A flat slab is a two-way slab generally of uniform thickness, but it may be thickened or otherwise strengthened in the region of columns by a drop panel, while the top of the column below the slab may be enlarged by a capital (round) or bracket (prismatic). If a drop panel is used to increase depth for negative reinforcement, the minimum side dimensions of this panel are L3 /3 and L2 /3, where L1 and L2 are the center-to-center spans in perpendicular directions. Minimum depth of a drop panel is 1.25h, where h is the slab thickness elsewhere. A waffle flat slab or waffle flat plate consists of a thin, two-way top slab and a grid of joists in perpendicular directions, cast on square dome forms. For strengthening around columns, the domes are omitted in the drop panel areas, to form a solid head, which also may be made deeper than the joists. Other variations of waffle patterns include various arrangements with solid beams on column centerlines both ways. Standard sizes of two-way joist forms are given in Table 9.21. The drop panel increases shear capacity. Hence, a solid flat slab can ordinarily be designed for concrete for lower strength than for a flat plate. Also, deflection of a flat slab is reduced by the added stiffness that drop panels provide. The depth of drop panels can be increased beyond 1.25h to reduce negativemoment reinforcement and to increase shear capacity when smaller columns are desired. If this adjustment is made, shear in the slab at the edge of the drop panel may become critical. In that case, shear capacity can be increased by making the drop panel larger, up to about 40% of the span. See Fig. 9.31 for bar details (column

Type of building Bathtubs or Drinking or occupancy Water closets b Urinals Lavatories showers fountains c Other (colleges, Male Female 1 per 35 Male Female 1 per 75 universities, adult centers) 1 per 40 1 per 30 1 per 40 1 per 40 Worship placeseducational Male Female 1 per 125 1 per 2 water closets 1 per 75 and activities unit 1 per 125 1 per 75 2 for 126250 2 for 76125 3 for 126250 Dormitories Male Female 1 per 25 Male Female 1 per 8 1 per first 75 e school or labor 1 per 10 1 per 8 Over 150, add 1 fixture for 1 per 12 1 per 12 For females, add 1 Add 1 fixture for each each additional 50 males Over 12 add one fixture for bathtub per 30. additional 25 males (over 10) each additional 20 males Over 150, add 1 and 1 for each additional 20 and 1 for each 15 per 20 females (over 8) additional females Dormitories Male Female 1 per 50 Male Female 1 per 8 for staff use 1 for 115 1 for 115 1 per 40 1 per 40 2 for 1635 3 for 1635 3 for 3655 4 for 3655 Over 55, add 1 fixture for each additional 40 persons Assembly places Male Female Male Female theaters, auditoriums, 1 for 115 1 for 115 0 for 19 1 per 40 1 per 40 convention hallsfor 2 for 1635 3 for 1635 1 for 1050 permanent employee use 3 for 3655 4 for 3655 Over 55, add 1 fixture for each Add one fixture for each additional 40 persons additional 50 males Assembly places Male Female Male Female 1 per first 75 e theaters, auditoriums, 1 for 1100 3 for 150 1 for 1100 1 for 1200 1 for 1200 convention hallsfor 2 for 101200 4 for 51100 2 for 101200 2 for 201400 2 for 201400 public use 3 for 201400 8 for 101200 3 for 201400 3 for 401750 3 for 401750 11 for 201400 4 for 401600 Over 750, add one fixture Over 400, add one fixture for Over 600, add 1 fixture for for each additional 500 each additional 500 males and each additional 500 males persons 2 for each 300 females TABLE 14.2 (Continued) Minimum Plumbing Fixtures for Various Occupancies TABLE 14.2 Minimum Plumbing Fixtures for Various Occupanciesa Type of building Bathtubs or Drinking or occupancy Water closets b Urinals Lavatories showers fountains c Industrial, warehouses, Male Female Up to 100, 1 per 10 1 shower for each 1 per 75 workshops, foundries, and 1 for 110 1 for 110 persons 15 persons similar establishments 2 for 1125 2 for 1125 exposed to for employee use g 3 for 2650 3 for 2650 Over 100, 1 per 15 excessive heat or 4 for 5175 4 for 5175 persons h to skin contam- 5 for 76100 5 for 76100 ination with poison- Over 100, add 1 fixture for ous, infectious, or each additional 30 persons irritating material Institutionalother than Male Female 0 for 19 Male Female 1 per 8 1 per 75 hospitals or penal 1 per 25 1 per 20 1 for 1050 1 per 10 1 per 10 institution (on each Add one fixture for each occupied floor) additional 50 males Institutionalother than Male Female 0 for 19 Male Female 1 per 8 1 per 75 hospitals or penal 1 for 115 1 for 115 1 for 1050 1 per 40 1 per 40 institutional (on each 2 for 1635 3 for 1635 Add one fixture for each occupied floor) 3 for 3655 4 for 3655 additional 50 males for employee use Over 55, add 1 fixture for each additional 40 persons

Restaurants, pubs, and Male Female 1 for 1150 Mae Female lounges i 1 for 150 1 for 150 Over 150, add 1 fixture for 1 for 1150 1 for 1150 2 for 51150 2 for 51150 each additional 150 males 2 for 151200 2 for 151200 3 for 151300 4 for 151300 3 for 210400 3 for 201400 Over 300, add 1 fixture for Over 400, add 1 fixture for each additional 200 persons each additional 400 persons a Based on Uniform Plumbing Code, 1990, International Association of Plumbing and Mechanical Officials, Walnut, Calif. The table lists the number of fixtures required for the number of persons indicated. Minimum exiting requirements determine the minimum number of occupants to be accommodated. Every building should include provisions for the physically handicapped. (Refer to local authorities or Specifications for Making Buildings and Facilities Accessible to, and Usable by, the Physically Handicapped, ANSI A117.1, American National Standards Institute.) Building categories not listed in the table should be considered separately by the administrative authority. Consideration should be given to the accessibility of the fixtures. Application of the table data strictly on a numerical basis may not produce an installation suited to the needs of building occupants. For example, schools should have toilet facilities on every floor on which there are classrooms. Temporary facilities for workers: one water closet and one urinal for every 30 male workers and every 30 female workers, or fraction thereof. Through urinals are prohibited. Walls and floors around every urinal should be lined with nonabsorbent materials. The lining should extend on the floor from the wall to 2 ft in front of the urinal lip, and on the wall, 4 ft above the floor and at least 2 ft on both side of the urinal. b The total number of water closets for females should be at least equal to the sum of the water closets and urinals required for men. c There should be at least one drinking fountain per occupied floor in schools, theaters, auditoriums, dormitories, and office and public buildings. Drinking fountans should not be installed in toilet rooms. Where food is consumed indoors, water stations may be substituted for drinking fountains. dOne kitchen sink for each dwelling or apartment unit. One laundry tray or automatic washer standpipe for each dwelling and two laundry trays or two automatic washer standpipes or combination of these for every 10 apartments. eOne additional fountain for each additional 150 persons. fOne laundry tray for every 50 persons. One slop sink for every 100 persons. gAs required by local authorities or Sanitation in Places of Employment, ANSI Z4.1. h Where there is exposure to skin contamination from poisonous, infectious, or irritating materials, one lavatory should be provided for every 5 persons. A wash sink 24 in long or a circular basin 18 in in diameter, when equipped with water outlets for these dimensions, may be considered equivalent to one lavatory. iAny business that sells food for consumption on th epremises is considered a restaurant. Employee toilet facilities should not be counted toward meeting the restaurant requirements in the table. Hand washing must be available in the kitchen for employees. The number of occupants for a drive-in restaurant should be taken equal to the number of