Of the total cost, the fixed equipment was 60% and the motive apparatus was 40% of the cost of the whole equipment.

The combined equipment has a relative life compared with that of its most durable part, which has been assumed to be such material as elevator guides and fixed ironwork, of 40%.

The fixed equipment has an average of.....


But the motive apparatus is only.......


The effect of the motive apparatus is, therefore, the greatest in reducing the total life of the building. The cost of the entire equipment in this case approximated 20% of the total cost, and if the building, upon dissection of its elements, should show, without equipment, a mean relative life of 77%, then the introduction of the equipment reduces the combination to 70%, or, in other words, the building alone would have a mean life of 57 3/4 years; but this would be reduced by the effect of the equipment to 52 1/2 years, involving on each one million dollars of total invested value an annual addition to the necessary sinking-fund for depreciation of about $7500 a year.

Fig. 13

Fig. 13

In an office building where no power plant is installed, but elevators and heating-boilers are included, we find that the relative life of this equipment is......... 45.7%

The building without the equipment is......


and the effect of the equipment is to reduce this to . .


In a dry-goods building the investment in the equipment and in a power plant was:

For the fixed equipment, elevators, sprinklers, and boilers for heating .... 20% of the cost of the building For the motive apparatus, or generating plant...... 6% of the cost of the building

The relative life of building alone being . . . .


The relative life of fixed equipment is.....


Thus the building and fixed equipment average . .


The relative life of the motive plant is, however, only


Reducing the average relative life of all to . . .


and reducing the mean life of the whole by about .


and increasing the proportionate sinking-fund by about ..............


The introduction of delicate and short-lived machinery into buildings, therefore, affects not only the proportion of funds for its own replacement, but that covering the duration of life of the entire structure.