THE COMPETENT PERSON & SOIL TESTING
This easy-to-use Leader’s Guide is provided to assist in conducting a successful presentation. Featured
are:
INTRODUCTION: A brief description of the program and the subject that it addresses.
PROGRAM OUTLINE: Summarizes the program content. If the program outline is discussed before
the video is presented, the entire program will be more meaningful and successful.
PREPARING FOR AND CONDUCTING THE PRESENTATION: These sections will help you set
up the training environment, help you relate the program to site-specific incidents, and provide program
objectives for focusing your presentation.
REVIEW QUESTIONS AND ANSWERS: Questions may be copied and given to participants to
document how well they understood the information that was presented. Answers to the review questions
are provided separately.
INTRODUCTION
Before OSHA issued the Construction Standard for Excavation, two people died each week as the result
of cave-ins at excavation sites. The standard is mostly common sense and designed to prevent painful
death. It provides the definition and the duties of the Competent Person, who is responsible for
classifying soil so adequate protection can be maintained.
This program defines the Competent Person and his duties in accordance with the Soil Classification
provisions in the Appendix of the standard.
PROGRAM OUTLINE
"A Competent Person is someone who is capable of identifying existing and predictable hazards in the
surroundings or working conditions which are unsanitary, hazardous or dangerous to employees and
who has authorization to take prompt corrective measures to eliminate them."
CLASSES OF MATERIALS
1) Stable rock: Solid mineral matter that can be excavated with vertical sides and remains intact while
exposed. Rock isn'
t stable if has been blasted, split or jackhammered.
2) Type A: Hard to break cohesive, non-fissured and undisturbed clay soil that can be excavated with
vertical slopes and is plastic when moist.
3) Type B: Unstable dry rock or clay that would normally be classified as Type A but is layered at a
slope of less than 4:1 due to fissures or exposure to vibration or traffic.
4) Type C: Sands, grains and silts that have no cohesive strength and include water submerged
excavations, disturbed soil and soil dipping into trenches at a 4:1 greater slope.
VISUAL TESTS
OSHA requires seven visual tests to help identify soil properties and conditions that affect the soil
stability around the excavation.
1. Look at the sides of the excavation and spoils for Type B or Type C soils.
2. Determine if spoils remain in cohesive clumps, or if they are granular and don'
t clump.
3. Look for cracks, fissures or spawling along the sides or surface.
4. Check for evidence of utility lines, previously disturbed soil or underground structures.
5. Identify soil layers that slope into the excavation and estimate the degree of slope.
6. Watch for water coming into the excavation at the bottom or sides, rainwater runoff, or surface water.
7. Check for sources of vibration in and around the area that affect soil stability.
MANUAL TESTS
OSHA requires one manual test under the standard after samples of the soil meet the conditions of
undisturbed, dry and saturated. The following are some of the manual tests:
Ribbon Tests (determines the "plasticity" or cohesiveness of a soil)
* Mold a disturbed sample of nearly saturated soil two or three inches in diameter.
* Roll out the sample to a thread about three quarters of an inch thick.
* With the thumb and fore finger, squeeze the roll until it is half flat; if it stays in one piece and ribbons
around the fingers the soil is cohesive Type B soil.
Dry Strength Tests
* Attempt to break a clump of dry spoil by hand. If it is hard to break and is fissured, it could be Type
A. Perform the test more than once if you think it is Type A; if it is fissured or breaks easier on
subsequent breaks, the soil is Type B.
* If the soil clump breaks under little or no pressure or breaks down into grains or powder, it is likely
Type C.
Thumb Penetration Tests
* The soil sample must be undisturbed and nearly saturated.
* If the thumb can penetrate the sample one half to one inch with moderate effort, the soil is Type B; if
the sample is easily penetrated for several inches and can be molded with light finger pressure, it is Type
C.
* If the thumb cannot bend into the sample, it is Type A.
OTHER STRENGTH TESTS
* Use a hand-operated Sheer Vein to estimate the unconfined compressive strength on an undisturbed,
saturated sample. Double the readings to get the actual measurement.
* A Pocket Penetrameter must be used on an undisturbed, nearly saturated soil sample. The device is pushed into
the smoothened surface of the sample; the measurement of unconfined compressive strength, shown at the top of the
device, is in Tons per Square Foot (TSF). Log results of testing 8 to 10 different samples. Disregard very
high or very low readings before averaging the results. Readings 1.5 TSF or greater indicates Type A; 0.5 to
1.5 TSF is Type B; less than 0.5 TSF is Type C.
Drying Test
This testis useful in determining Type A soil. Dry a 1"x 6" sample and examine the sample for cracks and
fissures.
Sedimentation Test
* Also known as the mixed media, glass jar or olive jar test, this test is used by Compliance Officers to verify the
soil classification of granular cohesive Type B or Type C. Fifty to sixty pounds of soil is taken from different parts of
the spoil pile, culled for rocks and debris, mixed, flattened, and cut into four sections. Two sections are thrown out,
the sample remixed, and the sample flattened and recut again. Two sections are thrown out again. This mixing and
cutting is done three times to get a representative sample.
* Place 1-1/2 inches of the dry, mixed sample into a jar the dimensions of an olive jar.
* Add five to six inches of water, cover and shake until mixed.
* Determine the sediment settlement rate; if 80% settles in 30 seconds, you will have Type C; if 80%
doesn'
t settle out in 30 seconds, then the sample is Type B granular.
COMPLIANCE OFFICER INSPECTIONS
* Do not consider a person a Compliance Officer until he provides proper identification.
* If necessary, you can request a reasonable period of type of about an hour to enlist additional company
personnel to assist in the inspection.
* Don'
t be confrontational with the Compliance Officer or become afraid; be professional and cite the
standard and the results of tests as the basis for your decisions.
PREPARE FOR THE SAFETY MEETING OR TRAINING SESSION
Review each section of this Leader'
s Guide as well as the videotape. Here are a few suggestions for using
the program:
Make everyone aware of the importance the company places on health and safety and how each person
must be an active member of the safety team.
Introduce the videotape program. Play the videotape without interruption. Review the program content
by presenting the information in the program outline.
Copy the review questions included in this Leader'
s Guide and ask each participant to complete them.
Maintain an attendance record and keep each participant'
s test paper as written documentation of the
training performed.
Here are some suggestions for preparing your videotape equipment and the room or area you use:
Check the room or area for quietness, adequate ventilation and temperature, lighting and unobstructed
access.
Check the seating arrangement and the audiovisual equipment to ensure that all participants will be able
to see and hear the videotape program.
Place or secure extension cords to prevent them from becoming a tripping hazard.
CONDUCTING THE PRESENTATION
Begin the meeting by welcoming the participants. Introduce yourself and give each person the
opportunity to become acquainted if there are new people joining the training session.
Explain that the primary purpose of the program is to provide information about properly classifying soils
at excavations sites.
Introduce the videotape program. Play the videotape without interruption. Review the program content
by presenting the information in the program outline. Lead discussions about preventing accidents and
injuries by using adequate soil classification in accordance with OSHA’s Construction Excavation
Standard. Use the review questions to check how well the program participants understood the
information.
After watching the videotape program, the viewer will be able to identify the following:
* The definition of the term “Competent Person” and his duties;
* Different types of soil and how to test it;
* What to do if a Compliance Officer visits the construction site.
THE COMPETENT PERSON & SOILS TESTING
REVIEW QUESTIONS
Name____________________________________________ Date________________________
The following questions are provided to check how well you understand the information presented during this program.
1.
a.
b.
c.
To be a Competent Person at an excavation site, you must be ___________________.
a foreman or crew leader
capable of identifying existing hazards
a geologist
2.
a.
b.
c.
The difference between Type A and Type B soils is ________________________.
the lack of cohesiveness of the clay in Type A
Type B could contain fissures while Type A cannot
Type A can be exposed to heavy traffic and Type B cannot
3.
a.
b.
c.
The primary difference between Type B and Type C soils is ________________________.
greater confined compressive strength of Type C
higher saturation of void spaces in Type C soils
the lack of clay content in Type C soils
4.
a.
b.
c.
How many manual tests are required under the standard?
7
1
6
5.
a.
b.
c.
Which conditions must be met in a plasticity test?
use of disturbed or undisturbed spoils of saturated soil
use of a soil mixture from different parts of the spoil pile
use of disturbed soil and nearly saturated sample
6.
a.
b.
c.
Manual tests mostly test for which soil types?
stable rock and Type A
Types A and B
Types B and C
7.
a.
b.
c.
The manual test that estimates the unconfined compressive strength of an undisturbed soil sample is ______.
plasticity
penetration
dry strength
8. To estimate a soil’s unconfined compressive strength using the hand-operated Sheer Vein, you must _____ the
results.
a. double
b. halve
c. average
9. A manual test not required by the standard but often used by a Compliance Officer to verify soil classification is the
______________________.
a. olive jar test
b. ribbon test
c. dry strength test
10. When dealing with a Compliance Officer, __________________________.
a. stand your ground when he challenges your decisions
b. back off and let your testing results stand by themselves
c. cite the standard as the basis for your decisions
9520: The Competent Person and Soils Testing
ANSWERS TO THE REVIEW QUESTIONS
1. b
2. b
3. c
4. b
5. c
6. c
7. b
8. a
9. a
10. c