# Knee clearance measurment under lav?



## Yikes (Dec 2, 2010)

Please take a look at page 2 of this pdf link for a sink mounting diagram that Kohler claims is the "recommended ADA installation":

http://www.us.kohler.com/onlinecatalog/pdf/105058_4.pdf

Notice that it looks like the required knee clearance (the shaded area) is actually going INSIDE the bottom of the porcelain sink.  What??!!

We have a client who they achieve the minimum required clearance where your knees would actually go (to the left and right), and at the main part of the bowl.  However, at the front+center of the bowl, the little porcelain bump-out from the overflow drain is sinking into the shaded area of the sketch.

The sink sketches in the ADAAG handbooks and in the California Bldg. Code use the words "knee clearance" but do not make a specific distinction as to where knee clearance occurs:

left and right of the lav

or left+ right+ CENTER of the lav?

Does the installation as described above represent a reasonable interpretation of CBC Title 24 / ADAAG?


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## mark handler (Dec 2, 2010)

The knee clearance space must be free of  equipment or obstructions.

Knee clearance that is at least 27 inches  high, 30 inches wide and 19 inches deep shall be provided underneath sinks.

*So no, the manufactures lit does not show compliance with the (CBC) code *


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## Yikes (Dec 3, 2010)

So Mark, you are saying that the words "knee clearance" mean not only the knees, but the _space between the knees_, correct?

If that is the case, then looking at the spec sheet tells me there is NO scenario in which this Kohler lav as-is could ever comply with title 24, or ADAAG for that matter.

Then only fix (short of buying a different sink) would be if they added some kind of apron on the front edge that would allow the 8 inch deep measurment to be taken further away from the overflow drain.


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## mark handler (Dec 3, 2010)

*Knee clearance that is at least 27 inches high, 30 inches wide *

THIS IS THE EXACT WORDING IN THE CBC

YOU CANNOT TELL SOMEONE THEY NEED TO SPREAD THEIR LEGS TO USE THE SINK


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## High Desert (Dec 3, 2010)

Some in a wheel chair are incapable of maneuvering their knees.


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## Gene Boecker (Dec 3, 2010)

*Hold on thar, Babalouie!*

The illustration shows the knee clearance extending into the sink overflow - not the basin itself. This is acceptable design.

Read the last sentence in Section 606.2 of the A117.1. This is also stated in exception #6 to Section 606.2 of the 2010 ADAAG.

The old ADAAG refers to Figure 31 which doe snot show an overflow in the front of the basin so the issue is up to interpretation. However, discussions with the Access Board indicate that this was always the intent since the overflow dip is centered under the basin and hence located between the knees.

btw: California is still using the language similar to that in the old ADAAG so the interpretation is up to the local officials.  The state does not offer interpretations of the text.  It is interpreted locally.  The hope is that with the new ADA Standards, the language will be changed to address that since the state is seeking certification and to not change would be counterproductive.


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## mark handler (Dec 3, 2010)

On this issue, There is no interpretation needed, the text is clear.


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## Gene Boecker (Dec 3, 2010)

mark handler said:
			
		

> On this issue, There is no interpretation needed, the text is clear.


I'll beg to differ - only to the extent that the question of an overflow is not addressed.  To that extent, it is ambiguous.

Yes, the language regarding the positioning says that the clearance under the lavatory must be "28 inches [to] a point located 8 inches back from the front edge."  However, it does not say that this space must be 30 inches wide.  That requirement is for the wheelchair "clear floor space" in the following section.  Re-read it: 1115B.4.3, items 2 AND 3.  You do not get a mixture of the two in the same section.  Thus it is still interpretive whether the overflow dip must be included in the clear space under the lavatory.


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## mark handler (Dec 3, 2010)

Gene Boecker said:
			
		

> I'll beg to differ - only to the extent that the question of an overflow is not addressed.  To that extent, it is ambiguous.  Yes, the language regarding the positioning says that the clearance under the lavatory must be "28 inches [to] a point located 8 inches back from the front edge."  However, it does not say that this space must be 30 inches wide.  That requirement is for the wheelchair "clear floor space" in the following section.  Re-read it: 1115B.4.3, items 2 AND 3.  You do not get a mixture of the two in the same section.  Thus it is still interpretive whether the overflow dip must be included in the clear space under the lavatory.


Knee clearance that is at least 27 inches high, 30 inches wide

THIS IS THE EXACT WORDING IN THE CBC

There is no interpretation needed, the text is clear


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## Yikes (Dec 3, 2010)

mark and gene - thank you both for your continued input, this is very helpful.  I tried to see if there was a clear discussion of the width of the knee clearance in the CBC.

In reading CBC 1115B.4.3, item #2 for lavatory clearances says:

"... with a vertical clearance measured from the bottom of the apron or the outside bottom edge of the lavatory of 29 inches (737mm) reducing to 27 inches (686mm) at a point located 8 inches back from the front edge."

I did not see a mention of width in this paragraph.

In the (separate) next paragraph #3 it states:

"A clear space 30 inches by 48 inches complying with section 1118B.4 shall be provided in front of the lavatory to allow forward approach.  Such clear floor space... shall extend a _maximum_ of 19 inches into knee and toe space underneath the lavatory.  See figure 11B-1D, Knee Clearance."

Here, the extension of the 30-inch width occurs at a _maximum_ of 19 inches depth, so in theory, if you extended the 30x48 space only 2-3 inches under the lav, you would be less than the expressed maximum, and therefore in compliance with CBC.

This paragraph #3 appears to connect-the-dots between the 30" wide x 48" long clear approach space and the knee clearance illustration 11B-1D, but again, it is expressed as a maxmimum (not minimum) encroachment into the lav space.


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## Yikes (Dec 3, 2010)

FYI, this is a new public school project that was already plan checked, approved, built and inspected via the DSA Access Compliance Unit.  DSA even specifically reviewed the cut-sheet of the Kohler lav linked in this thread.  The owner decided to hire an additional accessibility consultant, and that's who had concerns about the lav.


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