Test Details
Test Purpose
The objective of a siting evaluation is to protect personnel and facilities from explosive or other highly reactive operations through proper facility design or separation. The quantity of explosives and the required distance of separation (QD) determines facility siting. The QD tables as used by accepted industry and government methodologies (e.g. UBC, DoD) are based on TNT. If the TNT equivalence of an explosive is less than that of TNT than more of that substance can be located at a given site with a given QD specification. Likewise if the TNT equivalence of an explosive is greater than TNT then the opposite is true. Testing is performed to document a material’s TNT equivalence from the ratio of the overpressure at a given distance compared to the overpressure from the same mass of TNT at that distance.
Key Parameters
| Key Parameter | Objectives | Origin | Specs |
|---|---|---|---|
| Substance configuration | Ensure that a significant amount of the substance is tested to relate to the pressure of a similarly sized mass of TNT. Configuration can be process specific | Amount and configuration can be process specific | |
| Ignition stimulus (cap or booster) | Ensure the substance is subjected to a shock stimulus equivalent to a worst case condition under processing/ storage conditions | ||
| Overpressure measurement device (e.g. pencil probe) | Measure and record the pressure (side-on overpressure) as a function of time upon initiation of the substance |
Indicators
| Indicators | Detection Method | Assessment |
|---|---|---|
| Overpressure | Review of the overpressure data | The measured overpressure value is compared against that expected for TNT (TM5-1300 Figure 2-15 for side-on overpressure from a hemispherical TNT blast) |