NASA-LLIS-6776

Abstract

<strong>Description of Driving Event:</strong> <br>On August 26, 2011, a fire suppression sprinkler head leaked and then failed in Building 600 at the NASA/Caltech Jet Propulsion Laboratory (JPL), inundating several office cubicles. The initial leak was reported earlier in the day to the JPL Office of Protective Services (OPS), OPS contacted the building owner, and a maintenance crew was responding when the sprinkler head triggered the full water release. <br>The impact of the water damage was minor. However, the affected office space shares the fire alarm system with an adjacent data center that, among other activities, supported Mars Science Laboratory (MSL) Assembly, Test, and Launch Operations (ATLO). There was no water release in the data center, but it was believed that the fire alarm system was programmed to shut down power to the data center unless the shutdown was manually countermanded within ten minutes. The data center was not staffed because August 26 was an RDO*, the security guard arrived after the tenminute period had elapsed, and the data center suffered a power outage. <br>Building 600 is one of the few JPL buildings that is leased from a private owner. Although the procedure for placing the data center electrical system in bypass is posted in the electrical room of the data center, subsequent investigation found that the shutdown was immediate: there is no ten-minute delay in triggering the power shutdown after the fire alarm is triggered. JPL was misinformed, and such a delay is not compatible with the fire code. <br>To prevent a recurrence of this incident, JPL installed a double-interlock, preaction, fire suppression system to replace the existing system in the Building 600 data center. Preaction systems are suitable for water sensitive environments like data centers because (until a valve is electrically activated) they contain no water in the sprinkler piping so a sprinkler head failure does not release water. The double-interlock feature prevents flow of water until both a sprinkler head and a separate detector are triggered simultaneously. (Triggering only one of the two devices will produce an alarm, but no water flow into the system.) Because this fire suppression system is separate and isolated from the system in the Building 600 office space, an alarm in the office space will not trigger an electrical shutdown in the data center. *Most JPL personnel work a schedule that allows them an additional day off work every other Friday, and August 26, 2011 was such a Regular Day Off (RDO).