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Important Inflatable Terminology

Petersen® inflatable hot tap pipe plug insertion systems greatly reduce the time and costs associated with stopping the flow in pressurized pipelines. They allow you to quickly insert inflatable plugs into live pipelines without flow interruption. In order to better understand inflatable plugs and their hot tap insertion systems, it's important to understand the terminology.

  • Back Pressure is the pipeline amount of air or water that has built up behind or in front of a pipe plug.
  • Feet of Head or Head Pressure is the depth of the water from the pipe invert (lowest point) to the water's surface
  • Grade or Slope is the percentage that the pipe is slanted downward to allow the effluent to flow. For example, if the pipe is on a 1% grade that means the pipe gradually slants downward at a rate of 1 foot every 100 feet of pipe.
  • Pounds of Force is the amount of force being exerted on the plug from the pipeline back pressure. It is important to know the pounds of force that a plug is holding back to understand the force the plug and its anchoring system mist block and the amount of damage that can be caused if a pipe plug fails or deflates.

Important calculations for inflatable plugs

Pounds of Force Formula
3.14 x (radius of pipe²) = square inches or area of the pipe. Multiply this figure by PSI (back pressure) to calculate the pounds of force.

Calculating Feet of Head Using the Slope or Grade of the Pipe:
To calculate the feet of head or head pressure that is backing up behind a pipe plug, you must know the grade or slope of the pipe and the distance the water is backing up behind the plug.

If a pipe is laid on a 1% grade, and the water inside the pipe has backed up 500 feet behind the plug, then the plug will be holding back 5 feet of head. You calculate the feet of head by multiplying the number of feet of water backed up in the pipe behind the plug (500') by the slope or grade (1% or .01).

Important Conversions for inflatable Plugs

Conversion Table

Convert from Unit

Multiply by

Convert to Unit

PSI (Pounds per Square Inch)


Feet of Head

Feet of Head


PSI (Pounds per Square Inch)

Inches of Mercury


PSI (Pounds per Square Inch)

PSI (Pounds per Square Inch)


Inches of Mercury



PSI (Pounds per Square Inch)

PSI (Pounds per Square Inch















Contact Petersen to discuss whether inflatable hot tap insertion systems are right for your job.

How to Choose the Correct Flow Stop Solution

There is a wide range of different types and sizes of pipe plugs on the market made from a variety of materials and designed for many specific flow stop tasks. Choosing the right stopper is crucial for both saving you time and avoiding unnecessary costs. Follow these tips to ensure you have the right plug for the job at hand.

Types of pipe plugs

In general, there are two broad categories of pipe plugs, single size and multiple size models. Single size plugs are either mechanical or inflatable, while multiple size products are always inflatable, allowing them to conform to pipes of varying diameters. The difference is self-explanatory, however it's important to determine what type of jobs and pipes you will be working with to choose correctly. Specifically, decide whether you will be using the same plug to stop the flow for one or for multiple pipe sizes.

Steps for choosing the right pipe plug

Once you determine whether you'll be working with one or several sizes of pipes using the same plug, you need to consider the details of the conditions the stopper will be operating in.

  1. Find the exact diameter of your pipes to determine the size of the plug required.
  2. Determine whether it is wet or dry piping, and calculate the pressure that the plug will be subjected to. Ensure the plug's pressure rating is high enough for your particular job.
  3. Learn the temperature and type of liquid that will come into contact with the stopper, so that you choose a plug that can withstand both.
  4. In addition to identifying a plug that will match the pipe's diameter, you also need to ensure the plug will fit through your opening into the pipe itself. In tighter situations, you may need an inflatable plug.

Contact Petersen to Find the Right Flow Stop Solution for Your Job

Best Practices - 10 Safety Tips for Pipeline Workers

Pipeline jobsites include a large number of activities that require extreme caution in order to avoid accidents and injuries. Heavy equipment, hazardous materials, pressure vessels, and suspended loads all pose potentially dangerous situations. Following the best practices listed below just might help prevent a calamity that could have been prevented.

  1. Think ahead—Before the shift starts, identify every task being tackled that day. Then, note any potential hazards you may encounter and consider ways to eliminate a potentially dangerous situation. In other words, be prepared.
  2. Always use PPE—Personal protective equipment, including eye and ear protection, safety boots, hard hats, and gloves, is critical. Don all the accessories and garments that keep you safe whenever you're on the jobsite.
  3. Eye and back safety—Eye and back injuries are some of the most preventable. Always wear any and all goggles or back braces necessary to prevent injury. Also, always wash your hands before touching anything — especially your eyes. You don't want to accidentally have an abrasive substance in your eyes.
  4. Inspect hand and power tools—From wrenches to hydraulic gear, all equipment should be inspected at the beginning of the day to make sure there's no wear, tear, cracks or any other potential flaw that could lead to a malfunction or mishap.
  5. Clean and dry—Slips, falls and other such mishaps are often preventable. Keep walkways free of tools, cords and other debris, and make sure walkways are clean and dry to thwart gravity from getting the upper hand.
  6. Unfree your mind—It's easy to fall into a trance when performing repetitive motions, and that's how injuries happen, so always make sure your mind is in the game before handling equipment. If it's not, take a moment to focus before proceeding.
  7. Be safe with equipment—This seems obvious, but it bears repeating: make sure equipment operators have read and understand the operation manuals for all equipment they'll be working with on the site. Some of these machines are massive, and you need to be able to control them. Always read the operation and maintenance manuals.
  8. Pressure testing—Stop to inspect all materials and equipment before proceeding, guaranteeing it's safe to withstand pressure. Then, clear unauthorized persons, and you can begin testing. Keep personnel out of the line of site of any inflatable plug or mechanical plug that is not mechanically anchored. Never use an inflatable plug as the primary means of protection of people downstream.
  9. Safe evacuation procedures—Call 811 before digging, so you can locate any utilities buried beneath the work site. Consider and mark any potential hazards, as well as depth and utility, before embarking on any excavation. Work trenches and tunnels must be inspected by a trained professional for proper sloping or benching, and protective gear must be used at all times.
  10. Don't push it—Finally, and most simply, act properly. Don't go swinging a pipe around or trying to move heavy loads incorrectly. Always keep manufacturers' load recommendations accessible, and never load equipment beyond its limits.

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Pipe Plug Safety

Inflatable pipe plugs are devices used to temporarily stop flow in pipelines in order to isolate sections for repairs. They are typically cylinder shaped, but can have many different sizes, shapes, material compositions, and pressure ratings to accommodate a range of pipeline configurations and conditions. Pipe plugs work by being inserted into a pipe and inflated against the walls with air, water, nitrogen, or other substance to seal off the section.

Pipe plugs can create dangerous situations

There are risks that come along with using pipe plugs in every situation. The largest danger is the plug coming loose or rupturing, leading to a violent release of water pressure that can potentially cause injury to those in the vicinity. In these cases, the plug itself can become a deadly projectile. An Inflatable device is not appropriate as the primary means of protection of people downstream. An anchored mechanical pipe plug is acceptable. Never allow people to be in direct line with an inflatable pipe plug, It is extremely important to abide by all manufacturer and industry guidelines and take every safety precaution possible. Follow the tips below to help stay safe when completing pipeline work.

Pipe plug safety tips

Prepare the pipeline – Before stopping flow it's important to clean the pipe where the plug will be installed and inspect for any irregularities that may prevent a full seal or damage the plug.

Determine the right size – After cleaning and inspecting the pipe, measure its inside diameter. Plugs are usually installed at least one diameter length into the pipe with no part of it protruding from the pipe. Factors that affect the type and size of plug you'll need include the pipeline configuration, ingress and egress of the deflated plug, and the amount of pressure the plug is holding back.

Ensure the plug is in good condition – Once you find the correct size and type of plug, examine it for any signs of wear or damage. Follow the installation instructions provided by the manufacturer. Blocking or bracing may be needed to prevent the movement or dislodgement of the plug.

Use a properly calibrated gauge – Both over and under inflation can create dangerous situations for your team. Never exceed the plug's maximum inflation rating, as doing so may lead to a rupture. Under inflation, on the other hand, may cause the plug to slip and become dislodged because it cannot adequately hold the back pressure. After installation, use the gauge to closely monitor both the plug pressure and the pressure in the pipeline. Using two gauges in parallel will help assure accuracy.

Remove the plug carefully – Deflating and removing the plug should only be done from a safe distance after all of the back pressure has been relieved. If any back pressure remains, then the plug will dislodge during the deflation process, potentially damaging itself and harming workers. Once safely deflated, remove any blocking or bracing and then remove the plug itself.

Properly store the plug – Once the plug is removed, clean it and check for any visible signs of damage or wear. Follow the manufacturer's guidelines for storing the plug to ensure it's ready for the next use.

Read and understand manufactures instructions before using any Pipe Plugs! Failure to comply may result in property damage, serious injury, or even death.

DrainJet® Powers Through the Toughest Clogs

DrainJet Hydraulic Drain Flushers are one of the easiest and most efficient ways to clear a clog deep in your drain. This is the tool professionals rely on for clearing drains quickly, but they are simple enough for homeowners to use them, too.

What Is Drain Jetting?

Drain jetting harnesses the power of water to push through clogs. Connected to a powerful nozzle, this device uses water pressure to force water into the drain, moving any clogs through the pipe. Hot water is especially effective for clearing grease buildup in drains.

Why Use the DrainJet?

Environment and Cleanliness–DrainJets are far more environmentally safe than chemicals and often more effective than a plunger, the snake, and less messy than a high pressure Jetter and nozzle. There are even DrainJets for water jetters to help prevent the typical jetter wash back. Water pressure cleans not just the clog, but flushes the whole pipe, so the drain is clearer and less likely to be blocked in the future.

Adaptability–The compact DrainJet fits into areas where other tools can't, clearing most size pipes in far less time and without mess or damage.

How to Use the DrainJet for Residential Drains:

  1. Gather your supplies: a hose and a DrainJet. You may need an adapter to connect the hose to your kitchen or utility sink.
  2. Connect the DrainJet to the hose.
  3. Connect the hose to the faucet. Tip: If you can't reach water controls, use a hose with a cutoff valve, or better yet, ask a friend or family member to turn the faucet on and off.
  4. Slide the DrainJet into the drain past any branches between it and the blockage. If the clog is less than six inches in, just push it through the clog.
  5. When the DrainJet is in place, turn on the water. The DrainJet bladder will fill with water. Once it's full, pressure builds, forcing water out the other end and pushing out the clog.
  6. Turn off the water.
  7. Remove and rinse the DrainJet.
  8. Enjoy free running drains for months to come.

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Safe Pipe Plug Installation Guide

When installing pipe plugs, safety should be your top priority. Plugs and line stops are used in high pressure situations that can quickly become dangerous or even deadly if the proper procedures and precautions are not followed. To help avoid accidents or injuries, read this guide for tips and best practices to install pipe plugs in the safest way possible.

Know your plug's parameters

Prior to installing a pipe plug, you must understand its limits. Make sure you know the maximum and minimum diameters that your plug is designed for, as well as the required inflation pressure for an effective seal and its maximum back/test pressure. You also must understand the maximum possible forces that will be exerted on the plug for any given job. Never attempt to use a pipe plug in a pipe that is over its maximum diameter, always inflate sufficiently, and do not exceed the pressure it's rated for.

Check the condition of the plug

Before stopping flow, it's important to check your plug and ensure there aren't any missing or damaged fittings. Look at the lifting eye nuts, air fittings, and plugs for blocking bypass ports if they are needed for your particular project. You should also inspect the plug for cuts, gouges, cracks, and holes. Replace any missing or damaged fittings, and do not use the line stop if it is visibly damaged.

How to install and inflate your flow stop solution

Once you ensure that your pipe plug meets the size and pressure requirements for your job and that it is not damaged in any way, then you can move on to installation. You start by inserting the plug fully into the pipe with no part of it protruding from the tap. Inflatable plugs will spread in all directions like a balloon, so if it is not inserted all the way it could bulge out and burst. When it comes to these types of plugs, the rule of thumb is to install them one pipe diameter into the pipe.

You should always use an inflation kit or hose with a gauge to monitor the inflation pressure of the plug throughout the entire application while the pipe plug is in use.

Don't over or under inflate your plug

Underinflating pipe plugs may allow them to slip or dislodge when pressure is applied, as well as let water, sewage, air, or other materials leak past it. The same may happen if you exceed the maximum back or test pressure rating of the plug. On the other hand, over inflating the plug may cause it to burst, rupture, or explode, potentially causing damage and injury.

Brace the line stop

In order to ensure the plug doesn't move or become dislodged, the use of blocking or bracing is often recommended. Bracing systems should be constructed by certified engineers and customized for your particular pipe job and plug. Rubber eyelets, steel rings, metal eye bolts, eyelets, and eye nuts are not to be used for restraining pipe plugs. Always use multiple points of contact on the plug, in order to spread the back pressure or test pressure forces over the largest area possible.

Talk to an expert today!

Read and understand manufactures instructions before using any Pipe Plugs! Failure to comply may result in property damage, serious injury, or even death.

Helpful Tips for Test Plugs

Test plugs are an essential tool on any plumber's belt. Here we offer best practices for using air and water test plugs and for general plugs.

Using Any Pipe Plug

  1. Wear protection on eyes, head, and body in the form of protective clothing, and always use any required safety equipment.
  2. Test your pressure gauges ahead of time to guarantee accurate readings.
  3. Calculate the head pressure forces. Calculation formulas are here.
  4. Always use the appropriate plug for the appropriate application, one that's a fit for the size, pressure, temperature, and chemicals in use.
  5. Thoroughly clean the pipeline before inserting the plug.
  6. Be sure to stop pipeline flow before testing the plug.
  7. In a confined space, leave the doors or hatchways open.
  8. Never exceed the maximum rated head pressure.
  9. Provide an anchor, support, and/or bracing to secure the plug when back pressure is present.
  10. Generally, plugs must be mechanically anchored against slipping if blocking significant pressure. Avoid sharp edges or protrusions that may damage the plug.
  11. Stand clear of the plug, open the pipeline, or manhole when the plug is holding back pressure.
  12. Equalize the pressure before deflating, relaxing, or removing plug.
  13. Before and after each use, clean the plug and inspect it for surface tears, cuts, or any other damage.
  14. Rubber components are especially susceptible to deterioration from aging. Maintain your plug's integrity by storing it in a clean, dry area away from direct sunlight.

Using Inflatable Plugs

  1. Read and understand the plug inflation pressure calculations found in the link below.
  2. Never inflate your plug outside of a pipe or exceed its maximum inflation rating.
  3. Inflate the plug slowly, carefully building the pressure to the maximum rated inflation pressure. Check the inflation pressure every 15 minutes until the pressure stabilizes and then at least hourly thereafter.
  4. Stay clear of the plug when it is inflated.
  5. Always use two accurately calibrated air pressure gauges for monitoring the inflation pressure.
  6. Use a long enough hose to keep the inflation gauge and valve a safe distance from the plug.
  7. Check air line connections and hoses to make sure they are not damaged or leaking.
  8. Molded rubber plugs expand axially, so they must be inserted at least one pipeline diameter beyond the end of the pipe.
  9. Use a Kevlar or protective sleeve to help protect the plug if the debris in the pipeline cannot be removed.
  10. Use a bleeding type pressure regulator and a relief valve to maintain the correct pressure with changing temperatures and head pressure. Use a pressure relief valve or relieving pressure regulator to prevent over inflation.
  11. While air or inert gas is fine for most molded rubber plugs and smaller Multi-Flex® Plugs, larger diameter plugs are best filled with water. See water inflation calculations here.
  12. Plugs must be mechanically blocked or tethered. Anchor only to rated plug anchor points. Never anchor to plug positioning loops or eyebolts.
  13. Never remove the inflation hose until all back pressure is released and the plug is deflated. Deflate completely before removing, and remove the plug with a rope or cable.

See the Product Manual for Complete Instructions