[Code of Federal Regulations]
[Title 49, Volume 2]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR173.50]

[Page 473-474]
 
                        TITLE 49--TRANSPORTATION
 
   CHAPTER I--PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, 
                      DEPARTMENT OF TRANSPORTATION
 
PART 173_SHIPPERS_GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS--
Table of Contents
 
     Subpart C_Definitions, Classification and Packaging for Class 1
 
Sec.  173.50  Class 1--Definitions.

    Source: Amdt. 173-224, 55 FR 52617, Dec. 21, 1990, unless otherwise 
noted.


    (a) Explosive. For the purposes of this subchapter, an explosive 
means any substance or article, including a device, which is designed to 
function by explosion (i.e., an extremely rapid release of gas and heat) 
or which, by chemical reaction within itself, is able to function in a 
similar manner even if not designed to function by explosion, unless the 
substance or article is otherwise classed under the provisions of this

[[Page 474]]

subchapter. The term includes a pyrotechnic substance or article, unless 
the substance or article is otherwise classed under the provisions of 
this subchapter.
    (b) Explosives in Class 1 are divided into six divisions as follows:
    (1) Division 1.1 consists of explosives that have a mass explosion 
hazard. A mass explosion is one which affects almost the entire load 
instantaneously.
    (2) Division 1.2 consists of explosives that have a projection 
hazard but not a mass explosion hazard.
    (3) Division 1.3 consists of explosives that have a fire hazard and 
either a minor blast hazard or a minor projection hazard or both, but 
not a mass explosion hazard.
    (4) Division 1.4 consists of explosives that present a minor 
explosion hazard. The explosive effects are largely confined to the 
package and no projection of fragments of appreciable size or range is 
to be expected. An external fire must not cause virtually instantaneous 
explosion of almost the entire contents of the package.
    (5) Division 1.5 \1\ consists of very insensitive explosives. This 
division is comprised of substances which have a mass explosion hazard 
but are so insensitive that there is very little probability of 
initiation or of transition from burning to detonation under normal 
conditions of transport.
---------------------------------------------------------------------------

    \1\ The probability of transition from burning to detonation is 
greater when large quantities are transported in a vessel.
---------------------------------------------------------------------------

    (6) Division 1.6 \2\ consists of extremely insensitive articles 
which do not have a mass explosive hazard. This division is comprised of 
articles which contain only extremely insensitive detonating substances 
and which demonstrate a negligible probability of accidental initiation 
or propagation.
---------------------------------------------------------------------------

    \2\ The risk from articles of Division 1.6 is limited to the 
explosion of a single article.

[Amdt. 173-224, 55 FR 52617 Dec. 21, 1990, as amended at 56 FR 66267, 
Dec. 20, 1991; 66 FR 45183, Aug. 28, 2001; 68 FR 48569, Aug. 14, 2003]