Gerald I. Forstater, PE, PSP, CET and Daniel H. Broughton, EIT Fire Protection of mission critical 13kv Redundant Switchgear in buildings Gerald I. Forstater, PE, PSP, CET and Daniel H. Broughton, EIT

Defining the Problem Dual redundant switchgear 12.47 kV each side 1600 amps per phase – 4800 amps total Enclosed in building Business continuity

Codes, standards & References IBC – International Building Code, 2012 IFC – International Fire Code, 2012 NFPA – Pamphlet 13 Automatic Sprinkler Systems, 2010 NFPA – 2001 Non-Halogenated Gas Systems, 2010 NEC – 70 Electrical Code, 2010 NFPA – 72 Fire Alarm and Signaling Systems, 2010

NSA's Data Center Electrical Problems Aren't That Shocking By Tekla Perry Posted 16 Oct 2013 | 18:01 GMT   Last week, the Wall Street Journal reported that arc-fault failures – electrical problems that exceed the protective capabilities of circuit breakers and cause metal to melt and go flying – are delaying completion of the NSA’s controversial new Utah data-storage center. "A circuit breaker tries to open up, but the amperage is higher than it can handle, so when the contacts open it doesn’t break the circuit. Instead, you have an arc that is moving around between the contacts; it has huge magnetic forces to it, and it can’t be easily extinguished. You end up with molten metal flying around which is extremely dangerous."

arcing

Potential Heat Release Rates Three phase Fault – 20 MW One phase fault – 6.67 MW

Transformer Failure

Internal Arc

BUILDING FIRE PROTECTION ANALYSIS

BUILDING FIRE detection Pre-action actuation ANALYSIS

Detector Response Time Anticipated detector activation sequence upon fault: Linear heat detector Incipient smoke Spot Heat detector Smoke detector Sprinkler head element Many additional variables Enclosure gasketing Rain guards Ceiling slope Ventilation Calculations based on heat from fire not electrical

NFPA 2001 over 480 volts Covers the use of clean agent for Class C fires under 480 Over 480 volts subject to testing if equipment is to stay energized during and after discharge Recommends the minimum design concentration for Class C fires be 1.35 times the Class A concentration Class A: 4.5% concentration for most products Class C: 6% Other considerations Low leakage building Pressure testing Redundant agent supply No occupancy during discharge Post discharge purge

AHJ’s, Testing & Acceptance Conversation with Mr. Rivers of 3M about NOVEC Multiple tests at 6% concentration Madrid, Spain South America No formal test data available AHJ must accept these international tests to proceed with design Physical testing of a similar design at same concentration needed to confirm design

Final recommendations Suppression Sprinklers to protect building Pre-action with double interlock Detection Incipient smoke detection Linear heat detection Ion/photo smoke detectors Spot/compensated heat detectors Cross zoning

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Next study phase Temperature Set Points Real world Investigation Actual Test

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