VALVE MAGAZINE Fall 2025

ADVANCED SEALING TECHNOLOGIES FOR SUBSEA

ensure valve isolation integrity under extreme temperature and pressure conditions. • API 6D “Specification for Pipeline and Piping Valves:” Defines requirements for pipeline valves, including DBB and DIB configurations. It mandates rigorous testing, such as hydrostatic shell and seat tests, to verify sealing under high-pressure conditions. For DBB valves, it ensures effective block-and-bleed functionality, while for DIB valves, it specifies bidirectional sealing and, where necessary, external pressure relief mechanisms. • API 6DSS “Specification on Subsea Pipeline Valves:” Extends API 6D for subsea specific applications, addressing challenges like hyperbaric testing and material selection for extreme environments. It promotes DIB configurations for critical isolation to enhance safety and environmental protection. Compliance with these standards ensures subsea valves can withstand pressures up to 10,000 psi and operate reliably at depths exceeding 9,000 feet, minimizing risks of leaks or failures, and preventing costly interventions. Specific API configurations for subsea valves API 6D and 6DSS specify configurations for DBB and DIB valves based on SPE and DPE seat combinations, tailored for subsea performance. The table on p. 21 outlines these configurations. These configurations undergo rigorous testing, including hyperbaric and high-pressure seat tests, to ensure sealing integrity. Valves are marked (e.g., DBB, DIB-1, DIB-2) to indicate compliance and guide installation in subsea manifolds or flowlines. The selection of double block and bleed (DBB), double isolation and bleed-1 (DIB-1), or double isolation and bleed-2 (DIB-2) valve configurations depends on the valve’s opera tional role, environmental conditions and system redun dancy requirements.

FEATURED ARTICLE Advanced Sealing Technologies for Subsea Ball and Gate Valves Discover how single-piston effect (SPE) and dual-piston effect (DPE) seat designs are engineered to meet the demanding pressures and temperatures of subsea applications. Subsea oil and gas production environ ments impose extreme demands on valve performance requiring robust sealing systems to ensure operational reliability, safety and environmental compliance. Valves in these applications must meet qualification testing with pressures up to 10,000 psi, temperatures from -40°F to over 400°F, in order to ensure leak-tight isolation in application for decades without maintenance. Ball and gate valves, critical for flow control and emergency shutdowns, rely on advanced seat designs, particularly Single Piston Effect (SPE) and Dual Piston Effect (DPE) configurations, to meet these challenges. BY: MIKE HEDGER, Director of Engineering COMPANY: CDI PRODUCTS

Flow direction for ball valves for SPE and DPE seat seals. Source (all images): CDI

API standards governing valve configurations

The American Petroleum Institute (API) standards, specifically API 6D and API 6DSS, govern the design, testing, and performance of Double Block and Bleed (DBB) and Double Isolation and Bleed (DIB) valves for surface and subsea pipeline applications. These standards help to

20

VALVE MAGAZINE

FALL 2025