University updates fire pump

This case study describes redesigning the electrical system in one of the existing buildings at a university.


Figure 4: Two different sources supply power to a single-ended substation. The substation feeds all electrical loads of the building including the fire pump. Courtesy: Jacobs EngineeringA project a couple of years ago involved redesigning the electrical system in one of the existing buildings at a university. Even though the building was four stories high, it was not classified as a high-rise as the floor level of the fourth floor was less than 75 ft high. The building was approximately 161,000 sq ft, and housed the university library. After discussions with the client, we decided that the fire pump would be electrically powered and be located adjacent to the main mechanical and electrical rooms, on the ground floor, near one of the entrances to the building.

The building was part of a multibuilding, campus-style complex powered through a radial loop distribution system at medium voltage. The service was then stepped down to 480 V in a new single-ended substation with a duplex primary switch. According to NEC 695.3(C)(1), “Two or more feeders shall be permitted as more than one power source if such feeders are connected to, or derived from, separate utility services.”

Both sources were considered reliable; therefore, we decided that there was no need for another alternate power source for the fire pump. To connect the fire pump controller, we decided to tap into the secondary bus of the substation (see Figure 4). Following 695.4(B), we installed a single disconnecting means and overcurrent protection in the electrical room. The overcurrent device was sized to handle the locked rotor load of the fire pump motor.

Because it was a fully sprinkled building, we decided that exception 695.6(A)(2)(d) applied, which states that “The supply conductors located in the electrical room where they originate and in the fire pump room shall not be required to have the minimum 2-hour fire separation or fire resistance rating…”. We ran the conductors in EMT conduit while in the electrical room and in the fire pump room. The conduit run between the rooms was encased in 2-in. concrete.

Eduard Pacuku is electrical project engineer at Jacobs Engineering, where the majority of his time is spent designing electrical distribution systems for universities (including laboratories), health care facilities, and data centers. He has extensive experience with fire pump installations.

No comments
Consulting-Specifying Engineer's Product of the Year (POY) contest is the premier award for new products in the HVAC, fire, electrical, and...
Consulting-Specifying Engineer magazine is dedicated to encouraging and recognizing the most talented young individuals...
The MEP Giants program lists the top mechanical, electrical, plumbing, and fire protection engineering firms in the United States.
Salary survey: How much are you worth?; Dedicated outdoor air systems; Energy models and lighting
Fire, life safety in schools; Fire protection codes; Detection, suppression, and notification; 2015 Commissioning Giants; Emergency and standby power in hospitals
HVAC and building envelope: Efficient, effective systems; Designing fire sprinkler systems; Wireless controls in buildings; 2015 Product of the Year winners
Designing positive-energy buildings; Ensuring power quality; Complying with NFPA 110; Minimizing arc flash hazards
Implementing microgrids: Controlling campus power generation; Understanding cogeneration systems; Evaluating UPS system efficiency; Driving data center PUE, efficiency
Optimizing genset sizing; How the Internet of Things affects the data center; Increasing transformer efficiency; Standby vs. emergency power in mission critical facilities
As brand protection manager for Eaton’s Electrical Sector, Tom Grace oversees counterfeit awareness...
Amara Rozgus is chief editor and content manager of Consulting-Specifier Engineer magazine.
IEEE power industry experts bring their combined experience in the electrical power industry...
Michael Heinsdorf, P.E., LEED AP, CDT is an Engineering Specification Writer at ARCOM MasterSpec.