The PTR distance is the distance required between PTRs and explosive hazards.
Motor vehicles and rail cars are considered safe from blast effects at the PTR distance. This
equates to approximately 60 percent of the IBD.
The fragment distance for PTR with classes 1.1 and 1.3 may also be reduced 60% of the
minimum fragment distance for the explosive source under consideration, but never less than
that required by the class 1.1 and 1.3 QD Table. See Table 5.4 of TM 9-1300-206 (subcourse
Figure 7) for additional information.
(3) Intraline Distance (ID). This is the minimum distance permitted between any two buildings within one
operating line. See Figure 4. ID is also used:
For separating certain areas, buildings and locations even though actual line operations are
are considered class 1.1.
Intraline distance is expected to protect buildings from the propagation of explosion due to
blast effects and missile hazards.
Buildings separated by ID will probably suffer substantial structural damage.
A service type magazine shall be located at ID, based on the quantity of explosives in the
magazine, from the nearest operating building. Service type magazines will be separated from
each other by ID.
Separate facilities (excluding service magazines) may be less than ID, but not less than
prudent fire distance from operating buildings and ID from other explosive buildings. Such
facilities include low pressure heating boilers and paint storage buildings.
Figure 4. Operating line/intraline distance