FIGURE 16.16 Jacks commonly used for hydraulic elevators: (a) single-bearing plunger for guided loads; (b) two-bearing plunger for off-balance loads; (c) movable-bearing plunger for heavy service; (d ) cage bearing for long-stroke service; (e) double-acting plunger. For long-stroke service, a cage-bearing type can be used (Fig. 16.16d). The cagebearing is supported by a secondary cylinder about 3 ft below the main cylinder head. Oil enters under pressure just below the main cylinder head, passes down through holes in the bearing, and lifts the plunger. When the car or platform is not heavy enough to ensure gravity lowering, a double-acting cylinder may be used (Fig. 16.16e). To raise the plunger, oil is admitted under pressure below the piston; to lower it, oil is forced into the cylinder near the top, above the piston, and flows out below. Jack plunger sizes for the various types range from 21/2 in in diameter for small low-capacity lifts to 18 in for large lifts, operating at 150 to 400 psi. Hydraulic elevators have several advantages over electric elevators: They are somewhat less expensive and simpler. The car and its frame rest on or beside the hydraulic plunger that raises and lowers them. There are sometimes wire ropes. No overhead equipment or penthouse is required. Without heavy overhead loads, hoistway columns and footings can be smaller. Car safeties or speed governors are only required on the roped type. Speed of the elevator is low; so the bumpers need be only heavy springs. Capacity of hydraulic passenger elevators usually ranges from 1200 to 5000 lb at speeds from 75 to 150 ft /min. With gravity lowering, down speed may be 1.5 to 2 times up speed. So the average speed for a round trip can be considerably higher than the up speed. Standard hospital elevators have capacities of 3500 to 5000 lb at speeds of 75 to 150 ft /min. Capacity of standard freight elevators ranges from 2500 to 8000 lb at 50 to 125 ft /min, but they can be designed for much greater loads. (G. R. Strakosch, Vertical Transportation: Elevators and Escalators, John Wiley & Sons, Inc., New York.) Elevator service is judged by two primary criteria: quantitative, or the number of persons who can be moved by the system within a defined peak traffic period, and qualitative, which expresses the calculated time between departing elevators during the same heavy traffic period. 16.11.1 Number of Elevators Required The number of passenger elevators required for a particular building depends on the number of persons expected to work or live in the building. Traffic is measured by the number of persons requiring service during a peak 5-min period. For proposed buildings, a population estimate is generated on the basis of occupancy trends for that specific building type. Peak-traffic projections are based on the type of tenancy expected for the building. From the population and peak-traffic projection, the demand is established as a peak 5-min traffic flow. While peak traffic in most buildings is a rather complex pattern of two-way and interfloor movement, most models assume a simplified traffic pattern in which traffic is primarily incoming or outgoing. The lack of a complex model is more a result of the poor understanding of the existing model than of the absence of sophisticated measuring devices. After the peak 5-min traffic flow is established, an estimate may be made of the quantity of elevators required. The ability of a specific system to handle the traffic is tested against the projected traffic level. The 5-min handling capacity of an elevator is determined from the round-trip time.

Initial cost $300,000 $500,000 Life, years 10 20 Salvage value $50,000 $100,000 Annual costs $30,000 $20,000 TABLE 1.2 Example Comparison of Two Air-Conditioning Units Unit 1 Unit 2 Initial investment $300,000 $500,000 Present worth of replacement cost in 10 years P  V at 8% interest [Eq. Present worth of annual cost for 20 years at 8% interest [Eq. (1.3)] Present worth of all costs 710,340 696,360 Revenue: Present value of salvage value after 20 years at 8% interest [Eq. (1.2)] Net cost: Present worth of net cost in 20 years at 8% interest Cost of operation, maintenance, repairs, property taxes, and insurance are included in the annual costs. The present-worth method is used for the comparison, with interest rate i  8%. Conversion of all costs and revenues to present worth must be based on a common service life, although the two units have different service lives, 10 and 20 years, respectively. For the purpose of the conversion, it may be assumed that replacement assets will repeat the investment and annual costs predicted for the initial asset. (Future values, however, should be corrected for monetary inflation.) In some cases, it is convenient to select for the common service life the least common multiple of the lives of the units being compared. In other cases, it may be more convenient to assume that the investment and annual costs continue indefinitely. The present worth of such annual costs is called capitalized cost. For this example, a common service life of 20 years, the least common multiple of 10 and 20, is selected. Hence, it is assumed that unit 1 will be replaced at the end of the tenth period at a cost of $300,000 less the salvage value. Similarly, the replacement unit will be assumed to have the same salvage value after 20 years. The calculations in Table 1.2 indicate that the present worth of the net cost of unit 2 is less than that for unit 1. If total cost during the twenty year period were the sole consideration, purchase of unit 2 would be recommended. ASTM has developed several standard procedures for making economic studies of buildings and building systems, in addition to ASTM E917 for measuring lifecycle costs, mentioned previously. For example, ASTM E964 is titled Practice for Measuring Benefit-to-Cost and Savings-to-Investment Ratios for Buildings and Building Systems. Other standards available present methods for measuring internal rate of return, net benefits, and payback. ASTM also has developed computer programs for these calculations. Value Analysis Procedure. In building design, value analysis generally starts with a building system or subsystem proposed by the architect and consultants. The client or the clients representative appoints an interdisciplinary team to study the system or subsystem and either recommend its use or propose a more economical alternative. The team coordinator sets goals and priorities for the study and may appoint task groups to study parts of the building in accordance with the priorities. The value analysts should follow a systematic, scientific procedure for accomplishing all the necessary tasks that comprise a value analysis. The procedure should provide an expedient format for recording the study as it progresses, assure that consideration has been given to all information, some of which may have been overlooked in development of the proposed system, and logically resolve the analysis into components that can be planned, scheduled, budgeted, and appraised. The greatest cost reduction can be achieved by analysis of every component of a building. This, however, is not practical, because of the short time usually available for the study and because the cost of the study increases with time. Hence, it is advisable that the study concentrate on those building systems (or subsystems) whose cost is a relatively large percentage of the total building (or system) cost, because those components have possibilities for substantial cost reduction. During the initial phase of value analysis, the analysts should obtain a complete understanding of the building and its major systems by rigorously reviewing the program, proposed design and all other pertinent information. They should also define the functions, or purposes, of each building component to be studied and estimate the cost of accomplishing the functions. Thus, the analysts should perform a systems analysis, as indicated in Art. 1.2, answer the questions listed in Art 1.2 for the items to be studied, and estimate the initial and life-cycle costs of the items. In the second phase of value analysis, the analysts should question the costeffectiveness of each component to be studied. Also, by use of imagination and creative techniques, they should generate several alternative means for accomplishing the required functions of the component. Then, in addition to answers to the questions in Art. 1.2, the analysts should obtain answers to the following questions: Do the original design and each alternative meet performance requirements? What does each cost installed and over the life cycle? Will it be available when needed? Will skilled labor be available? Can any components be eliminated? What other components will be affected by adoption of an alternative? What will the resulting changes in the other components cost? Will there be a net

Fire Resistance and Sound Rating Brick Technical Manual 52 110mm - Standard Solid wall. 10mm mortar core between two leaves. 13mm cement render both sides. Wall thickness: 256mm. Rw 61 (-1;-5) ATF Report 1615 110mm - Standard Single skin bricks. 13mm plasterboard direct fixed one side. 13mm plasterboard screw fixed to 64mm Rondo Steel Stud built 15mm from wall with 64mm track top and bottom with insulation on other side. Wall thickness: 215mm. Discontinuous construction. Rw 62 (-3;-9) ATF Report 1125 110mm - Standard Single skin bricks. 13mm plasterboard screw fixed to 64mm Rondo Steel Stud built 15mm from wall with 64mm track top and bottom with 9kg/m3 polyester insulation both sides. Wall thickness: 294mm. Discontinuous construction. 110mm - Dry Press Cavity wall. 50mm cavity. Wall thickness: 270mm. Discontinuous construction. Rw 70 (-5;-13) ATF Report 1123 Rw 53 (-1;-3) ATF Report 1174 110mm - Dry Press Cavity wall. 40mm cavity. 10mm plasterboard direct fixed both sides. Wall thickness: 280mm. Discontinuous construction. 110mm - Dry Press Cavity wall. 50mm cavity. 13mm cement render both sides. Wall thickness: 296mm. Discontinuous construction. 150mm - TW Single skin bricks. 12mm cement render both sides. Wall thickness: 174mm. 150mm - TW Single skin bricks. 13mm sound resistant plasterboard direct fixed one side. 13mm sound resistant plasterboard screw fixed to resilient mounted furring channels with 9kg/m3 polyester insulation on other side. Wall thickness: 217mm. Rw 54 (-1;-4) ATF Report 1463A Rw 55 (-1;-4) ATF Report 1175 Rw 55 (-1;-5) ATF Report 1596 Rw 60 (-2;-8) ATF Report 1595