Lesson 4: Tape Corrections

Question 1

Rules in Tape Corrections

Answer 1

GENERAL STATEMENT

“When measuring with tape
TOO LONG, ADD;
TOO SHORT, SUBTRACT.
Do the reverse when laying out.”

Question 2

First Rule in Tape Corrections

Answer 2

When a line is measured with a tape that is
“TOO LONG”, corrections are ADDED

Question 3

Second Rule in Tape Corrections

Answer 3

When laying out a length with a tape that is
“TOO LONG”, corrections are SUBTRACTED

Question 4

Third Rule in Tape Corrections

Answer 4

When a line is measured or laid out with tape,
that is “TOO SHORT”, corrections applied are opposite of 1st and 2nd rules

Question 5

Corrections to Tape

Answer 5

1. Due to Tape Not of Standard Length
2. Due to Slope
3. Due to Alignment
4. Due to Temperature
5. Due to Tension
6. Due to Sag
7. Due to Wind

Question 6

• Often, due to imperfections in their
  manufacture, stretching, or wear
• Also due to the constant use of tapes becoming worn, kinked, and improperly repaired when breaks occurred.
• Corrections may vary by few millimeters or
  centimeters

Answer 6

Tape Not of Standard Length

Question 7

When distances are measured, the equivalent horizontal distance may correspondingly be determined by applying an approximate or exact correction

Answer 7

Due to Slope

Question 8

• Linear error due to inaccuracy of a tape
• Similar to the effect of slope
• Easier to control and smaller in magnitude
• Generally least important among different tape
  corrections

Answer 8

Due to Alignment

Question 9

• Change in the length of the tape due to variations in temperature
• It occurs when measurements are taken at
  temperatures above or below the standard
  the temperature of the tape
• Corrections are usually small and negligible
  Proportional to the number of tape lengths

Answer 9

Due to Temperature

Question 10

Arises whenever the pull applied is different from the standard tension used in calibration

A function of:
Difference between applied and standard pulls
Measured length
Cross-sectional area of the tape
Modulus of elasticity of the tape material

Answer 10

Due to Tension

Question 11

It occurs when tape supports are only at its ends or at the 2 points measured
Will sag because of its own weight
Similar to electric or telephone wires,
swings loosely between two posts

Answer 11

Due to Sag

Question 12

• Caused by wind blowing perpendicular to the
  direction of taping
• Wind moves the middle and is unsupported
  portion of the tape to one side of the line
  measured
• Similar to the effect of sag but is usually much
  less
• Preferable not to undertake any taping work
  during windy days

Answer 12

Due to Wind