Plumbing Formula Cheat Sheet
PLUMBING FORMULA REFERENCE
Reference Sheet
Tier 1 Plumbing
Common Conversions
- 1 Foot 12 Inches
- 1 Square Foot 144 Square Inches
- 1 Cubic Foot 1728 Cubic Inches
- 1 Gallon of Water 231 Cubic Inches
- 1 Gallon of Water 8.33 Pounds
- 1 Cubic Foot Water 7.48 Gallons
Geometric Formulas
Area
- Circle: \(A = \pi \times r^2\) (or \(D^2 \times 0.7854\))
- Triangle: \(A = \frac{1}{2} \times \text{base} \times \text{height}\)
- Rectangle: \(A = \text{length} \times \text{width}\)
Volume
- Cylinder (Pipe): \(V = \text{Area} \times \text{Length}\)
- Rectangular Tank: \(V = L \times W \times H\)
Offset Multipliers (Finding Travel)
45°
Multiplier
1.414
Offset × 1.414 = Travel
60°
Multiplier
1.155
Offset × 1.155 = Travel
22.5°
Multiplier
2.613
Offset × 2.613 = Travel
Note: To find the "Run" of a 45° offset, use the same measurement as the Offset.
Common Fraction-to-Decimal Conversions
1/8
0.125
1/4
0.250
3/8
0.375
1/2
0.500
5/8
0.625
3/4
0.750
7/8
0.875
1/16
0.0625
Plumbing Math Essentials Tier 1 Apprentice Resource
Pipe Power Math Test
PIPE POWER MATH TEST
Tier 1 Apprentice Assessment
Name:
Date:
Instructions: Show all work. Round decimals to the nearest thousandth. Do not include units in the answer line unless they are missing.
Section 1: Basics & Percentages
1. Convert fractions to decimals:
5/8 =
3/16 =
2. A plumbing job is quoted at $6,450.00. Calculate a 15% down payment for the customer.
Amount: $
Section 2: Area & Offsets
3. Calculate the area of a 4-inch diameter pipe (cross-section).
sq in.
4. Area of a triangle: Base = 24", Height = 18".
sq in.
5. 45° Offset (Rise = 14"):
Travel:
6. 60° Offset (Rise = 22"):
Travel:
7. 22.5° Offset (Rise = 9"):
Travel:
Section 3: Tank Capacity & Volume
8. RECTANGULAR TANK CAPACITY
A condensate tank measures 4 feet long, 3 feet wide, and 2 feet deep.
A) Total Cubic Inches:
cu in.
B) Total Gallons (1 gal = 231 cu in):
gallons
9. CYLINDRICAL TANK CAPACITY
A hot water storage tank has a diameter of 24 inches and a height of 72 inches.
A) Capacity in Cubic Inches:
cu in.
B) Capacity in Gallons:
gallons
10. PIPE VOLUME & WEIGHT
A 3-inch (inside diameter) schedule 40 pipe is 20 feet long.
A) Volume of water in the pipe:
cu in.
B) Total Weight of water (1 gal = 8.33 lbs):
lbs.
End of Examination • Comprehensive Plumbing Math Assessment
Pipe Power Math Answer Key
ANSWER KEY
Pipe Power Math Test • Instructor Key
Scoring Info
10 Problems Total
1. Fractions to Decimals:
5/8 = 0.625
3/16 = 0.1875 (0.188)
2. 15% Payment ($6,450):
\$967.50
3. Area of 4" pipe:
\(Radius = 2"\)
\(\pi \times 2^2 \approx 12.566\) sq in.
4. Triangle Area:
\(0.5 \times 24 \times 18 = 216\) sq in.
5-7. Offset Travels (Travel = Multiplier x Rise):
45°: 1.414 \(\times\) 14 = 19.796"
60°: 1.155 \(\times\) 22 = 25.41"
22.5°: 2.613 \(\times\) 9 = 23.517"
8. Rectangular Tank Capacity (48" x 36" x 24"):
A) Volume:
41,472 cu in.
B) Gallons (41,472 / 231):
179.532 gallons
9. Cylindrical Tank Capacity (D=24", H=72"):
A) Volume (\(\pi \times 12^2 \times 72\)):
32,572.032 cu in.
B) Gallons (32,572.032 / 231):
141.004 gallons
10. Pipe Volume & Weight (3" pipe, 20' long):
A) Volume (\(\pi \times 1.5^2 \times 240\)):
1,696.460 cu in.
B) Weight (Total Gallons \(\times\) 8.33):
Vol Gal: 1,696.46 / 231 = 7.344 gal
7.344 \(\times\) 8.33 = 61.176 lbs.
Strictly for Instructor Use Only
