Define "Opening" 2

[EIT2]

RE: IBC 1609.2 Definitions:

In the definition BUILDING, PARTIALLY ENCLOSED: A building that complies with both of the following conditions:

1. The total area of "openings" in a wall that receives positive external pressure exceeds the sum of the areas of openings in the balance of the building envelope ...

Will somebody please define "opening".
Is this a permanent, unclosable opening?
Can an opening be an operable doorway?
Are windows considered an opening?

Thank you!

 

[ishvaaag]

Certainly if I read this I interpret it any window or door or hole in a wall, irrespective of it being partially or entirely closed or be feasible so.

In Spain the generic way to refer to such thing is "huecos", that is, holes, and obviously most windows and doors ar entirely glazed or are opaque when closed. So a hole may be covered and still remain being called a "hueco" here.

 

[CTSeng]

EIT2,
I always thought deciding whether to classify a structure as enclosed or partially enclosed was a 'no brainer' but comments of others have created some grey area. It seems some judgement about whether the doors and windows are open remains with the engineer.

Have you read the commentary in ASCE7? It doesn't really clear anything up except that it is up to the engineer to make the call.

Also read through: thread507-76607 again not really decisive but informative.

In my opinion if the structure is in a hurricane wind borne debris region and windows and doors are not impact resistant and do not have hurricane shutters then the structure is designed as partially enclosed. If not in a wind borne debris region design the structure as enclosed unless permanent openings warrant otherwise.

 

[ERV]

An opening is defined as:
Apertures or holes in the building envelope that allows air to flow throughthe building ebvelope and that are designed as "open" during design winds as defined by these provisions. (ASCE 7-02).
This also includes windows that are not impact resistant in areas so required.

Consider a building with an opening to the windward side, internal pressure could be raised to the level of EX-plosion. An opening on the leeward side could net sufficient negative pressure to cause IM-plosion.

That is why we have pressure coefficients based on:

Open = 0.00
Enclosed = 0.18 and
Partially Enclosed = 0.55

The large difference in coefficient for the latter should be obvious.