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Btus (th)/second/sq. inch to Btus (IT)/second/sq. foot Converter (Btu/(s·in²) to Btu/(s·ft²))

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Live Conversion • ISO 80000-5:2019 Certified
1 BTU (th)/second/sq. inch = 143.90367759 BTU (IT)/second/sq. foot
1 Btu/(s·in²) = 143.903678 Btu/(s·ft²) • 1 Btu/(s·ft²) = 0.00694909 Btu/(s·in²)
BTU (th)/second/sq. inch to BTU (IT)/second/sq. foot: One BTU (th)/second/sq. inch is equal to 143.90367759 Btus (IT)/second/sq. foot.
Certified Authority Value
143.90367759
Btu/(s·ft²)
Exact: 1 Btu/(s·ft²) ≡ 0.006949092731 Btu/(s·in²)
Btu/(s·in²)
Btu/(s·in²)
Swap to BTU (IT)/second/sq. foot to BTU (th)/second/sq. inch
Swap to BTU (IT)/second/sq. foot to BTU (th)/second/sq. inch
Btu/(s·ft²)
Btu/(s·ft²) 143.90367759
Quick Values:
Conversion Formula
To convert BTU (th)/second/sq. inch to BTU (IT)/second/sq. foot, multiply by 143.90367759
Btu/(s·in²) × 143.90367759 = Btu/(s·ft²)

Calculation: 1 Btu/(s·in²) × 143.90367759 = 143.90367759 Btu/(s·ft²)

Common BTU (th)/second/sq. inch to BTU (IT)/second/sq. foot Calculations

Quick-lookup reference table showing calculated equivalents for standard increments between BTU (th)/second/sq. inch (Btu/(s·in²)) and BTU (IT)/second/sq. foot (Btu/(s·ft²)).

Tap any row to calculate
BTU (th)/second/sq. inch to BTU (IT)/second/sq. foot: Primary Direct Table (15 Steps)
BTU (th)/second/sq. inch to BTU (IT)/second/sq. foot Conversion Reference Table
Conversion & Equivalent Value Scientific Notation
0.001 Btu/(s·in²) 0.143904 Btu/(s·ft²) 1.439 × 10⁻¹
0.01 Btu/(s·in²) 1.439037 Btu/(s·ft²) 1.439 × 10⁰
0.1 Btu/(s·in²) 14.390368 Btu/(s·ft²) 1.439 × 10¹
0.5 Btu/(s·in²) 71.951839 Btu/(s·ft²) 7.195 × 10¹
1 Btu/(s·in²) 143.903678 Btu/(s·ft²) 1.439 × 10²
2 Btu/(s·in²) 287.807355 Btu/(s·ft²) 2.878 × 10²
5 Btu/(s·in²) 719.518388 Btu/(s·ft²) 7.195 × 10²
10 Btu/(s·in²) 1439.036776 Btu/(s·ft²) 1.439 × 10³
20 Btu/(s·in²) 2878.073552 Btu/(s·ft²) 2.878 × 10³
25 Btu/(s·in²) 3597.59194 Btu/(s·ft²) 3.598 × 10³
50 Btu/(s·in²) 7195.18388 Btu/(s·ft²) 7.195 × 10³
100 Btu/(s·in²) 14390.367759 Btu/(s·ft²) 1.439 × 10⁴
250 Btu/(s·in²) 35975.919399 Btu/(s·ft²) 3.598 × 10⁴
500 Btu/(s·in²) 71951.838797 Btu/(s·ft²) 7.195 × 10⁴
1000 Btu/(s·in²) 143903.677594 Btu/(s·ft²) 1.439 × 10⁵
BTU (IT)/second/sq. foot to BTU (th)/second/sq. inch: Reciprocal Summary
BTU (IT)/second/sq. foot to BTU (th)/second/sq. inch Conversion Reference Table
Reciprocal & Equivalent Value Scientific Notation
1 Btu/(s·ft²) 0.00694909 Btu/(s·in²) 6.949 × 10⁻³
5 Btu/(s·ft²) 0.0347455 Btu/(s·in²) 3.475 × 10⁻²
10 Btu/(s·ft²) 0.0694909 Btu/(s·in²) 6.949 × 10⁻²
50 Btu/(s·ft²) 0.347455 Btu/(s·in²) 3.475 × 10⁻¹
100 Btu/(s·ft²) 0.694909 Btu/(s·in²) 6.949 × 10⁻¹
View Complete 15-Row BTU (IT)/second/sq. foot to BTU (th)/second/sq. inch Table

Real-World Context & Everyday Benchmarks

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To help contextualize these units in everyday life, science, and engineering, here are verified real-world reference points for BTU (th)/second/sq. inch (Btu/(s·in²)) and BTU (IT)/second/sq. foot (Btu/(s·ft²)):

BTU (th)/second/sq. inch References:

  • Solar constant extraterrestrial solar irradiance at top of atmosphere 0.000833 Btu/(s·in²)
  • Clear sky direct midday summer sunlight striking sea level ground 0.000612 Btu/(s·in²)
  • Human body resting thermal metabolic heat radiation to room 3.1E-5 Btu/(s·in²)
  • Overcast winter day diffuse solar irradiance at sea level 6.1E-5 Btu/(s·in²)

BTU (IT)/second/sq. foot References:

  • Solar constant extraterrestrial solar irradiance at top of atmosphere 0.119843 Btu/(s·ft²)
  • Clear sky direct midday summer sunlight striking sea level ground 0.088055 Btu/(s·ft²)
  • Human body resting thermal metabolic heat radiation to room 0.004403 Btu/(s·ft²)
  • Overcast winter day diffuse solar irradiance at sea level 0.008806 Btu/(s·ft²)

Tap any benchmark above to automatically calculate its exact equivalent in BTU (IT)/second/sq. foot.

ISQ Dimension: [M T⁻³] Coherent SI Unit: watt per square meter (W/m²) Thermodynamics & Heat Transfer

How to Convert BTU (th)/second/sq. inch to BTU (IT)/second/sq. foot

Converting BTU (th)/second/sq. inch (Btu/(s·in²)) to BTU (IT)/second/sq. foot (Btu/(s·ft²)) is a core calculation in Heat Flux Density, which measures the rate of thermal energy transfer radiating or conducting through a unit area per second. This calculation navigates the boundary between the International Metric System (SI) and British Imperial / US Customary engineering standards. In contemporary metrology, Imperial units are defined in terms of exact SI standards via international agreements—notably NIST SP 811 and the 1959 International Yard and Pound Agreement. Exactly 1 BTU (th)/second/sq. inch equals 143.903678 BTU (IT)/second/sq. foot, while 1 Btu/(s·ft²) equals 0.00694909 Btu/(s·in²).

Direct Factor1 Btu/(s·in²) = 143.903678 Btu/(s·ft²)
Inverse Ratio1 Btu/(s·ft²) = 0.00694909 Btu/(s·in²)
Conversion ScaleMetric SI to British Imperial / US Customary Bridge
First-Principles SI Derivation ProofNIST SP 811 / ISO 80000 Compliance

Mathematical Conversion Derivation via Coherent SI Base Unit

Under the International System of Quantities (ISQ), dimensional conversion between non-SI units is rigorously resolved by bridging through the coherent SI base unit (watt per square meter (W/m²)) without arbitrary rounding:

Vtarget=Vsource×(ksource→SIktarget→SI)V_{\text{target}} = V_{\text{source}} \times \left( \frac{k_{\text{source} \to \text{SI}}}{k_{\text{target} \to \text{SI}}} \right)
Universal Dimensional Conversion Law (ISO 80000 / NIST SP 811)
1. Source SI Bridge (ksource):1 Btu/(s·in²) = 1634246 watt per square meter (W/m²)
2. Target SI Bridge (ktarget):1 Btu/(s·ft²) = 11356.527 watt per square meter (W/m²)
Step-by-step substitution for BTU (th)/second/sq. inch → BTU (IT)/second/sq. foot:V(Btu/(s·ft²)) = V(Btu/(s·in²)) × ( 1634246 / 11356.527 ) = V(Btu/(s·in²)) × 143.903678
Mathematical FormulaValue in BTU (IT)/second/sq. foot = Value in BTU (th)/second/sq. inch × 143.90367759Direct computational formula applied for standard conversion.
Worked Example

Converting 75 Btu/(s·in²) yields an exact output of 10792.77582 Btu/(s·ft²) in BTU (IT)/second/sq. foot. Under higher industrial throughput, 10000 Btu/(s·in²) translates to 1439036.775944 Btu/(s·ft²).

Inverse check: 1 Btu/(s·ft²) = 0.00694909 Btu/(s·in²).

Understanding BTU (th)/second/sq. inch and BTU (IT)/second/sq. foot

BTU (th)/second/sq. inch

Btu/(s·in²)
Imperial / US

A BTU (th)/second/sq. inch (Btu/(s·in²)) is an imperial and US customary unit for heat flux density.

Applications & Practical Context

In practical heat flux density terms, a solar constant extraterrestrial solar irradiance at top of atmosphere equals 0.000833 Btu/(s·in²), a clear sky direct midday summer sunlight striking sea level ground equals 0.000612 Btu/(s·in²), a human body resting thermal metabolic heat radiation to room equals 3.1 × 10⁻⁵ Btu/(s·in²).

Physical Setup

A physical magnitude of 1 Btu/(s·in²) corresponds to 1634246 W/m² in standard SI measurement.

Conversion to SI Unit: watt per square meter (W/m²)
1 Btu/(s·in²) = 1634246 W/m²

BTU (IT)/second/sq. foot

Btu/(s·ft²)
Imperial / US

A BTU (IT)/second/sq. foot (Btu/(s·ft²)) is an imperial and US customary unit for heat flux density.

Applications & Practical Context

In practical heat flux density terms, a solar constant extraterrestrial solar irradiance at top of atmosphere equals 0.119843 Btu/(s·ft²), a clear sky direct midday summer sunlight striking sea level ground equals 0.088055 Btu/(s·ft²), a human body resting thermal metabolic heat radiation to room equals 0.004403 Btu/(s·ft²).

Physical Setup

A physical magnitude of 1 Btu/(s·ft²) corresponds to 11356.527 W/m² in standard SI measurement.

Conversion to SI Unit: watt per square meter (W/m²)
1 Btu/(s·ft²) = 11356.527 W/m²

Domain Metrology & Engineering Applications

Governing Law & Equation

Thermal Transmission Flux (q = Q̇ / A)

Measurement Instrumentation

Rigorously quantified in laboratory and field settings using Schmidt-Boelter heat flux gauges, differential thermopile foil transducers, and calibrated Gardon radiant gauges.

Primary Industry Sectors

Applied across rocket nozzle combustion chamber analysis, fire resistance testing (ASTM E119), furnace wall heat loss auditing, and hypersonic aerothermal design under international metrology standard ISO 80000-5:2019, ASME PTC 19.3.

Institutional Metrology & Standard Authority:

Formulas, conversion coefficients, and base definitions on this page strictly adhere to the ISO 80000-5:2019, ASME PTC 19.3 and the BIPM SI Brochure (9th Edition). Governed by Thermal Transmission Flux (q = Q̇ / A) under ISO 80000 dimensional vector [M T⁻³].

Multi-Variable Engineering Bridge Thermal Radiation & Power Dissipation

Heat Flux Density to Total Thermal Power Bridge (Watts • Kilowatts • Megawatts • BTU/h • Horsepower)

Calculate total continuous heat dissipation power P = q" × A across surface barriers and exchangers, bridging heat flux density [M T⁻³] with thermal power [M L² T⁻³].

P = q" × A
Vector: [W/m²] × [m²] → [W]
Live Calculated Bridge Equivalent:
1 Btu/(s·in²) at Industrial Hydronic Radiator Panel (8 m²) = 1.3074 × 10⁷ W
Equals 13073.968 kW • 13.073968 MW • 17532.4799 hp
SI Power
1.3074 × 10⁷
W
Watts
Grid / Utility
13073.968
kW
Kilowatts
Power Plant
13.073968
MW
Megawatts
Mechanical Rating
17532.4799
hp
Horsepower (Mechanical)
Metric Horsepower
17775.6496
PS
Metric Horsepower (PS)
HVAC Thermal Rating
4.46 × 10⁷
BTU/h
BTU per Hour
  1. 1. Normalize Input to SI Base Unit (W/m²):
    q" = 1 Btu/(s·in²) × 1634246 = 1634246 W/m²
  2. 2. Apply Engineering Parameter (A):
    Selected condition: Industrial Hydronic Radiator Panel (8 m²) at A = 8 m²
  3. 3. Execute Governing Physical Law in SI Units:
    P = q" × A = (1634246 W/m²) × (8 m²) = 1.307397 × 10⁷ W
  4. 4. Convert to Standard Engineering Units:
    • W: 1.307397 × 10⁷ × 1 = 1.3074 × 10⁷ W (Watts) • kW: 1.307397 × 10⁷ × 0.001 = 13073.968 kW (Kilowatts) • MW: 1.307397 × 10⁷ × 1 × 10⁻⁶ = 13.073968 MW (Megawatts) • hp: 1.307397 × 10⁷ × 0.001341 = 17532.4799 hp (Horsepower (Mechanical)) • PS: 1.307397 × 10⁷ × 0.00136 = 17775.6496 PS (Metric Horsepower (PS)) • BTU/h: 1.307397 × 10⁷ × 3.4121 = 4.46 × 10⁷ BTU/h (BTU per Hour)
Explore Full Power Converter →
Engineering Substance / Operating Standard Parameter Value (m²) Reference State / Condition Typical Industrial & Engineering Application
Residential Window Glazing (4 m²) 4 4.0 m² Double-pane exterior window glass aperture
Industrial Hydronic Radiator Panel (8 m²) 8 8.0 m² Convective space heating radiator surface
Shell & Tube Heat Exchanger (50 m²) 50 50.0 m² Industrial process fluid cooling bundle
Power Boiler Waterwall (200 m²) 200 200.0 m² Thermal power plant steam generator wall
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Frequently Asked Questions

There are exactly 143.90367759 btus (it)/second/sq. foot (Btu/(s·ft²)) in 1 btu (th)/second/sq. inch (Btu/(s·in²)). To calculate larger amounts manually, simply multiply your total number of btus (th)/second/sq. inch by the conversion multiplier of 143.90367759.

The mathematical formula to convert btus (th)/second/sq. inch to btus (it)/second/sq. foot is: [value] * 143.90367759 = btus (it)/second/sq. foot. Rather than doing the math manually, you can use our high-precision online calculator to process this exact equation instantly without rounding errors.

To perform the reverse calculation from btus (it)/second/sq. foot back to btus (th)/second/sq. inch, you must divide your starting value by 143.90367759. Our bidirectional tool automatically computes this inverse equation the moment you type into the btu (it)/second/sq. foot input field.

1 BTU (th)/second/sq. inch is larger than 1 BTU (IT)/second/sq. foot. Specifically, 1 BTU (th)/second/sq. inch equals exactly 143.90367759 btus (it)/second/sq. foot, making it 143.9037 times larger (a difference of 2.16 orders of magnitude). Therefore, quantities expressed in btus (it)/second/sq. foot require a larger numerical value to represent the same physical amount.

Under standard international measurement guidelines, 1 BTU (th)/second/sq. inch converts to 143.90367759 btus (it)/second/sq. foot. Precise numerical conversion factors ensure consistency across laboratory, engineering, and field data.