Fire separation distance issues in the new oil depot regulations
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The 2014 version of the new oil depot codes also includes liquid chemical storage areas; the fire separation requirements are 0.6D for tanks with fixed roofs and 0.4D for those with internal floating roofs. There is no mention of nitrogen blanketing, so does that mean nitrogen blanketing cannot be considered as an equivalent to an internal floating roof?
It’s just my personal understanding; it can’t replace the official version! The theory behind the floating roof is to reduce the evaporation area and volume, while the theory behind nitrogen sealing is to isolate oxygen. The floating roof can be considered static, but nitrogen sealing is dynamic as it changes with temperature.
The purpose of the fire separation distance is to prevent the thermal radiation from the burning tank from igniting the surrounding storage tanks. Similar to internal floating roof tanks, the gas phase of the material in nitrogen-sealed tanks is not easily ignited; then why can’t the separation distances be the same? Personally, I feel that fixed-roof storage tanks with nitrogen sealing have a slightly higher safety factor compared to those with fusible material inner floating disks that do not use nitrogen
Hi, to be honest, I’m also a bit confused about the advantages and disadvantages of nitrogen sealing and floating roofs. However, when it comes to following the regulations, I don’t really think too much about that. There are probably two reasons for the differences in spacing: 1) In the past, oil depots hardly used nitrogen sealing, so the regulations didn’t take this very rare scenario into account; 2) Due to its dynamic nature, nitrogen sealing increases the risk of leaks in the event of an accident, compared to floating roofs. After all, standard spacing takes into account the impact of accidents rather than who is safer