Sizing Requirements. 15.19.2.1 Valve Sizing Each valve will be sized to relieve the maximum vapor or liquid load to protect the process system. Process relief loads due to blocked in conditions, reflux failure, cooling water failure, or runaway reactions, shall be obtained form the process material balance flow diagram, adjusted for set pressure conditions. Sizing calculations shall clearly state the basis. Relief loads due to fire, use API RP-520, latest revision, for the heat inputs. Rupture discs shall be sized on the same basis. Relieving pressure or popping pressure shall be at or under the protected equipment design pressure, or maximum working pressure. Set pressure is the difference between relieving pressure and constant back pressure for conventional valves corrected for temperature. For balanced valves, relieving pressure, and set pressure are the same, corrected for temperature. Allowable accumulation is per ASME Boiler and Pressure Vessel Code. For safety valves, the back pressure must be atmospheric. For conventional relief valves, the variation is superimposed back pressure cannot exceed 10 percent of the set pressure. For balanced valves, the variable back pressure cannot exceed 50 percent of the set pressure. Stagger the set pressures when two or more relief valves are used.
Sizing Requirements. The designer shall size the grease interceptor using the “Grease Interceptor Sizing Form” spreadsheet shown at the end of this section and the restaurant types as described below. The following descriptions are to be used to determine the recommended size of a grease interceptor for food preparation and/or food service establishments. To determine the grease interceptor size, consideration must be given to the fat content of the food prepared, number of kitchen drainage fixtures, seating capacity, customer turnover rate, previous problems with the service line or main, compliance history of the food establishment, eat-in or carryout, number of employees, hours of operation, frequency of kitchen use, size of kitchen, number and type of cooking appliances, etc. The food service categories described below function only as a guide. Every food service establishment may not fit clearly within one category; therefore, it may be necessary to combine characteristics and expected size ranges from more than one category to determine the grease interceptor size. • The minimum acceptable volume of a grease interceptor shall not be less than three hundred and twenty-five (325) gallons. (With a dishwasher – 1,000 gallons minimum size) • A copy of the kitchen mechanical or plumbing plan, showing the number of fixtures (3- compartment sink, dishwasher, hand sink, floor drains, etc.) is required to be submitted to the District Manager to confirm the size of the grease interceptor. Facilities often preparing three meals per day or having continuous food prep (cooking) throughout much of the day. These facilities may prepare large amounts of food for distribution to other locations. Examples may include full-service dine-in restaurants, buffets, hotels, large senior-living facilities, hospitals, food courts, grocery stores, caterers, etc. They typically have large or multiple kitchens with a wide range in plumbing fixtures. These facilities frequently have at least one large dishwasher with a large pre-wash sink, vegetable preparation sinks, mop sinks, hand sinks, etc. Food items may be served on disposable or washable dishware. • Expected Size Range of Grease Interceptor: 2,500 – 3,500 gallons Facilities often cooking two meals per day, such as lunch and dinner with washable eating utensils. They usually have a 50 – 150 person seating capacity. Examples may include small senior living facilities, steak houses, gourmet burger establishments, dine-in pizza places, seafood or e...
