Interceptors and Indirect Wastes 060403a Flashcards
What are the three main types of interceptors?
Grease, oil and solids
Specialty interceptors are also available for specific tasks such as what?
Neutralizing traps used in conjunction with acid waste piping
Which pipe type is more susceptible to grease build up because of its rougher inner surface?
Cast iron
Normally, who specifies grease trap sizing?
Engineer
What must never discharge into a grease interceptor?
Garburator
What is the minimum amount of vents required on an oil interceptor?
2
What are the 3 basic styles of grease interceptors?
- floor mounted
- recessed
- semi-recessed
Of the 3 major types of grease interceptors, which is the most common?
Conventional
Which type of grease interceptor requires the most maintenance?
Conventional
What is the process for sizing a grease interceptor?
- Calculate the capacity of each compartment in cubic inches
- length x width x depth
- Convert the capacity from cubic inches to US gallons per minute
- divide by 231
- Multiply by 0.75 for displacement
What is the most common material used to construct a grease interceptor?
Epoxy coated steel
Of the 3 styles of grease interceptors, which ones have an accessible drain opening?
Floor mounted and semi-recessed
Which interceptor type is usually specific to a singular fixture?
Solids interceptor
A drum trap shall not be used as a fixture trap unless what 2 requirements are met?
- required to serve as an solids interceptor
- access to servicing is provided
What 3 codes must be met when interceptor design is concerned?
- 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
Equipment discharge waste from what equipment/fixture shall not be located upstream of an interceptor?
Equipment discharging waste with organic solids (garburator)
Where a drain is provided in an elevator pit, the drain pipe that connects the sump to the drainage system shall have what?
A backflow preventer
An interceptor with an effective water seal of not less than ___ mm is permitted to serve as a trap
38mm
A cleanout shall be provided to permit the cleaning of piping downstream or upstream of an interceptor?
Downstream
Vents on an oil interceptor should be located where?
On opposite ends of the interceptor
How must vents connected to an oil interceptor be terminated?
Individually to outside air
How are vents connected to an oil interceptor sized?
One size smaller than largest connected drain pipe but minimum 11/4”
Oil interceptor vents that extend to open air must terminate at elevations that differ by at least how much?
12” (300mm)
Oil interceptor vents must terminate at what height?
6 feet (2m)
Grease interceptors are designed to have what % of air to what % of fluid?
20% air 80% fluid
If an interceptor serves more than one fixture, what provision must be made?
Each fixture must be separately trapped and properly vented
The current method of disposing of grease interceptor waste is what?
Composting it
What is the only fixture that may be either directly or indirectly connected?
Drinking fountain
What fixture may be indirectly connected to a storm drainage system?
Drinking fountain
An air break must be what size?
Equal to the size of the waste pipe, but not less than 1” (25mm)
What is the minimum sized air break you may have?
1” (25mm)
In a situation where fixtures require indirect connection on three or more storeys, what provision must be made?
The drainage pipe must extend through the roof independently
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?
11/4”
The most important part of an indirect connection is what?
The air break
What type of interceptor uses a baffle?
Grease interceptor
Indirect connections may not be located where?
In a crawl space
A cleanout must be installed in what location for an interceptor?
Downstream
What size is an 11/4” vent off an oil interceptor when it penetrates the roof to open air?
3”
How many cubic inches are in a US gallon?
231
What is the process for sizing an interceptor that is servicing multiple fixtures?
- 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
