Code of Federal Regulations Title 49. Transportation 49 CFR Pt. 172, App. B—TREFOIL SYMBOL

1. Except as provided in paragraph 2 of this appendix, the trefoil symbol required for RADIOACTIVE labels and placards and required to be marked on certain packages of Class 7 materials must conform to the design and size requirements of this appendix.

2. RADIOACTIVE labels and placards that were printed prior to April 1, 1996, in conformance with the requirements of this subchapter in effect on March 30, 1996, may continue to be used.

1=Radius of Circle—

Minimum dimensions

4 mm (0.16 inch) for markings and labels

12.5 mm (0.5 inch) for placards

2=1 1/2 Radii

3=5 radii for markings and labels

4 1/2 radii for placards.