One of the United Nations Classification Tests, i.e., a 6(b) stack test, was conducted in order to study the classification and its test procedures for fireworks shells. Fireworks shells of 180 mm or larger in diameter are classified as hazard division 1.1 on the classification table. Therefore, the fireworks shells that correspond to such a dangerous division can come under a large handling influence.
The test was conducted by selecting four kinds of samples with different structure, amount of the bursting charge and chemical composition of the star from among the 240 mm color shells (Palm Tree, Butterfly, Brocade Crown and Three color-
changing). The inner and external pressure of the shells and the noise generated by the tests were measured to investigate simultaneous explosion, and to deduce the simultaneous explosion number of the shells. The following results were obtained.
1) The acceptor shells caused explosion simultaneously with the donor shell when the inner pressure of the acceptor shells was high.
2) It was possible to deduce effectively the simultaneous explosion number of the shells by measuring the noise.
3) "Butterfly" was classified as hazard division 1.1, and the other shells were classified as 1.3 hazard division candidates.
煙火分類のデフォルト表，及び試験方法を検討するために，国連試験6(b)積み重ね試験を行った。この分類表では，玉の直径が180 mm以上の煙火玉は危険区分1.1として分類されるため，これらに該当する煙火玉の取扱いは多大な影響を受ける可能性が高い。本研究では，8号煙火玉の中から構造，割薬量，星の組成の異なる4種類の試料(椰子，蝶々，錦冠及び銀波先緑紅)を選定した。殉爆状況を調査し，その殉爆個数を推定するために，玉内外圧の計測，発生した騒音の計測を行い，以下の結果を得た。
1）受爆玉の内圧が高い状態の時に受爆玉の同時爆発が起きた。
2）煙火玉の殉爆個数を推定するには騒音の計測が有効であることがわかった。
3）「蝶々」は危険区分1.1，その他は危険区分1.3候補とした。
Simultaneous explosion, Fireworks shells, Gap tests in sand, Pressure and noise measurements.