# 704.1 Slope of Horizontal Drainage Piping



## Mech (Jun 22, 2016)

2009 IPC

*704.1 Slope of horizontal drainage piping.* Horizontal drainage piping shall be installed in uniform alignment at uniform slopes. The minimum slope of a horizontal drainage pipe shall be in accordance with Table 704.1. 


What is meant by "uniform alignment"?  Does it mean the pipe must be installed parallel and perpendicular to the building walls (assuming a rectangular building?)


I have underground piping running horizontally the length of the building. At point A, it turns 90 degrees (using 45 deg elbow and wye w/ cleanout) for 11 feet along the building width, and then turns 90 degrees, at point B, back to its original direction along the building length.  The owner is concerned about blockages and would rather replace the 90 degree direction change with a pipe running 45 degrees diagonally from Point A to Point B.  Is this allowed?  If so, is there a maximum length for this 45 degree angled section of pipe?  If it makes a difference, this is process sanitary waste in a commercial bakery facility, not for the domestic sewage.

Thanks


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## ICE (Jun 22, 2016)

706.3 Horizontal to Horizontal. Horizontal drainage lines
connecting with other horizontal drainage lines shall enter
through 45 degree (0.79 rad) wye branches, combination
wye and one-eighth bend branches, or other approved
fittings of equivalent sweep.

I have always held that uniform alignment means without dips and sags that will trap water or solids.


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## north star (Jun 22, 2016)

*$ = $*

From the `09 IPC, Section 708.3.3 requires a Cleanout
fitting to be installed in drainage piping greater than 45
degrees, or more.

Section 306.3 requires drainage piping to be installed
and properly "aligned" in the drainage piping trench.

The whole idea is to move the wastes from the point
of collection to the sanitary sewer system without any
points where it might hang up, ...slow down or speed
up, or stop !..........Installing 90 degree fittings as you
describe will require multiple Cleanouts, and all of the
Cleanouts must be accessible [* RE:* Section 708.9 ].

Installing 45 degree fittings, rather than 90 degree
fittings, would [  IMO  ] provide a system with less
of a potential for clogging.

Also, as the Tiger has mentioned, ...there should
not be any "dips or sags" in the piping that would
be a potential for clogging  [  *RE:* proper
installation within the drainage piping trenches,
Section 306.3  ].


*$ = $*


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## steveray (Jun 27, 2016)

Agree with ICE on that...Uniform alignment means workmanship in my opinion. Not square to the world. Every horizontal tie in to a drainage pipe should enter at a 45 (wye)as you cannot use San tees lying down for drainage connections


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## Francis Vineyard (Jun 29, 2016)

north star said:


> !..........Installing 90 degree fittings as you
> describe will require multiple cleanout



Further information from the code commentary. 


*708.3.3 Changes of direction. *Cleanouts shall be installed
at each change of direction greater than 45 degrees (0.79
rad) in the _building sewer_, _building drain _and horizontal
waste or soil lines. Where more than one change of direction
occurs in a run of piping, only one cleanout shall be required
for each 40 feet (12 192 mm) of _developed length _of the
drainage piping.

Commentary; "Earlier editions of the code required installation of a cleanout at every change in direction.  This section permits a single cleanout to serve up to 40 ft. of developed length of drainage pipe, regardless of the number of changes in direction that occur within that developed length.  This provision takes into consideration that modern drain-cleaning equipment can easily pass through fittings over this distance and that technological advances in the manufacturing of pipe and fittings have improved flow characteristics and decreased the likelihood of stoppages."

Of course it could depend on the flow of the bakery "process santary waste".


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## ICE (Jun 29, 2016)

Francis,
My code is substantially different than yours.  What code does you AHJ enforce?


2014 California Plumbing Code Based on the 2013 CPC and 2012 UPC
707.0 Cleanouts.
707.4 Location. Each horizontal drainage pipe shall be
provided with a cleanout at its upper terminal, and each run
of piping, that is more than 100 feet (30 480 mm) in total
developed length, shall be provided with a cleanout for
each 100 feet (30 480 mm), or fraction thereof, in length of
such piping. An additional cleanout shall be provided in a
drainage line for each aggregate horizontal change of direction
exceeding 135 degrees (2.36 rad).
Exceptions:
(1) Cleanouts shall be permitted to be omitted on a horizontal
drain line less than 5 feet (1524 mm) in length
unless such line is serving sinks or urinals.
(2) Cleanouts shall be permitted to be omitted on a horizontal
drainage pipe installed on a slope of 72 degrees
(1.26 rad) or less from the vertical angle (one-fifth
bend).
(3) Excepting the building drain and its horizontal
branches, a cleanout shall not be required on a pipe or
piping that is above the floor level of the lowest floor
of the building.
(4) An approved type of two-way cleanout fitting, installed
inside the building wall near the connection between
the building drain and the building sewer or installed
outside of a building at the lower end of a building
drain and extended to grade, shall be permitted to be
substituted for an upper terminal cleanout.


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## steveray (Jul 1, 2016)

UPC is way tougher than IPC....


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## HForester (Jul 24, 2016)

The 2015 IPC has a completely updated cleanout section (same update for the 2015 IRC)


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