API cat iii / iv mast, substructure & derrick inspections


API CAT III & IV Inspection Services

We are all very well aware that Drilling Derricks and Masts are expected to support enormous loads when drilling and running casing. To ensure your equipment is fit for purpose, in a safe condition, and keeps in service, Global 1 undertake both API RP 4G Category III and API RP 4G Category IV inspection and through our partners re-certification.

With our highly experienced and professional technicians and engineers that carry out API RP 4G Category III and IV Derrick / Mast and Sub-Structure Inspections in accordance with API-recommended practice, our customers can be assured that their drilling structure has been Inspected by trained professionals, making sure the derrick /mast and sub-structure is fit for purpose.

Global 1 technicians and engineers are able to mobilise anywhere in the world, and once the inspection is completed you can rest assured that your drilling structure and equipment is in accordance with both manufacturer and API standards.

When Global 1 carries out an API RP 4G Category III inspection our clients are advised of any components or structure members that are in need of, and recommended for repairs or replacement.

Once a Category IV inspection has been undertaken, the Global 1 engineering department will review the work undertaken, and verify that the equipment is fit for purpose, and in full operating condition in compliance with manufacturer and API standards.

API 4G Inspection
  • API 4G Inspection Bolt Inspection
    API 4G Inspection Bolt Inspection

Frequently asked questions

An API RP 4G Category III inspection is carried out every 2 years, and an API RP 4G Category IV is every 10 years.

An API RP 4G Category III inspection requires a thorough visual inspection of all load bearing components and members to determine the condition of the Mast/Derrick, or Sub-Structure, or both. And documented on an inspection checklist. Inspections on well servicing truck or trailer mounted masts should include observation on rig up/rig down operations.

An API RP 4G Category IV inspection shall include the requirements of a Category III inspection and also the following requirements:

  1. a) Critical joints shall be subject to non-destructive examination.
  2. b) All equipment shall be disassembled and cleaned to the extent necessary to conduct NDT of all defined critical areas.
  3. c) All welds (100 %) shall be visually examined.
  4. d) All welds in critical areas shall be inspected using NDT methods

Global 1 Inspection results from Category III and IV inspections shall be documented and maintained.

Derricks and Masts should have a permanent name plate attached to the structure indication the following:

  • Name of manufacturer
  • Modal and serial number, rating including static hook load capacity with number of lines strung to the traveling block

If guying is applicable, denote the recommended guying pattens as per requirements