Notify Protocol ( $3500~\textrm{psi}< p < 6000~\textrm{psi}$)

Notify protocol applies to pressures above 3500  psi up to 6000  psi with the additional restriction that the destructive capacity must remain below 27 cap feet. The yellow-shaded region in Fig. 2 indicates where this protocol applies. Within this protocol, the vessel may be operated throughout the day after conducting a building-wide public-address (PA) announcement that briefly describes the planned operation. An example of such a PA announcement might be

Attention please. The pressure vessel will be in operation for the next 90 minutes. The maximum pressure will be 5000 psi. Evacuation of the basement is required. For information about potential hazards, please see the operator in room 140.

In addition to the PA notice, illuminated signs indicating that the vessel is in operation (Moderate Pressure: Evacuate Basement.) will notify of ongoing operations. The PTV operations room should be cleared of people not directly involved. In addition, access to the basement should be restricted by locking the doors to the PTV pit and the test-tank observation room. When operations are complete an “all-clear” PA announcement should be made and the illuminated signs turned off.

A pressure of 6000  psi was selected for two reasons.

• A common design requirement for ocean-going pressure hulls is that they be rated for full-ocean depth. The mean depth of the ocean is about 4 Km or approximately 6 kpsi. Hence, this pressure will permit tests for full-ocean rating within the notify protocol. Although these operations will be conducted less frequently than ballasting operations, it is expected to be common enough that placing them in the evacuate protocol would impose considerable difficulties due to the restrictive nature of the evacuate protocol.

• Fig 2 shows that the potential energy stored in the half-volume PTV at 6 kpsi is only $\frac{1}{5}$ of that in a full-volume PTV at 10 kpsi. The typical sizes of full-ocean pressure hulls are small enough that the volume of the PTV can be reduced to $\frac{1}{4} V$ or $\frac{1}{2} V$. If for some reason a volume greater than $\frac{1}{2} V$ is required for a particular operation then it is permitted to trade volume for pressure as long as the destructive capacity is limited to 27 cap feet or less. Fig. 2 shows how to compute the trade-off between volume and pressure.