Blocking Plugs

When You Need a Complete Seal

A blocking plug stops all flow. No bypass, no bleed-through — the pipe is sealed. That’s what pressure testing, smoke testing, and construction isolation require: a reliable seal you can trust while your crew works or your gauges are reading.

Every blocking plug we carry is Cherne — the pneumatic plug that plumbing contractors and municipal crews have relied on for decades. Inflate to spec, verify the seal, and get to work.

Test-Ball vs. I-Series

Test-Ball — Single-size plugs. Each one fits a specific pipe diameter. The simplest, most proven design. If you know your pipe size and only work in one or two diameters regularly, Test-Ball is the straightforward choice.

I-Series — Multi-size range plugs. A single I-Series plug covers a range of pipe diameters, so one plug handles multiple sizes. Fewer plugs on the truck, more flexibility on-site. Better for crews that encounter varying pipe sizes across different jobs.

Blocking Plug vs. Bypass Plug

Blocking plugs create a complete seal — use these for pressure testing, air testing, and situations where zero flow is required. Bypass plugs (Muni-Ball) seal the pipe but divert flow through a channel — use those for sewer repair work where you can’t fully stop flow.

Related Categories

• Bypass Plugs (Muni-Ball)
• Mechanical Test Plugs
• All Cherne Products