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Engineering Calculator · 123

Sealed Gas Temperature & Pressure Calculator

Estimate pressure change of a sealed fixed gas quantity at constant volume using absolute pressure and kelvin temperatures.

Pressure & environment
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Live calculation

Enter the known values.

Units remain visible beside every field and result. Change any input to recalculate immediately in your browser.

01

Inputs

02

Results

Final internal absolute pressure106.822446kPa absolute
Final internal gauge pressure6.822446kPa gauge
Internal absolute-pressure change6.822446kPa

Formula
p2,abs=p1,absT2,KT1,Kp_{2,\mathrm{abs}}=p_{1,\mathrm{abs}}\frac{T_{2,K}}{T_{1,K}}p2,g=p2,abs−p2,ambp_{2,\mathrm{g}}=p_{2,\mathrm{abs}}-p_{2,\mathrm{amb}}

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Direct answer

What this result means

For a fixed amount of ideal gas at fixed volume, absolute pressure is proportional to kelvin temperature. Starting at 100 kPa absolute and 20°C, heating to 40°C gives approximately 106.82 kPa absolute. Gauge pressure then depends on the final outside ambient pressure.

Sealed Gas Temperature & Pressure Calculator engineering relationship diagramBoth gas temperatures are converted with TK = T°C + 273.15, and the starting pressure is absolute. The volume and gas quantity remain fixed. A breathable vent, a leak, condensation or enclosure deflection violates that model; actual thermal breathing requires a flow and transient model. This dedicated schematic represents sealed gas fixed volume temperature states and is not to scale.T₁,K · p₁,absT₂,K · p₂,absSame gas quantity · same volumeFIXED-VOLUME IDEAL GAS · TOOL 123Initial internal absolute …Final internal absolute pr…
Calculator-specific engineering relationship diagram — schematic, not a product drawing, and not to scale.

Formula & theory

Make the assumptions visible.

Both gas temperatures are converted with TK = T°C + 273.15, and the starting pressure is absolute. The volume and gas quantity remain fixed. A breathable vent, a leak, condensation or enclosure deflection violates that model; actual thermal breathing requires a flow and transient model.

Calculation relationship
p2,abs=p1,absT2,KT1,Kp_{2,\mathrm{abs}}=p_{1,\mathrm{abs}}\frac{T_{2,K}}{T_{1,K}}p2,g=p2,abs−p2,ambp_{2,\mathrm{g}}=p_{2,\mathrm{abs}}-p_{2,\mathrm{amb}}

Both gas temperatures are converted with TK = T°C + 273.15, and the starting pressure is absolute. The volume and gas quantity remain fixed. A breathable vent, a leak, condensation or enclosure deflection violates that model; actual thermal breathing requires a flow and transient model.

Formula terms

Variables

p₂,ambFinal external ambient absolute pressurekPa absolute
p₂,gFinal internal pressure relative to final ambientkPa gauge

Use sequence

From measurement to review

  1. Confirm the fixed-volume, fixed-gas-quantity assumption and the initial absolute pressure.
  2. Enter initial and final gas temperatures and the final external ambient pressure.
  3. Use the pressure difference as an idealized scenario, then assess actual vents, leakage, moisture and enclosure flexibility separately.

Limits

What this calculation does not confirm

  • The enclosure is rigid and sealed, and the gas behaves ideally with unchanged amount.
  • Gas temperature is uniform at each compared state; condensation, evaporation and chemical gas production are excluded.
  • This does not size a vent, predict breathing flow, estimate time to equilibrium or establish pressure containment.

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Calculator FAQ

Use the number without losing the engineering context.

These answers clarify what the tool calculates and where a product-specific review still begins.

01Calculator guidanceWhy does the sealed-gas equation use absolute pressure?

The ideal-gas equation is referenced to vacuum. Gauge pressure has an ambient offset and cannot be used directly in the temperature ratio. Convert the initial reading to absolute pressure first.

02Calculator guidanceCan this sealed-gas result size a breathable cable-entry vent?

No. A vent changes the gas quantity as pressure equalizes. Vent sizing requires flow characteristics, enclosure volume, temperature change with time and the allowable pressure difference.

03Calculator guidanceWhy can cooling produce a negative final gauge pressure?

Internal absolute pressure falls with kelvin temperature in the sealed model. If it becomes lower than the entered final ambient pressure, gauge pressure is negative while absolute pressure remains positive.

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