Use shut-off valves in front of the hoses. This configuration allows for the removal of the  hoses for a service procedure or relocation. Valves are not included in the order. A stainless  steel fitting is available for ordering. The fitting is barbed on one side and has a 2.54 cm (1 in.)  male national pipe thread (NPT). For more information about the tools that are needed for the  water supply connections, see the  IBM 3906 Installation Manual for Physical Planning, GC28-6965. In case of power shutdown, the optional Internal Battery Feature (IBF) provides sustained  system operations for a relatively short time, which allows a proper z14 server’s shutdown. In  addition, an external uninterrupted power supply system can be connected, which allows for  longer periods of sustained operation. The IBF can provide emergency power for the estimated time that is listed in Table 10-5. The  number of IFBs depends on the number of BPRs. For the number of BPRs that are installed  in relation to I/O units and the number of CPC drawers, see Table 10-5. They are installed in  pairs. You can have two, four, or six batteries (odd numbers are not allowed). 10.1.4 Internal Battery Feature Table 10-5 Internal Battery Feature holdup times Consideration:  The system holdup times that are listed in Table 10-5 assume that both  sides are functional and have fresh batteries under normal room ambient conditions.  Holdup times are greater for configurations that do not have every I/O slot plugged, the  maximum installed memory, and are not using the maximum processors. These holdup times are estimates. Your particular battery holdup time for any specific  circumstance might be different. Holdup times vary depending on the number of BPRs that are installed. As the number of  BPRs increases, the holdup time also increases until the maximum number of BPRs is  reached. After six BPRs (three per side) are installed, no other batteries are added;  therefore, the time decreases from that point. Holdup times for actual configurations are provided in the power estimation tool at IBM  Resource Link website. On the Resource Link page, click  Tools Machine information , select your IBM Z  system, and click  Power Estimation Tool . 396  IBM z14 (3906) Technical Guide a. I/O units = the number of I/O drawers or PCIe I/O drawers. CPC drawers Number of I/O units a 0 1 2 3 4 5 1 19.9 min 13.7 min 10.3 min 8.9 min 13.9min  12.4 min 2 8.8 min 12.5 min 10.5 min 9.0 min 7.9 min 7.1 min 2 9.6 min 8.3 min 7.4 min 6.6 min 6.1 min 5.0 min 4 6.7 min 6.1 min 5.0 min 4.5 min 4.0 min 3.7 min