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Volumetric Flux

LMHtogpm/ft²

Convert litres per square metre per hour (LMH) to US gallons per minute per square foot (gpm/ft²).

Factor1 LMH = 0.0004090502 gpm/ft²

Converter

LMH

Accepts numbers or expressions, e.g. 150 + 14.7

Result
0.40905gpm/ft²

Rendered to 6 significant figures.

Formula

Formula
gpm/ft² = LMH × 0.0004090502

Multiply any value in litres per square metre per hour by 0.0004090502 to obtain the value in US gallons per minute per square foot.

Worked example

Convert 1000 LMH to gpm/ft².

  1. 01Start with 1000 LMH.
  2. 02Multiply by the conversion factor: 1000 × 0.0004090502 = 0.40905 gpm/ft².
Result1000 LMH = 0.40905 gpm/ft²

Conversion table

LMHgpm/ft²
10.00040905
20.0008181
50.0020453
100.0040905
200.008181
500.020453
1000.040905
2000.08181
5000.20453
10000.40905

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from LMH to gpm/ft²?
1 LMH equals 0.0004090502 gpm/ft². To convert, multiply the value in litres per square metre per hour by 0.0004090502.
How do I convert 1 LMH to gpm/ft²?
1 LMH = 0.00040905 gpm/ft². For any value, multiply by 0.0004090502.
How do I convert gpm/ft² back to LMH?
Divide by the same factor — or equivalently, multiply by 2444.688. So 1 gpm/ft² = 2444.69 LMH.
When would I need to convert litre per square metre per hour to US gallon per minute per square foot?
Volumetric-flux conversions between LMH and gpm/ft² are routine in membrane filtration (RO, UF, MF, NF permeate flux), hydraulic loading specification, water-treatment design, hydrometallurgy and packed-bed column loading, and environmental engineering. LMH (L/m²/h) and gfd (gal/ft²/day) dominate membrane datasheets; m³/m²/h and m³/m²/day cover SI engineering ladders; m/day and cm/s appear as superficial velocity in hydromet and packed-bed work. Volumetric flux is the same physical quantity as superficial velocity (m³/m²/s ≡ m/s) but is kept distinct from the velocity and flow categories because the engineering intent is volumetric throughput per unit area, not bulk motion or total throughput.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).

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