Growths on the surface of the eye can be unsightly and frightening. Most growths on the eye, which often occur as people age, pose no threat to health or vision and aren&rsquo;t cancers.
The unit of measure for static pressure is often inches of water (in. water). one inch of water is the suction needed to draw water up a straw one inch. pound per square inch static pressure (1 psi) is equal to 27.7 in. water static pressure. static pressure is given as Pascals (Pa).
Better illustrated with an example. Take a fire hydrant and take the static pressure, say 80 psig. Open an adjacent hydrant. Take the static pressure again at the 1st hydrant. Say it now reads 50 psi. That is your residual pressure. From NFPA 13: The proper method of conducting this test is to use two hydrants in the vicinity of the property.