Maxwell theory of EM radiation - 1873)  Intensity of radiation depends on temperature (Boltzman) =  T 4 (Stefan’s Law)  = 5.6686 x 10 –8 Wm -2 K -4  All objects above absolute zero emit IR  Wavelength of peak radiation depends on temperature (Wien’s law)  Quantum Hypothesis (Planck – 1906)

Anderson Mechanical Services The infrared spectrum UV Infrared TV & radio TV & radio X-rays Visible Microwaves AM radio .1nm 1nm 10nm 100nm 1µm 10µm 100µm 1mm 10mm 100mm 1m 10m 100m 1km Wavelength Visible Infrared SW LW 100nm 1µm 10µm 100µm 1mm

Anderson Mechanical Services Important material properties  Emittance  Transmittance  Reflectance  Background temperature  Size  Distance  Thermal capacity

Anderson Mechanical Services Emittance, reflectance & transmittance r + a +t =1

Anderson Mechanical Services Imaging systems  1960s-70s systems

Anderson Mechanical Services Imaging systems  1970s systems

Anderson Mechanical Services Thermal imaging cameras

Anderson Mechanical Services Imaging systems  21 st Century systems  Low noise images - 80 mK thermal sensitivity  High definition images – 640x480 pixels resolution, 307,200 picture elements  Full speed 50 Hz images  High usability with voice and PDA interfaces  Sophisticated analysis software

Anderson Mechanical Services Benefits of thermal imaging  Quick inspection  Results clearly shown in pictures  Shows precise location of fault  Shows severity of fault  Shows compliance with regulations  Improves quality of products

Anderson Mechanical Services Building fabric thermography

Anderson Mechanical Services Building fabric thermography

Anderson Mechanical Services Defects  Cold bridging  Missing insulation  Air leakage  Slipped insulation

Anderson Mechanical Services 27.0°C Gaps in insulation 26 24 22 20 18 16 16.0°C

Anderson Mechanical Services insulation gaps - walls

Anderson Mechanical Services Thermography locates air leakage behind plasterboard 31.0°C 31 30 29 28 27 26 25.5°C

Anderson Mechanical Services Gaps in insulation 5.0°C 4 2 0 -2 -4 -4.0°C

Anderson Mechanical Services Cold bridges - steelwork 26.5°C 26 SP01 25 24 SP02 SP03 23 SP04 22 21.2°C

Anderson Mechanical Services Cold Bridge location 2 36.0°C 36 34 32 30 30.0°C

Anderson Mechanical Services Air leakage location 36.0°C 36 34 32 30 30.0°C

Anderson Mechanical Services Good structure U value 0.35 20 19.1 18.4 18 16 15.8 Block Brick Cavity 14 Air Air 12 Temperature, °C 10 Plaster 8 Insulation 6 4 3.9 2.8 2 0.2 0 0.00 0 50 100 150 200 250 300 Distance, mm

Anderson Mechanical Services Poor structure U value 0.85 20 18.2 18 17.1 16 Block Brick 14 Air Air 12 Temperature, °C Missing Insulation 10 Plaster 8 - 6.9 6 4 - 5 2 0.8 + 0 0.00 0 50 100 150 200 250 300 Distance, mm

Anderson Mechanical Services Mortar in poor structure U value 1.41 20 18 Dewpoint of Block 16.3 20°C air at 16 80% rh 14.5 Brick 14 = 16.5°C Mortar Air Air 12 Temperature, °C - 11.2 Missing Insulation 10 Plaster 8 6 6.4 4 2 0.8 + 0 0.00 0 50 100 150 200 250 300 Distance, mm

Anderson Mechanical Services Mortar in poor structure U value 1.41

Anderson Mechanical Services Chimneys / Flues

Anderson Mechanical Services 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 €1000 a year  generating nearly 4000kg of additional CO 2 .

Anderson Mechanical Services Extract from the thermographic report - before Note: this is inside of building but outside was warmer so the poorly insulated areas show up as warm

Anderson Mechanical Services Building fabric thermography  Construction defects

Anderson Mechanical Services Building fabric thermography  Construction defects  Remedial action

Anderson Mechanical Services Building Regulations Part L2 (2002) “The person responsible for achieving compliance should (if suitably qualified) provide a certificate or declaration that the provisions meet the requirements of Part L2(a); or they should obtain a certificate or declaration to that effect from a suitably qualified person. Such certificates or declarations would state: a) that appropriate design details and building techniques have been used or b) that infra-red thermography inspections have shown that the insulation is reasonably continuous over the whole visible envelope”

Anderson Mechanical Services But are the buildings acceptable?  Normally rely on skill and experience of thermographer  No guidance on what is acceptable  Standards and Guides do not set criteria  Proposals in England and Wales for certification by a competent thermographer

Anderson Mechanical Services What needs to change?  Certification of competence  Define acceptable limits  Show how to prove compliance

Anderson Mechanical Services Certification of competence  PCN Level 2 Civil  Possible ‘House Thermographer’ certification

Anderson Mechanical Services How do you show compliance?  Show thermal anomalies  Differentiate between real thermal anomalies and confounding factors  such as localised differences in air movement, reflection and emissivity  Quantify affected areas and their severity  State whether the anomalies and the building thermal insulation are acceptable

Anderson Mechanical Services Approach  Select critical temperature factor  Select acceptable defect area limit  Measure surface temperature difference caused by each anomaly  Measure or estimate area of the defects

Anderson Mechanical Services Critical surface temperature factor  Defined by risk of condensation and mould  Surface temperature factor, f Rsi Proportion of temp. diff. across fabric rather than internal  boundary layer f Rsi = T si – T e T i - T e  Critical surface temperature factor f CRsi Surface temperature factor that will lead to condensation or  mould growth in lowest design temperature 0.75 often used 

Anderson Mechanical Services Allowable area  Must maintain high standards without alienating construction industry by failing too many buildings  0.1% is suggested as suitable for large commercial and retail buildings  This leads to about one failure in six