# Dimensional tolerances?  again!



## JPohling (Mar 7, 2014)

2013 CBC  Chapter 11B.  I have been asked questions numerous times about "acceptable construction tolerances".

*11B-104.1 Dimensions*.  Dimensions that are not stated as "maximum" or "minimum"  are absolute.

*11B-104.1.1. Construction and manufacturing tolerances*.  All dimensions are subject to conventional industry tolerances except where the requirement is stated as a range with specific minimum and maximum end points.

Once again this is not the type of language that is completely clear.   It is pretty easy to understand that the current dimensional requirement for the location of a WC is 17" minimum to 18" maximum.  This allows a 1" tolerance between the two stated dimensions and nothing above or below that range should be accepted.

The confusion comes into play when dimensions are specified as a single number and not a range.   For example, the lavatory height is specified to be 34" AFF  "maximum".  In this case there is no "stated range with specific minimum and maximum end points"  There is just a single number specified as a "maximum".  Same thing with the width of an accessible toilet stall.  60" wide "minimum".  It has always been my position that in these instances that the other number was implied and I would not accept a number either above a "maximum"  or below a "minimum".   So in the case of the toilet stall I assumed that the minimum 60"  was the bottom of the range and the maximum was infinity, or as large as you wanted to make it.  In the case of the lavatory it would be 34" maximum on the upper end of the range and 0" as the minimum  (in concept)  quite possibly there would be a roll under dim of 29" that would determine the true range minimum.

The very first scoping and technical requirement regarding dimensions does not seem to back this up.  *11B-104.1 Dimensions*.  Dimensions that are not stated as "maximum" or "minimum"  are absolute. That would leave me to believe that the dimensions that ARE stated with a "maximum" or "minimum"  are not ABSOLUTE, and would be subject to some kind of dimensional tolerance.

What do you all think?  Is it only dimensions that are specifically specified as a range with both a minimum and maximum end point that are not subject to some sort of construction tolerance?

If that is the case what is an acceptable construction tolerance for the height of a lavatory?   the width of a toilet stall?  the height of a dispenser?


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## mtlogcabin (Mar 7, 2014)

JPohling said:
			
		

> 2013 CBC  Chapter 11B.  I have been asked questions numerous times about "acceptable construction tolerances".


FYI

Although it was written in 2007 it does provide some interesting reading and recommendations to the design community on how to eliminate some of the dimensional problems that arise due to "construction tolerance"

http://www.designingaccessiblecommunities.org/policies/InitiativeonDimensionalTolerancesinConstruction.pdf


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## mark handler (Mar 7, 2014)

Short and concise

All dimensions are subject to conventional industry tolerances *except* where the requirement is stated as a range with specific minimum and maximum end points.


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## JPohling (Mar 7, 2014)

Darn!  I been mistaken this whole time.  So where are these "conventional industry tolerances" discussed or defined?   Do you have any rules of thumb?


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## ICE (Mar 7, 2014)

Not all dimension requirements are equal.  A stair riser gets more respect that a toilet stall.  Even various stair riser dimensions differ in importance.  For example the maximum height and the 3/8" tolerance from one to another aren't equally important.  So the fact that :butt's in wheelchairs can sue because a toilet stall is 59" when is should be 5' is ridiculous.

Some will say, "That's too stinkin bad, they had an opportunity to get it perfect and blew it". So please tell me where else in construction work is the bar set so high.  For that matter pick any job or profession with such strict adherence to dimensions.  If it doesn't have to go into outer-space, I just don't get it.


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## JPohling (Mar 7, 2014)

I agree,  but can they sue if that stall is 59.5"  or 59.75"  what is an acceptable construction tolerance that would stand up to scrutiny.


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## ICE (Mar 7, 2014)

JPohling said:
			
		

> I agree,  but can they sue if that stall is 59.5"  or 59.75"  what is an acceptable construction tolerance that would stand up to scrutiny.


For me, I would say that as long as an inspector approved it, it was within tolerance.  What are you comfortable with?

Did a dimension mistake made by a construction worker mean that thousands of dollars worth of partitions are junk?

Invoke a Green Code.  Think about how much energy, water and trees went into producing that stuff.  Is it to be tossed out so the carbon footprint can be doubled?

Are you convinced that a person can't maneuver because of a 1" mistake?  The guy in the chair will have to get in there with his Lufkin to figure out that it's missing an inch.

Then the conundrum arises, where does it all stop?

I know how it works for me but I don't expect anyone else to agree, therefor I'm okay, you're okay.

Please don't take umbrage at my remarks if you are a person that's confined to a wheelchair.  It is the thieves in wheelchairs that shade my approach to all of this.


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## nitramnaed (Mar 8, 2014)

A good example would be Right-of-way construction.  I had a contractor who tried to argue this when his 2% cross slope was off by a micron and the city official asked for a correction.  I tried to help him but discovered there are "Industry Recommendations" for a cross slope tolerance of +0.5% but this is not a "Industry Standard".  Official made them cut and replace.  Technology (Laser Level) is sometimes a dangerous thing.  :banghd


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## fatboy (Mar 8, 2014)

nitramnaed said:
			
		

> A good example would be Right-of-way construction.  I had a contractor who tried to argue this when his 2% cross slope was off by a micron and the city official asked for a correction.  I tried to help him but discovered there are "Industry Recommendations" for a cross slope tolerance of +0.5% but this is not a "Industry Standard".  Official made them cut and replace.  Technology (Laser Level) is sometimes a dangerous thing.  :banghd


WOW, I guess gone are the days of a 4' level, and figuring it from there. And, the codes came into being back in those days, I think they probably anticipated some tolerances...........they didn't anticipate microns.........


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## JPohling (Mar 10, 2014)

These are existing conditions in a high rise where several lavatory counters are at 43.5" AFF  and several accessible stalls are 59.5" wide.  I need to be able to let this building owner know if these are acceptable tolerances that will stand up to scrutiny if there were a lawsuit filed.  These have all been previously accepted by the jurisdictions inspectors.  Is a .5" tolerance defend able?  I understand that a lawsuit COULD be filed as the dims are not per the letter of the law, but the code does allow  "acceptable construction tolerances"  I just cannot seem to find out what these super secret tolerances are.


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## ADAguy (Mar 10, 2014)

"It" depends, how is the judge feeling that day? What is the expert wearing in court?

43.5" "is not" 34" max.!

1/2" in 60" vs 1/8" in 10' exceeds acceptable tolerance (translates into 1/16" in 5', no?


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## JPohling (Mar 10, 2014)

ooops my dumb error,  I ment the lav counter was at 34.5" AFF,  or .5" over the "max"


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## JPohling (Mar 10, 2014)

http://www.wichita.gov/Government/Departments/OCI/GuideDocuments/Acceptable%20Construction%20Tolerances.pdf

Found this, but it is old.  It accepts .5" tolerances


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## pete_t (Mar 10, 2014)

Similar but more inclusive from SF 2008.

View attachment 1024


AB014 San Francisco 2007.pdf

AB014 San Francisco 2007.pdf


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