3. DESIGN PHILOSOPHY. In the design of facilities for the manufacture or
storage of explosive materials, the designer is concerned with maintaining a
cost effective design and at the same time, directing his efforts towards
reducing the risk of injury to people and damage to property from accidental
explosions. The trade-off between risk reduction and safety costs can be
balanced reasonably by enforcing the minimum design requirements provided in
this and similar design manuals. The design engineer needs a working
knowledge of these manuals to design and construct safe economical
facilities which comply with explosives safety standards. Several examples
are provided in this manual as an effort to satisfy this need.
4. CRITERIA FOR PERSONNEL AND MATERIALS. In the event of an accident,
personnel and material are exposed to hazards such as blast fragmentation
and debris. Present hazard classification of mass detonating ordnance
during manufacturing, transportation and storage is based on
quantity-distance standards which relate the net weight of explosive to
safe stand-off distances for personnel and buildings.
a. Safety Requirements. Principal documents which prescribe the
minimum safety requirements and proximity of explosive storage and
handling facilities to each other, to inhabited buildings and the like, are:
(1) NAVFAC P-397, Structures to Resist the Effects of Accidental
(2) AMCR 385-100, Safety Manual.
(4) DOD Manual 4145.26, Contractors' Safety Manual for Ammunition
b. Criteria and Design. NAVFAC P-397 establishes criteria for design
of structures to be resistant to explosions. AMCR 385-100 and DOD Manuals
6055.9-STD and 4125.26 prescribe safe methods and practices for safeguarding
personnel, insuring continuity of production, and preventing property
c. Reduction of Minimum Safety Distances. It should be stated,
however, that if it can be verified through tests or conservative analysis
that the blast pressures and fragments resulting from an explosion can be
completely contained, then the required minimum safety distances can be
5. SHORT AND LONG DURATION BLAST LOADS. The response of a structure to
blast loads depends on its location relative to the source of the
explosions. This response is expressed in terms of pressure ranges;
namely, high, intermediate, and low pressure ranges.
a. Impulse Design. When the initial pressures acting on a structure
are high and the durations short, compared to the response time of the
structure, then it has to be designed for the impulse (area under curve)
rather than for the peak pressure. The design of structures that respond
to impulse loads is presented in detail in NAVFAC P-397.