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Isolation & Test Plugs · Rent or Buy

Pipe Plugs for Isolation & Hydrostatic Testing

Test and isolate pipe without welding end caps. From no-pressure maintenance plugs to patented GripSafe® ST test plugs rated up to 10,000 psi, in sizes from 3/4" to 96". Stocked sizes ship same day, and our team is on call 24/7/365.

Get A Quick Quote Call (800) 456-8721

Shop by pressure: High Pressure Medium to High Low & No Pressure By Application

GripSafe ST hydrostatic test and isolation pipe plug animation

High Pressure · Patented GripSafe® Technology

GripSafe® Test & Isolation Plugs

Self-gripping wedges, Gritlock® surfaces, and Tri-Ply® seals for full hydrotest pressure with virtually no marks on the pipe.

GSST ORB

Hydrotest open-ended pipe, spools, and vessels. Grips on insertion.

Sizes: 3/4" – 36"
Pressure: Up to 10,000 psi

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GSST DBB

Test flange-to-pipe welds between the seals, or prove a double block & bleed isolation holds.

Sizes: 3/4" – 36"
Pressure: Up to 10,000 psi

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GSST IIB

Reverse pressure. Test flange welds with a ported blind flange, or block vessel outlets.

Sizes: 3/4" – 36"
Pressure: Up to 10,000 psi

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GripSafe® XL

Large bore hydrostatic and pneumatic testing.

Sizes: 36", 42", 48"
Pressure: Up to 3,000 psi

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Pressure ratings vary by size and schedule. See each product's size chart.

Medium to High Pressure

Weld Test & Inflatable Plugs

Flange Weld Test Plug

Hydrotest a flange-to-pipe weld without pressurizing the whole system.

Sizes: 3/4" – 24"
Flanges: 150# – 2500#

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Inflatable Plug

Pneumatic isolation in large or hard-to-reach lines.

Sizes: 2" – 96"
Type: Inflatable bladder

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Low & No Pressure

Mechanical Isolation Plugs

Isolation plugs that keep gases, debris, and unwanted elements out of the line during maintenance, hot work, and inspection.

Non-Gripping DBB

Positive isolation of upstream gases so hot work is safer. Test between the seals to prove it.

Sizes: 3/4" – 24"
Use: Isolation & test between seals

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Heavy duty expansion isolation pipe plug

Heavy Duty Isolation Plug

Isolate larger pipe for maintenance, cleaning, or inspection without welding plates.

Pressure: Isolation only

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Foreman Isolation Plug

Lightweight. One person can install most sizes.

Sizes: 4" – 42"
Pressure: Isolation only

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Wing Nut Plug

Hand-tightened plumber's type plug for low-pressure isolation and leak tests.

Sizes: 2" – 24"
Pressure: Up to 10 psi

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Selection Guide

Which Pipe Plug Is Right for Your Application?

Pipe plugs are matched first by pressure, then by the job. Find your application below, or send us your pipe size, schedule, and pressure and we'll recommend the plug.

ApplicationRecommended PlugWhy

Hydrotest open-ended pipe, spools, or vessels at full test pressureGSST ORB ›Grips on insertion. Up to 10,000 psi, 3/4" to 36".

Flange-to-pipe weld testing, or isolation you need to prove is holdingGSST DBB ›Pressure between the two seals tests the weld without pressurizing the line, and proves the isolation holds. Up to 10,000 psi.

Testing a flange weld with a ported blind flange, or blocking vessel outlet pipingGSST IIB ›Holds reverse pressure under the same loads as a full system hydrotest.

Hydrotesting 36", 42", or 48" pipeGripSafe® XL ›Large bore hydrostatic and pneumatic testing, up to 3,000 psi.

Testing a flange-to-pipe weld before tie-inFlange Weld Test Plug ›Tests the weld area without pressurizing the whole system. 150# to 2500# flanges.

Isolating large or hard-to-reach linesInflatable Plug ›Pneumatic bladder seal, 2" to 96".

Isolating upstream gases before hot workNon-Gripping DBB ›Positive isolation, with a test space between the seals to prove it.

Maintenance, cleaning, or inspection on larger pipeHeavy Duty Isolation Plug ›No welded plates. Reusable and maintenance-free.

Keeping debris out of a line during a shutdownForeman Isolation Plug ›Lightweight, 4" to 42". One person can install most sizes.

Low-pressure leak tests and drain linesWing Nut Plug ›Hand-tightened, 2" to 24", up to 10 psi.

Independent Lab Testing

GripSafe® ST vs. Competitive Gripping Plugs

SCH 80 plugs in ASTM A106 Grade B pipe, pressurized to 3,246 psi (full hydrotest pressure).

GripSafe® ST

Virtually No Surface Damage

Wedge-grip system holds the pipe wall without scarring it, so the pipe can go back into service.

Competitive Plugs A & B

Heavier ID Surface Damage

Serrated jaw grippers bite into the pipe, which can mean rework or temporary piping.

"...the contact of the competitive isolation plugs resulted in heavier ID surface damage than the GripSafe isolation plugs."
Anderson & Associates · Consulting Metallurgical Engineers and Testing Lab

View the Full Test Report (PDF)

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. Low risk of contamination or distortionHeat-affected zones, possible distortion, post-weld NDE

The Bottom LineIsolation and test plugs transform pressure testing from a bottleneck into a streamlined operation, delivering speed, savings, safety, and flexibility that welding end caps simply cannot match.

"GripSafe plugs have been valuable assets on the LNGC site. The quick and easy installation, use, and removal of the plugs have made testing plain end pipe simple... The design of the grippers leave little to no marks inside the pipe... Overall, the GripSafe plugs are an excellent product."
T. Read, Hydro Foreman, and S. Daigle · Global EPC Company

Need Help Choosing a Plug?

Send us these details and we'll recommend the right plug and quote it the same business day.

Pipe size and schedule
Pipe material
Test or back pressure
Isolation, hydrotest, or both
Rent or buy, quantity, and date needed

Get A Quick Quote Call (800) 456-8721

Quick Specs

Pipe Plugs Product Line

DS-PIP-PLUG-001 Rev. Current

Specification	Details
Sizes	3/4" – 96" (by model)
Pressure Range	Isolation only to 10,000 psi (by model, size, and schedule)
Plug Types	Gripping • Double Block & Bleed • Inflatable • Mechanical Expansion
Lab Tested	3,246 psi on SCH 80 ASTM A106 Gr. B pipe (GripSafe® ST)
Technology	Patented GripSafe® wedge-grip system
Materials Origin	USA
Availability	Rent or Buy • Same-day shipping on stocked items

ASME StandardB16.5

ASME StandardB31.3

ASME StandardPCC-2

Pipe Plug Basics

What Are Pipe Plugs?

Pipe plugs, also called isolation plugs or test plugs, are mechanical or inflatable devices inserted into the bore of a pipe to create a temporary seal. They install and remove in minutes with no hot work, no welder, and no grinding, making them the faster, safer way to isolate or test a section of pipe.

Isolation PlugsSeal off a section of pipe to block fluids or gases, so maintenance can happen without shutting down the entire system.

Hydrostatic Test PlugsHold test pressure in pipe, valves, and pressure-containing components so leaks and weaknesses are found before they become costly failures.

Why HydrotestA critical quality step during construction, maintenance, and repairs that confirms compliance with industry standards and protects workers and capital assets.

Patented Technology

How GripSafe® Wedge-Grip Works

Most competitive gripping plugs use serrated jaws that bite into the pipe. GripSafe® ST uses independently actuating wedges that expand evenly against the pipe wall and adjust to ovality. Grip increases with test pressure, and the Gritlock® surface holds without biting into the steel.

In independent lab testing at full hydrotest pressure (3,246 psi on SCH 80 ASTM A106 Grade B pipe), GripSafe® ST left virtually no surface damage. For spools going back into service, that matters.

GripSafe ST pipe plug installed in pipe, pressure side illustration

Common Questions

Pipe Plugs FAQ

How do I choose the right pipe plug?

Start with pressure. For hydrotesting at full test pressure, use a GripSafe® ST plug (ORB, DBB, or IIB) or the GripSafe® XL for 36" to 48" pipe. For weld testing, use the GSST DBB, GSST IIB, or Flange Weld Test Plug. For no-pressure maintenance isolation, use a Non-Gripping DBB, Heavy Duty, Foreman, or Wing Nut plug. Send us your pipe size, schedule, and pressure and we'll confirm.

Why use a test plug instead of welding end caps?

Plugs install cold in minutes and are reused job after job. Welded caps need hot work permits, cooling time, grinding, and post-weld NDE every time.

What sizes do pipe plugs come in?

Our plugs cover 3/4" to 96" depending on the model: GripSafe® ST from 3/4" to 36", GripSafe® XL in 36", 42", and 48", and inflatable plugs up to 96". Plugs are matched to the pipe's nominal size and schedule, and larger or custom sizes are available on request.

Will a test plug damage the pipe?

Serrated-jaw plugs can scar the pipe ID. GripSafe® ST plugs use a wedge-grip with a Gritlock® surface and left virtually no surface damage in independent lab testing at 3,246 psi.

Can I rent pipe plugs?

Yes. Plugs are available to rent or buy. See rentals.

How fast can you ship?

Stocked sizes ship same day, and our team is available 24/7/365 for emergencies.

Industry Terminology

Also Known As

Hydrostatic Test PlugsHigh pressure test plug, high pressure pipe plug, pipe plugs for pressure testing, pressure test plug, pipeline test plug, test plug, mechanical test plug, mechanical pipe plug, expandable test plug

Inflatable PlugsInflatable balloon plug, inflatable pipe plug, inflatable test plug, inflatable bladder plug, pneumatic pipe plug, balloon plug, sewer plug, low pressure test plug, expandable rubber plug

Mechanical Isolation PlugsCarber plug, isolation test plug, pipeline isolation plug, non-gripping isolation plug, mechanical isolation plug, positive isolation plug, hydrotest plug, internal pipe plug

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