Division of explosive hazard zones above the floating roof after the float settles on the ground
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In Appendix B of 50074, the area above the floating roofs of internal and external floating roof tanks is Zone 1. However, once the floating roof is in place and the ventilation openings are opened, oil and gas will definitely escape. The area above the oil level beneath the floating roof can certainly be considered Zone 0, while the area above the floating roof cannot be simply treated in the same way as a dome tank, with the area within a radius of 1.5 meters around the ventilation openings being classified as Zone 1. Because after the external floating roof deck touches the ground, the oil and gas above the deck cannot escape as quickly as in a dome tank. It will keep accumulating – is it possible to meet the standards of Zone 0? Brief summary: Could Zone 0 appear above the floating pad after it touches the ground? Is there anyone who can provide an answer?
Is the classification of hazardous areas not based on floor plans, covering the airspace directly? I don’t quite understand what you mean
I’m seeing this classification for the first time; usually it’s based on 50058, which is considered Zone 0, so I didn’t have this question before
It’s definitely not just a flat surface; oil and gas spread everywhere. Take a look at Appendix B of 50074 and you’ll understand
Zone 1 is also assigned to the area above the floating roof of tank 50058, not Zone 0
That is a floating roof; I think the internal floating roof is fixed