A compartment measures 14 feet wide, 12 feet long and 8 feet high, lined with ½ inch sheetrock and has a standard 36 inch by 80 inch door. What HRR is required for flashover?
To determine the heat release rate (HRR) required for flashover, we need to calculate the volume of the compartment and consider the fuel properties and fire growth characteristics.
First, calculate the volume of the compartment by multiplying its width, length, and height:
Volume = 14 ft x 12 ft x 8 ft
Volume = 1,344 cubic feet
Next, we need to consider the fuel load in the compartment and the heat release rate per unit area. Since you haven't provided any specific information about the fuel load, we will assume a typical value for a residential compartment.
A typical residential fuel load can range from 7-10 lbs/ft². Assuming a fuel load of 8 lbs/ft², we can calculate the total fuel load:
Fuel Load = Fuel Load per Area x Compartment Area
Before calculating the compartment area, we need to account for the wall surface area excluded by the door. Since the door size is given as 36 inches by 80 inches, we convert it to feet:
Door Area = (36 in x 80 in) / (12 in/ft x 12 in/ft)
Door Area = 20 ft²
Now, calculate the compartment area excluding the door area:
Compartment Area = 2 x (Width x Height) + 2 x (Length x Height) - Door Area
Compartment Area = 2 x (14 ft x 8 ft) + 2 x (12 ft x 8 ft) - 20 ft²
Compartment Area = 348 ft²
Finally, calculate the total fuel load:
Fuel Load = 8 lbs/ft² x 348 ft²
Fuel Load = 2,784 lbs
Once you have determined the fuel load, various fire growth models can be used to estimate the heat release rate required for flashover. One commonly used model is the Heskestad fire plume model.
Unfortunately, the Heskestad model is complex and involves multiple equations and calculations. It takes into account parameters such as compartment geometry, ventilation conditions, and fuel characteristics. Since the model requires detailed input data, it's not possible to provide a simple calculation for the HRR required for flashover in this case.
To determine the HRR required for flashover accurately, it's recommended to consult fire protection engineers or fire safety experts who have access to specialized fire modeling software and expertise in fire dynamics. They can conduct a thorough analysis and provide accurate estimates based on the specifics of your compartment.