Chapter 11

Question 1

In the US, an average of ___ to ____ workers die each year in trench cave ins

Answer 1

60, 100

Question 2

according to NFPA 1006, Level I rescuer is limited to conducting trench rescue operations to a non-intersecting trench that is no deeper than ____ ft.

Answer 2

8

Question 3

a narrow excavation made below the surface of the ground Not greater than 15 foot at the bottom

Answer 3

trench

Question 4

a registered professional engineer must design shoring plans for trenches deeper than ____ ft.

Answer 4

20

Question 5

5 soil types:

Answer 5

1. rock
2. cemented soils
3. cohesive soils
4. granular soils
5. loams

Question 6

cohesive soils are composed primarily of ______

Answer 6

clay

Question 7

4 general classifications of soil in the US

Answer 7

1. stable rock
2. A
3. B
4. C

Question 8

a cubic yard of soil can weigh over a ____

Answer 8

ton

Question 9

average weight of a trench wall is about _______ lbs. per cubic yard

Answer 9

2700

Question 10

plywood used for lip protection should have a minimum thickness of ____

Answer 10

3/4 inch

Question 11

industry standard in the US is for the spoil pile to be a minimum of ____ ft. away from the lip of the trench.

Answer 11

2

Canada is 1 meter

Question 12

place ___________ at both ends of the trench

Answer 12

ground ladders

Question 13

rescuers should not have to travel more than _____ ft. to reach a ladder

Answer 13

25

Question 14

tops of ladders should extend at least ____ ft. above the lip of the trench

Answer 14

3

Question 15

any trench deeper than ____ ft., employers are required to protect workers from cave-ins.

Answer 15

4

Question 16

in sloping, the angle of incline to prevent cave-ins is usually less than ______ from horizontal. this is used on trenches no deeper than 12 ft

Answer 16

34°

Question 17

sloping can be used on trenches no deeper than ____ft.

Answer 17

12

Question 18

Horizontal timber placed against sheeting planks in an excavation to keep the sheeting planks in place

Answer 18

wale

Question 19

cross braces should be located within ____ ft. from the top and bottom of trench and then no more than ____ ft. apart after that.

Answer 19

2, 4

Question 20

using ______ nails makes later removal easier

Answer 20

duplex

Question 21

space within 2 ft. in all directions of an installed support component

Answer 21

safe zone