Subpart P - Excavation Safety

Abrasive blasting with quartz sand puts workers at what risk of exposure to silica

High

The main parts of a shoring system are:

Sheeting, Wales, cross bracing

Two main types of support systems are trench shields and:

Shoring

Silica is a chemical compound called

Silicon dioxide

The most important factor in the maximum allowable slope is:

Soil type

The hazardous type of silica referred to throughout this discussion is

crystalline

In which of the following is silica found

sand, gravel, rocks

Any trench more than 4 feet deep is considered:

A confined space.

The three types of silicosis are

Accelerated, chronic, and acute

Grinding, jackhammering, blasting, and rock all

Allow silica dust to become airborne

After soil is cut, where is it most unstable?

At the bottom of the cut

Which one is not a duty of the competent person for excavation?

Firing unsafe workers.

How preventable is silicosis?

100%

A trench is a narrow excavation that is deeper than it is wide. It's maximum bottom width is _____ feet.

15

Keep spoil and material back at least _______ from the edge of excavation

2 Feet

A worker must have to travel no more than what to a safe exit

25 feet

To help identify hazardous conditions and take corrective action, the employer authorizes:

A competent person

When must employers notify utility companies before and excavation?

Before it begins

What is the leading cause of death in excavation work?

Cave-ins

Symptoms of silicosis include

Coughing and shortness of breath

How often must the competent person inspect the excavation?

Daily

When accidents happen during excavation, they usually result in:

Death and serious injury.

Type A cohesive soil is more stable than sandy soil because of its high ___ content.

Iron

Abrasive blasting may also pose a risk for exposure to

Lead, arsenic, cadmium

Install support systems in this order:

Mid point to bottom, then top

How many workers are at risk of exposure?

Nearly 2 million

Walking under loads handled by lifting or digging equipment is:

Never allowed.

An acceptable means of exit from a trench is:

One ladder placed midway in a 50 foot long trench.

There are two main dangers from allowing spoil, material, or equipment next to an excavation. One is objects falling or rolling into the excavation. The other is:

Overloading and collapsing the walls.

Two types of cave-in protective systems are sloping or benching and:

Support systems

You may enter a trench to rescue a coworker if

You have been trained to do it