Meter Water (4 °C) to Pound per Square Foot

Because pump engineers think in terms of how high the pump can lift water. A pump rated at 30 mH₂O can push water 30 meters straight up — no conversion needed to figure out if it can reach the tenth floor. The unit also makes friction-loss calculations intuitive: if a 100-meter horizontal pipe run has 5 mH₂O of friction loss, you subtract that directly from the pump's head rating.

Approximately 1 meter in fresh water. The unit references water at 4 °C under standard gravity; actual column pressure depends on water density and local gravity, so a real pool does not necessarily reproduce that reference exactly. Seawater is about 2.5% denser, so 1 meter of seawater corresponds to roughly 1.025 mH₂O of gauge pressure.

Municipal water mains deliver 20–60 mH₂O (roughly 2–6 bar or 30–85 psi) at the meter. A gravity-fed rooftop tank 10 meters above the tap provides about 10 mH₂O — barely enough for a decent shower, which is why booster pumps are common in buildings with rooftop storage. High-rise buildings need pressurisation systems because gravity alone cannot push water above about 60 mH₂O without boosting.

10.33 mH₂O ≈ 1 atmosphere ≈ 1.013 bar. For quick math: 10 mH₂O ≈ 1 bar (error about 2%). This rule of thumb is used constantly in plumbing and fire protection: a building with a water tank 40 m above ground level has roughly 4 bar of static pressure at the base. Multiply meters by 0.1 and you have bar — close enough for pipe sizing.

Temperature affects water density and therefore column pressure. The 4 °C reference is close to water's maximum density and specifies the conditions for comparing water-column units. This converter uses the fixed reference density of 999.972 kg/m³ and standard gravity, producing 9,806.3754138 Pa per meter. The metric and imperial factors retain the complete result while preserving their exact height relationships. This computational precision does not imply that a real manometer reproduces the reference density or gravity exactly.

Because building loads — snow, wind, furniture, people — are naturally distributed over large floor and wall areas measured in square feet. A residential floor designed for 40 psf live load makes intuitive sense: imagine 40 pounds sitting on each square foot of carpet. Converting to psi (0.278 psi) gives a fraction that obscures the physical picture. The US International Building Code specifies all loads in psf for this reason.

Residential living areas: 40 psf. Office floors: 50 psf. Retail stores: 75–100 psf. Library stack rooms: 150 psf. Heavy manufacturing: 250+ psf. Balconies and decks: 60 psf minimum. Roofs must handle snow load (varies by region — 20 psf in Atlanta, 50+ psf in Minnesota) plus a minimum 20 psf construction live load. These values have decades of structural failure data baked into them.

1 psf = 1/144 psi ≈ 0.00694 psi = 47.88 Pa. To go from psi to psf, multiply by 144 (since 1 ft² = 144 in²). Standard atmospheric pressure is about 2,116 psf — which demonstrates why the unit is sized for building loads, not gas pressures. For international projects, multiply psf by 47.88 to get pascals, or by roughly 4.88 to get kgf/m².

Wind pressure scales with the square of wind speed. At 70 mph: about 12 psf. At 100 mph: ~25 psf. At 150 mph (Category 4 hurricane): ~56 psf. Building codes apply additional factors for height, exposure, and shape — a tall building in open terrain sees higher effective psf than a squat building sheltered by trees. Cladding and windows are tested against these design pressures before installation.

Rarely. Most countries use kilopascals (kPa) or kilonewtons per square meter (kN/m²) for structural loads — both are SI-compatible and numerically equivalent (1 kPa = 1 kN/m²). The psf is essentially a US-only unit, found in IBC (International Building Code, despite the name) and ASCE 7 load standards. Engineers working on international projects routinely convert psf to kPa by multiplying by 0.04788.