1. What is Specific Gravity?

Specific Gravity (SG) is a dimensionless quantity that represents the ratio of the density of a substance to the density of a reference substance (air for gases). It indicates how dense a gas is compared to air at standard conditions.

2. How Does the Calculator Work?

The calculator uses the Specific Gravity formula:

Where:

• \( SG \) — Specific Gravity (dimensionless)
• \( Density_{gas} \) — Density of the gas (kg/m³)
• \( Density_{air} \) — Density of air (1.225 kg/m³ at standard conditions)

Explanation: The formula calculates how many times heavier or lighter a gas is compared to air under the same conditions.

3. Importance of Specific Gravity Calculation

Details: Specific gravity is crucial in various industries including chemical processing, HVAC, natural gas distribution, and environmental monitoring. It helps determine gas behavior, buoyancy effects, and is used in flow measurement calculations.

4. Using the Calculator

Tips: Enter gas density in kg/m³. The value must be greater than 0. The calculator uses standard air density of 1.225 kg/m³ at 15°C and 101.325 kPa.

5. Frequently Asked Questions (FAQ)

Q1: What does SG < 1 indicate?
A: SG < 1 means the gas is lighter than air and will tend to rise (e.g., natural gas, hydrogen).

Q2: What does SG > 1 indicate?
A: SG > 1 means the gas is heavier than air and will tend to settle (e.g., propane, butane, CO₂).

Q3: Why is air density fixed at 1.225 kg/m³?
A: This is the standard reference value for dry air at 15°C and sea level pressure (101.325 kPa).

Q4: Can I use different units for density?
A: The calculator requires kg/m³. Convert from other units (g/L, lb/ft³) before calculation.

Q5: How does temperature affect specific gravity?
A: Specific gravity values are typically referenced to standard conditions. For precise work, both gas and air densities should be measured at the same temperature and pressure.