Unbarricaded means without effective barricade between magazines, operating buildings, stacks, or
other buildings opposed one to another.
Barricades are normally constructed from earth, although they may be made from a combination of
earth and wood or even concrete.
Reading table 5-5 (fig. 2-14) is very similar to the IBD and PTR table (fig. 2-11) previously
discussed. The NEW of class 1.1 is shown in the first two columns, distance in feet is shown in the
following column. For example, 750 NEW of 1.1, the intraline distance would be 85 feet barricaded or
170 feet unbarricaded. (750 NEW is over 700, but less than 800.)
Now try this problem. You have 8,075 pounds of NEW of class 1.1 to be stored at an unbarricaded
site. What would be the intraline distance? See figure 2-14. Since 8,075 pounds is over 8,000 pounds
but less than 9,000 pounds, the distance would be 370 feet.
The next quantity application we will deal with is intermagazine distance.
Earth-covered igloo type magazines are considered barricaded (rear and sides). The
door or front of the magazines are unbarricaded unless an effective separate barricade is
provided near the door end.