Residential Class 4F & 4 Septic Systems (Guide Only)


Native soil percolation time for filter bed (5 - 50)

Number of bedrooms (1 - 10)

Plumbing fixture units (5 - 50)

Gross floor area m (10 - 600)

percolation time for mantle (5 - 15)

Filter height m (0 - 1.22)

Natural soil percolation for trench bed (0 - 50)

  Sunday, December 17, 2017 at 04:22:07
 User Design Data Input
  Class 4F Filter Percolation Rate is 10
  4 Bedrooms
  15 Plumbing Fixture Units
  150 m Gross Floor Area (1614.64 ft)
  Class 4F Mantle Percolation Rate is 7
  1 m Filter Height (3.28 ft)
  Class 4 Trench Percolation Rate is 20

Total Daily Design Flow Rates For Residential Occupancy "Q" (Litres per Day)

Design Criteria User Input

Litres/Day

Bedrooms up to 5 4 2000
Each bedroom over 5 add 500 0 0
Each plumbing fixture over 20 add 50 15 0
Each 10m (or part therof) of floor area greater then 200 m up to 400 m add 100 150 0
Each 10m (or part therof) of floor area greater then 400 m up to 600 m add 75 150 0
Each 10m (or part therof) of floor area greater then 600 m add 50 150 0

subtract the lesser of fixture units litres compared to floor area litres 0
Total Q = 2000

Septic Tank Size (minimum size required for this residential septic tank)
(Q) x 2 = Min. Tank Size 2000 x 2 = 4000 Litres

4000 Litres (879.9 Imp Gallons) (1544.5 US Gallons)

Percolation


(Filter T=10) Silty Gravely Sand

(Mantle T=7) Silty Gravely Sand

1.0 m (3.28 ft)raised filter system


Minimum filter area (if Q is less than 3000 than Q/75 else Q/50) Q/75=26.7 m (287 ft)
Minimum filter base contact area Q x filter T divided by 850 Q x filterT/850=23 m (248 ft)
Loading Area (mantle) Q divided by mantle T Q/mantleT=285 m (3068 ft)

Trench Bed (dug-in) System


Trench Percolation (T=20) Silty Sands
Pipe Length Required (min. 40 m) L=Q x Trench T/200 200.0 m (656 ft)


Septic Tank Minimum Clearance
  • 1.5 m (5 ft) from a structure
  • 1.5 m (5 ft) from a property line
  • 15 m (50 ft) from a well, lake, pond, reservoir, river, spring or stream

Distribution Pipe Minimum Clearance
(increased clearance by twice the bed height above grade. 2 x 1.0 = 2.0 m (6.56 ft)
  • 7.0 m (22.97 ft) from a structure
  • 5.0 m (16.40 ft) from a property line
  • 17.0 m (55.77 ft) from a well with a water tight casing to a depth of 6 m (50 ft)
  • 32.0 m (104.99 ft) from a well other than above
  • 17.0 m (55.77 ft) from a well, lake, pond, reservoir, river, spring (not potable) or stream

Pipe Requirements
  • minimum 4 in. trade size building sewer drain pipe from the structure to the septic tank
  • minimum 3 in. trade size distribution pipe for gravity flow systems (perforation holes face down)
  • distribution pipes have a uniform downward slope of 12 mm (1/2") over 3 m (10')
  • distribution pipe is set on top of at least 150 mm (6") of clear stone
  • distribution pipe has a clear stone cover of at least 50 mm (2")
  • the clear stone over the distribution pipe is covered with a permeable geo-textile fabric or untreated building paper

Filter Bed Requirements
  • distribution pipes should be evenly spaced over the surface of the filter medium no more than 1 m (3' - 3 3/8") apart
  • the unsaturated filter medium requires a depth of at least 750 mm (30") below the filter pipes and stone layer

Final Grading
  • no part of the sewage system should be under or within 3 m (10 ft) horizontally
    of 2.5 Kv or greater overhead conductor (hydro) wires
  • the finished grade must direct surface ground water away from the sewage system
  • 4:1 side slope stabilized against erosion. Projection from this bed design should be at least 4.0 m (13.12 ft)

Ontario Building Code
Go to PART 8 - SEWAGE SYSTEMS

    Sunday, December 17, 2017 at 04:22:07