Interpretation #7173
Published May 28, 2013
Original Request
- Code Version
- 2010
- Code
- PLUMBING
- Code Description
- Plumbing
- Chapter
- 11
- Section
- 1106
- Topic
- rain fall rate interpolation
Question
Is it the intent of the code to allow for interpolation of rain fall rates in table 1106.3 as it allows for interpolation in table 1106.2(1)?
Answer Published 05/28/2013 at 6:50 PM
No. If interpolation were to be permitted under Table 1106.3,
without a note expressly allowing it, what would be the
point of the notes associated with 1106.2(1) and 1106.2(2)?
Further, the hydraulics associated with horizontal and
vertical piping are different. Lacking background data
establishing unequivocally that the numbers in Table 1106.3
are linearly related, we must assume that they are not, and
linear interpolation should not be allowed.
without a note expressly allowing it, what would be the
point of the notes associated with 1106.2(1) and 1106.2(2)?
Further, the hydraulics associated with horizontal and
vertical piping are different. Lacking background data
establishing unequivocally that the numbers in Table 1106.3
are linearly related, we must assume that they are not, and
linear interpolation should not be allowed.
Commentary
The "interpolation" referred to in the footnotes of Tables
1106.2(1) and 1106.2 (2)is intended to permit different
sizes and shapes other than circular or rectangular pipes to
be used for vertical conductors. (See IPC proposal P95-07/08
for further explanation). There is no similar footnote in
Table 1106.3 because horizontal storm drainage is typically
circular pipe.