UN2911: Instruments and Articles Containing Radioactive Material

Why UN2911 Matters

UN2911 is one of the most practical classifications in radioactive material shipping. It applies to any device or instrument where radioactive material is built in as a functional component — smoke detectors, moisture gauges, static eliminators, well-logging tools, and dozens of other common industrial and commercial devices. The activity limits are far more generous than UN2910 (limited quantity) because the instrument housing provides additional shielding and containment.

I have seen it where shippers classify a gauge or instrument as UN2910 limited quantity because they default to thinking of the radioactive source inside it as “just material.” That works fine when the activity is low enough, but it becomes a problem when the source activity exceeds the limited quantity limits. If they had correctly identified the shipment as an instrument or article, the same source would have easily qualified as an excepted package under UN2911. Instead, they end up with full Type A packaging, labels, and carrier surcharges — all unnecessary.

Who Needs to Know This

UN2911 is relevant to anyone who ships:

• Smoke detectors containing Am-241 (commercial quantities or individual units)
• Static eliminators with Po-210 sources
• Moisture/density gauges with Cs-137 or Am-241/Be sources
• Electron capture detectors with Ni-63
• Level gauges and well-logging instruments
• Portable survey meters with built-in check sources
• Tritium exit signs
• Medical devices with small sealed sources
• Ion chambers with radioactive check sources

If your radioactive material is a permanent, integral part of a manufactured device — not just sitting loose in a container — you should be evaluating UN2911 before anything else.

What Qualifies as an Instrument or Article

Under 49 CFR 173.424, to qualify as UN2911, your shipment must meet all of the following conditions:

1. Integral component: The radioactive material must be an integral part of the instrument or manufactured article
2. Completely enclosed: The active material must be completely enclosed by non-active components of the instrument or article
3. Activity limits: The activity per individual item and per package must not exceed the instrument/article limits from Table 4 of 49 CFR 173.425
4. Dose rate: The radiation level at 10 cm from any point on the external surface of the unpackaged instrument must not exceed 0.1 mSv/h (10 mrem/h)
5. Instrument marking: The instrument or article itself must bear the marking “RADIOACTIVE”
6. General design: The package must meet 49 CFR 173.410 general design requirements

The most common mistake I see is people overlooking the “completely enclosed” requirement. If the radioactive source is accessible or removable without disassembling the device, you may have trouble making the case that it is completely enclosed by non-active components. A sealed source welded into a gauge housing clearly qualifies. A check source that clips onto the outside of a survey meter is more debatable — and in practice, I would classify the clip-on source separately as UN2910.

Activity Limits from Table 4 (49 CFR 173.425)

The instrument/article limits in Table 4 are significantly more generous than the limited quantity limits. There are two limits you must check — per individual instrument and per package:

Solid Material

Liquid Material

Gaseous Material

Notice the key difference from limited quantity: for solids, the per-instrument limit is 10⁻² × A1 or A2, and the per-package limit is the full A1 or A2 value. Compare this to the UN2910 limited quantity package limit of only 10⁻³ × A1 or A2. That is a 1,000-fold difference for the per-package limit.

Practical Examples: Real Calculations

Let me walk through three common scenarios to show how these limits work in practice. For each, you need the A1 and A2 values from 49 CFR 173.435.

Example 1: Smoke Detector (Am-241)

A typical ionization smoke detector contains approximately 1 μCi (37 kBq) of Am-241. Am-241 has an A2 of 0.001 TBq (1 GBq). Since the Am-241 is not in special form (it is typically an oxide deposited on a foil), we use A2. For a solid in normal form, the per-instrument limit is 10⁻² × A2:

• Per-instrument limit: 10⁻² × A2 = 0.01 × 1 GBq = 10 MBq
• Source activity: 37 kBq = 0.037 MBq
• Result: 0.037 MBq is far below 10 MBq — qualifies easily

Example 2: Moisture/Density Gauge (Cs-137 sealed source)

A portable moisture/density gauge contains a 10 mCi (370 MBq) Cs-137 sealed source in special form. Cs-137 has an A1 of 2 TBq. Since this is a sealed source (special form), we use A1. For a solid in special form, the per-instrument limit is 10⁻² × A1:

• Per-instrument limit: 10⁻² × A1 = 0.01 × 2 TBq = 20 GBq
• Source activity: 370 MBq = 0.37 GBq
• Result: 0.37 GBq is far below 20 GBq — qualifies easily

Example 3: Box of 100 Smoke Detectors

Now check the per-package limit. A box of 100 smoke detectors, each containing 37 kBq of Am-241. For a solid in normal form, the per-package limit is A2:

• Total package activity: 100 × 37 kBq = 3,700 kBq = 3.7 MBq
• Per-package limit: A2 = 1 GBq = 1,000 MBq
• Result: 3.7 MBq is far below 1,000 MBq — qualifies with enormous headroom

For low-activity instruments like smoke detectors, the per-package limit is rarely the constraint. But for higher-activity instruments, it absolutely matters. Consider shipping multiple Cs-137 gauges: each gauge at 370 MBq qualifies individually (370 MBq < 20 GBq per-instrument limit), but the per-package limit for special form solids is A1 = 2 TBq. Pack enough gauges and you approach that ceiling. The principle is the same — always check both the per-instrument and per-package limits, especially when shipping multiples of higher-activity instruments.

*Tritium exit signs vary in activity. At ~10 Ci (370 GBq), they qualify. Signs at the upper end (~25 Ci / 925 GBq) exceed the 800 GBq per-instrument limit for gaseous tritium and would not qualify as UN2911. Always verify the specific activity on the device label.

As you can see, most common instruments easily qualify. The instrument/article limits are designed to accommodate the vast majority of commercially manufactured devices containing radioactive material. That being said, I have encountered situations where older industrial gauges with higher-activity sources push close to or exceed the per-instrument limit — particularly Ir-192 sources in some radiography-adjacent equipment. Always run the numbers.

UN2911 vs UN2910: Understanding the Difference

This is one of the most important distinctions in excepted package shipping. The difference comes down to what you are shipping:

• UN2910 (Limited Quantity): The radioactive material itself — a standalone source, calibration standard, or sample not integrated into a device
• UN2911 (Instruments/Articles): Radioactive material that is an integral, functioning component of a manufactured instrument or device

*The dose rate for UN2911 is measured at 10 cm from any accessible surface of the unpackaged instrument/article, not at the package surface. The package itself must still meet 0.005 mSv/h at the surface per 49 CFR 173.421 general requirements.

Here's the reality: the activity limit difference between UN2910 and UN2911 is enormous. For a solid, special form source, the UN2911 per-package limit is 1,000 times higher than the UN2910 package limit (A1 vs. 10⁻³ × A1). This is because the instrument housing provides inherent containment and shielding that a loose source does not. If you have a device with a built-in source and you classify it as UN2910 when it should be UN2911, you may end up over-regulating a shipment that could have gone out much more simply. My approach is always to ask first: is this radioactive material part of a device? If yes, evaluate UN2911.

Shipping Requirements When You Qualify

Once your instrument or article qualifies as UN2911, here is what is required and what is excepted:

Still Required

• UN number marking: “UN2911” on outside of the shipping package
• “Radioactive” on the instrument: The device itself must bear the marking “RADIOACTIVE”
• “Radioactive” on inner packaging: The word “Radioactive” on the outside of the inner packaging or visible internal surface when opened
• Training: All hazmat employees handling these packages must be trained per 49 CFR 172 Subpart H
• Incident reporting: Per 49 CFR 171.15 and 171.16
• General design: Package meets 173.410 requirements (protect the instrument from damage during transport)
• Shipping papers: If the material is a hazardous substance or hazardous waste

Excepted (Not Required)

• Specification packaging (no DOT 7A testing)
• Radioactive labels (WHITE-I, YELLOW-II, YELLOW-III)
• Transport Index calculation
• Vehicle placarding
• Shipping papers (if not a hazardous substance or waste, and domestic ground)
• 24-hour emergency response phone number

I have seen a lot of confusion around the packaging requirement for UN2911. You do not need specification packaging — no DOT 7A testing, no certified containers. But the package still needs to prevent damage to the instrument during normal transport conditions. For a portable gauge, that usually means the manufacturer's carrying case inside a sturdy outer box with foam or padding. For a box of smoke detectors, it means a corrugated box with dividers so the units do not shift around and break. Think of it as “good commercial packaging” — the kind you would use if you cared about the device arriving undamaged, which you should.

How RadShip.com Helps

RadShip.com makes UN2911 classification straightforward:

• RAMcalc — Enter your isotope, activity, and indicate the material is in an instrument or article. RAMcalc automatically compares your activity against the per-instrument and per-package limits from Table 4 and tells you whether you qualify for UN2911.
• Determines the correct UN number — UN2911 vs UN2910 vs a fully labeled package
• LabelCalc — If your instrument does not qualify as excepted, LabelCalc determines the correct label category and TI for the next classification level
• Generates compliant shipping documentation when required

Here's the reality: you still need to look up the correct A1/A2 value, determine whether the source is special form or normal form, apply the right multiplier from Table 4, and verify the per-package limit when shipping multiples. The multipliers differ for solids, liquids, and gases. Getting any of those steps wrong means you could misclassify the package. Having a tool that handles this automatically removes that risk.

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Common Questions

Can I ship a gauge with the source removed as UN2911?

No. If the source has been removed, the gauge is no longer an instrument containing radioactive material. The source itself would ship as UN2910 (if within limited quantity limits), and the empty gauge housing is not regulated. If the gauge housing has residual contamination, it would need to be evaluated as an empty package under UN2908.

What if the instrument exceeds the dose rate at 10 cm?

It does not qualify as UN2911. If the unpackaged instrument exceeds 0.1 mSv/h (10 mrem/h) at 10 cm from any accessible surface, you cannot ship it as an excepted package. You will need to evaluate it as a fully labeled Class 7 shipment with appropriate packaging, labels, and documentation. Keep in mind that this is measured on the unpackaged instrument — the shipping container does not count toward meeting this limit.

Can UN2911 packages be shipped by air?

Yes. Excepted packages can be transported by all modes including air. However, IATA has its own provisions that align with but may add to DOT requirements. Air carriers may also have additional company-specific policies. Always verify with your carrier before tendering excepted packages for air transport.

Does a source pig or storage container qualify as an “article”?

No. A container whose sole function is to store or transport radioactive material does not qualify as an instrument or article. The radioactive material must serve a functional purpose within the device — measuring, detecting, illuminating, or performing some other non-storage function. A source pig is just shielded packaging, not an instrument. In my experience, this is one of the more common attempts at creative classification that does not hold up to regulatory scrutiny.

Summary: Your UN2911 Checklist

Before shipping as UN2911 instruments or articles:

• ☐ Radioactive material is an integral component of the instrument or article
• ☐ Active material is completely enclosed by non-active components
• ☐ Activity per instrument verified within Table 4 per-item limits (10⁻² × A1 for special form solid, 10⁻² × A2 for normal form solid)
• ☐ Total package activity verified within per-package limits (A1 for special form solid, A2 for normal form solid)
• ☐ Dose rate at 10 cm from unpackaged instrument ≤ 0.1 mSv/h (10 mrem/h)
• ☐ Package surface dose rate ≤ 0.005 mSv/h (0.5 mrem/h)
• ☐ External contamination within Table 9 limits
• ☐ Instrument bears the marking “RADIOACTIVE”
• ☐ “UN2911” marked on outside of shipping package
• ☐ “Radioactive” marked on inner packaging or visible internal surface
• ☐ Package meets 173.410 general design requirements (protects instrument from damage)
• ☐ Shipping papers prepared if material is a hazardous substance or waste

Or use RAMcalc to determine your classification and generate documentation automatically.

Regulatory References

DOT Requirements:

• 49 CFR 173.424 — Excepted packages for instruments or articles (UN2911)
• 49 CFR 173.425 — Table 4: Activity limits for excepted quantities, instruments, and articles
• 49 CFR 173.435 — Table of A1 and A2 values
• 49 CFR 173.421 — Excepted packages for limited quantities (UN2910 — for comparison)
• 49 CFR 173.422 — Additional requirements for excepted packages (marking)
• 49 CFR 173.410 — General design requirements
• 49 CFR 173.443 — Contamination control

IATA (Air Transport):

• IATA Dangerous Goods Regulations, Section 10 — Radioactive material provisions including excepted packages