4. Subdrain.

Question 0

2. What types of pumps are used in connection with sumps?

Answer 0

1. Sumps which receive the discharge of water closets and general plumbing fixtures are designed to handle solids.Pumps for this latter type of sump, commonly called sewage ejectors, normally have discharge outlets of 3 inches or more. Sumps which receive sewage should have airtight covers and should be properly vented.

Question 1

1. What type of electrically driven pump is used for pumping sewage?

Answer 1

Electrically driven sewage pumps are of the centrifugal type. Because of the solids, grit, etc., which the pump must handle, displacement-type pumps are not suitable.

Question 2

3. Sizes ejector pit?

Answer 2

1. The ejector pit shall be not less than 18 inches in diameter and 24 inches deep, unless otherwise approved.

Question 3

5. Capability of sewage (sump) pump or sewage ejector?

Answer 3

1. Ejectors shall be capable of handling spherical solids with a diameter of up to and including 2 inches.
2. ..Sum pumps shall be capable of handling spherical solids with a diameter of up to and including 1 inch.

Question 4

7. How are ejectors and sumps for large project called?

Answer 4

A sewage lift station and a storm water lift station.

Question 5

8. How are sump pumps sometimes called?

Answer 5

Bilge pumps.

Question 6

9. What will provide satisfactory pump cycling?

Answer 6

A minimum of five minutes of pump capacity between high and low water levels.

Question 7

10. The high and low water level in sum pit?

Answer 7

The high water level should be maintained at least 3 inches below the invert of the influent pipe so as not to flood the subdrain piping and to also provide air circulation throughout the system. The low level should always be maintained at least 6 inches above the bottom.

Question 8

11. When the ejector vent is connected to the building venting system it is necessary to convert the gpm discharge rate to an equivalent FU value to determine the additional load on the building system.

Answer 8

Assign 2 FU for each gpm of pump discharge for the conversion.

Question 9

12. The rate of discharge from a subsoil drainage from a subsoil drainage system?

Answer 9

1. 2 gpm for each 100square feet of area where the soil is sandy.
2. 1 gpm per100 square feet for clay soils.

Question 10

13. The rate of discharge where the runoff from paved and impervious areas is collected in a sump?

Answer 10

A value of 1 gpm per 24 sq. ft. can be assigned for locations where the annual rate of rainfall is 4 inches per hour.

Question 11

14. How is the head on a sump pump calculated?

Answer 11

It is good practice to select a capacity 1-1/4 times the maximum inflow rate to provide an adequate factor of safety for periods when the calculated maximum flow will be exceeded by unusual storm conditions.