Subsurface Hazard Recognition - Scaffolding
Designing a scaffold is engineering work, but building one takes experience and knowledge. Scaffolds are designed to provide a safe work environment for workers after it is built around a structure or a building. There are several maintenance works that are performed during turnarounds in industrial facilities. Large steam heaters or furnaces are being replaced or inspected within that short period of the time. In order to complete with all work tasks from an elevated platform the staging must be adequate and sturdy enough to provide safe work environment to the maintenance and/or inspection crew. It is important to build a scaffolding.
The image above is indicating a scaffolding project that looks properly done, possibly inspected and tagged by the following formal safety procedures.
There is always ONE type of HAZARD that people do not always think of that could pose a hazard, so most of the time it is not listed in the JSA. It is the SUBSURFACE HAZARD that should be taking it seriously and include it in the formal JSA. Subsurface hazard recognition should be taken as seriously as the lockout/tagout safety procedure. Subsurface defects such as void and sinkhole could develop underneath the concrete pad that is unseen until it collapses and caves in. That could cause serious issues in the facility.
Images below are showing a case study of a subsurface condition assessment around an industrial obstruction prior to building a scaffolding.
Scan area was engineered around the structure in the footprint of the scaffolding. The result of the GPR survey is shown on the following images.
The images above are radar cross sections that indicate anomalies (see RED markings) which are possible void locations beneath the pavement. Surface depression is noticeable on the last image that could be an indication of a developed sinkhole that is caving in.
The following image is an interpolated 3D radar image that is showing the lateral size of possible voids. Yellow rectangle is showing the footprint of the scaffolding.
In the result of the GPR survey, the unseen hazard was able to be recognized, thus mitigated, in the shallow ground zone.
