Interceptors and Indirect Wastes 060403a

Question 1

What are the three main types of interceptors?

Answer 1

Grease, oil and solids

Question 2

Specialty interceptors are also available for specific tasks such as what?

Answer 2

Neutralizing traps used in conjunction with acid waste piping

Question 3

Which pipe type is more susceptible to grease build up because of its rougher inner surface?

Answer 3

Cast iron

Question 4

Normally, who specifies grease trap sizing?

Answer 4

Engineer

Question 5

What must never discharge into a grease interceptor?

Answer 5

Garburator

Question 6

What is the minimum amount of vents required on an oil interceptor?

Answer 6

2

Question 7

What are the 3 basic styles of grease interceptors?

Answer 7

• floor mounted
• recessed
• semi-recessed

Question 8

Of the 3 major types of grease interceptors, which is the most common?

Answer 8

Conventional

Question 9

Which type of grease interceptor requires the most maintenance?

Answer 9

Conventional

Question 10

What is the process for sizing a grease interceptor?

Answer 10

1. Calculate the capacity of each compartment in cubic inches
   
   • length x width x depth
2. Convert the capacity from cubic inches to US gallons per minute
   
   • divide by 231
3. Multiply by 0.75 for displacement

Question 11

What is the most common material used to construct a grease interceptor?

Answer 11

Epoxy coated steel

Question 12

Of the 3 styles of grease interceptors, which ones have an accessible drain opening?

Answer 12

Floor mounted and semi-recessed

Question 13

Which interceptor type is usually specific to a singular fixture?

Answer 13

Solids interceptor

Question 14

A drum trap shall not be used as a fixture trap unless what 2 requirements are met?

Answer 14

• required to serve as an solids interceptor

- access to servicing is provided

Question 15

What 3 codes must be met when interceptor design is concerned?

Answer 15

• shall be designed so that it can be readily cleaned
• be designed to that it does not become air bound
• shall not have a water jacket

Question 16

Equipment discharge waste from what equipment/fixture shall not be located upstream of an interceptor?

Answer 16

Equipment discharging waste with organic solids (garburator)

Question 17

Where a drain is provided in an elevator pit, the drain pipe that connects the sump to the drainage system shall have what?

Answer 17

A backflow preventer

Question 18

An interceptor with an effective water seal of not less than ___ mm is permitted to serve as a trap

Answer 18

38mm

Question 19

A cleanout shall be provided to permit the cleaning of piping downstream or upstream of an interceptor?

Answer 19

Downstream

Question 20

Vents on an oil interceptor should be located where?

Answer 20

On opposite ends of the interceptor

Question 21

How must vents connected to an oil interceptor be terminated?

Answer 21

Individually to outside air

Question 22

How are vents connected to an oil interceptor sized?

Answer 22

One size smaller than largest connected drain pipe but minimum 11/4”

Question 23

Oil interceptor vents that extend to open air must terminate at elevations that differ by at least how much?

Answer 23

12” (300mm)

Question 24

Oil interceptor vents must terminate at what height?

Answer 24

6 feet (2m)

Question 25

Grease interceptors are designed to have what % of air to what % of fluid?

Answer 25

20% air 80% fluid

Question 26

If an interceptor serves more than one fixture, what provision must be made?

Answer 26

Each fixture must be separately trapped and properly vented

Question 27

The current method of disposing of grease interceptor waste is what?

Answer 27

Composting it

Question 28

What is the only fixture that may be either directly or indirectly connected?

Answer 28

Drinking fountain

Question 29

What fixture may be indirectly connected to a storm drainage system?

Answer 29

Drinking fountain

Question 30

An air break must be what size?

Answer 30

Equal to the size of the waste pipe, but not less than 1” (25mm)

Question 31

What is the minimum sized air break you may have?

Answer 31

1” (25mm)

Question 32

In a situation where fixtures require indirect connection on three or more storeys, what provision must be made?

Answer 32

The drainage pipe must extend through the roof independently

Question 33

A single fixture with two or more fixture outlet pipes may be directly connected to a indirectly connected branch that is no less than what size?

Answer 33

11/4”

Question 34

The most important part of an indirect connection is what?

Answer 34

The air break

Question 35

What type of interceptor uses a baffle?

Answer 35

Grease interceptor

Question 36

Indirect connections may not be located where?

Answer 36

In a crawl space

Question 37

A cleanout must be installed in what location for an interceptor?

Answer 37

Downstream

Question 38

What size is an 11/4” vent off an oil interceptor when it penetrates the roof to open air?

Answer 38

3”

Question 39

How many cubic inches are in a US gallon?

Answer 39

231

Question 40

What is the process for sizing an interceptor that is servicing multiple fixtures?

Answer 40

1. Determine flow rate from each fixture

2. Determine which has largest flow rate and add to it 50% of the second largest and 25% from all other fixtures