As the name suggests, As Built Data Capture is the process of taking measurements from existing buildings, plant and equipment and recording them.
Why use “As Built Data Capture?”
Over time plant and equipment is often modified and the necessary changes to the site plans can be forgotten and left unchanged.
This can cause a problem for safety where plans do not reflect the subsequent changes made. Missing hazardous area classifications or revisions where new installations prevent a clear fire exit route from buildings obviously have major safety implications.
As built data capture is versatile in its application and can also be used to check land settlement and subsidence. The results from the as built data capture method, when compared against original design data will highlight any movement thereby aiding planned preventative maintenance scheduling.
As built data capture also assists with cut and carve projects, allowing early identification of potential clashes, reducing re-work which can impact on both time and cost.
In addition to the above, surveying can also provide information that can be used to update P & I D’s, Asset registers, Valve and Instrumentation Schedules, which aids companies that hold or are working towards ISO 9000+ or are regulated by an external body – such as the pharmaceutical industry’s FDA as they are obliged to keep P&ID’s and Asset Registers etc fully updated.
What methods are available for obtaining As Built Data Capture?
- As Built Data Capture via Manual site surveys using tape measures
- As Built Data Capture via Laser Scanning
- As Built Data Capture via Photogrammetry
- As Built Data Capture via Topographical Surveys
- As Built Data Capture via Ultrasonic Testing
Depending on your requirements and your chosen method, as built data capture can vary greatly in terms of its accuracy, complexity, time taken and cost.
Deciding on the best option for your as built data capture depends on what you are surveying – if the site is relatively small and un-complex and your need is for a low accurate survey you can opt for the manual site survey using the traditional tape measure and measuring wheel.
If the area requiring as built data capture is complex (for example there is a vast amount of pipe work, it difficult to access, or there is a need to survey at height), Laser Scanning may be a better option. It is highly accurate, providing data at a +/- 4 mm accuracy over a distance of 50 metres. The use of Laser Scanning means that it removes the need for scaffolding or cherry pickers for at height working and therefore reduces the health and safety risk and the cost. Laser Scanning is also extremely accurate and quick to import the information into the appropriate software (for example AutoCAD) allowing easy manipulation.
Laser Scanning although accurate, does not work well if you are surveying equipment which contains glass wear or if the area you wish to survey is very dense. A better means of as built data capture would be to use Photogrammetry. Although more expensive and more time consuming in terms of image manipulation, Photogrammetry does provide accurate results.
Topographic surveys are a good choice for as built data capture, particularly for land surveying; using a total station and GPS, the topographical survey provides highly accurate data, including land elevation.
Ultrasonic Testing uses high frequency sound energy to obtain accurate dimensional data; it is highly sensitive to both surface and sub-surface discontinuities and the depth of penetration for flaw detection is superior to other methods of as built data capture. Ultrasonic Testing is a time effective means of as built data capture as its electronic equipment provides instantaneous results.