A pipe test plug is a device used to close an identified pipe opening while a section is isolated or tested. Mechanical and inflatable designs seal in different ways and have specified size ranges and pressure limits. Selecting the plug is one part of a test setup; the pipe's permitted test method remains a separate requirement.
A pipe test plug is a device used to close an identified pipe opening while a section is isolated or tested. Mechanical and inflatable designs seal in different ways and have specified size ranges and pressure limits. Selecting the plug is one part of a test setup; the pipe's permitted test method remains a separate requirement.
Mechanical and inflatable describe the device
Cherne's comparison guide distinguishes mechanical plugs, which expand or close mechanically, from pneumatic plugs, which are inflated. Its plumbing Test-Ball product uses an expandable rubber body and a separate inflation connection.
The intended task matters as much as the size. A blocking plug, a bypass device and a plug used for a specified test do not necessarily serve the same purpose. Some products also have approved long-term uses. Do not assume that a device selected for temporary testing is a suitable permanent cleanout closure.
The actual inside diameter must fall within the plug's specified sealing range. Nominal pipe size alone is not enough, particularly where the pipe is deteriorated, irregular or part of a different dimensional system. Access to the opening and the medium being restrained also affect selection.
Inflation pressure and pipe pressure are different
An inflatable plug has an inflation requirement for its own body. The water or other permitted test medium held behind it produces back pressure on the plug. Those are separate specifications; confusing them can produce an unsafe setup.
A plug's air fitting does not authorize air-testing the connected pipe. Charlotte Pipe prohibits testing its PVC and CPVC systems with compressed air or gas. Follow the actual pipe manufacturer's permitted test method and applicable code, rather than transferring an inflatable-device instruction to the piping.
Our top-out inspection guide explains where testing appears in the inspection sequence. This component explanation does not provide an alternative test procedure or a pressure target.
A restrained test setup needs a qualified operator
Cherne's pneumatic-plug safety manual warns that a failed plug can cause death, injury or property damage. It calls for proper blocking or bracing, calibrated gauges, suitable inflation equipment and keeping people outside the danger zone. It also requires releasing back pressure before deflation.
Ask the contractor which device, sealing range, back-pressure limit and restraint arrangement apply. The test plan should identify the isolated section, permitted medium and how pressure will be released safely.
Do not stand in front of a loaded plug, pull its hose or attempt to adjust it during a test. Do not enter a manhole or other confined space to reach one. Our cleanout explanation describes ordinary service access; a pressure-loaded test device at that opening has additional hazards.