Conclusiones Parciales

OVERVIEW

A fire scenario has also been developed in the kitchen area of this building. The intent of this scenario, Design Fire C, is to determine if an isolated fire in the kitchen space can spread untenable conditions into the adjacent server and dining spaces.

To address this concern a pallet of fruit and berry baskets was placed next to the cooking equipment in the center of the kitchen. It is assumed that a grease fire on the grill area spreads rapidly onto the pallet, igniting the plastic containers. The following assumptions were made to perform this analysis:

 The ansul system is not operational

 Plastic containers are made out of Polyethylene terephthalate plastic

 Sprinklers are operational

 Sprinklers are able to contain the fire once activated.

 Ambient temperature of the room is 20 C

The following image, Figure 77, is a representation of all components utilized in this simulation.

Figure 77: Design Fire C Layout

Monticello Office Building Page 80 FUEL SOURCE

The fuel source for this design fire is the pallet of fruit and berry baskets. The plastic containers are assumed to be made out of Polyethylene terephthalate, therefore the chemical properties of this material is as follows:

Polyethylene terephthalate (PET) (SFPE Handbook, Table 3-4.15)

 Carbon – 1

 Hydrogen – 0.80

 Oxygen – 0.40

The heat release rate (HRR) curve used to simulate this fire was gathered from the SFPE handbook. This graph provided below in Figure 78, illustrates the HRRs of various sizes of the single pallet of fruit and berry baskets. The configuration with the largest observable HRR was Sample A, where the maximum HRR was 4923 kW as described in Figure 79. This pallet configuration and HRR was used for this simulation. To replicate this fire, the values associated within the graph were extrapolated and entered into the PyroSim program.

Figure 78: Pallet of Berry Baskets HRR Figure 79: Pallet of Berry Baskets Criteria (SFPE, Table 3-1.2)

Byproducts were also required to be added into the PyroSim program to simulate the Carbon Monoxide concentrations and visibility throughout the smoke layer. Polyethylene terephthalate plastics, when burned, provide the following yields as described in the SFPE handbook, Table 3-4.16:

 CO Yield – 0.05

 Soot Yield - 0.053 PYROSIM

The PyroSim model was designed with the existing dimensions of the kitchen and surrounding areas. Several sprinklers were added into the model based on their existing locations within the building. In addition to the HRR and the information stated above, the following items have been added to run the FDS simulation:

 Slice Files:

o Visibility (1.8 m AFF) o Temperature (1.8 m AFF)

o Carbon Monoxide volume fraction. (1.8 m AFF)

 Ambient temperature: 20 C

 Duration: 2000 seconds

 Mesh Size: 0.25 x 0.25 x 0.25

Monticello Office Building Page 81 The following image, Figure 80, is a rendering of the PyroSim model prior to the simulation. The blue dots denote the sprinkler head locations and the red square in the center of the image represents the pallet of fruit and berry baskets. The area located to the north of the image is the servery space.

Figure 80: Design Fire C - PyroSim

DEVICE ACTIVATION

The two sprinklers located directly above the fire location activated almost simultaneously. It is observed in the following graph, Figure 81, that the sprinklers begin to discharge at approximately 200 seconds within this simulation.

Figure 81: Design Fire C – Sprinkler Activation

It is assumed that the sprinklers are able to contain the fire once they begin to discharge in this space. To account for this, the HRR is altered to account for the fire containment achieved by the sprinklers. To do this, the HRR were redeveloped to max out at the time in which the sprinklers activate (200s). After 200 seconds it is assumed that the HRR remains constant for the remainder of the simulation. Refer to Figure 82 for the revised HRR due to the sprinkler activation. The PyroSim model was re-run to accommodate this modification.

Figure 82: Design Fire C – Pallet of Berry Baskets HRR (Sprinkler)

Monticello Office Building Page 82 VISIBILTY REVIEW

The simulation was analyzed to determine if the visibility 1.8m above the finished floor decreased below 10 m. In the smoke view model, it can be observed that the visibility in the kitchen area drops to 10 m at about 90 seconds into the simulation, Figure 83. Shortly after, at 300 seconds, Figure 84, the visibility in the kitchen drops to zero. It is also observed that the visibility in the server room remains constant at the ambient conditions except directly next to the kitchen door locations. The decreased visibility in this location is contributed to the smoke plume from the kitchen area spreading into the servery space.

Figure 83: Design Fire C – Visibility (90s) Figure 84: Design Fire C – Visibility (300s)

TEMPERATURE REVIEW

The temperature of the area was also evaluated for tenability. The temperature in the kitchen reached the maximum tenable limit, 60 C, within 3.3 minutes (200 seconds) which can be observed in the image below, Figure 85. The following smoke view image of the simulation shows the temperatures at 1.8 meters above the finished floor. However, the temperatures within the server space remained at the ambient temperatures throughout the entire duration for the simulation.

Figure 85: Design Fire C –Temperature (200 s)

Monticello Office Building Page 83 CO CONCENTRATION REVIEW

Lastly, the carbon monoxide levels were analyzed for this scenario. It is observed in the following image, Figure 86, that the CO levels within the kitchen exceed 1000 ppm at about 400 seconds into the simulation. However, similar to temperature, the tenable conditions are limited to the kitchen area only.

Figure 86: Design Fire C –CO Concentration (400 s)

EGRESS ANALYSIS

The activation time of the first device occurred at 200 seconds after the ignition of the fuel source. At this time, occupants will be notified through the fire alarm system to begin the evacuation of the building. Adding the pre-evacuation time and the movement times that were determined in the Emergency Movement Section of this report, the calculated require safe egress time is approximately 15.4 minutes for the entire building. The conditions within the kitchen space reach the untenable limits at 3.3 minutes, which is far less than the RSET. However, these untenable conditions are limited to the kitchen area only. At no point during the design fire simulation, the tenability limits were observed in the adjacent servery space resulting in an acceptable egress performance.

Monticello Office Building Page 84