Date
6-2024
Degree Name
MS in Fire Protection Engineering
College
College of Engineering
Advisor
Frederick Mowrer and Christopher Pascual
Abstract
The new Student Center (SC) is planned as a 140,000 GSF four (4) story building with a basement. The program for the building includes classrooms, an auditorium, fabrication & assembly, glass blowing, student organizations that build & test vehicles, meeting rooms, demonstration kitchen, café, retail, and a lounge. An exterior courtyard is planned on Level 2 which allows for outdoor assembly spaces.
This report identifies major code requirements for means of egress, structural fire protection, fire suppression, and fire alarm systems. The report also identifies the major fuel loads in the building. A performance-based assessment is provided for roof construction fire protection. An equivalency approach is also provided for the potential building atrium condition.
The Type IIA building will contain Group A, B, F-1, S-1, and M occupancies and will be fully sprinkler protected and provided with an emergency voice/alarm communication system. Consideration should be given to build the project to Type IB construction due to the presence of 2-hour shafts and Level 1 being a 2-hour floor assembly.
The project contains two (2) floor openings that connect Level B to Level 1; and Level 1 to Level 2. Prescriptive code requires these floor openings to be fire separated.
The project contains three (3) exit stairs serving all levels above grade. Level 2 is also served by an open exit access stair located in the Level 2 floor opening. Level B is served by two (2) exit stairs and an open exit access stair located in the Level 1 floor opening. At Level 2, a stair (Stair A) has been permitted to have a rolling fire shutter complete its enclosure (equipped with an integral egress door).
The sprinkler system design does not require a fire pump. The sprinkler system design includes provisions to convert the Paint Lab from using water-based paints to flammable liquid-based paints. This future use will either impact the sprinkler design (increased riser size from 4” to 5”) or will require the rating of the room to be increased from 1-hour to 1.5-hour.
As noted above, the fire alarm system will be an emergency voice/alarm communication system with a Notifier NFC-50/100(E) fire alarm control panel. Achieving intelligibility will require a speaker in most rooms.
Calculations were performed to determine whether protecting the steel roof structure is necessary. 50mm of spray mineral fiber was shown to adequately protect analyzed structural members. Based on the results of the fire scenarios, the thickness of spray mineral fiber may be reduced to achieve a similar level of protection at a lower cost. Fire Scenario 3 did not require spray fireproofing, suggesting that some ancillary rooms similar to the multi-purpose room may not require fireproofing.
Smoke control is not required for the project; however, as requested by the AOR (architect of record), the fire separation between the two (2) project floor openings was requested to be removed. An equivalency was prepared based on two (2) design fires. Smoke control was found to be necessary to maintain tenable conditions. The smoke control system must be capable of operating for the specified total building RSET (51 minutes). The system must be equipped with primary and secondary power. It is recommended that the secondary power be achieved with an unlimited power supply to ensure the smoke control system is not interrupted by loss of power, to maintain tenable conditions.
The equivalency approach explores removing the fire separation between the project floor openings, which connects three (3) levels atmospherically. Since the Code permits two-story openings with no smoke control, the focus of the approach is smoke spread from Level B to Level 2. Also, since Stair A discharges to the interior of the building, the other focus of the approach is to maintain tenable conditions at Stair A’s discharge.
The design fires are based a t-squared fire model. The selected alpha value is for Polyfoam (rigid polyurethane) and is the worst-case value reported by the referenced document. Realistically, the test samples were small in the referenced document so a realistic fire should have a lesser growth rate factor.
Using the worst-case value ensures the equivalency approach is valid for a worst-case scenario (such as a vertical flame spread or a new novel material).
There are two (2) design fires, a fire based on a significant mass of Polyfoam being stored in a room (Composites Lab) (Design Fire 1) and 10 kg of Polyfoam stored directly at the base of the Level 1 floor opening (such that virtually all smoke rises to the level above) (Design Fire 2). The latter design fire assumes the 10 kg of Polyfoam is fully combusted with other combustibles (assumed to be cellulosic materials, red oak) continuing the fire.
Tenability for the design fires is assessed at Level 2, directly around the Level 2 floor opening, and at Level 1 at the Stair A discharge. The main criterion is maintaining the smoke layer height above 7.5 ft at these locations. Also, visibility (5 m) and temperature (60 C) are also included as tenability criteria. Tenability is also assessed for Stair E, the exit access stair located in the Level 2 floor opening, connecting Level 2 to Level 1.
Neither design fire maintained tenable conditions for the Stair A discharge.
Design Fire 1 passed the other specified criteria with approximately 133,000 CFM and smoke control activation at 92.5 seconds (detection time + alarm activation time).
Design Fire 2A did not pass the other specified criteria using the same exhaust airflow and exhaust system activation time as Design Fire 1.
Design Fire 2B added beam detection at 3 m above the Level 1 floor opening to detect the fire in approximately 10 seconds. Design Fire 2B did not pass the other specified criteria using the same exhaust airflow and a new exhaust system activation time of 20 seconds (detection time + system activation time).
Design Fire 2C retained the beam detection approach and modified the sprinkler spacing above the Level 1 floor opening to 6 ft to reduce the design fire size as well as increased the exhaust airflow rate. Design Fire 2C passed the other specified criteria with approximately 300,000 CFM and smoke control activation at 20 seconds (detection time + system activation time).
Therefore, the equivalency approach requires the following:
1) 300,000 CFM of mechanical exhaust at the Level 2 roof (Design Fire 2C)---Alternatively, close off the area below the Level 1 floor opening such that combustibles cannot be located in the floor opening and reduce to 133,000 CFM (Design Fire 1). 2) Beam detection above the Level 1 floor opening (not more than 9 ft AFF)---If the above alternative approach is taken, provide beam detection as a factor of safety. 3) Tight sprinkler spacing (6 ft) above the Level 1 floor opening (not required for alternate approach). 4) Primary and secondary power for the exhaust system. Secondary power should be an unlimited power supply (UPS) to ensure no disruption in smoke exhaust. 51 minutes of power supply based on the estimated time to evacuate the building. 5) Provide a Firefighter’s smoke control panel at the fire alarm annunciator (FAA) at the main entrance. 6) Enclose the Level B main electrical room with 1-hour construction since it contains the fire alarm control panel (FACP). The UPS and secondary power supply should be located in this room, another at least 1-hour rated room, or outdoors. The room is currently 2-hour rated. 7) Modify the Stair A discharge by protecting it with smoke-tight construction or relocate the discharge from Exit 5 to Exit 4.
https://digitalcommons.calpoly.edu/fpe_rpt/186
Final Presentation