N.C. Gen. Stat. § 95-69.16
All boilers and pressure vessels subject to the provisions of this Article shall be inspected by a commissioned inspector. The Commissioner may determine both the frequency and the method of inspection. In determining the frequency of inspection, the Commissioner shall give due consideration to the hazard involved and the need for the protection of the public. The method of inspection must provide an adequate procedure to insure the safety of individuals likely to be injured by an explosion or accident involving a boiler or pressure vessel.
No boiler or pressure vessel may be operated without an inspection certificate, except pressure vessels being operated under an owner-user provision where administrative procedures of equal safety and competency have been approved by the Commissioner. No more than 60 days grace period may be granted beyond the certificate expiration date.
N.C. Gen. Stat. § 95-69.16