Separation Distances for Radioactive Material on Aircraft

Why Separation Distances Matter

Separation distances ensure that people, animals, and radiation-sensitive cargo on the same aircraft receive acceptably low radiation doses during the flight. While the radioactive package itself meets surface dose rate limits, passengers or crew sitting near a package for hours accumulate dose over time. The separation tables are calculated to keep that accumulated dose well below regulatory limits.

As the shipper, you don't actually position the packages on the aircraft — that's the airline's load planner's job. But the load planner relies on the information you provide: the category labels, the Transport Index, and the package dimensions. If any of those are wrong, the load planner calculates the wrong separation distance.

I have seen a situation where a shipper wrote TI = 0.5 on the label instead of TI = 5.0 — a simple decimal error. The load planner positioned the package based on TI 0.5, which requires about 10 inches of separation. TI 5.0 requires over 3 feet. That's the kind of error that can result in a passenger receiving more dose than intended, a DGOR filing, and potentially regulatory consequences for the shipper.

Who Needs to Know This

This applies to:

• Shippers who prepare Category II-Yellow and III-Yellow packages for air transport
• Airline dangerous goods acceptance agents and load planners
• Freight forwarders handling radioactive air shipments
• Anyone who needs to understand why accurate TI and package dimensions on the DGD matter

Separation from Persons (Tables 10.9.C and 10.9.D)

Category II-Yellow and Category III-Yellow packages must be separated from persons on the aircraft. The minimum distance is measured from the surface of the package to the nearest inside surface of the passenger cabin or flight deck partitions or floors (IATA DGR §10.9.3.7).

Passenger and Cargo Aircraft (Table 10.9.C)

Table 10.9.C covers TI sums from 0.1 to 50.0 and applies to both passenger and cargo aircraft. The TI used is the total sum of all radioactive packages on the aircraft, not individual package TI values.

For larger TI sums (cargo aircraft only), see Table 10.9.D below.

Cargo Aircraft Only (Table 10.9.D)

Table 10.9.D extends the separation distances for cargo aircraft with TI sums from 50.1 to 300.0. TI sums above 200 require exclusive use.

TI sums above 200 require exclusive use. In practice, TI sums above 50 are uncommon for most shippers — they come into play for large industrial radiography campaigns, nuclear fuel shipments, or high-activity medical source shipments where multiple packages are consolidated on a single aircraft.

Grouping Packages

If multiple radioactive packages are on the same aircraft, they can be treated as a single group (using the total TI for separation) or separated into multiple groups. When separated into groups, each group's distance from persons is based on that group's TI sum, and groups must be separated from each other by at least three times the distance applicable to the group with the larger TI sum.

This grouping option gives load planners flexibility. In my experience, airlines typically keep all radioactive packages together in one group unless the TI sum is high enough that splitting into groups provides a meaningful loading advantage.

Separation from Undeveloped Film (Table 10.9.E)

Category II-Yellow and III-Yellow packages must be separated from undeveloped photographic film and plates. The separation distances in Table 10.9.E are calculated so that the total radiation dose to the film does not exceed 0.1 mSv (10 mrem) (IATA DGR §10.9.3.8).

The distance depends on two factors: total TI sum and journey duration. Longer flights require greater separation because the film accumulates more dose.

Note: The table is calculated so that radiation dose received by the films does not exceed 0.1 mSv (10 mrem). While undeveloped film is less common in the digital age, it still ships by air — particularly for medical X-ray film, professional photography, and industrial radiography film.

The most common situation I see where this matters is industrial radiography shipments. The Ir-192 source is shipping to a job site, and the same flight may carry film for a completely different customer. The load planner needs to separate them, and the separation distance for film is typically larger than the distance from persons at the same TI.

Separation from Live Animals

The live animal rule is the simplest separation requirement. Category II-Yellow and III-Yellow packages must maintain (IATA DGR §10.9.3.9):

• 0.5 meters for journeys of 24 hours or less
• 1.0 meters for journeys of more than 24 hours

Unlike the person and film separation distances, the live animal distance is fixed — it does not depend on the TI. Whether your total TI is 1.0 or 50.0, the minimum distance from live animals is the same.

This comes up more often than you might think. Livestock, research animals, and even pet relocations travel on cargo aircraft. If an airline is carrying both a radioactive shipment and live animals on the same flight, the load planner needs to ensure the 0.5 m or 1.0 m minimum distance is met.

What Shippers Need to Get Right

As the shipper, you don't calculate separation distances or position packages on the aircraft. But you provide the information the load planner needs to do it correctly:

• Accurate TI on the label — rounded up to one decimal place (IATA DGR §10.7.3.3.3). TI 1.04 becomes 1.1, not 1.0
• Correct category assignment — based on both TI and surface dose rate (whichever gives the higher category)
• Package dimensions on the DGD — required for Category II-Yellow and III-Yellow packages in Sequence 3. Load planners need dimensions to determine physical separation on the aircraft

The most common error I see is not a calculation mistake but a labeling one: shippers measure the TI correctly but write it on only one of the two labels, or write different TI values on the two labels because they measured from different surfaces. Both labels should show the same TI — the maximum measured value, rounded up to one decimal.

How RadShip.com Helps

RadShip.com ensures the information you provide for separation distance calculations is correct:

• RAMcalc — Determines the correct package category (I-White, II-Yellow, or III-Yellow) by checking both TI and surface dose rate
• Helps you understand Transport Index requirements and how TI affects aircraft eligibility
• Determines whether your shipment requires cargo aircraft only based on TI and other criteria
• Generates DGD documentation with category, TI, and dimensions pre-populated

Getting the TI right on the label is the single most impactful thing a shipper can do for separation distance compliance. Everything else — the table lookup, the load plan, the physical positioning — follows from that number.

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Common Questions

What determines the separation distance for radioactive material on an aircraft?

The total sum of Transport Index values. Add up the TI of every radioactive package on the aircraft, then look up the separation distance in IATA DGR Table 10.9.C (passenger and cargo) or Table 10.9.D (cargo only for TI > 50).

Do Category I-White packages need separation distance?

No. Category I-White packages have a TI of 0 and do not require any separation from persons, film, or live animals. The separation requirements apply only to Category II-Yellow and III-Yellow packages.

What is the separation distance from live animals?

0.5 meters for journeys of 24 hours or less, 1.0 meters for longer journeys (IATA DGR §10.9.3.9). This is a fixed distance that does not depend on the Transport Index.

Who is responsible for ensuring correct separation distances?

The airline is responsible for loading and positioning. The shipper is responsible for providing accurate category labels, Transport Index values, and package dimensions. If the shipper provides incorrect information, the load planner will calculate the wrong distance.

Does radioactive material need to be separated from undeveloped film?

Yes. Table 10.9.E provides separation distances based on TI and journey duration, calculated to keep film dose below 0.1 mSv. Film separation distances are typically larger than person separation distances at the same TI.

Summary: Your Separation Distance Checklist

To ensure correct separation distances on the aircraft:

• ☐ Transport Index is calculated correctly and rounded up to one decimal place
• ☐ TI is written identically on both sets of labels
• ☐ Package category is correct (based on both TI and surface dose rate)
• ☐ Package dimensions are included in Sequence 3 of the DGD (for Yellow categories)
• ☐ If total TI exceeds 50: cargo aircraft only and exclusive use may be required
• ☐ If shipping with live animals on the same aircraft: inform the airline so they can plan 0.5–1.0 m separation
• ☐ If undeveloped film may be on the same flight: airline load planner references Table 10.9.E

Regulatory References

IATA (Air Transport):

• IATA Dangerous Goods Regulations §10.9.3.7 — Separation from persons
• IATA DGR Table 10.9.C — Separation distances for passenger and cargo aircraft (TI 0.1–50.0)
• IATA DGR Table 10.9.D — Separation distances for cargo aircraft only (TI 50.1–300.0)
• IATA DGR §10.9.3.8 — Separation from undeveloped photographic film
• IATA DGR Table 10.9.E — Film separation distances by TI and journey duration
• IATA DGR §10.9.3.9 — Separation from live animals
• IATA Dangerous Goods Regulations — Official publication page

Related RadShip Guides:

• Transport Index Explained
• Labeling Basics (White-I, Yellow-II, Yellow-III)
• Passenger vs Cargo Aircraft: IATA Rules
• The DGD: Class 7 Guide
• Marking and Labeling for Air Shipment
• Shipping Radioactive Material by Air: IATA Overview