What Is Device Sequestration Protocol? (Faraday Bags)
A device sequestration protocol is a repeatable way to isolate a device from radio-frequency signals by placing it in a closed, tested conductive-shielding bag. No universal building-code protocol sets bag dimensions or performance. Choose a bag with assembled-bag test data, close it as directed, and inspect it regularly. A Faraday bag does not switch off or cool a device.
A device that cannot communicate may still be powered on, searching for a network, and using battery power. That is the paradox at the heart of sequestration: blocking a connection does not stop the device itself. A careful process must address both radio isolation and device safety.
Here, “device sequestration” means temporarily limiting a device’s radio communication by enclosing it in a conductive shield. It is not a universal building-code term or a single legally defined protocol. Follow any applicable workplace, evidence-handling, or agency procedure first. A Faraday bag is not a substitute for those rules.
Planning: Define the Isolation Need and Select a Tested Bag
Planning means deciding which device and radio signals need to be isolated, then choosing a bag whose size and documented performance fit that use. A product label alone cannot confirm that a finished bag blocks every relevant signal. If reliable isolation matters, review test information for the assembled bag, not just its fabric.
First, list the device’s radios and the reason for isolation. A phone may use cellular, Wi-Fi, Bluetooth, or other radio services. Different services use different frequency bands, and the bands in use vary by device, network, and location. Do not assume that evidence for one frequency range proves performance across all the others.
Ask the manufacturer for test data that identifies:
- The frequency range tested.
- Attenuation, in decibels (dB), at each reported frequency or band.
- The test method and test setup.
- Whether the test covered the assembled bag, including seams and closure.
- Whether the closure was fully closed as the manufacturer directs.
Attenuation describes how much a signal is reduced. A single headline dB figure is not enough to judge performance across a range of frequencies. Also, a fabric test is not the same as a test of a finished bag. Seams and closures can affect the result.
Two standards can help explain what test data does and does not show. ASTM D4935-18 describes a method for measuring shielding effectiveness of planar materials from 30 MHz to 1.5 GHz. A flat material coupon tested under that method does not establish the performance of a bag’s seams, closure, or assembled shape.
IEEE Std 299-2006 addresses measurement of shielding effectiveness for enclosures. It is a reference for enclosure testing, not a certificate for every consumer bag. For either standard, check the test scope and setup. If a procurement decision depends on compliance with a specific edition, confirm the standard’s current status and requirements with the standards body or a qualified test provider.
Access and Clearances: Fit the Device Without Compromising Closure
The bag should fit the device without stretching, sharply folding, or pressing its conductive liner. It must also close fully in the way its maker specifies. There is no universal clearance, bag dimension, airflow rating, or building-code size for Faraday bags. Fit depends on the device and the bag design.
Before using the bag, check its size and condition. A large phone case, attached accessory, or bulky device may stop the closure from lying flat or engaging as intended. Do not force the closure or leave it partly open just to make the device fit.
| Situation | What to check | Appropriate next step |
|---|---|---|
| Device fits with room to close | Liner is not strained; closure engages fully | Use the maker’s closing method |
| Device presses against the closure | Closure may not seal as intended | Choose a larger compatible bag |
| Bag has a tear, worn edge, or debris | Shielding or closure may be compromised | Do not rely on it until inspected or replaced |
| Only fabric-coupon data is available | Finished-bag performance is unknown | Request assembled-bag test results |
| Device is hot, swollen, or damaged | Battery may pose a safety hazard | Do not enclose it; follow appropriate safety guidance |
A bag does not need to be built into a wall, floor, or cabinet to work as a shielding enclosure. Avoid modifications that pierce, cut, or reshape its conductive layers. If a device or bag must be secured within a larger installation, make sure that arrangement does not damage the bag or prevent full closure.
Execution: Prepare, Enclose, and Close the Device
Execution is a simple sequence, but each step matters: review the device and bag, prepare the device for the intended use, insert it without damaging the liner, and close the bag fully. A closed bag limits radio communication only to the extent that its assembled shielding performance supports. It does not power down the device.
Use this sequence:
- Survey the device. Identify the device and the radios you need to isolate. Check its battery and the bag’s size, closure, condition, and manufacturer instructions.
- Prepare the device. If appropriate for the use case, power it down before insertion. Do not change or delete data if evidence-handling rules apply; follow the responsible organization’s procedure.
- Insert it carefully. Keep sharp edges and accessories from scraping or puncturing the conductive liner. Do not pack the bag so tightly that the closure cannot engage.
- Close it as directed. Use the exact fold, flap, zipper, or other closure method specified by the manufacturer. Confirm that it is fully closed and undamaged.
Never charge a device inside a Faraday bag. RF isolation does not stop heat production, battery drain, or other device activity. A powered device may keep searching for service, which can use power and may cause it to warm. Do not enclose a hot, swollen, damaged, or otherwise suspect battery. A shielding bag is not a fire-safe container.
If the device must remain powered for a defined process, follow that process’s safety controls and manufacturer guidance. Do not assume that the bag provides ventilation or temperature protection. No universal airflow or temperature rating applies to all bags.
Verification: Test the Assembled Bag and Inspect Its Condition
Verification means checking the complete bag under a suitable test method, with its closure in the required condition, and reviewing results across relevant frequencies. Phone signal bars or one failed call are not proof of isolation. Results can change with the device, network, location, frequency, and bag condition.
For assurance beyond casual use, ask for documented testing of the assembled bag. The report should state the frequency range, attenuation by frequency, test method, closure condition, and whether seams were included. A qualified test setup may be needed to make meaningful measurements. A fabric-swatch result or a single dB claim cannot fill in missing information about the finished product.
A phone-based check can be misleading. Signal indicators may update slowly, networks differ, and a device may behave differently across bands. A failed call may also result from poor coverage rather than shielding. For the same reason, a single consumer test should not be treated as proof that every radio path is blocked.
| Verification method | What it can tell you | What it cannot establish |
|---|---|---|
| Manufacturer’s assembled-bag test report | Reported results for the tested bag and setup | Performance after wear, damage, or a different closure method |
| ASTM D4935-18 material test | Shielding behavior of a planar material in its stated range | Finished-bag performance, seams, or closure |
| IEEE Std 299-2006 enclosure measurement | Enclosure shielding results under a stated test setup | A universal guarantee for every bag or environment |
| Phone bars or one call attempt | A limited, informal observation | Reliable isolation across devices, networks, and bands |
Inspect the liner, seams, and closure before use. Look for tears, contamination, folds that prevent closure, and worn or damaged edges. If the bag is repaired, damaged, or its closure changes, do not assume prior test results still apply. Re-test when assurance matters.
Field Scenarios: Apply the Protocol Without Overclaiming
These scenarios are practical examples, not reports of specific installations or test outcomes. They show how the same protocol changes with the device and the level of assurance needed. In each case, the key question is whether the assembled bag is suitable for the intended use and remains safe to use.
A homeowner setting aside a personal phone: The homeowner identifies which radios need isolation, checks that the bag fits without strain, and reviews available test documentation. If the phone can be powered down for the intended period, doing so reduces ongoing activity. A later “no service” display alone would not prove that the bag blocks all relevant bands.
A tradesperson carrying a work device: The worker checks the device maker’s battery guidance and the bag’s closure instructions before use. The device is not charged in the bag, and a damaged or hot battery is not enclosed. If the job requires ongoing communication, the worker should not rely on a shielding bag as a substitute for an approved work procedure.
An organization handling a device under evidence rules: Staff follow their organization’s documented evidence-handling process, including any rules for preserving the device’s state and recording custody. They do not power down, alter, or test the device unless that procedure allows it. A consumer bag cannot replace an approved process or establish that evidence was preserved correctly.
Across these scenarios, use a simple decision rule: if the purpose requires a defined level of isolation, seek test results that match the relevant frequencies and the assembled bag. If the purpose is governed by an organization, follow its procedure first.
Conclusion and FAQ
A sound device sequestration protocol is a repeatable process, not a special building detail or a promise on a product label. Identify the radios, choose a bag with relevant assembled-bag test data, protect the liner, close it as directed, and inspect it over time. Keep battery safety and any evidence-handling rules separate from the question of RF shielding.
What does “device sequestration protocol” mean?
It is a procedure for temporarily limiting a device’s radio communication by enclosing it in a closed shielding bag. The term does not refer to one universal building-code rule or a single mandatory standard.
Does a Faraday bag turn a phone off?
No. It may limit radio communication, but it does not power down the phone. A powered phone may keep running, search for service, use battery power, or warm up.
How can I tell whether a Faraday bag works?
For meaningful assurance, review test data for the assembled bag. It should state the frequency range, attenuation, test method, closure condition, and whether seams were included. A phone test alone is not proof.
Does ASTM D4935-18 certify a finished Faraday bag?
No. ASTM D4935-18 covers testing of planar materials from 30 MHz to 1.5 GHz. A material coupon result does not establish the shielding performance of a finished bag’s seams or closure.
What does IEEE Std 299-2006 measure?
It addresses measurement of shielding effectiveness for enclosures. The result depends on the test setup and scope; it does not certify every consumer Faraday bag or guarantee performance in every environment.
Is there a required gap around the device?
No universal clearance is specified. Choose a bag that fits without stretching or damaging the liner and still allows the closure to engage fully as directed by its manufacturer.
Can I charge a device inside a Faraday bag?
No. Do not charge a device inside the bag. RF shielding does not provide cooling or battery protection, and charging can create heat.
Should I put a swollen or hot battery in the bag?
No. Do not enclose a hot, swollen, damaged, or otherwise suspect battery. Follow suitable battery-safety guidance instead.
Do phone signal bars prove that the bag blocks signals?
No. Signal indicators and call attempts vary by device, network, frequency, and location. They cannot prove isolation across relevant radio bands.
When should I inspect or retest the bag?
Inspect it before use and after rough handling. Check for tears, contamination, worn closures, or damage. If it is damaged or repaired, do not rely on earlier test results without suitable reassessment.
(This article was written by one of our staff writers, Garrett Vance. Visit our Meet the Team page.)
