Setting Up RT Percentages for Each Spec

Random Radiography requirements involve testing a percentage of each welder’s welds on a project. For example, ASME Code B31.3, “Process Piping” requires five percent random radiography as the default inspection requirement. The five percent figure is applied to each “lot” of welds. If a defect is found, additional welds (“tracers” or “progressives”) from the same lot are tested and depending on the results, it may be necessary to test every weld in the lot.

This means that it is in the fabricator’s interest to limit lot sizes. In particular, it is desirable that all welds in any given lot remain in the fab shop until the lot has passed NDE requirements. At the same time, the fabricator does not want an excessive number of lots, because even at 5% RT, every lot must have at least one weld tested, even if the lot consists of a single weld.

SpoolFab can help with assigning welding lots. It is assumed that each lot is associated with a specific welder and general weld type (“genre”). Thus any given lot may contain only branch welds, buttwelds, fillet welds, or socket welds. It may or may not be permissible to mix welds from different pipe specs in the same lot. To accommodate this, SpoolFab uses the Specification Group or “SGroup” parameter, which is entered as part of the spec, see below.

The RTEditor utility allows editing and review of NDE requirements for all specs in a project at one time. RTEditor also allows for customization of the conditions under which a new welding lot is to be assigned. If the SGroup is left blank for all specs, all welds in the project will belong to the same SGroup, meaning that welds from any spec are allowed to coexist in the same lot. If all SGroups are different (as would be the case if each SGroup were the same as the corresponding spec), each lot will contain only welds from one pipe spec. If it is permissible for certain specs to coexist in a weld lot, those specs can be assigned the same SGroup. The screenshot below is from the RTEditor utility.

It is important to get the SGROUP and RT% set up correctly in all specs BEFORE assigning any lot numbers.

Assigning Lot Numbers

Display the first fabrication drawing for which lot numbers are to be assigned. Press Ctrl-T to bring up the weld editing window. The three columns highlighted below are needed for the lot assignment feature. If one or more of these columns is missing, select Set/Revert to default widths and headers.

The RT% column is just for information and is not editable. It shows the percent RT required for each weld according to the spec. The Lot No. column is normally filled in by the program. The Test/Pass/Fail column is filled in by the user, by entering the letter T, P or F. The existing column INSP1 is used to store the X-Ray number.

Before a welding lot number can be assigned to a weld, it must already have a WelderID and Weld Date. If some welds have not been done yet, you can still assign lot numbers to those welds that have been completed.

Assigning lot numbers is easy; you simply select Tools/Assign Lot Numbers or use the shortcut Ctrl-A. This will assign lot numbers to any Shop welds in the current fabrication drawing that have been assigned a WelderID and a Weld Date. For example, if no lot numbers exist so far in this project, the program will assign lot numbers as follows:

Rules on Assigning Lot Numbers:

Before a weld can be assigned a lot number, it must have at minimum a WelderID and a weld date. If welding procedure is to be considered in assigning lot numbers, then the procedure also needs to be entered before lot numbers are assigned.

SpoolFab assigns a maximum of 20 welds in any lot. If there is an existing partially-filled lot, more welds may be added to it. However, depending on the settings in RTEditor, the presence of entries under TEST/PASS/FAIL or an X-Ray number may close out the lot to any additional welds.

Currently, lot numbers can still be edited by the user. This should not be done without some special reason.

There are three reports to help with NDE. They are reached from Fabrication Status via the NDE menu.

RT Status, All Lots involving RT

This report lists all lots that exist for the job, whether they already have sufficient RT or not.

RT Status/Lots needing RT

This report lists lots for which insufficient RT has been completed. It is designed to help the user specify which welds are to be X-Rayed. The user designates welds for RT from the drawing by placing TEST in the PASS/FAIL column. TEST is replaced by PASS or FAIL once the result is known. These entries are made by pressing the T, P or F keys.

The report includes lots for which sufficient RT may have been scheduled, but whether that will be sufficient will not be known until the results come in.

RT Status/Welds needing RT

This report lists welds which have been designated for RT, but which do not yet have a result.

Welder Stats

This report is organized on the basis of weld genre and percentage RT required. It lists the number of welds done by each welder, along with the number X-Rayed, and the percentage rejected.

Flagging Welds as TEST, PASS, or FAIL

To flag welds for testing, or to enter test results, display the spool and press Ctrl-T or select Edit, Welds, Edit Weld Tags. To flag a weld for testing, place the focus on that weld’s Pass/Fail column and press T. Similarly, press P or F to record a Pass or Fail.

If a weld fails, press F to enter the result as a FAIL, then, with the focus still on the failed weld, select from the X-weld menu the item Add X-weld as repair. This weld will have to be tested again, so press T to schedule that weld for testing after it is repaired. You will also need to select two other welds from the same lot for testing as tracers. For clarity it is suggested you mark these tracer welds with TEST1 rather than TEST, and the result as PASS1 or FAIL1. To change FAIL to FAIL2, press the “2” key.

If one of the primary tracer welds fails, you will need to select two secondary tracer welds from the same lot. If this happens, it is suggested you use TEST2 to select the secondary tracers and PASS2 or FAIL2 to show the result. If one of the secondary tracer welds fails, you will need to test all the welds in the lot.

Marking any weld with FAIL2 means the lot will require 100% RT before it ceases to appear on the list of lots requiring RT. If for some reason 100% RT is required for a lot other than because a secondary tracer failed, it is suggested you make this clear by entering FAIL3 rather than FAIL2.

Flagging Welds as CLOSED

Prior to SpoolFab version 8-796, the only options for the PASS/FAIL field for welding lots were TEST, PASS, or FAIL, sometimes with the addition of 1, 2, or 3. There is now also the option of marking a welding lot as CLOSED to additional welds without having to commit to which welds are actually going to be tested.