# Units of Measurement

## Which unit system underlies the data, and why standardize units? {#which-unit-system-underlies-the-data-and-why-standardize-units}

Reported figures follow the International System of Units (SI), the metric standard used throughout scientific and industrial practice. Standardizing on a single system keeps quantities directly comparable across countries, regardless of local measurement conventions.

## How are imperial and metric units reconciled? {#how-are-imperial-and-metric-units-reconciled}

Imperial and other non-SI units are converted to their SI equivalents using fixed conversion factors. The table below groups the units encountered by quantity; the precise conversion factors are maintained in Intratec's Unit Conversion document, with three commonly referenced values noted inline.

## Conversion Reference {#conversion-reference}

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| Quantity | Units | Notes / key factors |
|----------|-------|---------------------|
| Length | inch (in), foot (ft) | Converted to metres (m) |
| Area | square inch (in²), square foot (ft²), hectare (ha) | Converted to square metres (m²) |
| Volume | cubic foot (ft³), litre (L), gallon (gal), barrel (bbl) | 1 bbl = 0.1589 m³ |
| Mass | pound (lb), metric ton, short ton | Converted to kilograms (kg) |
| Pressure | bar, atmosphere (atm), pound per square inch (psi) | Converted to pascals (Pa) |
| Temperature | degree Celsius (°C), Rankine (R), degree Fahrenheit (°F) | Base unit: kelvin (K) |
| Time | hour (h), day (d), year (yr) | 1 yr = 8,760 h |
| Energy | British thermal unit (Btu), kilowatt-hour (kWh), calorie (cal) | 1 Btu = 1,055.06 J |