Document kDM1GwkQong0bqkrr9Xn6mXyn

16 CHAPTER 44 1946 Guide maintenance generally go hand in hand. If a long depreciation period is to be used, then the item for maintenance, repair and replacement of wearing parts must be greater than for a short depreciation period. Obsolescence depends mainly on time required for the equipment to become out-moded. Air conditioning, particularly, would probably . Table 5. Approximate Life of Equipment (Including Obsolescence and Deterioration)a Life in Years 1. Heat Producing Equipment (a) Boilers--..... .................. . (4) Stokers and burners.... ..... 15 10 2. Heat Distributing Equipment (a) Piping--copper............ ...................... ........................ _.............. (4) Piping--iron....... ............ ............................................................ (c) Radiation--concealed..................... ....... .............................. .... {d) Radiation--direct............................... ..... :............................... (e) Valves and specialties-...... ..... _............. ........ ......... -.......... .... 20 10 12 10 5 3. Air Handling Equipment - (a) Filters--automatic..................................................................... (4) Heating and cooling coils-..................... ................ ................ ic) Spray humidifiers and dehumidifiers.......... ............... .............. id) Fans......... ..... ...... :______________._____ _______ _____ (e) Air conditioning units......... ........... :.................... ...................... if) Motors.;........................ ......... ............... ____________________ (g) Electrical starting equipment.--......... ....... ....... ....... ..... .... (4) Pneumatic control systems............................. 1....... .......... ...... (t) Electric control systems.-.............................. ........... ...... ....... 8 10 10 10 10 15 8 10 8 4. Air Distributing Equipment . (a) Ductwork................................... ................................ ........ ...... (4) Outlets, grilles.... ............. .......... .......... ............. ...................... (c) Duct insulation.................................................... .................... id) Painting....... .:.................................................... .......... ... ........ . 20 20 10 2 - 5. Refrigerating Equipment (a) -Centrifugal refrigerating machines................... _...................... (4) Reciprocating refrigerating machines_____________________ (c) Motors and starters (see Hem 3 above)..... .... ..... ..... ...... ..... id) Piping--copper....:.............. ............ .......... ........ ..................... () Piping--steel........ ..... ......... ........ ......... ... .............................. if) Pumps______ 1.................. :..... ............ ................ ..... .............. 15 10 20 15 15 6. Water Saving Devices (a) Evaporative condensers............................ ........... ................... 10 (4) Cooling towers..... ........................... ...... ..... ..... ..... ........ ........ 10 (r.) Wells............................. ........ :..... ................................. ............ . Varies Widely Modem Air Conditioning. Heating and Ventilating, W; H. Carrier, R. E. Cheme and W. A. Grant (Pitman Publishing Corp. 1940, p. 66). ' -' suffer more from obsolescence in small plants than in large establishments. In addition the obsolescence of the building or property in which the equipment is installed may have a similar effect-upon the equipment. An approximation of the'useful life of various items of equipment and parts of systems is shown in Table 5. It should be noted that if an appropriate maintenance item is not established,:the rate of equipment deterioration, may be substantially increased. Owning arid 'Operating Costs 81? Interest' The interest chargeable may not represent the existing money, rates. It may include an item to cover the diversion of capital or other items depending on existing tax laws which may make it necessary to charge interest due to diversion of capital as a cost item. It should be noted that interest may be based on an unamortized balance. As an example, a 15.year amortization period with a 4 per cent interest rate will approxi mate a 2.1 per cent average annual interest rate. Table 6. Owning and Operating Cost First Cost Cost of mechanical system...Other costs....,..-......;............ First Cost (FC)--Total Annual Fixed Charges Amortization--Depreciation period Y years................ Interest rate 1%.... --............ Amortization and Deprecia tion FC _ Y ...................... Interest: Y +--1 X I =--.... Taxes.--.............................. -- Insurance............................ Rent--.......................... ....... Annual Fixed Charges: (Total)....... ...... Annual Maintenance Costs Lubricating oil and grease.___ Painting for' corrosion pro tection or other purposes.__ Replacement of worn parts__ Refrigerant.:-- Wages of engineer or operator Annual Maintenance Cost-- totalJ__ 1__________ Annual Service Cost Electric Power Costs Fans..... ....... .......... -.......... ...... Pumps--Chilled water...... ....... Pumps--Condenser water Pumps--Well water.................. Cooling tower fans.................... Cooling tower pumps......... ...... Refrigeration machines Miscellaneous or other....... ...... Gas._...... ...................... .. ...... ...... Coal....... '............................... ...... Oil--for boilers or Diesel engines....... ............ ........... ...... Steam For direct heating..................... For Ventilation--preheat ers....................... ........... ...... For Ventilation--reheaters ___ For Turbine driven equip ment......... ....... ..... .......... ...... For Engine driven equip ment___ Sewers Charges for discharging well water into public drainage systems............. Annual Service Costs-- . TOTAL........................... Summary Annual Fixed Charges......... Annual Service Costs______ Annual Maintenance Costs Annual Owning and Oper ating Costs--TOTAL.___ ; Insurance The rate for insurance may vary considerably depending on the type of structure in which the equipment is located and upon other governing factors. A rate of about 80.60 per $1,000 may be considered as being representative for normal installations. Rent If the equipment under consideration is'to be located in rented or leased quarters it may be necessary to include an item for space rental.