Corrugated metal hoses are used for conveying of substances of different consistency (gaseous, liquid or solid). One of the important factors to consider in designing systems that implement metal hoses, is the loss of pressure. Due to its profile the pressure loss in corrugated hoses is significantly higher than in steel pipes – almost 100%, and about 20% to 25% higher for the stripwound hoses.
To find out pressure loss over a certain length of hose we can use Pressure Loss graph below – for example: we need to calculate the pressure loss in 85 feet long 2″ Corrugated Hose (which transfers water) with Flow Rate been 1400 cubic feet per hour. By using calculator below we find that 1400 ft3/hour. corresponds to 175 gal/min. Then we plot the 175 gpm on the X-axis of the chart below until we “hit” the line for 2″ hose ID, then by going over horizontally to the Y-axis, we find that Pressure Loss per foot of hose will be about 3.7 psi. So that the total pressure drop over the hose length will be 314.5 psi (3.7 x 85).
Keep in mind that if you transfer gaseous substance through the hose then you need to find the ratio of the density of gas over the density of water and adjust the pressure drop respectively. For example if you transfer natural gas (density = 0.050 lb/ft3) and knowing that water density = 62.4 lb/ft3 we can find out the pressure drop as the following: 3.7 x (0.050/62.4) = 0.0030 psi/ft or 0.255 psi for entire length of hose (85 x 0.003).
To convert flow rate from Cubic Feet per Hour to Gallons per Minute, use the Pressure Loss Calculator below: