Shielding Vents

Shielding Vents – What You Get for 40 dB, 60 dB, or 80 dB

We make shielding vents in our factory. Different cell sizes, different depths, different materials. Each one gives a different shielding number. Each one costs something different.

Customers ask: "Why does the 80 dB vent cost twice as much as the 60 dB one? They look the same."

They look the same until you cut them open. Here's what the extra money buys – and when it's worth it.

What Those dB Numbers Actually Mean

Shielding effectiveness in decibels. Most people don't know what the numbers mean in real terms.

40 dB blocks 99.99% of the signal.

60 dB blocks 99.999%. (1,000 times stronger than 40 dB)

80 dB blocks 99.999999%. (10,000 times stronger than 60 dB)

100 dB blocks 99.99999999%. (100,000 times stronger than 80 dB)

Every 20 dB step is a tenfold increase in attenuation. It's also a jump in manufacturing cost.

40-50 dB – Entry Level

Standard aluminum honeycomb. 1/8‑inch cells, 1/2‑inch deep. Chromate conversion coating. Foam gasket. Basic frame.

At 1 GHz, about 40-50 dB. Drops off at higher frequencies.

Price? For a 4x4 inch vent, $50‑150.

Where it goes: commercial electronics, basic EMC compliance, indoor gear with low EMI threat.

Good parts: cheap, light, good airflow (85% open area), in stock.

Bad parts: limited to a few GHz, corrosion resistance is minimal, foam gaskets don't last.

Bottom line: good enough. Basic FCC or CE testing, indoor – this works.

60-70 dB – The Workhorse

Better aluminum or tin‑plated aluminum. Tighter cell tolerances. Better gaskets – conductive silicone or knitted wire mesh. Stiffer frame.

At 1 GHz, 60-70 dB. Tin‑plated aluminum gives 60-80 dB in some frequency ranges.

Price? $100‑300 depending on size.

Where it goes: telecom cabinets, industrial control panels, military ground systems, medical gear.

Good parts: balanced cost and performance. Wide frequency coverage. Better than entry‑level.

Bad parts: still aluminum – not for harsh environments. Airflow drops (75‑80% open area).

Bottom line: what most people actually need. If you're not sure, start here. 80% of applications.

80-100 dB – High‑End

Steel or tin‑plated steel honeycomb. Deeper cells (1 inch or more). Full brazing. Heavy‑duty frame. Beryllium copper or silver‑filled silicone gaskets. Nickel or tin plating.

At 1 GHz, 80-100 dB. Steel gives 20‑40 dB better than aluminum at low frequencies – steel has magnetic permeability. Aluminum doesn't.

Price? $200‑600+.

Where it goes: military (MIL‑STD‑461, MIL‑STD‑810), TEMPEST, EMP protection, radar shelters, MRI rooms, high‑security comms.

Good parts: real shielding. Works where aluminum fails. Lasts decades.

Bad parts: heavy. Expensive. Lower airflow (60‑75% open area). Longer lead times.

Bottom line: when it absolutely has to work. Lives or national security? Spend the money.

100+ dB – Extreme

Multi‑layer honeycomb or cross‑cell designs. Special materials – Monel, Hastelloy X, stainless. Custom engineering.

At specific frequencies, 100+ dB. Not always across all frequencies.

Price? $500‑1,500+.

Where it goes: shielded rooms, TEMPEST, nuclear EMP protection, aerospace.

Good parts: maximum possible shielding.

Bad parts: very expensive. Very heavy. Very low airflow. Custom only.

Bottom line: only if you really, really need it. You'll know if you do.

What Drives the Price Jump

Material. Aluminum is cheap. Steel costs more. Tin plating adds cost. Stainless adds more. Monel is expensive.

Depth. Deeper cells mean more material and longer machining. A 1‑inch deep vent costs about 30% more than a 1/2‑inch vent.

Brazing. Spot welding is cheap. Full brazing – every cell wall bonded – takes time and furnace capacity. Cheap vents are spot‑welded. High‑end ones are fully brazed.

Gaskets. Foam is cheap. Conductive silicone costs more. Beryllium copper fingers are expensive.

Plating. Chromate conversion is cheap. Electroless nickel plating is not.

Testing. Entry‑grade vents might not be tested at all. High‑grade ones come with MIL‑STD‑285 test reports. That testing costs money.

When to Spend More

You don't always need the highest grade.

Basic commercial, indoor, low EMI → 40‑50 dB

Telecom, industrial control, medical → 60‑70 dB

Military ground, high‑security comms → 80‑100 dB

TEMPEST, EMP, shielded rooms → 100+ dB

Also consider your environment. Outdoor, coastal, chemical – aluminum won't last. You need stainless or plated steel, which pushes you into higher grades anyway.

If airflow is tight, don't overspec. A high‑grade vent with 1/16‑inch cells and 1‑inch depth might give 80 dB, but your fans will scream. Sometimes 60 dB with better airflow is the smarter choice.

Different shielding grades exist for a reason. 40 dB vents are cheap because they're simple. 80 dB vents are expensive because they're engineered.

The cheapest isn't always the best value. The most expensive isn't always necessary.

Match the grade to the threat. If you're near a cell tower or radar, spend more. If you're in a quiet lab, save your money.

We make all grades. We'll tell you what you actually need – not what costs more.

That's what we do.