Conversion Factors & Formulas
The following is a list of common conversion units and formulas that should help you answer any conversion or formula questions.
CONVERSION UNITS
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Multiply By To Get
To Get By Divide |
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BOILER HORSEPOWER 34.5 LBS/HR OF STEAM BOILER HORSEPOWER 33,479 BTU/HR CUBIC FEET 7.48 GALLONS CUBIC FEET/MIN 62.43 LBS OF WATER/MIN CUBIC FEET 1728 CUBIC INCHES FEET OF WATER 0.4335 LBS/SQ IN GALLONS 0.1337 CUBIC FEET GALLONS 3785 CUBIC CENTIMETERS GALLONS OF WATER 8.3453 LBS OF WATER INCHES OF MERCURY 1.133 FEET OF WATER INCHES OF MERCURY 0.4912 LBS/SQ IN INCHES OF WATER 0.03613 LBS/SQ IN INCHES OF WATER 0.07355 INCHES OF MERCURY KILOWATT HOURS 3415 BTU/HR LITERS 0.2642 GALLONS METERS 39.37 INCHES MILLIMETER 0.03937 INCHES OUNCES/SQ IN 0.0625 LBS/SQ IN POUNDS/SQ FT 0.01602 FEET OF WATER POUNDS/SQ IN 2.307 FEET OF WATER POUNDS/SQ IN 2.036 INCHES OF MERCURY TEMP °C + 17.78 1.8 TEMP °F TEMP °F – 32 .555 TEMP °C WATTS 0.05692 BTU/MIN WATTS 1000 KILOWATTS WATTS 3.413 BTU/HR |
FORMULAS
• STEAM TO WATER HEAT EXCHANGER:
(DT °F IS: TEMPERATURE OF THE LEAVING WATER MINUS TEMPERATURE
OF THE ENTERING WATER)
• STEAM COIL HEATING AIR:
(DT °F IS: TEMPERATURE OF THE LEAVING AIR MINUS TEMPERATURE
OF THE ENTERING AIR)
• HOT WATER COIL:
• ELECTRIC HEAT COIL:
• CHILLED WATER COIL:
BTU/HR = 8.3453 x 60 x DT °F OF WATER
1 GPM = 5000 BTU/HR AT A WATER DT OF 10°F
• LIQUID FLOW IN PIPES:
• AREA OF A CIRCLE:
AREA = 3.1416 X RADIUS SQUARED
OR = DIAMETER SQUARED X .7854
• CIRCUMFRENCE OF A CIRCLE:
CIRCUMFERENCE = RADIUS X 6.2832
OR = DIAMETER X 3.1416
• CAPACITY OF A TANK IN GALLONS:
(ALL MEASUREMENTS MUST BE IN INCHES)
-CYLINDRICAL TANKS:
GALLONS = LENGTH X DIAMETER SQUARED X .0034
-RECTANGULAR TANKS:
• LINE CURRENTS, ELECTRIC HEATERS:
- SINGLE PHASE -
- THREE PHASE -
PH
While not a conversion or formula, the PH table is included because all hydronic heating and cooling systems should be tested for the PH level of the circulated fluid. High acidity causes corrosion whereas high alkalinity causes scale deposits. Hydronic system fluid should have a PH level between 7.5 and 8.5.
Some industrial specifications may include the PH of a fluid being measured, so the proper materials that come in contact with the fluid can be selected.
A PH of 7 is “neutral.” A PH number lower than 7 is acidic. A PH number higher than 7 is alkaline. Note that as you go up or down the PH scale from 7, each successive number is 10 times a stronger value!
Table 1.
|
PH Value |
Relative Strength |
Representative Product |
|
1 |
1,000,000 |
Hydrochloric Acid |
|
2 |
100,000 |
Gastric Juices |
|
3 |
10,000 |
Vinegar |
|
4 |
1,000 |
Orange Juice |
|
5 |
100 |
Molasses |
|
6 |
10 |
Milk |
|
7 (Neutral) |
1 |
Pure Water |
|
8 |
10 |
Sea Water |
|
9 |
100 |
Borax Solution |
|
10 |
1,000 |
Soap |
|
11 |
10,000 |
Tri-Sodium Phosphate (TSP) |
|
12 |
100,000 |
Household Ammonia |
|
13 |
1,000,000 |
Lye |
