Issuing body
API
Latest edition
21st Edition (2018, A1 2021)
Region
USA, Global
Equipment items
1
Scope
Wellheads, Christmas trees and surface equipment for upstream service.
Key requirements (8)
- Wellhead, christmas tree and choke valve equipment for upstream oil & gas.
- Pressure ratings: 2,000 / 3,000 / 5,000 / 10,000 / 15,000 / 20,000 psi.
- Material classes: AA, BB, CC, DD, EE, FF, HH (increasing severity for sour/cryogenic).
- Temperature classes: K, L, N, P, R, S, T, U, V, X, Y (range −75 to 350 °F).
- PSL (Product Specification Level) 1 to 4 — increasing QC stringency.
- Hydrotest: 1.5 × rated working pressure × 3 minutes minimum.
- Sour service: NACE MR0175 / ISO 15156 compliance.
- Fire-safe per API 6FA where required.