Inspection Solutions
Inspection Solutions

API 4G Derrick Inspections

Masts and derricks support enormous loads when drilling and running casing. API-recommended practice for mast and derrick inspections is a critical element to avoiding potentially non-productive time or even serious incidents and catastrophic events during drilling operations or following rig reactivation.

Cenergy offers full API 4g derrick inspections in line with API-recommended practice. API-recommended practice 4g has established four categories for drilling and well servicing structure inspections and sets forth personnel qualifications for these inspections.

Category I

Category I inspections are carried out by general rig personnel conducting daily observation of the mast/derrick and substructure during operation to determine indications of inadequate performance.

Category II

Category II inspections are performed by personnel having adequate experience and knowledge in masts/derricks.

Category III

Our Category III inspectors are in possession of a recognized degree, certificate, or professional standing, or who by knowledge, training, or experience have successfully demonstrated the ability to resolve problems related to the subject matter or work in question.

Category IV

Category IV inspections are closely supervised by a professional engineer, original equipment manufacturer representative or other manufacturer of drilling structures' authorized representative. Cenergy Category IV inspectors satisfy the requirements of Category III inspectors and are also qualified to perform weld inspections.


Cenergy derrick inspectors are IRATA-qualified rope access technicians with a background in derrick building and maintenance. They are also PCN qualified NDT inspectors.