Project: 8 UNITS TWO-STOREY APARTMENT
Location: Along Mercury St., Upper Quezon Hill, Baguio City, Philippines
CAPACITY & DIMENSIONS OF SEPTIC TANK
REFERRENCES:
RA 1378 : Revised Plumbing Code of the Philippines
Table B-2, Table B-3, Table B-5 & Table 7-2
PD 856: Sanitary Code of the Philippines
DAO-AO-2019-004
*_ Dimensions of septic tank
1./ Referring to table below:
Item Description Qty Units
2 UNITS APARTMENT *_Flow per day in TYPE OF ESTABLISHMENT see table B-2 gallons
*_Bedrooms in TYPE OF ESTABLISHMENT 2 per units
Total flow per day in gallons 1200 gallons per septic tank
NOTE: Each septic tank will cater 2 units (up and down). Total of 4 septic tank will be constructed on site location.
COMCOMPUTATION FOR THE SIZE OF SEPTIC TANK`
1.1 By selecting the minimum capacity of septic tank in gallons, identify the no. or type of dwellers based on no. of bedrooms/ units
see Table B-2
1.2 To calculate total drainage fixture units, collect all the existing fixtures drawn on the plan and sum up based on Table 7-2.
FIXTURE QTY DFU NOTE:
1. WATER CLOSET 1 4 Since the individual septic tank will cater 2 units,
2. KITCHEN SINK 1 3 multiply the Total DFU/unit by 2 to get the total
3. LAVATORY 1 1 dfu based on table B-2
4. FLOOR DRAINS 1 2
TOTAL 1O DFU/ UNIT x 2 = 20 DFU FOR 2 UNITS (See Table 7-2 )
1.3 Calculate the volume of septic tank based on the minimum capacity in gallons/liters.
1 cubic meter = 264.172 gallons
Capacity of septic tank= 1200 Gallons (Table B-2)
1200 gallons
v=
264.172 gallons
Volume= 4.5425 cuM
Formula:
Volume= L x W x H Note:
Airgap Liquid Depth
4.5425 cuM = Length ( ?) x .90 (Width) x 1.5 (Height) RA 1378
Plumbing Code 228.6 mm .60 m to 1.8 m
4.5425 m³ RA 856
L=
.90m x 1.5 m Sanitary Code 200 mm minimum of 1.2 m
Length = 3.36 meters
DIMENSIONS OF SEPTIC TANK NOTE:
Minimum of 2 Chambers based on RNPCP
OPTION 1: 3.2 m x 1.2 m x 1.5 m Municipalities requires 3 chamber
Volume= 5.76 cuM
OPTION 2: 3m x 1.2 x 1.5 m
Volume= 5.4 cuM
*For additional chamber, just add another length based on the 1/3 size of the original computed dimension.
Therefore: Each septic tank will have a dimensions of 4m x 1.2m x 1.5 m based on 3 chamber requirements.
Total of 18. 18 cubic meter of wastewater combined (referrence for the computation of Sewage Treatment Plant if required)
Note: Below 100 occupants will not require an STP (Referrence DAO-AO-2019-0047)
