1. Taping Corrections
Incorrect length
Slope
Temperature
Sag
Stretch

2. Incorrect Length Sources of Error CL = (Ltrue-L)
Bad repair
Poor standardization
CL = (Ltrue-L)
Determining - add correction
Establishing - subtract the correction

3. Incorrect Length - Determining
Your Task: Measure distance A to B
You measure ’
Your tape is actually ’ long
Actual length = ’
CL = (100.02’ – 100’) = 0.02’/pull
Dtrue = Dmeasured + CL
Dtrue = *(.02’) = ’

4. Incorrect Length - Establishing
Your task: Establish point B exactly feet from point A
Your tape is actually ’ long
B is set 5(100.02’) = ’ from A
CL = (100.02’ – 100’) = 0.02’/pull
Correct by subtracting 5(.02’) = 0.10’

5. Slope
Trigonometry
Horizontal: h = s*cos()
Calculation s h v a

6. Slope Example If s = 300.00’  = 5° If you had measured v = 26.15’
h = 300 cos(5) = ’
v = 300 sin(5) = 26.15’
If you had measured v = 26.15’
CS = v2/2S = / = 1.14’
h = v – CS = – 1.14 = ’

7. Temperature

8. Temperature Example Tape calibrated to 100.00’ at 68°F
Determine Dist AB = ’ at 22°F
Calculate true distance
CT = (22-68)(368.50) = -0.11’
True Dist AB = = ’

9. Sag
Example:
2.8-lb chain calibrated at ’ when supported throughout
Established B ’ from A
P = 12 lb, Supported at the ends only
Measured 3 pulls of 100 ft, one of 48.75’
CS=-[3(2.82*100) *48.753]/(24*122)=-.71’
If P = 18 lb, CS = -0.31’ (Pull hard!)
If pulls are 6 at 50’ plus 48.75’, P = 12 lb, CS = -0.20

10. Sag and Tension
W = 2.8, A = 0.015, PS = 12 Trial and error -> P = 31 lb
If P = 18-lb, PS = 12-lb, L = 100’, A = in2,
CP = (18–12)100/(0.015*29,000,000) = ’

11. Taping Precision
1/ Poor
1/ Average
1/10,000 - Good