API TR 6AF3

Technical Report 6AF3 provides design guidelines for API 6BX style flanges utilized as end and outlet connectors in high-pressure, high-temperature (HPHT) surface and subsea applications.

For this document, HPHT applications are intended to mean flanges assigned a temperature rating greater than 350 °F or a pressure rating greater than 15,000 psi.

This document does not address thermal effects including gradient effects or subsea production equipment. Service temperature ratings above 550 °F (288 °C) are outside the scope of this technical report. The flange designer should address thermal effects when designing flanges rated for high temperatures.