Evacuation and Calculations

Question 1

What are protective measures?

Answer 1

Actions taken to taken to reduce the hazard from UXO/IED prior to gaining access to or conducting work on a UXO/IED.

Question 2

What does BODR stand for and explain what it is.

Answer 2

Blast overpressure distance range - The over pressure above the ambient pressure in the blast wave at a given distance from the explosive site.

Question 3

What does HFDR stand for and explain what it is.

Answer 3

Hazardous fragmentation distance range - Always a minimum of 100m. The minimum withdrawal distance for protection from hazardous primary and secondary fragmentation.

Question 4

What does MFDR stand for and explain what it is.

Answer 4

Maximum fragmentation distance range - The range at which hazardous primary and secondary fragmentation is not expected to pose a threat to an exposed person in the open. Always a minimum of 400m.

Question 5

What does VSD stand for and explain what it is.

Answer 5

Vertical safe distance - The distance is the minimum safe height over the explosive site. It is enforced by a Notice to Airmen (NOTAM.)

Question 6

What is explosive K factor?

Answer 6

A scaling factor which relates to the maximum overpressure generated at a distance from an explosion based on it’s total NEQ.

K(m) is the metric calculation.

The lower the number the closer to the source and the greater overpressure.

Question 7

What defines items to be stacked? How does this change the BODR and Fragmentation calculations?

Answer 7

The distance between items is smaller than the radius of the largest item.
The BODR is calculated off the sum of all the NEQ items. The frag distances are calculated of the single largest item and it’s donor charge then multiplied by 1.33.

Question 8

How do you calculate TNT equivalencies on Pyrotechnics fills and unknown explosives? What pyrotechnics are not considered for NEQ calculations?

Answer 8

Multiply the weight by 1.5. It’s not be added are WP, Smoke, irritants and dyes.

Question 9

What are the rounding rules for;
NEQ
BODR/HFDR/MFDR
VSD
QDR
K Factor

Answer 9

NEQ is rounded up to 3 decimal places
BODR/HFDR/MFDR - Rounded up to the nearest metre
VSD - Round up to the nearest 100ft
QDR - Round up to the nearest 10m
K Factor - Rounded down (cut off) 2 decimal places