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Type III Construction
Lately we have been discussing different types of construction. So far we have covered the characterisitics of Type I and Type II construction. This is some really basic rookie school stuff, but it is so important to be able to identify these different building charaecteristics. We know that fire behavior is directly linked to the type of construction and the fuels invovled. It also plays a major role in determining our tactics as company officers and firefighters on the fireground.
So, a quick review of what we have covered so far:
Type I or Fire Resistive is protected, non-combustible construction. Typcially steel and concrete with it’s structural components protected with fire resistant materials to meet or exceed two hour fire ratings.
Type II or Non Combustible is just that, non combustible construction. It’s structural components are not protected by fire resistive materials, but can be sprinklered. These too are usually built with steel and concrete, similar to Type I construction but without the fire resistant protection.
On to Type III construction. Type III construction is also referred to as Ordinary construction and is very common in a great deal of our older downtown areas. It is not limited to those areas but this was the primary method of building during the early and middle part of the 20th century.
This type of construction is identified by masonry or brick exterior walls with wood joists and interior structural components. Type III construction is very rarely protected with sprinklers and they have concealed spaces. These buildings in many communities have been remodeled and altered due to the age and use of the building, so concealed spaces are a real concern.
During a fire the interior structural components are attacked and failure of these components can cause an exterior wall to fail at the same time. The joists, for example, will rest in the masonry or brick wall and may be used to support the exterior walls. When these joists fail or burn out, they can compromise the support of the exterior wall it is connected to.
Here are some pictures that show some Type III construction.
Take a look at your area and determine where your different types of construction are. Discuss and plan for fires at those buldings and how you would operate at each one. What are some different challenges each pose for you as a firefighter or company officer operationally?
Train hard and remember, master the basics.
Replies to This Discussion
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Permalink Reply by John Crabbe on
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Perhaps important to note, that just because the exterior may have brick, it doesn't mean the building is a type III. There are many buildings today that are actually type V, wood frame construction, with brick veneer. Type V with a brick veneer, typcially the bricks are all the same direction.
One way to tell if the building is actually a type III is to look at the brick courses, you will see the courses change direction about every 5 rows. There will be about 5 rows of bricks going in the same direction and then a row where the bricks ends are facing out, then another row of 5 and then switch etc. This is for structural support.
A Type III construction, the masonry walls should be able to be supported by themselves, for the most part, meaning there isn't a dependancy on interior structural members. This is why many Type III buildings can be gutted and renovated so often, thus creating many void spaces as mentioned. Whereas a Type V with brick veneer, the veneer must rely upon the wood structure in order to stay supported.
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Permalink Reply by Jason Hoevelmann on
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Those are great points and I will appreciate the comments. I will highlight the difference between the brick in regards to ordinary and wood frame. Thanks again.
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Permalink Reply by jorden caldwell on
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john also you can tell the difference in veneer and true brick wall because a true brick wall has a soldier course on them where bricks are staggered off
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Good note as well.
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