Cell biology (formerly called cytology, from the Greek ÎºÏÏÎ¿Ï, kytos, vessel) is a branch of biology that studies the different structures and functions of the cell and focuses mainly on the idea of the cell as the basic unit of life.
(B) For a cylinder having a water capacity over 12 pounds-- (1) By hydrostatic test without determination of expansion (modified hydrostatic test method). A retest must be performed 12 years after the original test date and at 7-year intervals; or (2) By hydrostatic test using the water jacket method. A retest must be performed 12 years after the original test date and at 12-year intervals thereafter.
(OP). I have a hydrostatic pressure test for a HWS/R system, 1-1/4 pipe, approx 40 ft in length. Initial test pressure was 225psi and after 4 hours the test pressure increase to 280psi. I'm used to test pressure decreasing due to a leak but never seen test pressure increase by 55psi.