Geotechnical Laboratory’s Guide to AGS Data

The speed with which consultants are able to analyse and plot laboratory data is the main reason why AGS data is requested for medium to large construction projects.    For a significant number of laboratories the production of AGS data is causing a number of problems but these can be easily avoided if the requirements are clearly thought out at the start of a project.

This article highlights the two most common problems and details the best way laboratories can benefit from AGS data.

The data contained within an AGS file generated by a laboratory can be split into two broad categories: sample data and test data.

The Sample Data is generally passed to the laboratory from the customer and consists of location data and sample parameters.   This data is traditionally supplied to the laboratory either via an Excel schedule sheet or simply via a paper hard copy.

The Test Data are the results that the laboratory has produced from the tests carried out.  Each set of test parameters is linked back to the source sample using 4 reference parameters: Location ID, Top Depth, Type and Reference Number.  If more than one test has been carried out on a sample then a unique specimen number and/or depth are assigned to each test to make it uniquely identifiable.

The biggest AGS-related problem that laboratories is:-

  • Maintaining the client’s sample reference data

AGS Sample References.

The biggest single cause for AGS data disputes between consultants and laboratories is that the returned test data references samples that do not exist in the client’s data.  This is caused either by the laboratory incorrectly entering and storing the client’s data or the client changing the reference data after they have supplied it to the laboratory.

The laboratory’s job is therefore to ensure that it does not change the client’s references. Further, if the client changes the references, the laboratory can prove without doubt that the problem lies with the client and not the data produced.

The secret to avoiding the above scenarios is to get the sample data from your client in an electronic format, preferably in AGS format.

The majority of customers who ask for AGS as a deliverable will be able to produce their sample and location data in AGS data format when they schedule their testing. 

A key point for laboratory managers “If they ask for AGS data then you ask for AGS data at the start of the project”.

Once you have the AGS data it is important that you keep a copy of the file to send back to them.  Let me repeat that-  you are going to send the very same file back to them at the end of the project!

The next step is to produce your test data in AGS format, but do not include the location and sample tables in your exported AGS file.  If your software does not allow you to exclude this information, don’t worry. The AGS Toolkit has a replacement feature that allows you to replace the LOCA and SAMP table in your Test results file with the original data from your client. 

If the AGS checker finds errors with the sample referencing between the files, the laboratory has entered the data incorrectly. These errors will need to be fixed before you submit the data to your client. 

If there are no errors with the data, then you can send both files to the client and know that if they come back with sample referencing problems in the file, then these problems were caused by the client.   You will know this for a fact as you saved their own file and have included their SAMP and LOCA tables back in exactly the same format they sent it to you.

Watch out for SAMP_ID

AGS added a 5th sample reference called SAMP_ID to work as a single sample reference when it is important for environmental testing locations to remain anonymous. This field is to be completed only if the client has included it in their file. For the majority of clients this fields will be blank. Most Lab software that produce AGS, such as KeyLAB have an option to not include the data in SAMP_ID on the export.

Benefits for the Laboratory

AGS data is often seen as a hassle and costly request from a client.  However if the laboratory focuses on the benefits that AGS data can provide the laboratory at the start of a project then it can save them a large amount of time in setting up projects by getting their client to do the data entry for them.

If the simple procedure outlined in this article is also followed, then the laboratory should never be involved with sample referencing disputes with their clients.