How do you convert between L/min (LPM) and GPM? What's the difference between US gallons and UK gallons?
Conversion: 1 GPM (US gallons per minute, US gallon) ≈ 3.785 L/min ≈ 0.227 m³/h; 1 L/min ≈ 0.264 GPM. Note there are two types of gallons: US gallon (USG) = 3.78541 liters, which this tool uses; UK gallon/Imperial gallon (IG) = 4.54609 liters, historically used in the UK, Canada, and Australia, now largely replaced by liters but still found on some older equipment. The US, Central America, and parts of South America use US gallons; this tool calculates GPM based on US gallons. If equipment specifies UK gallons, multiply by 1.2 (1 IGPM ≈ 1.2 USGPM).
How many L/min is 1 m³/h equal to? How to calculate mentally?
1 m³/h = 1000 liters ÷ 60 minutes ≈ 16.667 L/min ≈ 16.67 L/min. Mental calculation method: m³/h to L/min multiply by 16.67 (or approximately by 17), L/min to m³/h divide by 16.67 (or approximately multiply by 0.06). For example: a household faucet fully open is about 10-15 L/min ≈ 0.6-0.9 m³/h; a toilet flush is about 6-9 L per flush, if filled in 20 seconds ≈ 18-27 L/min ≈ 1.1-1.6 m³/h; a shower head is about 8-15 L/min ≈ 0.5-0.9 m³/h.
What unit is m³/s? In what scenarios is cubic meters per second used?
m³/s (cubic meters per second) is the base SI unit for volumetric flow rate, used for large flow scenarios: river flow (Yangtze River at Three Gorges average flow about 14,000 m³/s, Amazon River about 209,000 m³/s), flood flows (e.g., 100-year flood), large pump stations/turbine flows (Three Gorges single unit flow about 900 m³/s), large municipal water supply pipelines, ventilation/air conditioning air volume (m³/s), etc. 1 m³/s = 3600 m³/h = 60,000 L/min ≈ 15850 GPM, which is a very large flow; civil and small industrial applications typically use m³/h or L/min.
What is the typical flow rate for household faucets/showers/toilets?
Common civil water supply flow reference: kitchen/basin faucets about 4-8 L/min (water-saving type ≤6L/min); shower heads about 8-15 L/min (water-saving type ≤9L/min, rain showers can reach 20L/min); toilet tanks about 6-9L per flush, filling time about 20-40 seconds ≈ 10-25 L/min; washing machine inlet about 10-15 L/min; household booster pumps typically selected at 10-30 L/min; household main water supply pipe about 1-2.5 m³/h (about 17-42 L/min); garden watering about 15-25 L/min. GB national standard specifies water-saving faucet flow ≤0.15 L/s (i.e., 9 L/min).
How to select a household pump/booster pump? Do both flow rate and head need to be considered?
A water pump has two core parameters: flow rate (Q) and head (H). Selection key points: 1) Flow rate based on demand: ordinary household tap water booster select 1-3 m³/h (about 17-50 L/min); whole house water supply + water heater + multiple faucets simultaneously need 3-5 m³/h; 2) Head based on building height and resistance: each 1 meter floor height requires about 1 meter head, plus pipe resistance (about 5-10 meters), a 3-story home typically selects 15-25 meters head; 3) Note pump type: self-priming pumps for drawing from wells (suction lift about 8-9 meters), centrifugal pumps for pipe boosting, submersible pumps placed in water; 4) Pipe diameter matching: DN25 (1-inch pipe) suitable for flow 2-6 m³/h, DN32 (1.2-inch) for 5-10 m³/h. Flow rate and head are inversely related — for the same pump, shut-off head (valve fully closed) is highest, and higher flow means lower head.
How to convert between pipe flow velocity and flow rate? How to calculate velocity given pipe diameter and flow rate?
Formula: Flow rate Q(m³/s) = Velocity v(m/s) × Pipe cross-sectional area A(m²), where A=π×(d/2)² and d is the pipe inner diameter. Common recommended velocity ranges: domestic water supply 1-2 m/s, fire water supply ≤2.5 m/s, pump suction pipes 0.5-1 m/s, hydraulic system suction lines 0.5-1.5 m/s, pressure lines 2-6 m/s, compressed air 8-12 m/s. For example, DN25 pipe (inner diameter about 27mm) at velocity 1.5m/s: A=π×(0.027/2)²≈0.000573m², Q=1.5×0.000573≈0.00086m³/s≈3.1m³/h≈52L/min. This tool is for unit conversion; specific velocity-flow calculations need to account for pipe diameter.
How to select a pool circulation pump flow rate (GPM)?
Pool pump selection principle: turnover rate generally requires 4-8 hours (public pools 4 hours, residential pools 6-8 hours), meaning the total pool water volume circulates once within 4-8 hours. Calculation formula: Required GPM = Total pool water (gallons) ÷ 60 minutes ÷ Turnover hours. Example: 50m³ private pool (about 13,200 US gallons), 6-hour turnover: GPM=13200÷60÷6≈37 GPM≈140 L/min≈8.4 m³/h; standard 25×12m public pool (about 600m³) with 4-hour turnover: flow rate about 660 GPM≈150 m³/h. Also consider pipe resistance (head) and filter flow rate.
How to calculate hydraulic system flow L/min and hydraulic cylinder speed?
Hydraulic cylinder extension speed formula: v(m/s) = Flow rate Q(m³/s) ÷ Piston area A(m²); commonly used in engineering: v(m/min) = Q(L/min) ÷ A(cm²) × 10. Example: cylinder bore 63mm (area about 31.2cm²), pump flow 40L/min, cylinder speed = 40÷31.2×10≈12.8 m/min≈0.21 m/s. Hydraulic systems commonly use gear pumps with flow 4-40 L/min, piston pumps can reach hundreds of L/min; excavators and loaders have total hydraulic pump flows of 200-500 L/min. Hydraulic motor torque is inversely proportional to flow rate; higher flow means higher RPM, and torque varies with pressure.
How to calculate HVAC chilled/hot water flow rate?
Air conditioning chilled/hot water flow formula: Q(m³/h) = Cooling capacity(kW) × 0.86 ÷ Temperature difference(℃). This is because the specific heat capacity of water is 4.187 kJ/(kg·K), 1 m³ water = 1000kg, and the heat carried away at 5℃ temperature difference: each m³/h flow carries about 5.8kW of cooling capacity (5×1.163). Common scenarios: 1 five-horsepower air conditioner (cooling capacity about 14kW) with 5℃ supply-return water temperature difference requires flow ≈2.4 m³/h≈40 L/min; 1000 RT refrigeration ton chiller (about 3517kW) about 600 m³/h. Underfloor heating systems use about 2-4 L/min per circuit, and the manifold calculates total flow based on the number of circuits.
What is the flow rate of a gas pump nozzle? How long does it take to fill 50 liters?
Gas station fuel nozzle standard flow rate: gasoline nozzles generally about 40 L/min (about 2.4 m³/h, about 10.6 GPM), diesel nozzles about 40-60 L/min (large truck diesel nozzles can reach 80-120 L/min). Filling a 50-liter tank takes about 50÷40=1.25 minutes (about 1 minute 15 seconds); a large truck 300-liter tank with a 60 L/min nozzle takes 5 minutes. Aviation refueling flow is much larger (civil aviation underwing refueling can reach 2000-4000 L/min) to reduce ground time. Note: liters (L) displayed at gas stations is a volume unit, not a flow rate unit.
What unit is CFM? How to convert to m³/h? (CFM not supported by this tool)
CFM (cubic feet per minute) is an imperial air volume unit, 1 CFM ≈ 1.699 m³/h ≈ 28.32 L/min. CFM is commonly used for HVAC ventilation, fans, air compressors, and exhaust fans (e.g., household exhaust fans about 50-150 CFM, air compressors 10-100 CFM, central air conditioning fans thousands of CFM). Note: this flow rate converter supports liquid flow units (m³/h, m³/s, L/min, gal/min); CFM/CMM (cubic meters per minute) are air volume units and are not within the supported scope of this tool; use a dedicated air volume conversion tool. The gal/min in this tool is liquid gallons, not cubic feet.
Which flow units does this tool support? What is the relationship between flow rate, pressure, and velocity?
This flow rate converter supports 4 volumetric flow units: m³/h (cubic meters per hour), m³/s (cubic meters per second), L/min (liters per minute/LPM), gal/min (US gallons per minute/GPM). Conversion relationships: 1 m³/s=3600 m³/h=60000 L/min≈15850 GPM; 1 m³/h≈16.67 L/min≈4.40 GPM. Note: Flow rate (Q) is the volume flowing per unit time, and must be distinguished from flow velocity (v, unit m/s) and pressure (P, unit Pa/bar/MPa) — the relationship between the three is determined by pipe characteristics (pipe diameter, resistance, pump characteristic curve) and they cannot be directly converted to each other. Pipe flow velocity formula Q=v×A, hydraulic power P(kW)=Flow rate Q(m³/s)×Pressure(Pa).
