Propane tanks require a certain certification, a “pedigree.”  They have to be constructed to some very specific requirements, depending on their expected use.

The tanks we see in common use are made to either US DOT specifications or to the American Society of Mechanical Engineers Code.  There are a few other tanks allowed for very specific services, such as railcars, but these are not allowed for common service.

DOT cylinders have collars on them that contain information about what rules applied to their manufacture.  Steel cylinders have a different specification than aluminum cylinders or composite cylinders.  You can see the applicable specification on the collar and it will guide you to the rules for requalification, continued use, and other requirements.  That’s one reason a cylinder’s collar must be firmly attached to the cylinder.  That is a cylinder’s pedigree.

Tanks built to the ASME Code can have their pedigree traced through the information on the name plate (dataplate).  There is nothing else on these tanks that provides that traceability, so the name plates must be protected from corrosion, impact, abrasion, or any other form of degradation.  When the name plate is lost or gets to the point when it cannot be read, the tank’s pedigree cannot be verified.

No pedigree; no service from that container.

Repairs That Require an R Stamp Name Plate

Any repairs made to ASME tanks that require cutting or welding on the pressure boundary of the tank require that work to be performed according to some strict requirements, including being witnessed and certified by a commissioned inspector. The forms for reporting this work are available through the National Board of Boiler and Pressure Vessel Inspectors (NBBI) website.

Such repairs also require an R stamp name plate to be added to the tank. Only those shops with an R certification are allowed to perform this work. You can get information from the NBBI about this certification.

Paper work that explains what was done to tanks should accompany the tanks for the rest of their service life in case some question comes up about some concern.

Reattachment of a Name Plate

The NBBI has a form NB-136 and instructions for how to submit it when a name plate must be reattached.  Please read the instructions carefully and pay extra attention to when an inspector, ours or a National Board Commissioned Inspector, is required, in some cases as a witness.  This form must be completed and submitted any time a name plate is reattached. If you get tanks from a tank refurbisher, you need to specify that this form will be supplied with the tanks, as necessary. An inspector may question a name plate that is not attached with the original method, and this paper trail will provide the justification.

A question came up about whether or not the name plate was ever completely removed from the tank. Some tank manufacturing experts were questioned about detaching one side at a time to clean and paint under the plate, never completely removing the plate.  The opinion was that a NB-136 would not be needed in this case.  However, since an inspector cannot tell how the work was done, he is entitled to see a paper trail of an NB-136 or a procedure or statement showing how the work was accomplished.

Some tanks from refurbishers appear that the tank shell was drilled into so the name plate could be attached by a pop-rivet.  That is not allowed.  You can never drill into the shell unless the hole is repaired according to procedures that require an R stamp name plate to be added.  And that is a whole new level of certification, covered by the above section.

Name plate integrity is a concern because we know that name plates have been improperly swapped by at least one company in North Carolina.  At one point we had three inspectors following up on leads provided by propane companies about improperly modified tanks.  In that case, several tanks were condemned and many propane companies and consumers lost a lot of valuable property - the use of their tanks.  We also know that some companies take shortcuts when doing tank maintenance, not documenting some R-stamp-type work or name plate reattachments. 

Duplicate Name Plates

There are times when the only reasonable action is to get a duplicate name plate for a tank so it can be remain in service or be moved. There is a general statute (G.S. § 119-61) that allows us to issue a plate to replace a rusting or partially-detached name plate. The fee is $20.00 per name plate. We will not remove the original plate, if it is still present, but will glue the duplicate next to it.

We must be assured that the data for the duplicate plate is accurate. The needed data must be retrieved from the existing plate or we must be able to see enough information (manufacturer, serial number and/or National Board number, at a minimum) that we can be assured that the correct manufacturers' data report is available to determine the required information.

If you have the original manufacturer's name and the National Board number assigned to that tank, then you can order a Manufacturers' Data Report for Pressure Vessels, for that tank. This form contains the required information for a us to provide a replacement name plate. You will be prompted to create a new account to access this information and they do change a fee. 

Inspection Requirements

If an inspector sees a tank where the name plate appears to have been reattached, you need to have a paper trail for what was done available for the inspector’s review.  The paper trail can be an NB-136 or it can be the procedures and records from the refurbishing company showing what they do during refurbishing for different problems and which tanks (serial numbers) underwent those procedures. 

If a tank is missing a name plate, it is unreadable, or suffcient information is not available to create a duplicate name plate, the that tank has lost it it's pedigree. We do allow such a tank to remain in service at that specific location. However it cannot be moved elsewhere, even on the same property as that would be viewed as a new installation, and placed into service.