leads to a compression of the underlying porous soil or rock structure. Since subsidence is due to a secondary influence (extraction of oil or groundwater), its effect on the structure would be included in the second basic type of settlement. 6.5.3 Foundation Design Parameters Determining the settlement of the structure is one of the primary obligations of the geotechnical engineer. In general, three parameters are required: maximum total settlement (max), maximum differential settlement (), and rate of settlement. Another parameter that may be useful in the design of the foundation is the maximum angular distortion ( /L), defined as the differential settlement between two points divided by the distance between them. Figure 6.19 illustrates the maximum total settlement (max), maximum differential settlement (), and maximum angular distortion ( /L) of a foundation. Note in Fig. 6.19 that the maximum angular distortion ( /L) does not necessarily occur at the location of maximum differential settlement 6.5.4 Allowable Settlement The allowable settlement is defined as the acceptable amount of settlement of the structure and it usually includes a factor of safety. The allowable settlement depends on many factors, including the following (D. P. Coduto, Foundation Design, Principles and Practices, Prentice-Hall, Inc., Englewood Cliffs, N.J.): The Type of Construction. For example, wood-frame buildings with wood siding would be much more tolerant than unreinforced brick buildings. TABLE 6.13 Allowable Settlement Type of movement Limiting factor Maximum settlement

3. Estimate, for every space, heating or cooling loads from adjacent unheated or uncooled spaces. 4. Carefully check architectural drawings for all building materials used for walls, roofs, floors, ceilings, doors, etc., and determine the necessary thermal coefficients for each. 5. Establish values for air infiltration and exfiltration quantities, for use in determining heat losses and heat gains. 6. Determine ventilation quantities and corresponding loads for heat losses and heat gains. 7. Determine heat or cooling loads due to internal machinery, equipment, lights, motors, etc. 8. Include allowance for effects of solar load. 9. Total the heat losses requiring heating of spaces and heat gains requiring cooling of spaces, to determine equipment capacities. 10. Determine system type and control method to be applied. 13.3.4 Temperatures Determined by Heat Balances In cold weather, comfortable indoor temperatures may have to be maintained by a heating device. It should provide heat to the space at the same rate as the space is losing heat. Similarly, when cooling is required, heat should be removed from the space at the same rate that it is gaining heat. In each case, there must be a heatbalance between heat in and heat out when heating and the reverse in cooling. Comfortable inside conditions can only be maintained if this heat balance can be controlled or maintained. The rate at which heat is gained or lost is a function of the difference between the inside air temperature to be maintained and the outside air temperature. Such temperatures must be established for design purposes in order to properly size and select HVAC equipment that will maintain the desired design conditions. Many other conditions that also affect the flow of heat in and out of buildings, however, should also be considered in selection of equipment. 13.3.5 Methods of Heat Transfer Heat always flows from a hot to a cold object, in strict compliance with the second law of thermodynamics (Art. 13.2). This direction of heat flow occurs by conduction, convection, or radiation and in any combination of these forms. Thermal conduction is a process in which heat energy is transferred through matter by the transmission of kinetic energy from molecule to molecule or atom to

As part of the Energy Policy Act of 1992, all water closets manufactured after January 1, 1994, for use in the United States were required to have a maximum water use of 1.6 gallons per flush. Blowout water closets were required to have a maximum water use of 3.5 gallons per flush and urinals were required to have a maximum water use of 1.0 gallon per flush. Air Gaps. These should be provided to prevent backflow of wastewater into the water supply (Art 14.6.4). At plumbing fixtures, an air gap must be provided between the fixture water-supply outlet and the flood-level rim of the receptacle. Building codes usually require a minimum gap of 1 to 2 in for outlets not affected by a nearby wall and from 11/2 to 3 in for outlets close to a wall. Table 14.3 lists minimum air gaps usually used. In addition to the usual drain at the lowest point, receptacles generally are provided with a drain at the flood-level rim to prevent water from overflowing. The overflow should discharge into the wastewater system on the fixture side of the