bearing it non bearing walls for Tables 602 and 602?
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Jonathan, it's essentially one of those "whichever is greater" situations. According to Table 602 (comment a), load bearing walls shall also comply with the fire resistance ratings of table 601". Therefore if your exterior wall is load bearing, it should have the fire resistance rating of either table 601 or table 602. Whichever is greater. I hope that helps!
Relevant chapter here: https://codes.iccsafe.org/content/IBC2018/chapter-6-types-of-construction
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hi benjamin
thanks for the answer here. apologies for the admittedly scatter-brained presentation. it is a lot if information and it seems it is all scattered to the four winds. so trying to drill down on something specific like this which should in reality be quite practical is sort of rather chaotic for a lot of testers.
can i ask you this please with the understanding that i will be re-reading then code here in a coupe of days?
it seems to me there was a section in these two charts that required you to make a determination of whether a wall was load-bearing or not load bearing. and in my recollection at least the rating in the code would depend on which function this wall performed. load bearing or not load bearing.
meaning if i show you a plan with four walls on it (or a fable roofed structure or whatever) you would have to assume the walls were load bearing to make a determination. or assume that they were not load bearing. since it gives a value for load bearing or not load bearings
and you would have to do this before comparing two values since at least one of the values would be dependent upon what function the wall performed.
i see here i discussed this ruth david but i think the link may be scrubbed since i can’t access some of the old posts on here. i could post a screenshot i suppose but i think you have to upload to ftp to do this.
anyway, don’t you have to determine load bearing or not load bearing before you can get any value i guess is what i am asking. -
Jonathan, my short answer to your question is yes. You’d need to know load bearing or not. However, step outside the context of the ARE’s. In a real world situation you would know whether a wall you designed was load bearing. If a question came up on the exams asking you to determine the fire separation rating, they would likely give you all the relevant information like “load bearing” or not. Hope that helps.
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hi benjamin.
thanks again. this code expertise is helpful.
i guess this is kind of a theme for these exams but i would like to ask what to do if you find a question “cognitively confusing”.
i mean - in this chart if you /don’t/ see a literal statement about whether the wall is load bearing it not - i mean do YOU NEED TO KNOW if the wall is load bearing or not in this chart to get a correct answer? i mean don’t you need to know if it is load bearing or not to get at least one of the two values to compare? i am saying if you DON’T know if an exterior wall is load bearing or not you cannot get one of the two values to compare because you don’t know which value - the load bearing one or the non load bearing to choose.
if you are to compare A to B and to find B you need to choose between a higher value B1 (load bearing) or a lower value B2 (non load bearing) to be able to compare A to “B” how can you do this problem set?
or are you supposed to get A then skip the fact you don’t know if it is load bearing and get B1 and B2 and then compare A to B1 and B2 and choose the highest value even though you don’t know whether B1 or B2 is valid i guess is what i am asking. -
Jonathan and Benjamin,
I had a run-in with the Division of the State Architect (DSA) here in California regarding an unrelated code interpretation issue relating to this section, so I know my way around it VERY well.
Ben's initial response stated that it is "this or that", but that is not always the case, and it is important to first understand the purpose of each table to truly internalize why they are different.
The row in Table 601 FIRE RESISTANCE RATING REQUIREMENTS FOR BUILDING ELEMENTS > Bearing Walls > Exterior - relates directly to exterior bearing wall rating. The purpose of this table row is essentially to protect a building from collapse in the event of a fire, and to preserve lives within the structure long enough for rescue (by stopping the spread of fire from exterior to interior, or to structural elements).
Table 602 FIRE RESISTANCE RATING REQUIREMENTS FOR EXTERIOR WALLS BASED ON FIRE SEPARATION DISTANCE relates to Exterior walls within the fire separation limits. All of your exterior walls that are located within fire separation limits regardless whether or not they are bearing. The purpose of this section is stop the spread of fire from building to building, or from from your building to adjacent properties.
So yes, you do need to meet the minimum requirements for both, but in some cases your exterior walls may not be bearing, and in some cases they are.
If you have an exterior wall (think curtain wall) that is not bearing, and the building is not too close to any other structures or property lines that would trigger table 602, then you need only be concerned about Table 601. However, if that wall IS within the fire separation distance limits, it would have to be of rated construction per Table 602, and then you would have to consider both tables and take the higher rating.
In this example, let's assume a Type V structure that is just a rectangle, as depicted, and the exterior walls are bearing. In table 601 it states Type V A requires a 1 hours exterior wall rating, and 0 for Type V B.
If this Type V building is B, you do not require fire ratings on the walls per Table 601, but you will per table 602 based on its distance away (like you see above).
If the building is Type V A, you will require a minimum of 1 hours rating on exterior walls, regardless the distance, per table 601, but still subject to the requirements of table 602. In the example above, the most-distance building requiring 0 hours would then need a 1 hour rating per table 601, the middle remains unchanged as both tables 601 and 602 calls for 1 hours, and you would need a 2 hour rating in the closest configuration per Table 602.
I hope this is clear, and helpful. Good luck Jonathan!
Kevin Griendling, AIA
http://xQ.intersectartsstudio.com
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hi kevin
i THANK YOU for your input here and i will look forward to studying this documentation.
in the interest of time.
1. what is the best way to contact you external to here? linked in? email? website (somewhere specific on the websites?). 2. dumbing this topic down a bit for obvious reasons. if you find yourself in a “cognitive quandary” with these TWO charts for testing or problem set purposes - should you A. just ASSume the values for B1 and B2 will be lower than the value for A so that A will override the fact you cannot makes a determination about B1 or B2. meaning this seems like the only “logical way” you could resolve the missing information or B. the fact you don’t think you know whether it is load bearing is user error and the problem solver needs to revisit the stated problem set since anything involving these charts NECESSARILY means you need to know the data to find two values to compare (so you can choose the most restrictive)? or
C. you may have missed “geometrically cognitive” information in the drawing like the fact that fable end walls are generally not load bearing or that there may be very teeny tiny text you old eyes missed (so take off your glasses and put your eyeballs closer to the screen).
thoughts...? -
I admit I am thoroughly confused by your line of questioning. I think you may be overcomplicating it, and overpreparing for scenarios you will NOT encounter. My word of advice is to look forward to what you believe you WILL encounter, and use logical reasoning to make an attempt at working through something unexpected that comes up.
If vision is that much of a concern perhaps you can approach NCARB about special accommodations.
I will try to attempt to answer your questions though.
A. Don't assume anything about these charts. There is no rhythm to which one is lower or higher in any algebraic pattern. You just need to know how to read the chart.
B. I am not sure this statement included a question, so I don't know how to respond. The question SHOULD clearly indicate all information necessary to properly answer the question though...
C. Remember that these exams are designed to test if you are minimally competent to protect the health, safety, and welfare of the general public, and the exam isn't trying to trick you. A question that uses a structural condition that is questionably structural, would not be a very good question. NCARB's item writers aren't perfect or infallible, but your job is to prepare for what you most likely will encounter, which is that 95%+ of the questions should be of sufficiently high quality for you not to have to worry about "semantics".
You can reach me at kg@intersectartsstudio.com
Kevin Griendling, AIA
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hi kevin.
i think what i was driving at with the glasses is that these exams are not “graphically coherent”. we could discuss this more. but essentially if the stated problem set in the text does not provide a straightforward question, then testers find themselves searching what are oftentimes confusing (or difficult to access or to view) drawings.
this is a repeated theme in these exams. totally IMHO of course. but i think it is impossible to state otherwise personally.
so what i am asking here at base condition is whether you should EXPECT to see the TEXT state “the north (or south or whatever) exterior wall is /isn’t load bearing” when determining fire rating. yes or no? IS THIS something you would/should expect in this problem set?
i mean with your help we HAVE concluded with your help that it is NECESSARY REQUIRED FACT to properly answer this question. you need it so you can determine the second rating.
QA. would you expect it to be stated in the problem or problem set?
B. if it is NOT stated explicitly - would you expect it to be stated in text in the drawing?
C. if it is not stated in the text in the drawing then it seems to me you are a point at which you are trying to ascertain structural meaning from geometry or from poche. and i am not sure there us any significance to a POCHEED WALL on these exams. so it seems you need to know load bearing or not STATED IN TEXT. -
Jonathan,
Some more advice that I think should help alleviate your concerns. In our profession we use both graphic, and written communication to build buildings. You cannot predict what format this exam will test. You may only get a drawing, you may only get a verbal description. Focus on understanding the tables and their implications and how to be an effective architect and you will be simultaneously preparing for both!
Have a great Thanksgiving weekend,
Kevin Griendling, AIA
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kevin,
this is a specific question related to the graphic content (or lack thereof) in the exams.
the question is if you should be expected to discern load bearing or not load bearing in the GRAPHIC CONTENT or if you should see it STATED IN WORDS.
one of the massive problems in this exam is the non-professional presentation of the graphic content.
so as a specific example i am saying you CANNOT answer a question related to these tables absent a TEXTUAL STATEMENT (i.e. it has to be stated in text).
i am specifically stating that you CAN NOT and SHOULD NOT plan to see a graphic “load bearing” or “non load bearing” graphic representation. because it is not there.
so this fact has to be stated in text.
i mean what would YOU EXPECT TO SEE to designate load bearing or non load bearing in this exam is maybe the question you can answer??
you are saying testers should be able to discern a wall is load bearing or not load bearing in these exams apparently? if so what is the graphic designation that would indicate this? -
Jonathan,
I am saying you can't predict it.
Theoretically you are correct in most cases, but as an oversimplified example, if a floor plan shows just a rectangle and no columns or other walls, you would have to assume those walls are load bearing. Be prepared for both methods of evaluation.
Kevin Griendling, AIA
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hi kevin. thanks for a direct response. and also for the expertise you are kind enough to supply. i can’t discuss these things floating out in space as some kind of professional standard of attention or competence.
so bottom line what we are saying is that as it relates to 601 and 602 you need both values to compare - in order to choose the more restrictive value.
and that one value - absent any of the convoluted text explaining this - is derived by ASSuming a line drawing of a rectangle or square shows four load bearing walls. basically. -
kevin, benjamin.
please.
following kevin’s example here. 1. Table 601 Type V A (sprinklered) -> 1 hour. Type V B (unsprinklered) -> 0 hour. we don’t need to know occupancy for exterior bearing walls. we just need construction type and if it is sprinklered.
2. now. as far as i can tell you only move to 602 IF your exterior walls are non-load bearing. you have no need to go to 602 unless you have non-load bearing walls. so presumably if it states load bearing walls you use only 601. or even if it states nothing you are supposed to just use 601 since you don’t have enough info to make a decision to go further.
ALSO. i’m not following kevin’s example. he appears to move to 602 and provides values for 5’ @ 2 hr and 9’ @ 1 hr and 35’ @ 0 hr. well i am not seeing how to read this chart. he appears to come to these numbers without any statement about occupancy. which is the top row. Q1. how can you make a determination about fire rating in exterior non-loadbearing walls without specifying occupancy? Q2. how do you make a determination about construction Type V A? i don’t even see it listed. it is included under “others” as a catchall category for each fire separation distance? Q3. if that is the case then <5’ shows an ALL category for Type V A and Type V B which will be 3 hour, 3 hour or 1 hour depending on occupancy for EXTERIOR NON-LOAD BEARING walls. the <10’ example will result in either 2 hour or 1 hour rating - again for exterior walls. and 30’ or over does result in 0 hours across the board but just because all categories show 0 hours where the other fire separation distances do not in fact show this.lastly, i read these charts as independent. and if you read note A it seems to me 602 would more clearly be titled “Exterior non-load bearing walls...”
but either way you need to know if an exterior wall is load bearing or not. and if it is not you need the occupancy to be able to read the chart. -
i see here 692 will override 601 for exterior bearing walls in some cases. i wonder if anyone already did the work to see which specific cases. can’t be that many.
also, you do appear to need construction type to read 602. and you do need to make some type of sssumption about bearing or not bearing if you are reading tables 601/692 to determine exterior wall fire rating. if it is a bearing wall it will have one value. if non load bearing it will have another value. so presumably a question about fire ratings for exterior walls will have to have a text description of the structural status of the wall...
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