The Drawings Lied.
You've been there. The drawings said the wall was 1" thick. It turned out to be 6". Or somebody added 4" of soundproofing after the survey. Or you opened up what was supposed to be sheet metal and found a modular panel with structural members inside. Or the cable routing changed and now the filter needs to be mounted somewhere completely different.
Whatever happened, the result is the same. The EMI filter you ordered three months ago will no longer fit and the installation just stopped.
For most of the shielding industry, that's a project delay. You can get the correct penetration length. You just have to wait while the manufacturer removes the existing penetration, welds on a new one, re-finishes the assembly, and ships it back. Meanwhile a multi-million dollar shielded room is waiting on a piece of nickel-plated pipe.
Why We Built UMS
After more than twenty years supplying EMI filters to SCIFs, MRI suites, EMC chambers, and TEMPEST facilities, we noticed something. The filter was rarely the problem. The wall was.
Wall thickness changed. Requirements changed. Drawings were wrong. Penetrations got damaged. Installations evolved after construction started.
Yet most filter manufacturers still build fixed-geometry penetrations into their products as if every project goes exactly according to plan.
We built the Universal Mounting System because real-world projects don't work that way.
To the best of our knowledge, no other EMI filter manufacturer serving the SCIF, TEMPEST, MRI, and EMC markets offers interchangeable, field-replaceable penetration lengths across their product line.
What UMS Actually Is
The Universal Mounting System consists of a threaded hub on the filter body and a series of interchangeable penetration pipes. The penetration pipe screws onto the hub. To change penetration length, simply remove the pipe with a wrench and install a different length. Total elapsed time: about three minutes.
The filter body doesn't change. The gasket doesn't change. The flange nut doesn't change. The hole in the wall doesn't change. Only the penetration pipe changes.
Standard penetration lengths are:
- 1"
- 3"
- 9"
- 12"
Custom lengths are available on request.
Five Jobsite Problems UMS Solves
1. The Wall Wasn't What the Drawings Said
The project was surveyed six months ago. The drawings looked perfect. Now you're standing in front of a wall that's substantially thicker than expected. Instead of replacing the filter, simply install a longer penetration pipe and keep moving. Changing the penetration length takes about three minutes.
2. The Penetration Panel Is Full
The filter was supposed to mount on the penetration plate. Then additional connectors, waveguides, and communication penetrations appeared. Now there isn't enough room. Install a longer penetration pipe and relocate to the shield wall where the filter body is far away from the crowded area. Problem solved.
3. It's a Retrofit
The existing GigaFOIL has been in the wall for fifteen years. The hole is already there. The wall is already finished. Remove the old filter. Install the appropriate penetration length on the new ACTIV or Pasif filter. Use the same hole. No demolition. No patching. No painting. No explaining to the customer why a finished wall needs to be opened up again. Retrofitting an existing opening takes about three minutes.
4. Somebody Added Insulation
The original wall was 1" thick. The acoustic contractor added several inches of soundproofing after the design review. With a traditional filter, that can become a custom-order problem. With UMS, it's a penetration pipe swap.
5. No Idea How That Happened
The filter arrives on site and the penetration pipe is bent. Or the threads are damaged. Or somebody dropped something heavy on it. Or somebody introduced it to an angle grinder. It happens. Replace the penetration pipe and keep working. The filter body remains in service. Replacing a damaged penetration takes about three minutes.
Friday at 4:30 PM
The room turnover is scheduled for Monday morning. The customer is flying in. The penetration length is wrong. With a traditional filter, you're making phone calls and hoping somebody can help. With UMS, you walk to the truck, grab a different penetration pipe, swap it out, and finish the installation. That's the difference between a minor inconvenience and a schedule problem.
Installation Overview
Installation is intentionally simple:
- Drill a 1-3/8" hole through the shield wall.
- Thread the penetration pipe onto the filter body.
- Slide the gasket onto the penetration pipe.
- Insert the filter through the wall.
- Thread the flange nut onto the penetration.
- Tighten the flange nut against the gasket to create an RF-tight seal.
- Connect cables and power (if required).
To change penetration lengths in the future:
- Remove the flange nut.
- Withdraw the filter.
- Remove the penetration pipe with a wrench.
- Install a different penetration length.
- Reinstall the filter.
The process typically takes only a few minutes.
Keep One of Each in the Truck
Most installers carry spare connectors. Most installers carry spare hardware.
We recommend carrying one of each standard penetration length:
- 1"
- 3"
- 9"
- 12"
A small penetration kit can solve the vast majority of wall-thickness surprises without waiting for replacement parts.
For the Project Managers
If you're managing a SCIF, MRI suite, TEMPEST facility, or EMC chamber project, you already understand the economics.
One day of project delay typically costs more than an entire penetration kit.
A complete penetration kit costs a fraction of a single day of project delay. The day you need it, it may become the smartest line item on the purchase order.
Ordering
Filters ship with one penetration pipe by default. Specify the desired penetration length when ordering, or order a complete penetration kit when wall thickness is uncertain.
Need something different? Custom penetration lengths are available. Send us the required dimension and we'll provide a quotation.
Compatible Filters
The Universal Mounting System is standard on nearly every DJM filter.
Compatible products include:
If you've installed one DJM filter, you've installed them all.
Mechanical Specifications
| Mounting Hub Thread | 1-20 UNEF-2A external (filter body) 1-20 UNEF-2B internal (penetration pipe) |
|---|---|
| Penetration Pipe | 1.315" diameter Use 1-3/8" hole saw 1" NPS thread |
| Material and Finish | Aluminum 6061-T6 Electroless nickel plated |
| Standard Penetration Lengths | 1" · 3" · 9" · 12" Custom lengths available upon request. |
Ready to Put It into Practice?
Contact our engineering team for application support, custom configurations, or to request a quote.