Building Diagnostics



Outer Walls of Buildings

Finishing materials for outer wall of buildings, such as tile and coated structures, tend to peel from the base concrete because of defective construction or age deterioration. When the peeling or release area expands, finishing materials may release and fall from the wall and injure pedestrians.  Recently, falling material accidents have become and increasing social problem.  Accordingly there has been a focus on outer wall material failure preventive maintenance.

The Ministry of Construction of Japan has issued diagnostic guidelines for outer walls using the "Infrared Equipment Method". Outer wall diagnosis is now being conducted by this "Infrared Equipment Method", External Appearance Observation Method, Tapping Method, Repulsion Method, or a combination of these methods.


Principles of “Infrared Equipment Method”

In the peeled area, spacing develops between base concrete and finishing materials, such as tile or coated structure, where the space forms thin aerial layer which does not tend to conduct heat. Generally, when sunlight hits and heats up the outer wall of building, heat flows from outer wall to inner wall, creating a temperature gradient with the outer wall higher in temperature and inner wall lower. In this state, the temperature gradient is different between intact area of wall and peeled area, where an aerial layer is created. Assuming the condition of sunlight is constant, the temperature of peeled area is higher than that of intact area. (Fig.1) Also, the temperatures of those areas vary according to changing sunlight conditions. (Fig.2) Therefore, by measuring the temperature on the wall surface, peeled area can be detected as temperature difference. This method, using Infrared Thermal Image Equipment, is called as "Infrared Equipment Method" in the diagnostic guidelines.


Deterioration States of Mortar under Beam
High temperature portions in upper left and left of window frame represent crack and peeling respectively. (by TVS-2000MkIILW)


Advantage Infrared Equipment Method for Outer Wall Diagnosis

As compared with the conventional standard diagnosis method by tapping outer wall of buildings with test hammer, "Infrared Equipment Method" has the following advantages.

  1. Higher efficiency, because of non-destructive and short time diagnosis for wider area.
  2. Higher safety and lower cost, without the need of constructing scaffolding.
  3. Effective and persuasive image data of measurement, which can be recorded and saved.

Regarding the Committee of Building Diagnostic Researches by TVS 

For those who are trying the diagnosis with TVS for the first time, support is provided by the Committee of Building Diagnosis with TVS in Japan. This committee is organized by members from diagnostic servicing companies for building outer wall, to improve diagnostic quality of diagnosis of outer wall of building by Infrared Equipment Method, and also provides the following services voluntarily:

  1. Training for newly joined members.
  2. Presentations of diagnosis examples.
  3. Lectures by academic authorities.

It was established in 1983, and has members of 90 companies (as of April 1996).

Observation of coated structure wall of a condominium.
Peeled areas are detected as the high temperature portions. (by TVS-2100)

Thermal image of the outer wall after epoxy resin has been injected into gap created from peeling.
Even the number of injection holes and the resin extent can be observed (by TVS-2100)