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Definition of open container

Definition of open container

Definition of open container

While it might seem obvious, I am wondering if there is a written definition of what NFPA considers as an "open container" and a "closed container."

We have a production room that has been self designated as an H3 room. However, we are using ethanol in our process where ethanol is being dispensed from an outdoor AST through piping into 1,000 gallon stainless steel tanks that have a lid on them but are not sealed shut such that vapor can still exit. In addition, once the ethanol is in the tanks the lids are opened to put other materials into the vats.

So I am wondering if the fact that the tanks are not hermetically sealed, as it were, would make the room an H2 rather than an H3 hazardous occupancy.

Thank you

RE: Definition of open container

Cannot get stuff to copy and paste. definition can be found in NFPA 30 and most fire codes

Use and Quantity of Hazardous Materials

After identifying the categories of hazardous materials, one needs to determine the quantities that will be used—not just stored quantities, but also the quantities that are in use. The IFC and IBC identify two types of use systems: open and closed.

A closed system, as defined by the IFC, includes a vessel and associated piping that does not permit the release of vapors from a solid or liquid chemical or does not expose the chemical to the atmosphere at any time during its use. An open system is defined as a vessel or system that is continuously open that allows vapors from a solid or liquid chemical to be released or exposes the chemical to the atmosphere during its use.


RE: Definition of open container

Under the IBC your situation is a Use-Open System. Based on the information that your process uses ethanol as a feed stock (Class IB flammable liquid) and the tanks can be opened, the occupancy classification would be Group H-2. See Chapter 3 of the 2012 International Building Code.

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