Thermography—Infrared Thermographic Investigation

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Introduction

Infrared (IR) thermography is a nondestructive investigative tool used in numerous applications within buildings for preventative maintenance, energy conservation, quality control and security functions. It is also used for quality control purposes in the commissioning of architectural, structural electrical and mechanical systems in new buildings and major retrofits and evaluations of architectural, structural electrical and mechanical systems for building condition reports on existing buildings.

Infrared thermographic imaging is a powerful investigative tool that extends the perception of the human eye beyond visible wavelengths.Footnote * High resolution images developed using the infrared spectrum show where heat is concentrated by either false colour or gray tones. For example, they can show where heat is leaking out of a building or where warmer surface temperatures exist.


West Elevation, Bank of Montreal Building, Ottawa, air leakage patterns on masonry wall assemblies on ground floor.

Application

Inspections of exterior walls of buildings identify air leaks, insulation defects, voids within materials, moisture accumulation and potential mould and fungi formation leading to indoor air quality problems. Roof inspections detect roof leaks though water accumulation within insulation layers. Electrical systems inspections identify hot spots that could lead to potential system failures. Mechanical system inspections locate overheating motors and bearings that again could lead to potential component failure. Road and bridge deck inspections detect voids that result in structural deck de-lamination and breakdown.

To date, over 80 thermographic investigations have been undertaken on building envelopes and roofs in the National Capital Area (NCA). These files are also linked to Capital Asset Planning System (CAPS) and can be retrieved through the appropriate building file.

Thermographic images must be taken and interpreted by American Standards for Non Destructive Testing (ASNT) certified consultants. See below for the relevant standards, training and certification.

How to Find Thermographic Consultants

Equipment operators are certified by the American Standards for Non Destructive Testing (ASNT) certification process through accredited training centres in North America. These centres provide both course certification as well as ASNT certification of infrared equipment operators. There are three levels of certification available for the industry and it is important to ensure that you specify the appropriate level of expertise from the consultant. Generally level 1 is sufficient to obtain credible imagery. Level 2 consultants are required for interpretation of complex imagery and quantification of imagery. Level 3 is reserved for those wishing to train in house staff and those dealing with research and development of new methodologies within the industry. These courses deal with the various American, Canadian and Internationals standard test procedures developed over the past 25 years for building envelope, electrical, roofing, mechanical and bridge deck diagnostics.

Limiting conditions for inspection activities

For electrical and mechanical systems: these systems are generally inspected under normal to full loads to assess live performance. There are no minimum environmental parameters required but work is generally carried out at room temperatures indoors. Outdoor work can be carried out night or day and although not limited to any one season, generally done under favorable mild temperatures.

For roof moisture detection, inspections are carried out generally immediately after sunset in spring, summer and fall when roofs are clear of moisture and snow cover. Roof moisture detection using thermal gradient heat loss procedure is also possible (temperature variations of 20°C or greater allow this work to be carried out 6 to 8 hours after sunset).

For building envelope assessment for air leakage and moisture detection and thermal bridging, a minimum temperature differential of 10°C is required but generally 20 to 30°C variance is recommended. Therefore this type of inspection is reserved for winter months.

Commissioning Procedures for Electrical and Mechanical Systems

When setting up an IR inspection program for an electrical distribution system, keep the following in mind:

The building Heating, Ventilating, and Air-conditioning (HVAC) system s should be operated under normal conditions or close to full load. For commercial buildings this may involve overriding the HVAC system controls.

Lastly, infrared inspections should only be performed by ASNT certified infrared thermographers who are thoroughly familiar with the system(s) being inspected. (Building science knowledge, either professional, technical or field knowledge for envelopes and roofs, electrician or electrical engineer for electrical and mechanical systems, etc.)

Electrical and mechanical systems should be inspected by accredited Level 1 ASNT thermographers and severity of faults and recommendations can be provided also by ASNT Level 1 thermographers but for more complex systems Level II thermographers should be requested to provide analysis of imagery.

Roofing assemblies should be inspected by accredited Level I ASNT thermographers and they also can provide recommendations for required cut tests to determine presence of moisture within the roof assembly.

Building enclosure assemblies should be inspected by accredited Level I ASNT thermographers and severity of faults and recommendations should be provided by Level II thermographers and professionals having training in building sciences related to design and analysis of building envelopes.

Technical Documentation

Note: Most of these documents are available and can be obtained by contacting tpsgc.sngp-npms.pwgsc@tpsgc-pwgsc.gc.ca.

Examples and Infrared Images, Building Envelopes


Marshall / Four Corners Building, South Elevations, Air Leakage Testing, air leakage from interior to assembly immediately behind the metal mansard roof assembly on the third floor. (As indicated by lighter colours on top of elevation).


Lester B. Pearson Building, East elevation of west tower, reflective heat patterns at corner conditions, air leakage patterns at parapets with moisture accumulations behind spandrel panels.


Federal Food Lab, Agassiz, BC. Air leakage at wall / roof joint on end wall of office section of lab.


Roof leak pattern


Roof leak at parapet

Examples and Infrared Images, Electrical Systems

Examples of Maintenance Testing Using Infrared Cameras Images:

Internal breaker connection problems are shown in these infrared images here.

Examples of Mechanical Systems

See Predictive Maintenance Using Infrared Cameras Images for other examples.


Piping - IR camera assess the condition of dozens of vessels and miles of piping, all of which operate under extreme heat and pressure.


Belt Drive (before): Note high temperatures present in the left thermogram.
First Thermogram: 8/28/97


Belt Drive (after): Second thermogram presumably after repair or alignment.
Second Thermogram: 9/18/97

Some of the mechanical systems that can be successfully inspected by thermography are:

List of Reports

Date:
Pre 1998
Location:
National Capital Region

Project / Building - National Capital Region

Location:
Quebec (Montreal)

Project / Building - Quebec

Location:
Nova Scotia

Project / Building - Nova Scotia

Location:
Newfoundland and Labrador

Project / Building - Newfoundland and Labrador

Date:
1998
Location:
National Capital Region

Project / Building - NCR 1998

Date:
1999
Location:
National Capital Region

Project / Building - NCR 1999

Date:
2000
Location:
National Capital Region

Project / Building - NCR 2000

Location:
Montreal, Quebec

Project / Building - Quebec 2000

Date:
2001
Location:
National Capital Region

Project / Building - NCR 2001

Location:
Montreal, Quebec

Project / Building - Quebec 2001

Date:
2002
Location:
National Capital Region

Project / Building - NCR 2002

Location:
Prince Edward Island

Project / Building - PEI 2002

Date:
2003
Location:
Montreal, Quebec

Project / Building - Quebec 2003

Location:
Agassiz, British Columbia

Project / Building - BC 2003

Location:
Sault St. Marie, Ontario

Project / Building - Ontario 2003

Inquiries

For further information, please contact tpsgc.sngp-npms.pwgsc@tpsgc-pwgsc.gc.ca.

Associated Documents

Standards

Toolkit

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