Top 3 Indications You Need an R-Stamp Repair

ASME (American Society of Mechanical Engineers) and NB (National Board) certification is an extensive procedure. An R-Stamp repair is required by the NB when the pressure vessel’s barrier is broken. These repairs include, but are not limited to, weld repairs, installation or replacement of nozzles, and attachment of components related to pressure parts. Here are 3 situations that may ultimately require recertification of ASME:

  1. Pressure boundary failure
  2. Field Modification
  3. Accident
Pressure Boundary Failure

Leaks coming out of the jacket, inlets, or pipes may be a sign that you need repair to the pressure-affected components or zone.

Examine the insulation cladding weep hole, normally in the lowest area of the cladding, to check for flow of fluid or steam that could be coming from the heating and cooling jacket. This may be the result of a crack or defect in the jacket.

Symptoms of increased water, steam, or glycol usage in the process, can occur in all types of ASME U or ASME UM vessels and all styles of jackets (shell, dimple, or half-pipe) as a result of the cracking or defect.

Field Modification

A new nozzle addition, or any weld to a code ASME vessel, for even a ladder bracket, may require a certified R-Stamp repair.

Before any field repair or modification of an ASME pressure vessel, consult the manufacturer or a qualified ASME / NB repair service. As the owner of an ASME pressure vessel, you are responsible for workplace safety and the liability and ASME certification of all repairs.

In extreme cases, unqualified work may result in scrapping the vessel. Material traceability and other ASME processes required for NB filing and certification become difficult to verify and prove.


In some accidents, improper thermal cycling may cause cracking of inlet and outlet areas of piping and cause stress detachment in the welds of the jacket and base material.

A damaged vessel wall or vessel internals from a tool dropping can cause damage to require repairs to a pressure boundary zone.

It is important to update organizational compliance standards, training, and work procedures to assess how damage and safety issues occur to develop prevention measures.

Whether a pressure boundary failure, field modification, or accident causes the need for repair, the first step is a Repair Evaluation. When accessible, thermal imaging, dye penetrant examination, or a radiographic inspection can help locate the defective areas. Then an estimated time of the job is performed with a schedule for production downtime. Apache’s qualified ASME R-Stamp repair technicians work with an inspection firm for R-Stamp repair. Apache Stainless, as a qualified R-Stamp manufacturing organization, will work with the customer, NDE firm (if required), and third-party inspector during the process and will provide the R-stamp documentation once complete.

Component replacement and shell repairs are typically completed on-site by a certified ASME repair service tech. Apache updates R-forms and are files the forms with the NB and the customer. A history of all repairs is indicated on the ASME data report.

There are significant requirements for R-stamp approval including:

  • Qualified material documentation
  • Supporting calculations
  • Qualified and certified welder, and welding procedures
  • ASME inspector and witness to R test and attachment of stamp
  • Registering with the National Board.

Apache’s Technicians are fully certified ASME welders. For over 40 years, Apache has continued to maintain rounds of audits and inspections from ASME compliance and safety professionals that speak to the consistency of the welders and the effectiveness of the quality control department. We hold these certifications: ASME U Certificate, ASME UM Certificate, National Board of Boiler & Pressure Inspectors R Certificate, and National Board of Boiler & Pressure Vessel Authorization to Register Certificate.