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.
Hydrostatic testing intervals for fire extinguishers are outlined in NFPA 10(98), Sec. 5-2 and Table 5-. 2. Test intervals for some of the most commonly found extinguishers are as follows: â¢ Pressurized water, carbon dioxide and wet chemical extinguishers â every 5 years. â¢ Dry chemical extinguishers â every 12 years. As mentioned earlier, the exception to the rule for hydrostatic testing is nonrechargeable stored.