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All Categories  > Interceptors  > MI-G-RL Series - Replacement Lids for Ml-G Series Grease Interceptors
MI-G-RL Series - Replacement Lids for Ml-G Series Grease Interceptors

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Specification: MIFAB MI-G-RL Series (specify Model #) of replacement lids are manufactured from ¼” thick diamond platepowder epoxy coated steel.

Function: Used to replace the lid of an existing MI-G grease interceptor.

No. of Lids


Item Name

MI-G-RL Series Replacement Lids for MI-G Series Grease Interceptors


MI-G-RL Series Replacement Lids for MI-G Series Grease Interceptors

MIFAB Design

MIFAB is a recognized industry leader in the field of interceptor design and production.
As such, we offer a variety of specialized options and site-specific applications too numerous to list in this price guide. Features such as sacrificial anode packs, all stainless steel construction and a variety of other special features available.

Maintenance & General Considerations
To obtain optimum operating efficiency of a properly sized and installed PDI certified grease interceptor, a regular schedule of maintenance must be adhered to. All PDI certified grease interceptors are furnished with manufacturer's operating and maintenance instructions, which must be followed to insure efficient satisfactory operation.

Reliable performance of any grease interceptor is dependant on its being correctly sized to handle the anticipated drainage load from the fixtures it serves. Each MIFAB interceptor is flow and capacity rated for easy selection when sizing requirements have been established and met. Sizing is based on fixture drainage period, service required and volume of wastewater to be handled. These factors combine to establish the anticipated flow rate and the size of the interceptor required. The flow control fitting that is provided with every MIFAB grease interceptor sized 50 GPM and smaller, is installed in the fixture drain line ahead of the interceptor and controls the flow of drainage to the interceptor's rated capacity. This is especially important when the drainage load exceeds that for which the interceptor is sized to handle. The following sizing formula is based on the P.D.I. G-101 (Plumbing and Drainage Institute) requirements:

  1. Calculate the volume in cubic inches of all the fixtures to be served by the Grease Interceptor. (length x width x depth = capacity)
  2. * Eg: 15" x 10" x 24" = 3600 cubic inches. Since a three compartment sink is serving the grease interceptor, multiply the single compartment cubic inch capacity by three to obtain the total capacity in cubic inches. (10,800 in2). Divide this number by 231 to convert the volume to US gallons. * Eg: Cubic capacity of 10,800 in2+231 =46.75 gallons; multiplied by 75% = 35.06 U.S.G. Use MIFAB® model number MI-G-6 which has a rated flow capacity of 35 G.P.M.
  3. These capacities are based on a one minute drain-down time with the interceptor adjacent to the fixture(s). If a two minute drain-down time is acceptable, then divide the capacity by two.
  4. The flow control fitting, supplied with the interceptor, must be in position at all times. If this is removed, or not provided, the interceptor will not function to P.D.I. standards.
  5. If an interceptor is to be installed with the top level at the finished floor, an extension type may be required. In that instance, the "C" dimension is required, (center line of inlet/outlet to top of the finished floor) and must be specified at time of ordering.
Fixture Unit Sizing Method

The majority of plumbing codes list the drainage fixture-unit values for plumbing fixtures. For fixtures not listed, the codes provide drainage fixture-unit values based on drain outlet or trap size. Drainage fixture-unit values are converted to GPM discharge rates on the basis of one drainage fixture-unit equaling 7.5 GPM fixture discharge rate. The drainage fixture-unit sizing for grease interceptors is included for those that prefer this approach as an alternative to the conventional (volume) sizing. The following table provides the suggested PDI size grease interceptor based on drainage fixture-unit sizing method.

The following factors may require an increase in the size of the grease interceptor: location, presence of detergents in the waste water, ratio of grease to water, specific gravity weight of the grease filtrates, speed of incoming water flow, presence of large particles mixed with the grease laden water, and percentage of maximum flow capacity. The interceptor should be installed as close as possible to the source of grease to prevent pipes draining into the grease interceptor from becoming clogged as grease-laden water cools before entering the grease interceptor.


Disposition of Intercepted Materials
Grease and other waste matter that has been removed from the interceptor should not be introduced into any drain, sewer, or natural body of water. This waste matter should be placed in proper containers for disposal. Where recovery of grease is desired, it can be handled in a manner suitable to the authorities.
Grease Interceptors
Grease, which also includes fats and oils, has historically caused problems in plumbing drainage systems. Grease easily adheres to the inner surface of most commonly used drainage piping material and over time will form into a hard crust as tough as baked clay. The rougher the inner surface of the pipe, the easier this adherence will occur. Grease is also a problem for sewage treatment plants as it taxes the bacterial process used to break down these complex compounds. The purpose of a grease interceptor is to trap and store the suspended grease from the water passing through it. They are usually connected to kitchen sinks, floor drains, and any other plumbing fixtures in restaurants, hotels and institutions that discharge grease laden waste water. MIFAB's grease interceptors operate on the principle of separation by flotation. As our environmental laws have become more restrictive and maintenance costs have increased, public sewer departments have responded by tightening the list of materials allowed to flow into their systems. Severe fines may be levied on those users found to be in violation. Grease that is removed from the drainage system as close as possible to its source and before it becomes contaminated with other material, can be sold to rendering companies and recycled into a variety of products. It can therefore become an economic asset rather than liability.
Gallons Per Minute [Flow Rate]

All grease interceptors must be cleaned regularly. The frequency of grease removal is dependent upon the capacity of the interceptor and the quantity of grease in the waste water. Grease removal intervals may therefore vary from once a week to once in several weeks. When the grease removal interval has been determined for a specific installation, regular cleaning at that interval is necessary to maintain the rated efficiency of the interceptor. After the accumulated grease and waste material has been removed, the interceptor should be thoroughly checked to make certain that inlet, outlet and air relief ports are clear of obstructions.
Dimensional Drawing
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Dimension F
Dimension E
Dimension D
Dimension C

No. of Bolts


Dimension B
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