MS in Fire Protection Engineering
College of Engineering
Frederick Mowrer and Christopher Pascual
Enclosed in this report is a comprehensive analysis of the fire protection and life safety components of the Illinois Department of Transportation (IDOT) District Six Headquarters building. The original building was constructed in 1972 and renovation operations were recently completed in 2022. The building is four stories in height with an aggregate floor area of approximately 69,300 square feet. The building functions as an office space for IDOT staff, therefore the majority of floor space is used as open office and private office space. The business spaces are supported by assembly spaces such as conference and break rooms on each floor of the building. In addition to the spaces required by IDOT, the building is supported by utility rooms that include storage, mechanical, electrical, telecommunication, and elevator machine rooms. The building was evaluated to determine compliance with the applicable prescriptive code criteria. Furthermore, a performance based analysis was conducted to determine the feasibility of the fire protection features to adequately meet the fire safety strategy of the building based on the fuel loads and hazards found within the building.
First, the life safety and means of egress components within the building were examined. Means of egress components include travel paths, exit signage, doors/stairs, and the arrangement of exits. Each floor contains an adequate number of exits for the calculated occupant load, which are adequately marked by illuminated exit signage. When not readily visible, the path of egress travel is also marked by illuminated exit signage. The exit signage and additional components of the means of egress must comply with both the International Building Code (IBC) and NFPA 101, with the more stringent code criteria being utilized whenever the codes conflict. It was determined that the life safety features of the building comply with the code criteria, however caution must be taken to ensure that the use of each space on the fourth floor of the building is maintained as classified as the occupant load is only 7 people less than the exit capacity.
The building is also required to be provided with a fire alarm and detection system in accordance with the IBC and NFPA 72. All public spaces are provided with occupant notification through combination horn/strobe appliances. The horn/strobe appliances are ceiling mounted and spaced such that the visual requirements of NFPA 72 are met. Additionally, the horn/strobe devices are placed such that the sound level produced from a fire alarm condition will exceed 15 dB greater than the expected ambient sound level of an office occupancy. Initiating devices present in the building include manual pull stations, smoke detectors, waterflow switches, tamper switches, duct smoke detectors, and heat detectors. The fire alarm and detection meets prescriptive code requirements and is discussed further in the “Fire Alarm and Detection” section of this report.
As mentioned above, the fire alarm and detection monitors the building’s automatic suppression system. The building is provided with a wet pipe sprinkler system in accordance with NFPA 13. The sprinklers are quick response throughout and are recessed pendent type in the areas with ceilings and upright type in areas without ceilings.
There is no dedicated smoke control system required or provided for the building. Passive smoke management is provided through fire barriers and smoke resistant partitions. This is discussed in more detail in the “Smoke Control” section of this report.
On the performance-based side of the results, each of the design fires were used to determine the effectiveness of the buildings fire safety strategy. The analysis can be used further to develop a performance-based design solution for the entire building. Overall, the initial two design fires suggest the building’s fire safety strategy is adequate for the fuel loads and hazards present if proper precautions are taken. Design fire one was a fire within the open office space of the fourth floor of the building. This was selected due to the large amount of this space in the building and it having the potential to affect the largest number of occupants. In design fire one, the RSET was calculated to be 357 seconds using all applicable pre-movement, delay, and travel times. The ASET was determined to be 450 seconds and was determined through analysis of applicable test data that was adapted to the District 6 Headquarters building. The result is 26 percent safety factor for a worst-case design fire on the fourth floor of the building. A 26 percent safety factor on the ASET vs. RSET calculation is plenty adequate to account for occupants who may not be intimate with the building as well as those familiar with the space. A second design fire was analyzed within the record storage room on the second floor of the building. This design fire was selected because it represents the greatest hazard present in the building. In design fire 2, the sprinkler system was proven to be adequate with an activation time approximately 40 seconds before ignition of adjacent shelving units. Furthermore, the addition of a smoke detector to the space was modeled in FDS and was found to give responding personnel an additional 75 seconds of response time to a fire in the record storage room. Based on these results, smoke detection should be added to the storage rooms.
The analysis showed several areas of concern to maintain the buildings fire safety strategy. First, the owner should be aware of the occupant load on the fourth floor that is close to exceeding the exit capacity for the floor. If an assembly space is added, the occupant load is likely to exceed exit capacity. I would recommend the owner keeps a close eye on the occupancies present on the fourth floor. Additionally, Design Fire #2 showed a heavy reliance on the building sprinkler system to maintain the fire safety strategy. Due to this, I recommend that the building owner be made aware of the Inspection, Testing, and Maintenance standards for fire alarm and fire suppression systems. Also, the building owner should keep organized records onsite and review them to ensure compliance.