© Presby Environmental, Inc., Maine Design & Installation Manual, June 2019 Edition -12-
16.0 Basic Serial Distribution (Multi-Level™)
Basic Serial Multi-Level™ systems can use AES or ES pipe and must conform to the requirements for single level
basic serial systems except:
a) Pipe requirements per
Table E
b) Row spacing per
Table F
c) All Multi-Level™ beds require venting. Upper and Lower Level Rows may be vented separately. If only a
single vent is used, it must be connected to the last row in the series on the Lower Level.
d) Multi-Level™ systems are limited to Soil Profiles 2, 4, 5 & 6.
e) For beds sloping over 10% the System Sand Extension must be 12 in. thick
f) The fill extension is measured from the AES or ES pipe (measured from the Upper Rows) before starting
the 4:1 side slope tapers.
g) A minimum of 6 in. of System Sand separates the Upper Level Rows from the Lower Level Rows
h) Effluent is delivered first to the Upper Rows, which then connects to the Lower Level Rows by way of a
Drop Connection.
i) The Drop Connection must pitch downward toward the Lower Level at least 2 inches.
Illustrations of Multi-Level™ Basic Serial Systems:
Illustration of sloping Multi-Level™ Basic Serial System:
17.0 Bottom Drain
A bottom drain is a line connected to the hole in the 6 o’clock position of a double offset adapter at the end of each
serial section or each row in a D-box Distribution Configuration which drains to a sump and is utilized to lower the
water level in a saturated system or to facilitate system rejuvenation.
1
0
'
M
IN
BOTTOM
DRAIN SUMP
SOM
E ROW
S
N
O
T
S
H
O
WN
VENT
4"Ø BOTTOM
DRAIN MANIFOLD
SOM
E ROW
S
N
O
T
S
H
O
WN
SOM
E ROW
S
N
O
T
S
H
O
WN
VENT
18"
LOCK OR BOLT
COVER CLOSED
BOTTOM DRAIN CONNECTED TO SIX O'CLOCK POSITION OF DOUBLE OFFSET ADAPTERS AT THE END
OF EACH ROW OR SERIAL SECTION. THE VENT MANIFOLD IS ATTACHED TO THE TWELVE O'CLOCK
POSITION OF THE DOUBLE OFFSET ADAPTER (OVER EACH BOTTOM DRAIN CONNECTION).
3'
VENT MANIFOLD - CONNECT ENDS OF ALL
ROWS OR ENDS OF ALL SERIAL SECTIONS
TYPICAL BOTTOM DRAIN APPLICATION
PAVEMENT
