In response to a disturbing finding of the industry practice of transporting aerial shells alone, and without reloadable tubes, the Pipeline and Hazardous Materials Safety Administration (PHMSA) recently issued a formal guidance on the requirements for transporting an aerial shell kit with a reloadable tube as UN0336, 1.4G. Aerial shell kits are designed to operate within the tolerances and standards of its component parts (i.e. shell, tubes); in theory, using additional shells may compromise the integrity and tolerances of a reloadable tube, causing it to fail. As a legal matter, the practice of transporting aerial shells without reloadable tubes violates the federal Hazardous Materials Regulations, 49 C.F.R., Parts 171-180, and also runs afoul of American Pyrotechnics Association Standard 87-1, Version 2001.
APA Standard 87-1 describes the requirements for an aerial shell kit with a reloadable tube, at section 188.8.131.52, by specifying that a kit must contain (i) a launching tube and (ii) not more than twelve (12) aerial shells (complimentary in size to the reloadable tube), each not to exceed 60 grams of chemical composition that, in the aggregate, do not exceed 400 grams. Seemingly for purposes of clarity and completeness, in the preceding paragraph, 184.108.40.206, APA Standard 87-1 explicitly prohibits aerial shells without a launching tube from being approved or transported as UN0336, 1.4G. In short, in those instances where aerial shells are unaccompanied by a launching tube they can only be approved for transportation as 1.3G UN0335, implying that an aerial shell, by itself (and unaccompanied by a reloadable tube), is not a consumer product but, rather, a product intended for commercial, professional, use only. You can find the requirements to obtain approval of an aerial shell as a 1.3G UN0335 fireworks at APA Standard 87-1, section 4.1.1.
An EX approval classification for transportation as a 1.4G aerial shell kit with reloadable tube (in accordance with APA Standard 87-1) is only valid when the kit contains a fully assembled and usable launch tube constructed from either cardboard, high density polyethylene, or equivalent material that is capable of firing twice the number of shells in the kit without tube failure. In all instances, each kit is limited to twelve (12) aerial shells, and no one shell may exceed 60 grams of chemical composition and, in the aggregate, all of the shells may not exceed 400 grams in chemical composition. Finally, aerial shell kits containing a reloadable tube and meant for retail sale must be transported in commerce from the manufacturer in a finished state.