© Presby Environmental, Inc., Maine Design & Installation Manual, June 2019 Edition -7-
Design Example #1 (Single Level):
Single Family Residence, (3) bedrooms (270 GPD), Soil Profile 4, 10% sloping
system to match existing terrain.
Step #1:
Pipe required from Table A = 210 ft. min.
Step #2:
Table B: minimum row spacing = 1.50 ft
Step #3:
M
inimum number of serial sections → 3 bedrooms x 90 GPD/bedroom = 270 GPD, which is less than 900
GPD. Only one serial section is required (basic serial system).
Step #4:
The site will accommodate a row length of 70 ft., which evenly divides the 210 ft. of pipe required from Step
#1 into 3 rows.
Step #5:
From Table C - a row length of 70 ft. requires 3 rows. The pipe layout width = 4 ft. at 1.5 ft. row spacing.
Step #6:
Because the system slope is not greater than 10% no system sand extension is required.
Illustration of Example #1, Basic Serial Distribution:
Design Example #2 (Single Level)
: Single Family Residence, (7) bedrooms (630 GPD), Soil Profile 8, design for a
12% sloping system as an elevated bed. Note: when the system slopes over 10% a 3 ft. system sand extension is
required down slope.
Step #1:
AES or ES pipe required from Table A = 517 ft. Take the pipe required for 6 bedrooms (443 ft.) and add an
additional (74 ft.) from the “Add’l Room” column.
Step #2:
Minimum row spacing from Table B = 1.50 ft. (row spacing for all single systems is 1.5 ft. minimum).
Step #3:
M
inimum number of serial sections → 7 bedrooms x 90 GPD/bedroom = 630
GPD, which is less than 900
GPD. One serial section is required (basic serial system).