This grease trap/interceptor shall be inspected and thoroughly cleaned on a regular and frequent basis. Failure to do so could result in damage to the piping system, and the municipal or private drainage system(s).
248 CMR 10.09: Table 1:
RECOMMENDED PROCEDURE FOR SIZING
GREASE TRAPS AND INTERCEPTORS INSIDE BUILDINGS
EXAMPLE (Single Compartment)
STEP 1. Determine the cubic content of the fixture by multiplying length x width x depth, (of each comp)
A sink 48" long by 24" width by 12" deep. Cubic content 48" x 24" x 12" = 13,824 cu. in. or Cubic contents 4' x 2' x 1' x 7.5 Gals. = 60 Gals.
STEP 2. Determine the total capacity in gallons. 1 gallon = 231 cubic inches
Contents in Gallons 13.824/231 = 59.8 Gals.
STEP 3. Determine actual drainage load. The fixture is usually filled to approximately 75% of the capacity with waste water. The items being washed displace about 25% of the fixture content. Actual drainage load = 75% of fixture capacity.
Actual Drainage Load .75 x 59.8 Gals. = 44.9 Gals
STEP 4. Determine the flow rate and the drainage period. In general, good practices dictate a one minute drainage period, however where conditions permit, a two minute period is acceptable. Drainage period is the actual time required to completely empty the fixture.
Calculate flow rate for one minute period. Flow rate 44.9 Gals. 1/min. = 44.9 G.P.M.
For two minute period
Flow rate 44.9 Gals./2min. = 22.5 G.P.M.
STEP 5. Select the interceptor which corresponds to the flow rate calculated Note: Select larger size when flow rate falls between two sizes listed.
NOTE: The example above is representative of acceptable method(s) when purchasing an interceptor based on the total fixture flow rate capacity in gallons. When purchasing an interceptor based on grease retention pounds only, multiply the total gallon flow rate capacity of the fixture by two.
248 CMR 10.09Table 2:
SIZING FORMULAS FOR LARGE CAPACITY
GREASE INTERCEPTORS (INSIDE OR OUTSIDE BUILDINGS)
Other Establishments with Commercial Kitchens:
(S) X (GS) X (HR/12) X (LF) = Effective Capacity of Grease Traps and Interceptors in Gallons
(M) X (GM) X (LF) = Effective Capacity of Grease Traps and Interceptors in Gallons
S = Number of Seats in Dining Area
GS = Gallons of Waste Water per Seat:
HR = Number of Hours Restaurant Is Open.
LF = Loading Factor
Use 25 Gallons for Restaurants with China Dishes and/or automatic dishwashers
Use 10 Gallons for Restaurants with Paper or Baskets and no dishwashers.
M = Meals Prepared per Day
GM = Gallons of Waste Water per Meal (Use 5 Gallons)
LF = Loading Factor
Use 1.00 with dishwashing machines and 0.75 without dishwashing machine.
Use 2.00 Interstate Highway,
Use 1.00 Main Highway,
Use 0.75 Other Highways
Use 1.50 Other Roadways
Use 1.25 Recreational Areas
248 CMR 10.09: Table 3:CAPACITY OF GREASE TRAPS AND INTERCEPTORS
Total Flow Through Rating (g.p.m)
Grease Trap/Interceptor Retention Capacity (pounds)
248 CMR 10.09