If power costs 5 cents per K. W. Hr. the yearly saving will be $26.25, which, capitalized at 16%, will equal $164.00. This is the amount which the owner would be justified in paying for the more economical plant above the price asked for the cheaper, but less economical, system.
In order to guard against any bidder guaranteeing a lower power consumption than he can actually show on test, it is necessary to impose a penalty for failure to meet the guarantee which is in excess of the increase in price shown to be justified by the evaluation.
The author recommends that this penalty be made not less than 150% of the increase in price shown by the evaluation.
Actually, the owner will not lose by the less efficient plant any more than the amount shown by the evaluation if he junks the plant at the end of ten years. However, it is more than likely that he will either use it for a longer time or will be able to realize something for the plant when it is displaced. The increased penalty, therefore, is justified, and it is absolutely necessary to make this penalty greater than the increased value to prevent the bidder guaranteeing a power consumption lower than he can show on test.
The following pages contain sample specifications for apparatus of each of the four classes of systems described in [Chapter XII] and a specification permitting the widest competition, with evaluation and penalty clauses.
CLASS 1
Plant for Residence or Small Office Building of One-Sweeper Capacity.
1. General Description. The work included in this specification shall be the installation of a complete vacuum cleaning system for the removal of dust and dirt from rugs, carpets, floors, stairs, furniture, shelves, walls and other fixtures and furnishings throughout the building, and for conveying said dust and dirt to suitable receptacles located where shown, together with all of the necessary cleaning tools, hose, piping, separators, exhauster, motor, etc., as hereafter more fully specified.
2. Exhauster. The exhauster in all of its details shall be made of the best materials suitable for the purpose and shall be of approved design and construction, and may be either of the positive displacement (rotary) or of the multi-stage fan type.
3. Rotary Exhauster. The rotary displacement exhauster shall be either of the two-impeller type or of type having single impeller without sliding vanes revolving without friction contact with case and with oscillating follower.
4. Exhausters fitted with sliding blade or blades will not be acceptable.