I have good news and bad news. The bad news first: The current trend is to build a 100,000-plus-square-foot building constructed mostly out of steel that houses excessive amounts of combustibles. The good news is that it is required to be protected by automatic sprinkler systems-big automatic sprinklers systems.
A working fire in one of these “big box” stores will tax the largest departments in the country. Let’s do some math: Length × Width divided by 3. I know that those who espouse this fire flow formula say it is only “relatively” accurate for flows up to 1,000 gpm. To my way of thinking, it still provides a rule of thumb for fire flow to start with-and even I can do the math: 100,000 ÷ 3 = 33,000 gpm. Let’s see: How many 1,500-gpm engines will that require if the building is totally involved?
Let’s say only one-tenth of the building is involved: two engines + the additional engines to flow the required water. How many firefighters will it take to flow 3,333 gpm out of handlines? In my quick-math world, that would be about 10 2 1/2-inch lines. That’s not counting ventilation efforts, searches, and all the other “stuff” we do! Thank God for automatic sprinkler systems.
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