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Low Pressure Isolation & Testing

Non-Gripping DBB Double Block & Bleed Isolation Plug

Two separate seals positively isolate upstream gases, so modifications, repairs, and hot work are safer, quicker, and easier. A vent between the seals lets you verify seal integrity and hydrotest the weld by positioning it between the two seals.

3/4"‑24"Standard Sizes*

2,500PSI Between the Seals

<1 GalWater to Test

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*Larger sizes available on request.

USA Industries non-gripping double block and bleed isolation pipe plug

Non-Gripping DBB Plug‹›

Overhead View‹›

Front View‹›

Weld Between the Seals‹›

Non-gripping DBB plug installed in pipe with the weld positioned between the two seals — Weld Positioned Between the Seals

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Size (3/4" to 24", larger on request)
Pipe schedule
Extended reach, if needed
Quantity needed
Rental or purchase
Date needed

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Technical Data Sheet

Non-Gripping Double Block & Bleed

DS-DBB-NG-001 Rev. Current

Specification	Details
Standard Sizes	3/4" – 24" NPS (larger on request)
Working Pressure	2,500 psi between the seals (172.4 bar)
Seal Material	Urethane (high-temperature seals on request)
Seal Temperature	180°F continuous (standard urethane)
Water Usage	Less than 1 gallon (cuts fill time and treatment costs)
Body	Lightweight aluminum and steel assembly
Seals	Dual compression seals • Bleed / vent port between
Pipe Protection	Non-gripping. Won't damage pipe walls
Testing	Small test volume • Hand pump compatible
Options	Extended reach • Custom sizes
Availability	Rent • Purchase

Why the Non-Gripping DBB

Isolate the Gas. Test the Weld.

EfficiencyCuts repair and weld-testing time and the labor that comes with it.

SafetyBuilt-in safety factor helps reduce NDE requirements.

Purge ReductionMinimizes purge gas usage and waste generation.

Cost ReductionLess than one gallon of water cuts fill time, waste, and treatment costs.

Product Overview

How the DBB Plug Isolates

Dual SealsTwo independent compression seals create a positive isolation zone that contains upstream gases and protects the work area.

Bleed VentThe vent between the seals verifies seal integrity and lets you pressure test a weld positioned inside the isolation zone.

Pressure RatingThe isolation zone can be pressurized up to 2,500 psi (172.4 bar) for weld testing and verification.

MonitoringMonitor the isolation zone and upstream pressure to prevent back pressure build-up during testing.

Pipe ProtectionNon-gripping design won't damage internal pipe walls during installation or removal.

FlexibilityHydrostatic testing, weld isolation, and temporary line blocking in maintenance work.

How It Works

Six Steps from Hot Work to Hydrotest

InstallSet the DBB plug upstream of the hot work area after confirming pipe size and schedule.
Expand the SealsTighten the compression nut(s).
Pressurize the ZoneInject inert gas or water between the seals.
MonitorWatch the isolation zone and upstream pressure throughout the hot work.
RepositionAfter the weld cools, release pressure and move the isolation zone over the weld.
Hydrotest the WeldPressurize the isolation zone up to 2,500 psi (172.4 bar).

Custom 44 inch double block and bleed isolation plug from USA Industries — Custom 44" Double Block & Bleed Plug

Need a size or reach outside the standard range? Ask us about custom DBB plugs.

Pressure Testing Solutions

Test Plugs vs. Welding End Caps

Test PlugsWelded End Caps

SpeedInstalls in minutes, ready to test right awayWeld, cool, test, then grind off. Hours per cycle

CostReusable. No welders, consumables, grinding, or NDESingle-use caps, welder labor, consumables, and inspections

SafetyNo hot work permits, arc flash, fumes, or burnsOpen flame and hot metal. Permits, fire watch, and PPE required

FlexibilityReposition and reuse across spools and test setupsPermanently welded. Changes mean cutting off and starting over

Pipe QualityNo heat-affected zone from a cap weldHeat-affected zones, possible distortion, post-weld NDE

The Bottom LineTest plugs turn pressure testing from a bottleneck into a streamlined operation, with speed, savings, safety, and flexibility welded end caps can't match.

Critical Safety ReminderPressure testing is hazardous. Make sure all connections, valves, flanges, and fittings are suitable for the test, and verify the line ID falls within the plug's range. Never stand in front of a test plug or enclosure during testing; a discharge can cause severe injury or death.

Need Higher Pressure?

Ask About the GripSafe® ST DBB

Our best-in-class GripSafe® ST double block & bleed plug grips the pipe wall for weld testing and isolation up to 10,000 psi.

GripSafe® ST DBB All GripSafe® ST Plugs

Available to Rent or Buy

Save Money. Rent.

Lower upfront cost and no storage between jobs.

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Common Questions

Non-Gripping DBB FAQ

Do these plugs have venting capabilities?

Yes. A vent between the compression seals lets you verify seal integrity and pressure test a weld positioned between the two seals.

Are these plugs rated to hold back pressure?

The isolation zone between the seals is rated up to 2,500 psi (172.4 bar). Monitor the isolation zone and upstream pressure to prevent back pressure build-up during tests.

What material is the seal made of?

Urethane.

What temperature are the seals rated to?

Standard urethane seals are rated for 180°F continuous operation. High-temperature seals are available on request.

Does the DBB plug have extended reach capabilities?

Yes. Several extended reach sizes are available. Tell us the reach you need.