вопрос по станции СО2,срок прохождения гидротеста баллонов?

правило достаточно универсально - практически промышленный стандарт. Раз в 10 лет не менее 50%.
Может отличаться требованием к количеству (доле) тестируемых баллонов.

В целях безопасности раз в 5 лет, если законом страны не установлен иной срок, необходимо делать гидравлический тест баллона. При этом, определяют усталость металла и принимают заключение о возможности его дальнейшего использования.
Перед гидравлическим тестом внутренняя полость баллона осматривается на предмет коррозии и при необходимости производят очистку.

Malta Maritime Authority Merchant Shipping Directorate:

FIXED HIGH PRESSURE CO2 FIRE-EXTINGUISHING SYSTEMS Inspection Every 3 months, the ship’s crew shall check ... Hydrostatic Pressure Testing Over a maximum period of 10 years at least 50% of the CO2 bottles shall be tested by hydraulic pressure at an approved shore-based servicing station. ...

IMO стр 3 аннекса circ 1318, п. 6.1.2:

.2 the hydrostatic test date of all storage containers should be checked. High
pressure cylinders should be subjected to periodical tests at intervals not
exceeding 10 years. At the 10-year inspection, at least 10% of the total number
provided should be subjected to an internal inspection and hydrostatic test**.
If one or more cylinders fail, a total of 50% of the onboard cylinders should be
tested. If further cylinders fail, all cylinders should be tested. Flexible hoses
should be replaced at the intervals recommended by the manufacturer and not
exceeding every 10 years; and

circ 1432, page 10 of annex

10.1 Fixed gas fire-extinguishing systems
.1 perform a hydrostatic test and internal examination of 10 per cent of the
system's extinguishing agent and pilot cylinders. If one or more cylinders fail,
a total of 50 per cent of the onboard cylinders should be tested. If further
cylinders fail, all cylinders should be tested;

администрация Сингапурского флага говорит так:

(i)CO2 bottles of fixed CO2 fire extinguishing installation should be hydraulic pressure tested 20 years after the date on which the bottles were put into use, and every 5 years thereafter;

12.3.
Testing
Per NFPA 12, Section 1-9.5.1 and FIST Vol. 4-1B, Section 12.2, high-pressure CO2cylinders
must not be recharged without a hydrostatic test (and remarking) if more than 5 years have
elapsed from the date of the last test. Cylinders continuously in service (or spares) without
discharging may be permitted to be retained in service for a maximum of 12 years from the date
of the last hydrostatic test. At the end of 12 years, they must be discharged and retested before
being returned to service.