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Double Block and Bleed

3 in-depth engineering guides on Double Block and Bleed — specification, selection, testing and procurement.

Everything on Double Block and Bleed

Vajra's engineering team has published 3 technical guides covering Double Block and Bleed for industrial valve selection, specification, testing and procurement. Browse the full set below.

Valve Lockout/Tagout (LOTO): Energy Isolation Safety Guide

Lockout/tagout (LOTO) is the discipline of isolating hazardous energy so equipment cannot be started or release stored energy during maintenance. Valves are the primary isolation point for pressure, fluid, and gas energy. This guide covers LOTO principles, valve lockout hardware, and a safe isolation procedure.

2026-07-108

Valve Interlock Systems: Mechanical Key Interlocks for Safe Operation

Mechanical valve interlocks enforce a safe, predetermined sequence of valve operations using a trapped-key principle - preventing operator error in high-risk procedures like pig launching, vessel isolation, and pressure relief. This guide explains how they work and where to use them.

2026-06-288

Double Block and Bleed (DBB) Valves: When to Specify and How They Work

Double block-and-bleed (DBB) valves are specified wherever personnel safety or environmental protection requires positive isolation - not just flow shutoff - of a process stream. Understanding when API 6D and OSHA regulations require DBB isolation, and the difference between a true DBB valve and a two-valve workaround, is essential for correct specification.

2026-05-177

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Reviewed by Engineering Editorial Team, Vajra Industrial SolutionsDiscipline: Industrial Valve Engineering ContentLast reviewed: 20 June 2026

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