New Common Sense for Article 12 Inspections: Record Deteriorated Areas with AR, Achieve Zero Oversights and Complete Safety Management

Overview of Article 12 Inspections and On-site Challenges

Article 12 inspections are periodic inspections required under Article 12 of the Building Standards Act for building owners of structures of a certain scale used by unspecified large numbers of people (so-called specified buildings). Hospitals, schools, department stores, and apartment buildings are subject to these inspections, which aim to ensure that buildings continue to be used in a safe condition. Deterioration of exterior elements such as exterior walls, rooftops, and emergency staircases can pose serious life-threatening risks, such as tile detachment accidents or leaks in rooftop waterproofing, so early detection and response through Article 12 inspections are required.

However, on-site practice points out various challenges in conducting and reporting these periodic inspections. The burden of preparing documents that compile inspection results into photos and drawings is heavy, and manual work often causes recording errors. In addition, differences in inspectors’ experience and skills lead to missed issues and inconsistent evaluations, resulting in variance in survey accuracy. These problems have increased demand for achieving “zero oversights” to ensure complete safety management.

One promising approach is a new inspection method using AR (augmented reality) technology. By combining AR on smartphones or tablets with 3D scanning, it has become possible to dramatically improve the recording accuracy of deteriorated areas and work efficiency. This article provides a detailed explanation of the benefits of AR utilization as the new common sense for Article 12 inspections, concrete usage scenarios, and how the innovative solution LRTK transforms inspection work.

Conventional inspection methods and their limitations

Currently, in many cases Article 12 inspections are conducted using an analog approach with paper drawings and photographs. Inspectors carry building layout plans and elevation drawings, and each time they find a deterioration they mark circles or numbers by hand on the drawings. At the same time they take photos with a digital camera and later match the numbers to the photos to record them. Discovered defects—such as blistering of rooftop waterproof sheets, cracks in exterior wall tiles, or rust on emergency staircases—are all managed with paper ledgers and photographs, and ultimately compiled into the prescribed report form for submission to the authorities.

However, this conventional method has several problems. The main issues are as follows:

• Complexity of recording tasks: Organizing inspection results using drawings and photos requires significant effort. Marking drawings, numbering photos, and transcribing into reports involve much manual work, so human errors are likely and the workload is very heavy.

• Ambiguity of deterioration location: Hand-drawn marks have limits in pinpointing deterioration locations. For example, even if a crack is found on the north exterior wall, a circle on the drawing alone may not convey the exact part, and a photo alone may make it difficult to grasp the extent or location. As a result, repair personnel may have to search around on site or risk missing the spot.

• Mismatch during re-inspection: When trying to compare past records at the next inspection, differences in marking methods or scale between the previous and current inspections can make it hard to determine whether they are the same location. On paper media it is also difficult to quantitatively track deterioration progression, so understanding of long-term changes tends to be insufficient.

• Inspection accuracy dependent on the individual: Methods such as sounding inspections rely heavily on inspectors’ experience and intuition, creating a difference in the risk of oversight between seasoned and novice inspectors. High-elevation inspections often depend on binocular visual checks, so results can be influenced by an individual’s eyesight and attentiveness. Inspection quality is not standardized, and accuracy varies depending on who conducts the inspection.

In this way, the traditional methods have limits in achieving zero oversights, causing inconsistencies and inefficiencies in inspection work.

The innovation in 3D scanning and AR recording achieved by LRTK

A solution that addresses these challenges is LRTK. LRTK is an innovative inspection support system that combines a smartphone (iPhone) with a dedicated device to achieve high-precision positioning, 3D scanning, and AR display. By using LRTK, the “accurate understanding of current conditions” and “efficient recording” in inspection work can be dramatically improved. Its main functions are as follows:

• 3D point cloud scanning: Use the iPhone’s built-in LiDAR sensor or camera to convert the building exterior into three-dimensional data. High-precision point clouds can be acquired with global coordinates (geodetic coordinates) attached, allowing three-dimensional recording of the building’s shape and deteriorated areas.

• AR-based deterioration marking: The model obtained from the 3D scan can be projected into real space, allowing virtual marks to be placed on deteriorated areas as seen through the screen. LRTK includes high-precision positioning technology (RTK-GNSS), so model-to-actual alignment is performed automatically and marked points do not shift. With a single tap you can place markers on cracks found on site and record their positions accurately.

• Photos with coordinates: Photos taken during inspection are automatically linked with information such as latitude, longitude, altitude, and camera orientation. This makes it intuitive to know “which location the photo shows” when reviewing photos later. Photos themselves act like pins on a map, preventing omissions and mix-ups without having to cross-reference drawings or notes.

• Dimension measurement and area calculation: On the acquired 3D data, you can measure dimensions and calculate areas of deteriorated parts on the spot. For example, you can immediately measure the length of a crack or the extent of a rusted area within the app, allowing quantitative assessment of deterioration.

• Cloud connectivity: Inspection data can be saved and shared in the cloud, making it easy to review details on a PC after returning to the office or to share data with stakeholders. Even those without specialized software installed can view 3D models and photos via a web browser, lowering the barrier to information sharing.

These functions collectively resolve the conventional problems of complex recording tasks and ambiguous location information. On-site recording work is greatly streamlined, and the obtained data are extremely accurate and systematic. Because deteriorated areas can be understood spatially without relying on drawings or handwritten notes, the same information can be shared by anyone conducting the inspection, reducing individual variation. LRTK introduces digital power into Article 12 inspections and can truly be called an innovative tool that becomes the new common sense for inspection work.

Examples of AR use in specific inspection scenarios

Rooftop waterproofing blisters

Rooftops of large buildings are prone to blistering (bulging) or tearing of waterproof sheets due to aging. Traditionally, inspectors would walk thoroughly across the wide rooftop looking for abnormalities by eye, mark found blisters with chalk, and photograph them. This leaves concern about missed spots, but AR-enabled inspections greatly reduce that concern.

First, if you scan the entire rooftop with LRTK to obtain a 3D model, the whole rooftop surface is recorded as data. Inspectors can view the rooftop in AR mode and place markers on waterproof layer blisters or cracks on the spot. For example, if a bulge about 30 cm (11.8 in) in diameter is found, the inspector can tap the corresponding spot on the smartphone screen to place a marker and take a photo. That bulge is then recorded at the precise position on the 3D model, and the photo retains coordinate information. If all anomalies are recorded in the same way, it becomes immediately clear where on the rooftop the deteriorations are located.

An advantage of AR is that even on a large rooftop you can intuitively grasp which areas you have already inspected. Because markers are visualized on the digital 3D model, you can instantly check for uninspected spots. Furthermore, LRTK allows you to measure the size of each blister on the spot. Quantifying the blister diameter or area and recording it helps in later repair planning. At the next inspection, you can easily compare marked locations from the previous inspection to see whether new blisters have appeared or existing blisters have enlarged. For achieving precise rooftop inspections with zero oversights, AR and 3D data are powerful tools.

Detached exterior tiles

On tiled exterior walls, aging can reduce adhesion of tiles or mortar, causing tiles to detach from their substrate. If these detached tiles are left unattended, tile fragments may fall and cause accidents. Therefore, full-area sounding inspections or infrared thermography surveys are used to identify detached areas and determine repair needs. Traditionally, inspectors would mark near the abnormal tiles with chalk or tape and record positions with photos and drawings. This method often had to rely on vague expressions like “the tiles a few pieces above the right side of the window of room XX,” making it difficult to pinpoint the exact location later.

With AR inspections, even high-elevation detached tiles can be recorded accurately. Create a 3D model of the building exterior with LRTK and, while conducting close-up surveys from scaffolding or aerial work platforms, place markers on the exterior wall model displayed on the smartphone each time a detached tile is found. The mapped detached spots are all saved as three-dimensional coordinate data. For example, a single detached tile on the north-facing exterior wall of a 10-story building can be registered pinpoint on the building model, enabling repair personnel to find the exact location on site without confusion. Whereas before they had to stare at drawings and guess “probably around here,” AR visual guidance prevents location mix-ups and oversights.

Moreover, improved recording accuracy makes follow-up observation easier. By overlaying the tile positions marked at the previous inspection in AR during re-inspection, you can accurately track condition changes at the same spot. Information such as “the tile that was previously detached is now protruding further” or “new detachments have appeared nearby” will not be overlooked, allowing repair priority to be determined based on data. LRTK gives exterior wall surveys—previously prone to subjectivity—a concrete measure in the form of coordinates, contributing to reliable and safe inspections.

Rust on emergency staircases

External emergency staircases are constantly exposed to wind and rain, making them prone to rust. Regular inspections check railings, treads, and bolt joints for corrosion, but it is not easy to record the progression of rust in detail. With traditional methods, inspectors might note “rust near the landing on an intermediate floor” or get only a rough idea of rust areas from photos, making it difficult to pinpoint the same location at the next inspection.

Using LRTK AR inspections, you can comprehensively capture rust locations even on complex stair structures. By scanning the entire staircase in 3D, you can create a three-dimensional record that includes typically hidden areas such as the underside of treads or handrail joints. Then, by zooming in on parts of interest in AR, inspectors can sequentially add markers to rusted spots. For example: “advanced rust at the ladder-shaped handrail joint between the 3rd and 4th floors,” or “paint delamination under the floorboard of the 2nd floor landing.” Such fine deterioration information can be plotted on the staircase model.

This approach enables different inspectors to share exactly the same defect locations. At the next inspection, you can display the markers from the previous inspection in AR and check whether the rust has progressed or whether repairs were properly carried out. If repairs are completed, markers can be deleted, allowing the building’s maintenance history to be accumulated on the staircase’s electronic model. When creating reports, instead of vaguely writing “west side of stairs” on paper drawings, you can capture images of the 3D model with arrows and annotations to produce clearer materials. Utilizing AR and point cloud data makes inspections of complex emergency staircases both efficient and reliable.

Digitalizing inspection records into electronic medical records: report creation and time-series comparison

Digital Article 12 inspections offer the significant advantage of turning each building’s inspection records into an “electronic medical record.” With paper reports, individual inspection results were only stored in files, but using LRTK allows you to accumulate inspection histories for each building in a database from past to present. Much like managing a patient’s clinical history with an electronic medical record in a hospital, you give a building a digital chart.

This electronic medical record makes time-series comparison and analysis easy. For example, you can switch between a photo from three years ago and one from this year on LRTK to instantly determine whether a crack has widened. Because the photos are linked to coordinates, you can precisely track long-term changes from exactly the same angle and position. The more inspection data you accumulate, the more you can analyze deterioration trends and predict repair timing, enabling preventive maintenance beyond single inspections.

Report creation is also greatly simplified. Traditionally, photos were pasted into ledgers and locations and conditions were described in text, but with LRTK you can directly use marker-attached photos and 3D model captures for each inspection item. The cumbersome task of annotating drawings is eliminated, and reports can include persuasive visual materials. Digital data can be shared with colleagues or clients with one click, reducing communication errors in reporting. In the future, transcription into administrative periodic reports may even be automatically output from the system.

By digitalizing Article 12 inspections into electronic medical records in this way, building safety management becomes continuous and systematic. Since data are updated with each inspection, you can monitor a building’s “health” over the long term and develop appropriate maintenance plans. For building owners, digitally managed past inspection results can also serve as materials for asset valuation or insurance procedures, creating additional benefits.

Conclusion: The future of Article 12 inspections and recommendations for adopting LRTK

With advances in technology, Article 12 inspection methods are undergoing a major transformation. The Ministry of Land, Infrastructure, Transport and Tourism has begun to formally accept surveys using drones and sensors, and DX (digital transformation) of inspection work will accelerate further. In this context, AR-based inspection methods are attracting attention as the key to realizing the ideal of zero oversights and complete safety management.

The LRTK introduced here is a platform that supports such next-generation inspections. Its combination of the convenience of smartphones and dedicated devices with surveying-grade precision for 3D scanning and position recording is a major strength. Because LRTK’s data are based on advanced GNSS positioning and tied to map coordinates, it is easy to integrate inspection results with overall building management information and drawing data. LRTK also includes simple surveying functions, enabling applications such as measuring accurate dimensions and displacements of sites or structures during inspections. The acquired point cloud data can be useful for future integration with BIM and maintenance management systems. With this broad compatibility, adopting LRTK can drive DX not only for Article 12 inspections but for overall building maintenance management.

For safe and secure building operation, it is important not to cling to old methods but to actively adopt new technologies. The new common sense for Article 12 inspections using AR has already begun. Why not consider LRTK-based inspection methods at this opportunity? It is time to leverage the latest technology and take building safety management to the next level.