New Standard for Article 12 Inspections: Record Deterioration Sites with AR for Zero Oversights and Complete Safety Management

Overview of Article 12 Inspections and On-site Challenges

Article 12 inspections are regular inspections mandated for owners of buildings above a certain scale that are used by an unspecified large number of people (so-called specified buildings), under Article 12 of the Building Standards Act. Targets include hospitals, schools, department stores, and apartment complexes, and the purpose is to confirm that buildings remain in a safe condition for continued use. In particular, deterioration of building exteriors—such as exterior walls, rooftops, and emergency staircases—carries serious life-threatening risks like falling tiles or rooftop waterproofing leaks, so early detection and response through Article 12 inspections are required.

However, various issues have been pointed out in the field regarding the execution and reporting of regular inspections. The burden of preparing documents that consolidate inspection results into photos and drawings is heavy, and manual work often leads to recording errors. In addition, differences in inspectors’ experience and skill lead to omissions and variability in assessments, causing disparities in survey accuracy. These problems have driven demand for making safety management “zero oversights.”

Attention is therefore turning to new inspection methods that leverage AR (augmented reality) technology. Combining AR on smartphones or tablets with 3D scanning makes it possible to dramatically improve the accuracy of recording deterioration sites and the efficiency of work. This article explains in detail the benefits of AR utilization as a new standard for Article 12 inspections, concrete usage scenarios, and the transformational impact of the innovative solution LRTK on inspection operations.

Conventional Inspection Methods and Their Limitations

Currently, in many cases, Article 12 inspections are conducted using an analog approach that relies on paper drawings and photographs. Inspectors carry building plans and elevation drawings, and each time they discover a deterioration site they mark a circle or number by hand on the drawing. Simultaneously they take situation photos with a digital camera, and later match the photos to the numbers to record them. Detected defects—such as bubbled waterproofing sheets on rooftops, cracks in exterior wall tiles, or rust on emergency staircases—are all managed with paper ledgers and photos, and eventually compiled into the prescribed report form submitted to authorities.

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

• Cumbersome recording work: Organizing inspection results with drawings and photos requires significant effort. Marking drawings, numbering photos, transcribing into reports—because much of this is manual, human errors easily occur and the workload is very high.

• Ambiguity of deterioration location: Hand-drawn marks have limits in precisely identifying locations. For example, even if a crack is found on the north exterior wall, a circle on a drawing alone may not accurately convey the exact spot, and a photo alone may not make the extent or precise location clear. As a result, repair personnel may search the site or miss the location.

• Mismatch at re-inspection: When comparing past records at the next inspection, differences in marking methods or scales between then and now make it hard to determine whether it is the same spot. On paper it is also difficult to quantitatively track deterioration progression, so understanding long-term change tends to be insufficient.

• Inspector-dependent inspection accuracy: Methods like sounding surveys rely heavily on an inspector’s experience and intuition, creating differing risks of oversight between veterans and newcomers. High-elevation inspections often rely on binocular visual checks, so individual eyesight and attention can affect results. Inspection quality is not standardized, and accuracy varies depending on who performs the inspection.

As such, the traditional approach has limits in achieving zero oversights, and inspection work has been subject to inconsistencies and inefficiencies.

LRTK’s Innovation in 3D Scanning and AR Recording

A solution that has emerged to address these issues 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. Using LRTK dramatically improves “accurate current-state understanding” and “efficient recording” during inspection work. Its main features are:

• 3D point cloud scanning: Using the iPhone’s built-in LiDAR sensor and camera, the building exterior is converted into three-dimensional data. High-precision point clouds with global coordinates (geodetic coordinates) can be obtained, recording the building’s shape and deterioration sites in three dimensions.

• AR-based deterioration marking: The model obtained from the 3D scan is projected into real space so that virtual marks can be placed on deterioration sites as seen through the screen. Because LRTK is equipped with high-precision positioning technology (RTK-GNSS), model-to-reality alignment is performed automatically and markers do not shift. With a single tap, an inspector can place a marker on a crack or other defect and accurately record its position on the spot.

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

• Dimension measurement and area calculation: On the acquired 3D data, the dimensions of deterioration sites and area calculations can be performed on-site. For example, the length of a crack or the extent of a rusted area can be measured immediately in the app, enabling quantitative assessment of deterioration.

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

These functions collectively eliminate the traditional inspection problems of cumbersome recording work and ambiguous location information. On-site recording work becomes vastly more efficient, and the collected data is highly accurate and systematic. For example, without relying on drawings or handwritten notes, deterioration sites can be understood spatially so the same information can be shared by anyone who inspects the site, reducing person-dependent variability. LRTK introduces digital capability to Article 12 inspections and can be considered an innovative tool that truly represents a new standard for inspection work.

AR Use Cases in Specific Inspection Scenarios

Rooftop Waterproofing Blisters

Large building rooftops are prone to blistering (bulging) or tearing of the waterproofing membrane due to aging. Conventionally, inspectors would walk across the entire rooftop and visually search for abnormalities, mark discovered blisters with chalk, and photograph them. This leaves concerns about potential oversights, but AR-based inspection greatly reduces those worries.

First, if the entire rooftop is scanned with LRTK to obtain a 3D model, the whole rooftop surface is recorded as data. Inspectors in AR mode can survey the rooftop and place markers on bulges or cracks in the waterproof layer on the spot. For example, upon finding a blister about 30 cm in diameter, an inspector taps the corresponding spot on the phone screen to place a marker and take a photo. That blister is then recorded on the 3D model at an accurate position, and the photo retains coordinate information. By recording all anomalies in this way, where and how many deterioration sites exist on the rooftop becomes immediately clear.

An advantage of AR is that, even on a large rooftop, inspectors can intuitively see which areas have already been checked. Because markers are visualized on the digital 3D model, it is easy to verify at a glance whether any areas were missed. LRTK also allows on-site measurement of each blister’s size. Recording blister diameters or areas numerically helps with later repair planning. At the next inspection, previous markers can be compared to determine 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 Tiles on Exterior Walls

On tiled exterior walls, tiles or mortar can lose adhesion over time and detach from the substrate, a condition known as tile detachment. If left unaddressed, detached tiles can fall and cause accidents. Therefore, comprehensive sounding tests or infrared thermography surveys are used to identify detached areas that require repair. Traditionally, inspectors would mark or tape near abnormal tiles and record locations with photos and drawings. This often forced reliance on vague descriptions like “the tiles a few pieces above the right side of room ○○’s window,” making later precise location identification difficult.

Using AR for inspections enables accurate recording of detachment locations even at height. By creating a 3D model of the building exterior with LRTK and conducting close-up surveys from scaffolding or elevated work platforms, inspectors place markers on the exterior wall model displayed on their smartphone whenever they find a detached tile. All mapped detachment sites are saved as three-dimensional coordinate data. For example, even a single detached tile on the north face of a ten-story building is registered pinpoint on the building model, allowing repair crews to find the exact spot on site without confusion. Whereas previously one had to search while comparing drawings and guessing “probably around here,” AR’s visual guidance prevents location mix-ups and oversights.

Moreover, improved recording accuracy makes it easier to monitor detachment over time. During re-inspection, overlaying previous markers in AR enables precise tracking of condition changes at the same spot. Whether “a previously detached tile has further lifted” or “new detachments are appearing nearby,” such changes are not missed, allowing repair priorities to be determined based on data. LRTK provides an objective metric—coordinates—to what was previously subjective in exterior wall surveys, contributing to reliable and safe inspections.

Rust on Emergency Staircases

External emergency staircases are constantly exposed to wind and rain, making them prone to corrosion. Regular inspections check handrails, treads, and bolt joints for corrosion, but it is not easy to record the progression of rust in detail. Using traditional methods, inspectors might note “rust near the landing on an intermediate floor” or roughly capture rust areas in photos, making it difficult to locate the exact same spot at the next inspection.

AR inspections with LRTK allow exhaustive capture of rust occurrence even on complex staircase structures. By scanning the entire staircase in 3D, inspectors can record three-dimensional data that includes typically hidden areas such as the undersides of treads and handrail joints. Inspectors can zoom in on parts of interest in AR and add successive markers to rusted areas. For example, notes like “advanced corrosion at the ladder-like handrail joint between floors 3 and 4” or “coating peeling on the underside of the floorboard at the second-floor landing” can be plotted precisely on the staircase model.

With this approach, different inspectors can share exactly the same defect locations. At the next inspection, previous markers can be displayed in AR to check whether rust has expanded or whether appropriate repairs were performed. If repaired, markers can be deleted, enabling the staircase’s maintenance history to be accumulated on the electronic model. For report preparation, instead of vaguely writing “west side of the stairs” on a paper drawing, inspectors can capture images of the 3D model with arrows and annotations to create clearer materials. Using AR and point cloud data makes inspection of complex emergency staircases both efficient and reliable.

Digitizing Inspection Records: Report Preparation and Time-Series Comparison

Digital technologies applied to Article 12 inspections not only streamline on-site work but also offer the major advantage of turning each building’s inspection records into an ‘electronic medical record’. With paper reports, individual inspection results were filed away, but with LRTK inspection histories can be accumulated in a database for each building from past to present. The idea is like managing a patient’s medical history electronically in a hospital—each building can have a digital chart.

This electronic medical record makes time-series comparison and analysis straightforward. For example, for the same crack in an exterior wall, LRTK can switch between a photo from three years ago and one from this year so you can immediately determine whether the crack has widened. Because the photos are tied to coordinates, you can accurately 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 appropriate repair timing, enabling preventive maintenance rather than one-off inspections.

Report creation is also dramatically simplified. Previously, photos were pasted into ledgers and locations and conditions were described in text, but with LRTK you can directly use marker-attached photos or captures of the 3D model for each inspection item. Tedious drawing annotations are no longer necessary, and reports can include persuasive visual materials. Digital data can be shared within the company or with clients with one click, reducing miscommunication about report contents. In the future, routine report entry into administrative forms may even be automatically output from such systems.

By digitizing Article 12 inspections into electronic medical records, building safety management becomes continuous and systematic. Each inspection updates the data, allowing you to monitor a building’s “health” over the long term and supporting the development of appropriate maintenance plans. For building owners, digitally managed past inspection results also provide secondary benefits such as materials for asset valuation or insurance procedures.

Conclusion: The Future of Article 12 Inspections and Why You Should Consider LRTK

With technological advances, Article 12 inspection methods are now at a turning point. The Ministry of Land, Infrastructure, Transport and Tourism has begun formally accepting surveys using drones and sensors, and DX (digital transformation) of inspection work will accelerate further. Within this movement, AR-based inspection methods are gaining attention as a key to realizing the ideal of zero oversights and complete safety management.

The LRTK introduced here is a platform that supports this next-generation inspection approach. Its strengths lie in the ease of use with a smartphone and a dedicated device while delivering surveying-grade accuracy for 3D scanning and position recording. Because LRTK’s highly accurate GNSS-based positioning links data to map coordinates, integrating inspection results with building-wide management information and drawing data is straightforward. With basic surveying functions included, LRTK also enables applications like measuring precise site or structure dimensions and displacements during inspections, and the acquired point cloud data will be useful for future integration with BIM and maintenance management systems. Thanks to this wide compatibility, introducing LRTK can drive DX benefits 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 proactively adopt new technologies. The new standard for Article 12 inspections using AR has already begun. Why not take this opportunity to consider LRTK-based inspection methods? Now is the time to harness the latest technologies to elevate your building safety management to the next level.