1. Fire Blocking Requirements For All Buildings;
BC Building Code
Fire Block Requirements
Disclaimer: Presentation has not been prepared or approved by the Province of BC
Fire Blocking Requirements For All Buildings;
Including Houses
Fire blocking has been specified within the National Building Code for over 47 years or longer, under the former name of “fire stopping”.
These requirements have always applied to houses as well as larger buildings however, due to often misguided comparisons with the requirements for fire separations, many buildings have not been correctly fire blocked.

2. Fire Spread BC Building Code Fire Block Requirements
One of the fastest ways fire can spread throughout any building is through concealed spaces, especially when there is an unobstructed oxygen path that is interconnecting other parts of a building with one another.
When firefighters arrive at an incident their first task is to find the fire.
Visible fires can be quickly extinguished, however, a fire within a concealed location is almost impossible to detect and often requires the dangerous operation of tearing down a complete ceiling or wall to find the fire.

3. Fire Spread BC Building Code Fire Block Requirements
Even worse than a concealed fire, is one that has started within a concealed space that has not been fire blocked at the required locations or at the maximum distances between these barriers.
It is these concealed, undetectable, unrestricted fires, that can cause a building to quickly become engulfed in flames and smoke.
This quicker fire spread drastically reduces the time occupants have to escape from a building, especially children, and additionally puts the firefighters themselves at risk of harm.

4. BC Building Code Fire Block Requirements
Which Building Code Requirements Apply ?
Subsection Fire Blocks
Article Required Fire Blocks in Concealed Spaces
Vertical concealed spaces in interior walls and exterior walls shall be separated by fire blocks
one from the other, and
b) from horizontal concealed spaces.
These are blanket requirements which apply to All vertical concealed spaces in walls.
Clause (1) a) is intended to apply to intersecting walls.
Intersecting walls must be fire blocked “one from the other”.

5. BC Building Code Fire Block Requirements
One example is a stud at the end of a wall, which is not only backing for the installation of gypsum board, it’s more important function is to act as a fire block system between 2 vertical walls.

6. BC Building Code Fire Block Requirements
Clause (1) b) is intended to apply to the connection of a wall to a ceiling. (connection to horizontal concealed space).
Correct fire blocking
If fire blocking were not installed at this location, then a fire in either the wall, or the ceiling, would quickly spread to any, and all, interconnected locations.

7. BC Building Code Fire Block Requirements
Sentence (2) is basically a repeat of the sentence we just read, but in reverse.
Sentence (3) Expands the requirement of Sentence (1) to ensure that coved ceilings, dropped ceilings and soffits are also fire blocked from one another and from other interconnecting parts of the building where the materials within those spaces have a Flame Spread Rating (FSR) higher than 25.
Wood framing normally has a FSR of 150, gypsum board has a FSR of 25.

8. BC Building Code Fire Block Requirements
(3) Requires fire blocking at the interconnection of a wall with a soffit or drop ceilings.
Sentence (4) requires fire blocking at the top and bottom of stairs where those stairs are interconnected with “open” horizontal concealed spaces. (joist spaces)

9. BC Building Code Fire Block Requirements
Article
Sentence (5). In unsprinklered buildings of combustible construction, every concealed space created by a ceiling, roof space or unoccupied attic space shall be separated by fire blocks into compartments
a) not more than 60 m in greatest dimension, and
b) where such space contains exposed construction materials having a surface flame-spread rating greater than 25, not more than 300 m2 in area.
Sentence (6) No dimension of the concealed space  described in Clause (5)(b) shall exceed 20 m.
These requirements do “APPLY to HOUSES”

10. What does “compartments” mean ?
BC Building Code Fire Block Requirements
What does “compartments” mean ?
CNBUSTBLE
VERTICAL
MORE
Ensure that mansard roof structures are not interconnected with adjacent walls or the adjacent attic space.
Divide attic into fire block compartments, each that has no dimension greater than 20 meters and no area larger than 300m2.
Compartment fire blocking must be installed at 20 m horizontal intervals, as well as at each fire separation wall.
Dropped or concealed spaces under floor systems also must meet the 20 m and 300m 2 limits.

11. BC Building Code Fire Block Requirements
Which materials must be used for fire blocking
Article lists the following permitted materials;
Clause (2) a) .38 mm sheet steel,
b) 12.7 mm gypsum board,
c) 12.5 mm plywood, OSB or waferboard, all with joints having continuous supports.
d) 2 layers of 19 mm lumber with joints staggered, or
e) 38 mm lumber.
NOTE that mineral wool, or insulation of any type, is not included in this list,
Why is insulation not listed as a fire block material?

12. BC Building Code Fire Block Requirements
Insulations, including fiberglass and mineral wool , are porous materials that will allow air, smoke and flames to pass through them, and, when exposed to heat or flame, they will shrink which could allow them to fall out of place before the required 15 minutes mentioned in Sentence (1) of the BCBC.
The appendix notes to Article mentions mineral wool for use when sealing penetrations of fire separation walls however, it must be pointed out that there are no known listings for penetrations of fire separation walls that allow mineral wool to be used without the addition of firestop calking on top of it.

13. BC Building Code Fire Block Requirements
Sentence (1) Requires that all walls that have vertical concealed spaces over 3 meters in height, or concealed spaces longer than 20 meters in horizontal length, must be fire blocked. (This includes spaces created by furring)
One example of fire blocking installed mid span of a wall that is over 3 meters in height.

14. BC Building Code Fire Block Requirements
There are several exemptions to fire blocking, all of which apply only to the heights of walls.
Clause d) of Sentence (2) exempts fire blocking in walls over 3 meters in height, if the complete wall is filled with insulation.
The exemptions in the above Sentence are not applicable to the requirements for fire blocking mentioned in any other code reference, such as required fire blocking at a dropped ceiling level.
This wall could be filled with insulation from top to bottom however,
fire blocking is still required, between the studs, at the dropped ceiling level.

15. Fire Blocking Do’s and Don'ts
BC Building Code Fire Block Requirements
Fire Blocking Do’s and Don'ts
Don’t – Allows air flow from the wall to interconnect with the horizontal space
Do - Rafter hangs down past top plate.

16. Fire Blocking Do’s and Don'ts
BC Building Code Fire Block Requirements
Fire Blocking Do’s and Don'ts
Do - Correct
Don’t – Allows air flow from a vertical concealed space to interconnect with the horizontal floor joist space

17. Fire Blocking Do’s and Don'ts
BC Building Code Fire Block Requirements
Fire Blocking Do’s and Don'ts
Don’t – Allows air flow from vertical to horizontal space
Do – Correct for trayed ceiling

18. Fire Blocking Do’s and Don'ts
BC Building Code Fire Block Requirements
Fire Blocking Do’s and Don'ts
Don’t – Allows air flow from the joist space to the concealed space surrounding the tub.
Cover the hole with drywall or OSB.
Do – Correct, only if approved fire block caulking or fire block spray foam is used.

19. Fire Blocking Issues & Solutions
BC Building Code Fire Block Requirements
Fire Blocking Issues & Solutions
Issue - Framing in front of
a basement foundation
Solution – Close off the gap between the foundation and the wall framing.

20. Fire Blocking Issues & Solutions
BC Building Code Fire Block Requirements
Fire Blocking Issues & Solutions
Solution – Install full height
fire blocking between the joists
Issue – Open wall to floor joist connection

21. BC Building Code Fire Block Requirements
While not specifically mentioned in the BCBC, the following materials are generally accepted for use as fire blocking of small holes.

22. BC Building Code Fire Block Requirements
Accepted Fire Block Spray Foam
and Caulking
Spray Foam
Caulking
Both are ok for fire blocking but neither are acceptable for fire “stopping”
Spray foam that is intended to be a thermal insulation is not an acceptable fire block material because it is extremely flammable and combustible.

23. Questions BC Building Code Fire Block Requirements
Do these fire blocking requirements apply to a crawlspace ?
Answer:
Yes, but normally only applies to holes through the actual sub floor.
Walls and joists in a crawlspace are rarely covered over with finishes, therefore, no “concealed” spaces exist within the crawlspace.
The key is, if a fire can be extinguished, without removing finishes, then it is not concealed.
In a Part 9 building, crawlspaces do not need to be divided into fire block compartments of any specific size unless a ceiling is installed.
In a Part 3 building crawlspaces are always limited in size when built with combustible construction.

24. Questions BC Building Code Fire Block Requirements
If a 2nd floor, wood joist cavity exceeds 20 meters in length, does that joist space, and others like it, need to be fire blocked ?
Answer:
Yes, horizontal concealed spaces, of any type, in which the material within them exceeds a FSR of 25, must be fire blocked at 20 meter intervals.
With the recent, large open designs of homes, this can be an issue to watch for in floor joist spaces and within attic spaces, especially when the attic has an attached garage as part of the design.

25. BC Building Code Fire Block Requirements
Example of a Large House Plan
Attic distance exceeds 20 meters, (exceeds 65’ 8” in length.)
Double Garage

26. www. NationalBuildingCodeInfo.com
BC Building Code Fire Block Requirements
Your Questions
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Presentation has not been prepared or approved by the Province of BC