Max. Area of Ext. Openings & Fire Separation Distance

[T-Bird]

Confirming that fire separation distance applies to openings located on the same wall plane, when said wall plane is divided by a perpendicular fire wall. In which case one would measure from opening jamb to opening jamb to determine the spearation distance.

 

[T-Bird]

In the case of a non-rated building, those openings could be unlimited, yes? (705.8.1 Exception 2)

 

[RLGA]

Using the image below, which dimension are you trying to determine: A or B?

 

[T-Bird]

Using the image below, which dimension are you trying to determine: A or B?

View attachment 8609

A

 

[classicT]

706.5 Horizontal Continuity
Fire walls shall be continuous from exterior wall to exterior wall and shall extend not less than 18 inches (457 mm) beyond the exterior surface of exterior walls.

Exceptions:

1. Fire walls shall be permitted to terminate at the interior surface of combustible exterior sheathing or siding provided that the exterior wall has a fire-resistance rating of not less than 1 hour for a horizontal distance of not less than 4 feet (1220 mm) on both sides of the fire wall. Openings within such exterior walls shall be protected by opening protectives having a fire protection rating of not less than 3/4 hour.
2. Fire walls shall be permitted to terminate at the interior surface of noncombustible exterior sheathing, exterior siding or other noncombustible exterior finishes provided that the sheathing, siding or other exterior noncombustible finish extends a horizontal distance of not less than 4 feet (1220 mm) on both sides of the fire wall.
3. Fire walls shall be permitted to terminate at the interior surface of noncombustible exterior sheathing where the building on each side of the fire wall is protected by an automatic sprinkler system installed in accordance with Section 903.3.1.1 or 903.3.1.2.

 

[classicT]

T-Bird... I think that you are asking about applying Exception #1 or #2 to IBC Section 706.5. See my preceding post for the code section.

 

[RLGA]

A

The fire separation distance is measured perpendicular to the face of a wall to a lot line (Dimension B per my image)--not between openings.

Opening protection is dependent on which option you use per IBC Section 706.5.1.

 

[classicT]

706.5.1 Exterior Walls
Where the fire wall intersects exterior walls, the fire-resistance rating and opening protection of the exterior walls shall comply with one of the following:

1. The exterior walls on both sides of the fire wall shall have a 1-hour fire-resistance rating with 3/4-hour protection where opening protection is required by Section 705.8. The fire-resistance rating of the exterior wall shall extend not less than 4 feet (1220 mm) on each side of the intersection of the fire wall to exterior wall. Exterior wall intersections at fire walls that form an angle equal to or greater than 180 degrees (3.14 rad) do not need exterior wall protection.
2. Buildings or spaces on both sides of the intersecting fire wall shall assume to have an imaginary lot line at the fire wall and extending beyond the exterior of the fire wall. The location of the assumed line in relation to the exterior walls and the fire wall shall be such that the exterior wall and opening protection meet the requirements set forth in Sections 705.5 and 705.8. Such protection is not required for exterior walls terminating at fire walls that form an angle equal to or greater than 180 degrees (3.14 rad).

 

[T-Bird]

T-Bird... I think that you are asking about applying Exception #1 or #2 to IBC Section 706.5. See my preceding post for the code section.

thanks classicT