Commercial contractor study guide
Do all septic tanks need to be constructed on site - ANS-No, only large ones
How large should the first compartment of the first septic tank be - ANS-At least 2/3 the
volume of the total 24 hour flow
Minimum septic tank size - ANS-1000 gallons
Tanks shall be constructed with what size and material tee, - ANS-4inch pvc, I let and
outlet
How deep should tees extend? - ANS-Into the liquid a minimum of 25% and maximum
50% depth
Where should the invert of the outlet tee be located - ANS-2inch below the invert of the
inlet tee
How long should a tank be - ANS-1 1/2 times the width
How many compartments should a tank have - ANS-2
Where should the tank compartment partitions be located - ANS-A point no less than
2/3 and no more than 3/4 the length of the tank from the inlet end
How should compartment partitions be constructed - ANS-So a pass thru hole equal to
or greater than the diameter of the inlet pipe is positioned below the liquid surface a
minimum of 25% to a max of 50% of total liquid depth
Should the walls and bottoms of a poured in septic tank be reinforced - ANS-Yes
How can reinforcing (pour in tank) be accomplished? - ANS-Using a minimum 6 inch by
6 inch no.10 gage welded Steel reinforcing wire or fibrous reinforcing conforming to
ASTM specifications
How should tank lids be reinforced? - ANS-Using 3/8 inch steel reinforcing rods which
shall be spaced 12 inch on center each way extending a minimum of 2 1/2 inch and a
max of 3 inch
, In general How much should a tank be able to withstand how much - ANS-A uniform
live load of 150 pounds per square foot in addition to all the loads to which an
underground tank is normally subjected
When should additional reinforcement be required - ANS-When loads on a concrete
tank are exceeded by subjecting it to a vehicular traffic or when the top of the tank is
placed deeper than three feet below the finished grade.
What is the minimum thickness of walls bottoms and lids of poured in tanks - ANS-4
inch
How should take lids be constructed - ANS-One or two pieces , securable, moveable
access openings located so the inlet and outlet tees can be readily accessed
Access openings min and max - ANS-Min 15 inch free space max 24
Tanks w more than 12 in cover must.... - ANS-Extend access openings to signing 12
inch of ground surface
Pour in place concrete comprehensive strength (how many days per square inch) -
ANS-28 day of 4000 lbs per square inch
How to eliminate honeycomb for concrete - ANS-Vibrating
Whose responsibility of quality of product - ANS-Contractor
Minimum filed line length - ANS-500ft w dosing device
Systems More than 1000 feet need what - ANS-Alternating pumps w alternating fields
When 2 piece dosing tanks are used what must they be joined by - ANS-Mastic butyl
rubber or other pliable sealant water proof corrosion resistant
Is there required length for dosing tank - ANS-No
Can dosing tank have single compartment - ANS-Yes
If partition is used in dosing tank, it must have how many holes, how larger and how far
above tank bottom - ANS-Two four inch holes no more than 12 inch above tank bottom
Do all septic tanks need to be constructed on site - ANS-No, only large ones
How large should the first compartment of the first septic tank be - ANS-At least 2/3 the
volume of the total 24 hour flow
Minimum septic tank size - ANS-1000 gallons
Tanks shall be constructed with what size and material tee, - ANS-4inch pvc, I let and
outlet
How deep should tees extend? - ANS-Into the liquid a minimum of 25% and maximum
50% depth
Where should the invert of the outlet tee be located - ANS-2inch below the invert of the
inlet tee
How long should a tank be - ANS-1 1/2 times the width
How many compartments should a tank have - ANS-2
Where should the tank compartment partitions be located - ANS-A point no less than
2/3 and no more than 3/4 the length of the tank from the inlet end
How should compartment partitions be constructed - ANS-So a pass thru hole equal to
or greater than the diameter of the inlet pipe is positioned below the liquid surface a
minimum of 25% to a max of 50% of total liquid depth
Should the walls and bottoms of a poured in septic tank be reinforced - ANS-Yes
How can reinforcing (pour in tank) be accomplished? - ANS-Using a minimum 6 inch by
6 inch no.10 gage welded Steel reinforcing wire or fibrous reinforcing conforming to
ASTM specifications
How should tank lids be reinforced? - ANS-Using 3/8 inch steel reinforcing rods which
shall be spaced 12 inch on center each way extending a minimum of 2 1/2 inch and a
max of 3 inch
, In general How much should a tank be able to withstand how much - ANS-A uniform
live load of 150 pounds per square foot in addition to all the loads to which an
underground tank is normally subjected
When should additional reinforcement be required - ANS-When loads on a concrete
tank are exceeded by subjecting it to a vehicular traffic or when the top of the tank is
placed deeper than three feet below the finished grade.
What is the minimum thickness of walls bottoms and lids of poured in tanks - ANS-4
inch
How should take lids be constructed - ANS-One or two pieces , securable, moveable
access openings located so the inlet and outlet tees can be readily accessed
Access openings min and max - ANS-Min 15 inch free space max 24
Tanks w more than 12 in cover must.... - ANS-Extend access openings to signing 12
inch of ground surface
Pour in place concrete comprehensive strength (how many days per square inch) -
ANS-28 day of 4000 lbs per square inch
How to eliminate honeycomb for concrete - ANS-Vibrating
Whose responsibility of quality of product - ANS-Contractor
Minimum filed line length - ANS-500ft w dosing device
Systems More than 1000 feet need what - ANS-Alternating pumps w alternating fields
When 2 piece dosing tanks are used what must they be joined by - ANS-Mastic butyl
rubber or other pliable sealant water proof corrosion resistant
Is there required length for dosing tank - ANS-No
Can dosing tank have single compartment - ANS-Yes
If partition is used in dosing tank, it must have how many holes, how larger and how far
above tank bottom - ANS-Two four inch holes no more than 12 inch above tank bottom
