ndt inspection aperture plug 4 and 3 inch3 inch inspection plug Peak HoleFor over 25 years The patented Peak Hole has been the practical way to access UT and vibration inspection points through the cut plug hole in insulated piping, vessels and tanks in the petrochemical refining and cryogenic industries.

Permanent Attachment.3 inch inside cover open ndt inspection aperture

The Peak Hole provides a fixed monitoring point that attaches permanently to vessels, pipes and tanks.

Quick & Simple Installation.

The Peak Hole can be installed in minutes with two screws or fastening material of your choice.

Rapid Access.

The swing cover allows you to access the surface for UT point, tempera­ture or vibration monitoring immediately.

Single Unit Cover Design.

Cover is securely attached to aperture body. No more lost or cracked plugs or lids, or broken lanyards.

Adapts to Irregular Surfaces.

The Peak Hole attaches easily and securely to sheet metal and corrugated metal coverings.

Eliminates Exposure to Asbestos/Ceramic Fiber.

When applied with a proper sealant, the Peak Hole serves as a liner to the cut plug hole.

Lightweight, Rigid, & Strong.

Yet the Peak Hole can be contoured to fit against pipewalls, vessels, and/or tanks. Easy to handle and weighs approximately 2-1/2 ounces for inexpensive UPS shipping.


4 and 3 inch peak holes ndt inspection ports

Provides the ability to install insulation to cut heat loss or gain.

No Sharp Edges.

Smooth edges reduce cuts and scrat­ches to NDE/UT Technicians and personnel

Provides Strength.

The rigid body of the Peak Hole provides reinforcement to the cut plug hole.

Optional Extensions.

Extensions are available in various lengths to accommo­date any thickness of insula­tion.

4 inch inspection plug peak hole

Extensions are easily connected to the tapered body of the Peak Hole.


The Peak Hole inspection port / insulation plug is a liner for an access hole cut through an insulation material enclosing or placed upon a pipe vessel or tank (sometimes called “cheese holes”), especially of the type used in cryogenic or high temperature systems, such as found in petrochemical refineries, chemical processing equipment, power generation facilities and the like.

It makes for easy access for Non-Destructive Testing NDT for Ultrasonic UT and Vibration testing equipment in process piping, steam piping, and vessels used in various industrial processing industries.

The detection of erosion or corrosion of the metal wall in process piping is essential to the safe operation and maintenance schedule of any industrial process facility. The Peak Hole is an essential aid to access the process pipe’s surface for NDT UT testing and failure prediction and aversion.

Many other access plugs and inspection ports have been tried, but de-mountable plugs are easily lost and provide no internal integrity for the insulation material surrounding the removed plug causing potential exposure to workers. Whenever the insulating material contains ceramics or other hazards, there exists the possibility of contamination of workers and nearby areas.

The Peak Hole inspection port / insulation plug provides the preferred type of insulation aperture liner and means of access which can be easily opened to permit necessary measurement of wall thickness, yet seals off the insulation material from exposure to workers.

Check our Products page for our line of inspection apertures. Online ordering is available, or email PO to orders@securesealcorp.com. Fax PO to 360-424-7862.

Feel free to drop us a line at 360-424-8432 with any questions or comments. You can also reach us at info@securesealcorp.com