Seal Off Requirement in Hangars Space

[faresos]

Hi,
I have two questions with regrads sealing off conduits in hangar space that i'm confuse with and any help will be appreciated:

1. My understanding is that the hangar space in many location is classified as Class 1 Div 2 if it was below 18”. If equipment or devices (receptacles) that are located higher than 18”, is a seal off (EYS fitting) still required even though the devices (receptacles or switches) or equipment are not explosion proof?
2. If a seal off is provided at the hangar space, is a second seal off also will be required in the electrical room that is located in unclassified area?

Thanks in advance,

 

[rbalex]

1. In general, yes; because this is a boundary seal, not an enclosure integrity seal. In general, Art 513 treats below grade "as if" it were Division 1. [See Section 513.8(A)] However, below grade is also generally considered to be the same classification immediately above the floor. [See Section 513.8(B)] This eliminates requiring two seals.

2. Again yes; since below grade is considered classified by Section 513.8(B), a boundary seal is required at the point of emergence from grade.