The inner tank combined pressure and vacuum relief valves and rupture disc model numbers must follow Figure 7 manufacturer requirements, unless otherwise agreed.3.8.3.2Relief Device block valves listed in Figure 7 may be an alternative equivalent, with a standard lock at minimum.Captive key lock is not required unless specified in the PES.3.8.3.3All other components listed in Figure 7 may be an alternative equivalent.3.8.4All relief tree piping or piping supports shall be designed with enough flexibility to permit piping movements upon tank cooldown and warm-up without tank operator intervention.