Can a internal floating roof gasoline and diesel storage tank without circumferential vent holes do without a nitrogen seal?
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I would like to ask about existing internal floating roof gasoline and diesel storage tanks that only have a vent valve and an emergency pressure relief valve. However, it seems that according to API650, Appendix H, “H.5.2.2.3. If vent holes are not installed as required above, inert gas protection or other measures shall be employed to prevent the accumulation of flammable gases.” In addition, vacuum protection measures shall be taken in accordance with the requirements of 5.8.5, subject to the information provided by the buyer. ” Currently, the storage tank is in operation and cannot be stopped, nor is it likely that the vent holes will be opened again. Is it necessary to use a nitrogen seal? What are the “other measures” mentioned above? If I install a flame arrester under the breather valve, is it okay not to use a nitrogen seal? Are there any other standards that can be used as a reference? Actually, my internal floating roof is made of aluminum, so the chances of sparks being generated inside the tank are practically zero. In theory, it’s sufficient to prevent external flames from getting in; installing a flame arrester should be enough. But I’m not entirely sure, so I came here to ask for everyone’s advice. Thank you so much!
Same request. The vent holes serve to prevent the accumulation of flammable gases. Without using a nitrogen seal, can standard requirements be met simply with a breathing valve and a flame arrester?
It’s mainly due to environmental regulations; gasoline needs to be sealed with nitrogen, while diesel doesn’t require that – a flame arrestor vent is sufficient. .
There is a conflict as mentioned by the original poster; if a breathing valve has already been installed, what additional ventilation holes are needed? In the early days of China’s petrochemical industry, diesel tanks, especially those for heavy diesel, generally featured insulation and a fixed roof, allowing them to be in direct contact with the outside environment. In recent years, diesel tanks have often been designed with an internal floating roof, a flame-arresting vent valve, and an emergency release device. In my opinion, your design meets the regulatory requirements; I recommend checking whether it satisfies the VOC emissions standards set out in Document No. 177 issued by the Ministry of Environmental Protection, as these standards were introduced recently and will be applied during inspections in July 2017.
Thank you for your reply. Could you please tell me what the reason is for using nitrogen sealing for gasoline but not for diesel? Thank you!
Thank you for the reply. Currently, a breathing valve is being used without any vent holes, but it seems that this does not meet the API650 standards; in the absence of vent holes, it is necessary to employ a nitrogen purge or other measures to prevent the accumulation of flammable gases.