By: Sarchia Khursheed (سەرچیا خورشید)

1. 1
Soran University
Faculty of Engineering
Civil Engineering Department
TWO PEG TEST
Student: Sarchia Khursheed
Group: E
Date: 20.10.2015
Supervisor: Eng. Anwar Jabbar
Introduction

2. 2
All instruments are subject to errors. The checking of the
instrument (in this case level) is therefore important. The
main error is where the line of sight is not parallel to the
horizontal line of collimation. In this case levels will not be
correct. A test for checking the level is known as the two
peg test. Two peg test must be carry out before strating the
leveling job to insure the instrument in good condition. This
test determines the amount of errors and if an error occurs
notify the technician (the level must be serviced).
Purpose of Test
Purpose of doing this test is to determine the collimation
error of a level instrument.
Equipments
List of equipments and tools need to completing the two peg
test:
 Auto Level
 Staff
 Tripod
 Tapes (50 meters)
 Marker (Spray)
 Pen, Paper, and Calculator
Procedure
Steps of a two peg test:

3. 3
1. Establish two points (A and B) approximately 50 meters
apart on level ground, and put the level staffs in each
point, and the level half way between the two points.
2. Take readings on both pegs, and find the difference in
elevation.
3. Move the level as close ass possible to one of the peg
(5 meters). Take the two staff readings again.
4. If the difference in height is the same the level is okay.
If not, the instrument needs to be serviced.
Calculation
Peg A Peg B Difference
Readings
(from middle
point)
1.473 1.447 E1 = 0.026
Readings
(from point C)
1.457 1.417 E2 = 0.04
ΔE = E2 – E1 = 0.04 m – 0.026 m = 0.014 m
Result and Conclusion

4. 4
In conclusion we know that the two peg test is very simple,
but provides a way to test the accuracy of a level, and help
to know which screw to turn (for analog instruments) or
menu to follow (for the degital level), it can be adjust to
remove the error.
For a good or normal level the result from calculation of two
peg test must be smaller than 0.002, if the result is greater
than 0.002 the level must be serviced. Because the result
0.014 is greater than 0.002 the instrument (level) must be
fixed and serviced.