# fire rated walls construction types



## MARC (Nov 24, 2009)

TABLE 601

FIRE-RESISTANCE RATING REQUIREMENTS FOR BUILDING ELEMENTS

what exactly does a & b building element stand for under for example under type 1 or 2

Thanks for your help.


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## Bryan Holland (Nov 25, 2009)

Re: fire rated walls construction types

TYPE A = Protected Elements

Type B = Unprotected Elements

The term "protected" does not mean systems referenced in Chapter 9 of the building code such as fire sprinklers, etc., but does include fire resitive products used on structural elements.


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## mueller (Nov 25, 2009)

Re: fire rated walls construction types

From commentary-

Type I, II, III and IV construction are further subdivided

into two categories (A and B). Type A and B construction

are not defined in the code. The designations

simply refer to the hourly fire-resistance rating required

for the structural elements. A Type A designation

will have a higher fire-resistance rating for the

structural element than a Type B designation. Sometimes,

Type A and B are referred to as protected and

unprotected construction, respectively. Please note

this terminology does not refer to whether the building

is sprinklered.


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## cda (Nov 25, 2009)

Re: fire rated walls construction types

MY suggestion for this site is a """"frequently asked question"""" section.

And once a question is answered move it to the FAQ section!!!!!!!!!!


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## Examiner (Nov 25, 2009)

Re: fire rated walls construction types

Some people are confused about protected and unprotected construction.  Some even AHJ have the misconception that protected references the use of a fully automatic fire suppression system.  I just encounter a Building Official who thinks that Type II-A is protected using a fire suppression system (sprinklers) only.

Protected construction, designated as A in the various Construction Types, is the application of fire proofing of the structural components of the building and maybe some of the non-bearing walls.  Using protected construction allows a building to be larger than the same type building that is unprotected.  Sprinklers gives both A and B additional area and story heights.

Unprotected is construction that does not require the structural components to have some kind of fireproofing.  Again using sprinklers gives additional area and story heights.

Some Type I-B types may require fireproofing on some of its building components.


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## Gene Boecker (Nov 25, 2009)

Re: fire rated walls construction types

_*Generally*_. A & B stand for "with a fire rating" and "without a fire rating."  Except for Type I and II.  Those are both really the same thing (non-combustible everything) with different ratings because both IA and IB have ratings of 3- and 2-hours for the structural frame.  (And then IIA has a 1-hour rating - so they kinda run together.)


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## brudgers (Nov 25, 2009)

Re: fire rated walls construction types

The confusion of "A and B" with "spinklered and unsprinklered" is rooted in the way SBC table 500 was structured.

Protected and unprotected were treated as different construction types and area increases for sprinkelers were tabular rather than by calculation.


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## Mule (Nov 25, 2009)

Re: fire rated walls construction types

Another crazy thing is a designer can classify the building as a B but include fire protection for different areas and have fire sprinklers. A Walmart can be a Type V B!


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## brudgers (Nov 25, 2009)

Re: fire rated walls construction types



			
				Mule said:
			
		

> Another crazy thing is a designer can classify the building as a B but include fire protection for different areas and have fire sprinklers. A Walmart can be a Type V B!


Nothing wrong with that so long as it meets the requirements.


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## Mule (Nov 25, 2009)

Re: fire rated walls construction types

That's why I posted it. A few members may not be aware of it. I just realized this a few months ago.

Most of the time people relate Type V construction with residential. That was the reason for the comment. It still seems crazy but it is what it is!


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## brudgers (Nov 26, 2009)

Re: fire rated walls construction types



			
				Mule said:
			
		

> That's why I posted it. A few members may not be aware of it. I just realized this a few months ago.Most of the time people relate Type V construction with residential. That was the reason for the comment. It still seems crazy but it is what it is!


Type V does not *require* combustible construction.

Non-combustible buildings can be an are classified as Type V everyday.

There's no good reason to classify a building to a more restrictive type (unless percentage of construction cost is the architect's basis for compensation).


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## Examiner (Nov 30, 2009)

Re: fire rated walls construction types

I was once informed by the ICC that your minimum construction type is based on the Occupancy use group and the building area.  The Architect may choose a non-combustible construction for the building, say Type II-B but the actual area even after area increases would allow the building a lesser Construction Type, say Type V-B.

Why you would classify a building a lesser construction type than what it is to be construction of you may ask?  Because, lesser Construction Types usually are smaller buildings and can encroach closer to the property line before a rated exterior wall is required.

However, if the building is ever to be expanded then the actual Construction type will be needed information at that time to avoid a possible fire wall.

Type V Construction is combustible construction.  Their size and occupancy use may deem them to be Type V even though they are constructed as a Type II or some Construction type other than Type V.  It should be clearly noted on the drawings the minimum allowable Construction Type per Code and the Actual Construction Type that the building is constructed as.  The Architect may chose Type II over Type V due to structural spans required of the design exceed what combustible products would allow.

An Architect’s fee is usually based on the Cost of Construction but most that I have worked for do not choose one construction over another just to get their fee up.  Sometimes combustible construction is more expensive than non-combustible and you can weigh in the owner's possible savings on insurance also.  Usually the Owner gives the Architect a budget and building area they want which is usually more than the budget.  Owners always want more than they can get.


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## JBI (Nov 30, 2009)

Re: fire rated walls construction types

602.1.1 Minimum requirements.

A building or portion thereof shall not be required to conform to the details of a type of construction higher than that type, which meets the minimum requirements based on occupancy even though certain features of such a building actually conform to a higher type of construction.

602.5 Type V.

Type V construction is that type of construction in which the structural elements, exterior walls and interior walls are of any materials permitted by this code.

Forget about 'combustible' versus 'non-combustible', that is not the issue. Type V _allows_ but does not require combustible materials. It also allows the use of materials that have very low fire resistance (again does not require them), and has no requirements for protecting the structural elements. In other words, it is *cheaper* to build. That's the reason


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