Need some clarification on what the hydrostatic retest requirements are for 3 rows of 2500 psi Nitrogen tanks installed in bank for water mist suppression system in an underground fuel vault (not buried, in conditioned space within a dedicated room for deployment system) accessible from surface via ladder way.
Refill is conducted via truck through 100' hose from the surface to dedicated manifold that fills all tanks simultaneously(or as valves are opened/closed) all tanks have relief valves, gauges, (hoses are supposedly hydro required every 5 years iaw the O&M)
The markings on the tank Identify them as DOT-3AA (no * ) looking through the DOT regulations 173.34 (e)(16) & (19)
I feel our tanks would fall under the section 173.34(19)b.(ii) giving them a 12 year hydro date. With all of the caveats and additional references it muddies the water so much I cannot clearly state to the owner this is the requirement as per...etc.
The other question is: Since the tanks do not move and are inspected daily, weekly, monthly by operators, Simplex inspects system Semiannually and annually Do they actually fall under DOT requirements or NFPA requirements?
If you could clarify this form me I would greatly appreciate it.