Understanding Calories per Second-Centimetre-Degree Celsius to BTU per Hour-Foot-Degree Fahrenheit Conversion
The calorie per second-centimetre-degree Celsius, cal/(s-cm-°C), is a CGS thermal-conductivity unit common in classical physics and legacy materials tables. The BTU per hour-foot-degree Fahrenheit, BTU/(h-ft-°F), is the standard imperial unit used by US HVAC and thermal engineers, expressed per foot of thickness rather than per inch. This conversion links scientific reference data to everyday North American engineering practice.
Conversion Formula
To convert Calories per Second-Centimetre-Degree Celsius to BTU per Hour-Foot-Degree Fahrenheit, multiply by this factor:
Step-by-Step Example
Convert 25 Calories per Second-Centimetre-Degree Celsius to BTU per Hour-Foot-Degree Fahrenheit.
How to Convert Calories per Second-Centimetre-Degree Celsius to BTU per Hour-Foot-Degree Fahrenheit
This method converts a CGS conductivity into the imperial per-foot unit.
- Take the CGS value: Begin with the conductivity in cal/(s-cm-°C), for example 25.
- Multiply by 241.7471: This is the number of BTU/(h-ft-°F) in one cal/(s-cm-°C).
- Calculate: .
- State the result: 25 cal/(s-cm-°C) equals 6043.68 BTU/(h-ft-°F).
Calories per Second-Centimetre-Degree Celsius to BTU per Hour-Foot-Degree Fahrenheit conversion table
| Calories per Second-Centimetre-Degree Celsius (cal/(s-cm-°C)) | BTU per Hour-Foot-Degree Fahrenheit (BTU/(h-ft-°F)) |
|---|---|
| 0 | 0 |
| 1 | 241.7471 |
| 2 | 483.4941 |
| 3 | 725.2412 |
| 4 | 966.9882 |
| 5 | 1208.735 |
| 6 | 1450.482 |
| 7 | 1692.229 |
| 8 | 1933.976 |
| 9 | 2175.723 |
| 10 | 2417.471 |
| 15 | 3626.206 |
| 20 | 4834.941 |
| 25 | 6043.676 |
| 30 | 7252.412 |
| 40 | 9669.882 |
| 50 | 12087.35 |
| 60 | 14504.82 |
| 70 | 16922.29 |
| 80 | 19339.76 |
| 90 | 21757.23 |
| 100 | 24174.71 |
| 150 | 36262.06 |
| 200 | 48349.41 |
| 250 | 60436.76 |
| 300 | 72524.12 |
| 400 | 96698.82 |
| 500 | 120873.5 |
| 600 | 145048.2 |
| 700 | 169222.9 |
| 800 | 193397.6 |
| 900 | 217572.3 |
| 1000 | 241747.1 |
| 2000 | 483494.1 |
| 3000 | 725241.2 |
| 4000 | 966988.2 |
| 5000 | 1208735 |
| 10000 | 2417471 |
| 25000 | 6043676 |
| 50000 | 12087350 |
| 100000 | 24174710 |
| 250000 | 60436760 |
| 500000 | 120873500 |
| 1000000 | 241747100 |
What is the Calorie per Second-Centimetre-Degree Celsius?
The calorie per second-centimetre-degree Celsius is the CGS-based unit of thermal conductivity, historically common in physics and physical-chemistry literature. It measures the heat in calories flowing per second through a one-centimetre thickness for each degree Celsius of temperature difference.
Definition
One calorie per second-centimetre-degree Celsius represents a heat flow of one calorie per second through a one-centimetre cube per degree Celsius across it. Using the thermochemical calorie (4.184 J):
The value follows from 4.184 J/s per (0.01 m · 1 K) = 4.184 ÷ 0.01 = 418.4 W/(m·K). If the International Table calorie (4.1868 J) is used instead, the factor is 418.68 W/(m·K).
Origin and History
The unit arose in the CGS era, when heat was measured in calories, lengths in centimetres and temperature in degrees Celsius. It appears throughout older thermal-conductivity tables and heat-transfer texts, especially in chemistry and metallurgy, before the watt per metre-kelvin became standard.
Law and Notable Facts
Though largely superseded by SI, the unit is still encountered in legacy data and some scientific traditions. Its large size is convenient for metals: because 1 cal/(s·cm·°C) equals 418.4 W/(m·K), even highly conductive copper is under 1 in these units, whereas most materials are small fractions.
Real-World Examples and Conversions
- Copper conducts at about 0.94 cal/(s·cm·°C), i.e. roughly 400 W/(m·K).
- Iron is about 0.18 cal/(s·cm·°C).
- Water is roughly 0.0014 cal/(s·cm·°C).
- 1 cal/(s·cm·°C) = 418.4 W/(m·K); conversely 1 W/(m·K) ≈ 0.00239 cal/(s·cm·°C).
What is the BTU per Hour-Foot-Degree Fahrenheit?
The BTU per hour-foot-degree Fahrenheit is the customary unit of thermal conductivity in the United States and other imperial-using industries. It measures the heat, in British thermal units per hour, conducted through a material one foot thick for each degree Fahrenheit of temperature difference.
Definition
One BTU per hour-foot-degree Fahrenheit corresponds to a heat flow of one BTU per hour through a one-foot thickness for a one-degree-Fahrenheit temperature difference. In coherent SI units:
The exact value depends on the definition of the British thermal unit used; based on the International Table BTU (1055.05585262 J), 1 BTU/(h·ft·°F) = 1.730734666 W/(m·K).
Origin and History
The unit is built from three imperial and customary quantities: the British thermal unit (the heat needed to raise one pound of water by one degree Fahrenheit), the foot, and the Fahrenheit degree. It became the standard for U.S. thermal-property data long before SI was widely adopted and persists in North American engineering practice.
Law and Notable Facts
While the SI watt per metre-kelvin is preferred internationally, BTU/(h·ft·°F) remains entrenched in U.S. mechanical, HVAC and building codes. A useful benchmark: pure copper conducts at about 231 BTU/(h·ft·°F), roughly 400 times better than the fibreglass batts used to insulate walls.
Real-World Examples and Conversions
- Structural steel is about 26 BTU/(h·ft·°F); concrete roughly 0.8–1.0.
- Water conducts at about 0.35 BTU/(h·ft·°F).
- 1 BTU/(h·ft·°F) ≈ 1.7307 W/(m·K) ≈ 1730.7 mW/(m·K).
- Conversely, 1 W/(m·K) ≈ 0.5778 BTU/(h·ft·°F).
Frequently Asked Questions
What is the conversion factor from cal/(s-cm-°C) to BTU/(h-ft-°F)?
One calorie per second-centimetre-degree Celsius equals 241.7471 BTU per hour-foot-degree Fahrenheit. Multiply by 241.7471 to convert.
How do I convert BTU/(h-ft-°F) back to cal/(s-cm-°C)?
Multiply the BTU/(h-ft-°F) value by 0.004136555. So 241.7471 BTU/(h-ft-°F) returns to exactly 1 cal/(s-cm-°C).
What is the difference between the per-foot and per-inch imperial units?
BTU/(h-ft-°F) is normalized to one foot of thickness, whereas BTU-in/(h-ft2-°F) is per inch; the per-inch value is 12 times larger. Choose whichever matches your datasheet.
Where is BTU/(h-ft-°F) typically used?
It appears in US mechanical and HVAC engineering for metals, pipe materials, and structural components, where conductivity per foot is a natural scale for heat-transfer calculations.
Does 25 cal/(s-cm-°C) represent a metal or an insulator?
That value converts to about 6044 BTU/(h-ft-°F), characteristic of a very conductive metal; insulating materials would be far below 1 BTU/(h-ft-°F).
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Complete Calories per Second-Centimetre-Degree Celsius conversion table
| Unit | Result |
|---|---|
| Watts per Metre-Kelvin (W/(m-K)) | 418.4 W/(m-K) |
| Milliwatts per Metre-Kelvin (mW/(m-K)) | 418400 mW/(m-K) |
| BTU per Hour-Foot-Degree Fahrenheit (BTU/(h-ft-°F)) | 241.7471 BTU/(h-ft-°F) |
| BTU-Inch per Hour-Square Foot-Degree Fahrenheit (BTU-in/(h-ft2-°F)) | 2900.965 BTU-in/(h-ft2-°F) |