Grease interceptor sizing and selection using spreadsheet

First of let me explain you what's grease interceptor about it's function and installation location. Later I explain in steps about sizing and selection of grease interceptor. So let's start

So basically grease interceptor is an automatic or manual device used to separate and retain grease, oil and fats. If we talk about Installation location then each grease interceptor shall be so installed and connected that it shall be at all times easily accessible for inspection, cleaning and removal of the intercepted grease. It shall be placed as close as practical to the fixtures it serves. It is recommended that a sample box be located at the outlet end of all grease interceptors so that the Administrative Authority can periodically sample effluent quality

Designing and selection of grease interceptor

Calculation will be done in 6 simple steps listed below

Step1:

Number of Meals Per Peak Hour

Number of Meals Per Peak Hour = Seating capacity x Meal factor

Establishment Type: Meal Factor
Fast Food (45 min)                               1.33
Restaurant (60 min)                             1.00
Leisure Dining (90 min) 0.67
Dinner Club (120 min) 0.50

Number of Meals Per Peak Hour = 20 x 1.33

Number of Meals Per Peak Hour = 26.6

Step 2:

Waste Flow Rate

Conditions Flow Rate (Gallons)

With dishwashing machine 6

Without dishwashing machine 5

Single service kitchen 2

Food waste disposer only 1

So based on the condition of waste flow rate without dishwashing machine = 5 gallons

Step 3:

Retention Time

Commercial Kitchen Waste

           Dishwasher               2.5 Hrs

Single Service Kitchen

           Single Serving 1.5 Hrs

So based on the condition retention time for single service kitchen = 1.5hrs

Step 4:

Storage Factor

Storage

Kitchen Type      Factor

Fully Equipped Commercial

Hours of Operation
8 Hours 1.00
12 Hours 1.50
16 Hours 2.00

24 Hours 3.00

Single Service Kitchen 1.50

                                                           

So based on the condition of fully equipped kitchen with 8hrs of operation per day storage factor = 1.00

Step 5:

Calculate grease interceptor size

Interceptor size = Step1 x Step2 x Step3 x Step4 

Interceptor size = 26.6 x 5 x 1.5 x 1  

Interceptor size = 199.5 Gallons

Step 6:

Select from manufacturer/supplier catalogue

Now from the approved manufacturer/supplier catalogue we have to select the standard size for the grease interceptor

Below in video everything is explained in detail. Please watch it and do let me know if you have any questions. Thank you