No anti-siphon trap or deep-seal siphon-jet fixture shall be approved until it has successfully passed such test as may be prescribed by the Board of Standards and Appeals. A set of not more than three wash trays may connect with a single trap, or onto the trap of an adjoining sink, provided both sink and tub waste outlets are on the same side of the waste line, and the sink is nearest the line. When so connected, the waste-pipe from the washtrays must be branched in below the water-seal. The sizes for traps must not be less than those given in the following table: Traps for slop sinks 3″ in diameter Traps for kitchen sinks 2″ in diameter Traps for wash-trays 2″ in diameter Now, of course, all the foregoing relates to the whole house as well as to the kitchen. But, as the kitchen sanitary conditions depend upon the same regimen, the foregoing is a basis for kitchen usage. The kitchen is mainly concerned with the water supply and water waste, which is the result of cooking, washing, cleaning, and storage (refrigerator). SINKS AND CONNECTIONS The entry of water to the kitchen is effective through faucets, for the most part, in some sort of a sink. What then should these sinks be, and what should be the nature of their connections? For the most part, the building law will take care of the connections, but you should see to it that the traps are below the sinks and are in plain sight, and that the materials used, for your own good, should not only be within the law, but a little above it. Another thing you must remember, in ordering sinks, is that they should be smooth, in one piece if possible, having a seamless interior, non-absorbent, non-rusting, and with a certain amount of elasticity, so that when hit by sharp and heavy utensils, neither the utensil nor the sink is cracked or injured by the impact. The materials to be used in the making of sinks are tin, wood, soap-stone, galvanized iron, slate, copper, enamel, enamel over iron, a porcelain-like material over metal, and solid porcelain. Stone and slate are poor because they are too absorbent. Wood is bad for the same reason. Tin rusts, copper is difficult to keep clean and is rarely used for anything but pantry sinks. Enamel over iron is excellent, porcelain over iron is better, solid porcelain is regal but has the disadvantage of having so little resiliency that dishes are apt to break when coming too effectively in contact with it. This is often obviated in the pantry by enclosing the pantry sink in a wooden casing. The surface of good porcelain over metal will not scratch. SECOND GRADES