Floor space. The figures given are probably not supposed to apply to assembly rooms, but to study and recitation rooms. This is stated plainly in some of the laws. Ohio is the only State which has varied the amount according to the age of the students. The minima in square feet per pupil are as follows: Sq. ft. 12-North Dakota. 15-Montana, New York, Pennsylvania, Utah, Virginia. 16-Ohio (primary grades). 18-Minnesota, New Jersey, Ohio (grammar grades), South Dakota1, Vermont. 20-Ohio (high schools). 35-Minnesota (rooms for manual training or domestic science). Air space. Minima in air space per pupil may be fixed either in gross or by specifying the floor space per pupil and also the height of ceiling. Where the two methods have been combined, it sometimes happens that the air space required is greater than the product of minimal floor space and height of ceiling; hence at least one of the minima must be exceeded. Where this is the case the figures in parentheses are given to indicate the legal minima in floor space and ceiling height. The numerals at the beginning of each line below is the minimum cubic feet of air space per pupil. Cu. ft. 200-Louisiana, Montana, New York, North Dakota (12 by 12) Ohio (primary grades), Pennsylvania, Utah, Vermont, Virginia (12 by 15). 216-Minnesota, New Jersey, South Dakota. 225-Indiana, Ohio (grammar grades), Oklahoma. Ohio has also a varying arrangement for ceilings, significant for lighting as well as for ventilation. The minimum height for toilet, play, and recreation rooms is 8 feet; for all other rooms not less than half the average width of the room, and in no case less than 10 feet. Rate of air change. Nothing in school hygiene is more conventionalized than the amount of fresh air per pupil per minute. Thirty cubic feet is the standard in all the States listed in this column of Table 5, with the exception of Ohio. The requirement is not unconditional, however, in each case. In Pennsylvania it does not affect even the new buildings which are only one story high and cost less than $4,000. The possibility of the use of windows is suggested by three States that say nothing on windows in their legislative or admininstrative requirements; Massachusetts holds for 30 cubic feet of fresh air if the outside air is below 30° F.; Minnesota maintains the 30 cubic feet only when outside and inside temperatures differ by over 30° F.; Texas waives the minimum except in cold weather. There is also a rule of the Texas State Board of Health that 50 cubic 1 State Bd. of Health, Bull., July, 1913, p. 37, par. 103. feet per minute shall be furnished, but the legislative enactment calling for 30 cubic feet is so much younger as to suggest that the rule of the board of health had fallen into abeyance, if it were ever effective. The Ohio law states that the air in all parts of the building, except corridors, halls, and storage closets, shall be changed at least six times per hour. In view of the minimum air space per pupil this would mean from 20 to 25 cubic feet per pupil per minute. Rate of air change is measured in various ways, some of which are very misleading. Indiana alone has described how the calculation is to be made. The rules of procedure of the State board of health are as follows: The anemometer test shall be made over the foul-air vents in the classrooms, if jacketed heaters or gravity systems are used; over the fresh-air inlet of the fresh-air room and the fresh-air inlet in classrooms, if a plenum system is in use; at the fresh-air intake and at the foul-air vents in classrooms, if a double system of mechanical ventilation is in use. In every test five readings shall be taken, one near each corner and one at the center of the air opening to be tested. A deduction of 5 per cent shall be made for a grill in the air opening. The inlets in buildings of over one room are to be screened with 8-inch gauge wire of 11-inch mesh. This accounts for the small deduction made for grill work. Location of inlets and outlets. On the position of inlets and outlets, either in relation to each other or to the room, seven States have had something to say. They must be on the same side of the room in Indiana (in buildings of over one room), Minnesota, North Dakota, and Vermont (usually). For the larger schools it is common to find the inlets placed well up on the walls. In Indiana the height is not less than 5 feet above the floor. Minnesota and Ohio place inlets 8 feet or more above the floor, but Ohio permits foot warmers in the floor. Vermont says merely that they must be near the ceil ing, while North Dakota goes no further than to forbid their being in the floor. Vents are to be placed at floor level in Indiana, Minnesota, and Texas; at or near the floor level in North Dakota and Vermont; not over 2 inches above the floor line in Ohio; at the base of the chimney in South Dakota. If the wardrobe is not separated from the classroom, the vent shall be placed in the former (Indiana, Ohio). "Foot warmers" in the floor are forbidden in Indiana. Size of inlets and outlets.-The size of flues may be governed by their relationship (1) to the size of room, (2) to the size of other flues, (3) to the size of registers. Very different bases have been adopted for the determination of size of flues in relation to size of room. Indiana requires only that ventilating ducts shall be ample to withdraw the air four times per hour, but the State board of health has standardized with commendable accuracy and has made somewhat different requirements when the foul-air and smoke vents are separate than when they are the same or when a different system of ventilation is employed. The cubic feet of air space in the room is the guide; but if ceiling height is figured at 12 feet, the minimum permitted, we can approximate the minimum ratio of cross section of inlet to floor area. For one-room buildings it will vary according to conditions from about 1 to 350 to 1 to 650, which is considerably less than in the other States compared in the next paragraph. For the larger buildings with plenum systems of ventilation inlets may have a minimum cross-sectional area of 9 square inches for each occupant, while for gravity systems the minimum is 16 square inches per occupant. Supposing the room once again to have the minimum ceiling of 12 feet and to be filled to its capacity of one person per 225 cubic feet of air space, the ratio of cross section of inlets to floor area would be about 1 to 300 for a plenum system and 1 to 170 for a gravity system. For an ordinary one-room school with a jacketed stove and 30 pupils in the room Vermont demands an inlet 24 inches by 30 inches; New Jersey fixes 1 square foot per 10 pupils as the cross section of intakes. South Dakota and Minnesota make the size of intakes dependent upon floor area. By utilizing the minimum requirements of floor area per pupil, we can secure a ratio between the cross section of inlets and the floor area for comparison of the four States as follows: 1 to 108- Vermont. 1 to 144-South Dakota. 1 to 160-Minnesota (gravity system, connected with furnace or steam plant). 1 to 180-New Jersey. 1 to 270-Minnesota (plenum system). 1 to 400-Minnesota (buildings of less than four rooms with furnaces or jacketed stoves). The results for Minnesota, at least, are quite closely comparable with those for Indiana (see preceding paragraph). Absolute minima.-Minnesota has also set absolute minima, regardless of the size of the room. The State superintendent, in passing upon applications for State aid, will hold for inlets and vents 15 inches in diameter for one and two-room schools. These minima will maintain the ratio 1 to 400 for rooms 18 feet by 24 feet to 18 feet by 27 feet. For furnace heat and homemade systems of ventilation the State superintendent in granting State aid stands for inlets and outlets 20 inches by 20 inches, the latter perhaps containing a smokestack of 8 inches diameter. The fixed minima for inlets and outlets in Indiana is 12 inches by 12 inches. Relative size of inlets and outlets.—Consideration of the size of flues in relation to size of other flues means a comparison of inlets and outlets. Usually the requirement is that the outlets shall be at least as large as the inlets (Massachusetts, New Jersey, Ohio, South Dakota). The State superintendent of North Dakota takes the opposite view. In Indiana, however, the policy is reversed according to the method of ventilation employed. If it is the plenum, the inlets may be 10 per cent smaller than the outlets; if it is by gravity, the outlet may be one-eighth smaller than the inlet. Relative size of registers and flues.-Registers of the same size as the horizontal area or cross section of warm-air ducts are branded as inefficient in Minnesota. The State superintendent asks for an excess of 25 per cent in register area over flue area, to compensate for grill work, whereas in Indiana an allowance of but 5 per cent is made for this factor. Registers for vents are declared unnecessary in Minnesota, and forbidden in Indiana except with stoves and heaters. The latter State permits an approved damper to close the vent when not in use. The Ohio law calls for vent registers 50 per cent larger than vent flues, if a register is used. Windows or doors in ventilation.-A half dozen States frankly admit their reliance upon doors or windows for ventilation. This is seen in the requirement that all windows must lower from the top and raise from the bottom (Delaware); that windows must be capable of being lowered from the top and the transoms opened (Louisiana); that if windows alone must be relied upon they must be readily adjustable at top and bottom (Pennsylvania). More direct is the rule that doors and windows shall be opened at each intermission to flood the room with fresh air (California, Indiana, Oklahoma, Oregon, Washington). Miscellaneous.-Miscellaneous regulations on ventilation can not be conveniently summarized because of their diversity. A few general provisions may be placed first: There must be a satisfactory means of exhaust and "some form of forced ventilation in buildings of more than four rooms" (Montana). There shall be facilities for exhausting the foul air "independently of atmospheric changes" (New York, Utah, Virginia). Rural schools which, among other things, install "an adequate system of ventilation" are entitled to special State aid of $50 per year for three years (Wisconsin). The State superintendent is empowered to fix the standards, and the county and district superintendents are empowered to rule whether the standards are met.1 The State board of health "shall also examine into and devise as to * * * the ventilation and warming of public halls, churches, schoolhouses," etc. (West Virginia). The velocity of the air introduced shall not be over 300 feet per minute (New Jersey), or it shall be between 300 and 400 feet per minute (New York). In a steam gravity system for each square foot 1 These standards were briefly referred to on p. 55. ante. of horizontal area of fresh-air flues there must be 50 square feet of indirect radiation, and an accelerating coil equivalent to not less than 20 square feet shall be provided for each vent flue (Minnesota). The object of the first part of this provision is the heating of the fresh air, a point that is not overlooked by the State superintendent in examining petitions for State aid. Fresh air must be heated before it is discharged into the schoolroom (North Dakota). The introduction of fresh air at the base of a direct radiator is prohibited (Minnesota). Each classroom must have separate inlet and outlet flues (New Jersey). The smoke pipe from a jacketed stove shall enter the vent flue not over 6 feet from the floor (Vermont). An approved ventilating stove is allowed in one and two room buildings (New Jersey). The State superintendent in approving plans will expect the cold-air duct to be lined with metal, with the outer end so sloping as to keep it dry and all openings screened against entrance by animals (South Dakota). In a plenum system of ventilation the air pressure inside the room shall be in excess of that outside (Minnesota). By a separate system of ventilation through vertical flues, hoods shall be provided in all domestic-science rooms and chemical laboratories sufficient to conduct away offensive odors. This system shall be operated by electric fans if an electric current is available or by accelerating coils if steam or hot water is used for heating (Ohio). Gas plates or gas stoves used in connection with either cooking or laboratory work shall be connected by hoods with a separate vertical vent flue, in which an upward draft shall be constant (Indiana). Humidification. One item certainly merits the distinction of a separate paragraph. In Minnesota the State superintendent, before he allows State aid to any school, requires that furnace heaters be supplied with a reservoir to humidify the air on its way to the schoolroom. If other simpler forms of heating are in use, an evaporating dish or vessel must be properly placed near the source of heat. exception is made in favor of steam heat. An X. CLEANING AND DISINFECTING. Ordinary and extraordinary cleaning and disinfecting. Provisions for cleaning and disinfecting in relation to the school plant in general are considered here, since discussion of the special care of toilets and outbuildings has been shifted to the section which treats of those accommodations. In over one-fourth of the States only has this important subject been controlled in any degree outside the districts themselves. Some of the laws or regulations are almost model; others are wholly inadequate. State boards of health are to be thanked for nearly all that has been accomplished. Aside from |