What LabelCalc Determines
- Transport Index (TI) — calculated from your 1-meter dose rate with the rounding rules in 49 CFR 173.403
- Label category — WHITE-I, YELLOW-II, or YELLOW-III per 49 CFR 172.403, checking both the TI and the surface dose rate
- Placard requirements — including the YELLOW-III trigger in 49 CFR 172.504 and HRCQ square-background placarding
- Exclusive use status — flags when your dose rates push the shipment into exclusive use under 49 CFR 173.441(b)
How the Transport Index Calculator Works
The transport index is the maximum radiation dose rate in mrem/hr measured at 1 meter from the external surface of the package, rounded up to the first decimal place. Measure all accessible sides, take the highest reading, and round up: 0.82 mrem/hr becomes TI = 0.9. The one exception is at the bottom of the scale — a reading of 0.05 mrem/hr or less at 1 meter gives a TI of 0.
LabelCalc applies these rules automatically, accepts readings in mrem/hr or mSv/h, and checks your surface reading at the same time — because the label category is determined by whichever measurement is more restrictive. For the full measurement procedure, see Transport Index Explained.
Label Selection Criteria (49 CFR 172.403)
| Label | Transport Index | Max Surface Dose Rate |
|---|---|---|
| RADIOACTIVE WHITE-I | 0 | ≤ 0.5 mrem/hr (0.005 mSv/h) |
| RADIOACTIVE YELLOW-II | ≤ 1 | ≤ 50 mrem/hr (0.5 mSv/h) |
| RADIOACTIVE YELLOW-III | ≤ 10 | ≤ 200 mrem/hr (2 mSv/h) |
| YELLOW-III (exclusive use required) | > 10 | > 200 mrem/hr |
Both conditions must be satisfied for a category — if either the TI or the surface dose rate exceeds the limit, the package moves to the next higher label. The most common labeling mistake is calculating the TI, picking a label, and never checking the surface reading. For label placement and completion details, see Radioactive Material Labeling Basics.
Exclusive Use and Placards
When the TI exceeds 10 or the surface dose rate exceeds 200 mrem/hr, the package cannot move as a routine shipment — it requires exclusive use of the vehicle under 49 CFR 173.441(b), with surface dose rates permitted up to 1,000 mrem/hr in a closed transport vehicle and written instructions provided to the carrier. LabelCalc flags this condition and tells you why.
Any shipment containing a YELLOW-III labeled package requires RADIOACTIVE placards on the transport vehicle. Class 7 appears in Table 1 of 49 CFR 172.504, which means the 1,001-lb placarding exception that covers most other hazard classes does not apply — one YELLOW-III package is enough.
Frequently Asked Questions
How is the transport index (TI) calculated?
Measure the maximum radiation dose rate at 1 meter from the external surface of the package in mrem/hr, then round up to the first decimal place. A reading of 0.82 mrem/hr becomes TI = 0.9. The one exception: if the reading at 1 meter is 0.05 mrem/hr or less, the TI is 0 (49 CFR 173.403).
Which label does my radioactive package need?
It depends on two measurements, and the higher one controls. WHITE-I requires TI = 0 and a surface dose rate of 0.5 mrem/hr or less. YELLOW-II requires TI of 1 or less and a surface dose rate of 50 mrem/hr or less. YELLOW-III applies up to TI 10 and a surface dose rate of 200 mrem/hr. If either measurement exceeds a category limit, you must use the next higher label (49 CFR 172.403).
When is exclusive use required?
When the transport index exceeds 10 or the surface dose rate exceeds 200 mrem/hr (2 mSv/h). Exclusive use shipments under 49 CFR 173.441(b) permit surface dose rates up to 1,000 mrem/hr in a closed transport vehicle, but require additional controls including written instructions to the carrier.
When does a radioactive shipment need placards?
A RADIOACTIVE placard is required whenever any package bearing a YELLOW-III label is transported — Class 7 is in Table 1 of 49 CFR 172.504, so there is no 1,001-lb small-quantity exception. Certain exclusive use LSA and SCO shipments also require placards even when individual packages are not labeled. Highway route controlled quantities (HRCQ) additionally require the square background placard under 49 CFR 172.507.
Can I try LabelCalc before subscribing?
Yes. Demo mode loads sample dose rate values so you can see exactly how the calculator determines the TI, label category, placard, and exclusive use requirements. Full access with your own dose rates starts with a 7-day free trial, then $49/month.
Related Guides
- Transport Index Explained: What It Is and How to Calculate It
- Radioactive Material Labeling Basics: WHITE-I, YELLOW-II, YELLOW-III
- Package Types Explained: Excepted, Type A, Type B, and Industrial
- Shipping Paper Requirements for Radioactive Material
Last reviewed July 29, 2026. Regulatory citations reflect the current 49 CFR. This page describes labeling requirements for domestic ground transport; air shipments are additionally subject to IATA requirements — see the IATA air shipping overview.