Chapter XIV: Specifications (2)

76. To test the capacity of the plant, .... hose lines each 75 ft. long shall be attached to the inlets, each hose to be fitted with standard vacometer with ⁷⁄₈-in. opening. Under these conditions a vacuum of 1 in. mercury must be maintained in each vacometer.

77 and 78. Same as for Class 1.

CLASS 5

TO GIVE WIDEST COMPETITION.

1. Same as for Class 1.

2. Exhauster to be piston, rotary or centrifugal fan type.

3. The piston type of exhauster shall be double-acting and so designed that the cylinder clearance shall be reduced to a minimum, or suitable devices shall be employed to minimize the effect of large clearances.

4. The induction and eduction valves may be either poppet, rotary or semi-rotary, and shall operate smoothly and noiselessly.

5. The piston packing shall be of such character as to be practically air tight under working conditions and constructed so that it will be set out with its own elasticity without the use of springs of any sort. If metallic rings are used, they must fill the grooves in which they are fitted, both in width and depth, and must be concentric; that is, of the same thickness throughout. The joint in the ring or rings to be lapped in width but not in thickness, and if more than one ring is used they are to be placed and doweled in such position in their respective grooves so that the joints will be at least one-fourth of the circumference apart.

6. The piston shall have no chamber or space into which air may leak from either side of the piston. All openings into the body of the piston must be tightly plugged with cast-iron plugs.

7. The piston-rod stuffing box to be of such size and depth that if soft packing is used it can be kept tight without undue pressure from the gland. If metallic packing is used, it must be vacuum tight without undue pressure on the rod. Proper means shall be provided for the continuous lubrication of the piston rod.

8. The exhauster of the piston type shall be fitted with an approved cross-head suitably attached to the piston rod; machines having an extended piston rod for guide purposes will not be acceptable.

Insert paragraphs 3 to 15 from specifications for Class 1.

15a. Reciprocating exhauster shall be provided with the necessary devices for the removal of the heat generated by friction and compression, that shall prevent the temperature of cylinders or eduction chambers rising more than 100° F. above the surrounding atmosphere after two hours’ continuous operation under full load conditions.

15b. _Speed._ Reciprocating exhauster with poppet valves shall operate at an average piston speed not exceeding 200 ft. per minute, with rotary valves not exceeding 300 ft. per minute.

Insert paragraphs 16 and 17 from specifications for Class 1.

Omit 18.

18a. _Base Plate, Foundation, etc._ Provide suitable base plate to rigidly support the exhauster and its motor as a unit, which shall be large enough to catch all drip of water or oil. Provide a raised margin and pads for feet of exhauster frame, motor, and anchor bolts, high enough to prevent any drip from getting into the foundation or on the floor.

18b. Provide suitable foundation of brick or concrete, to which the base plate shall be firmly anchored. The foundation shall be built on top of the cement floor of the basement, which shall be picked to afford proper bond for the foundation.

18c. Construct the foundation of such a height as to bring the working parts of the machine at the most convenient level for operating purposes. Exposed parts of the foundation to be faced with best grade white enameled brick. If the base plate does not cover the foundation, the exposed top surface is to be finished with enameled brick using bull-nose brick on all edges and corners.

19 to 23. Same as for Class 1.

23a. The guaranteed efficiency of motor shall not be less than 78% at half load and not less than 84% at full load.

24 to 32. Same as for Class 1.

32a. Motors shall be subject to shop test to determine efficiency, heating, insulation, etc. Manufacturers’ certified test sheets of motor, giving all readings taken during shop test, together with calculated results, must be submitted to the architect for approval before motor is shipped from factory.

33. _Rheostat._ Furnish and install where shown, upon a slate panel hereinafter specified, a starting rheostat of proper size and approved make, designed for the particular duty it has to perform. It must have an automatic no-voltage and overload release. All resistance for rheostats is to be placed on the back of the tablet. Contacts must project through board to front side. All moving parts must be on front of board.

33a. _Tablet._ Furnish and place where shown, a slate tablet not less than ³⁄₄ in. thick, supported by a substantial angle bar frame, so placed that there will be a space of not less than 4 in. between the wall and back of resistance. Mount on the tablet one double-pole, 250-volt knife switch, with two 250-volt enclosed fuses and one starting rheostat, as specified hereinbefore. The connections shall be on the back of the tablet. The space between the column and the tablet shall be enclosed with a removable diamond-mesh grill of No. 10 iron wire in channel frame.

34, 35 and 36. Same as for Class 1.

36a. _Automatic Control._ Suitable means shall be provided in connection with the reciprocating and rotary exhausters that will maintain the vacuum in the separators within the limit of the machine at point found to be most desirable, irrespective of the number of sweepers in operation.

36b. Controller shall consist of a suitable means provided in the exhauster, or as an attachment thereto, which will automatically throw the exhauster out of action by admitting atmospheric pressure to the exhauster only, but not to the system; or that shall cause suction from the system to cease whenever the vacuum in the separators rises above the point considered desirable, and throw the exhauster into action when the vacuum falls below the established lower limit.

36c. _Vacuum Breaker._ In addition to the controlling devices above specified, if a reciprocating or rotary exhauster is used, there shall be placed in the suction pipe to the exhauster an approved positive-acting vacuum breaker having opening equivalent to the area of 1-in. diameter pipe and set to open at 12 in.

36d. If centrifugal fan is used, no control or vacuum breaker will be required.

37. _Dust Separators._ There must be provided at least one separator between the pipe lines and exhauster having a volume of not less than 3 cu. ft. per sweeper of plant capacity. This separator must be so constructed that no part thereof will receive the direct impact of the dust. If rotary exhauster is used, this separator must also contain a bag so placed that only the lightest dust will reach same and must be arranged to be readily cleaned without dismantling the separator. If a centrifugal exhauster is used, this apparatus may or may not contain a bag, and, if piston pump is used, this separator must contain no bags or screens whatever. If a piston type of exhauster is installed, an additional separator must be placed between the first separator and the exhauster. This must be a wet separator and may be contained in the base of the machine or consist of a separate tank.

Omit 38.

38a. Same as for Class 1.

38b. Wet separators, whether separate from or integral with the base of the machine, must be provided with an attachment which will positively mix the air and water, thoroughly break up all bubbles, separate the water from the air, and prevent any water entering the exhauster cylinder.

38c. Suitable means must be provided to automatically equalize the vacuum between wet and dry separators upon the shutting down of the exhauster.

38d. The separators must be provided with suitable openings for access to the interior for inspection and cleaning, and the interior arrangement of the separators must be such that they may be readily cleaned without dismantling.

38e. All parts of the wet separator tank (if used) not constructed of non-corrosive metal must be thoroughly tinned or galvanized both inside and outside. The interior of the wet separator formed in base of exhauster shall be painted with at least two coats of asphalt varnish or other paint suitable to prevent the corrosion of same.

38f. Separators must be provided with all necessary valves or other attachments for successful operation, including a sight glass for the wet separator (if used), through which the interior of same may be observed.

38g. The wet separator (if used) shall be properly connected to water supply where directed and discharge to sewer where shown on plans.

38h. A running trap with clean-out shall be installed in the waste line.

39 to 41. Same as for Class 1.

41a. Waste and water pipe, in connection with wet separator and jacket, except waste pipe below basement floor, to be standard galvanized wrought-iron or steel screw-jointed pipe free from burs. Waste pipe below the basement floor is to be best grade, “extra heavy” cast-iron pipe, with lead-calked joints.

42 to 45. Same as for Class 1.

45a. Fittings on water lines to be standard galvanized beaded fittings.

45b. Fittings on waste line above basement floor to be galvanized recessed screw-jointed drainage fittings and those below basement floor to be “extra heavy” cast-iron with hub joints.

46 to 50. Same as for Class 1.

50a. If reciprocating exhauster is used, the exhaust pipe is to be fitted with an approved first-class muffler not less than 12 in. in diameter and 60 in. high, closely riveted and constructed of galvanized iron not less than ¹⁄₈ in. thick, and in event an exhauster requiring lubrication is furnished this muffler is to be arranged so that it will also be an efficient oil separator. Drip connection is to be arranged at bottom of muffler.

51 to 56. Same as for Class 1.

56a. _Tool Cases._ Furnish ... approved hardwood cabinet-finished cases for cleaning tools. Each case to be made as light as possible and of convenient form for carrying by hand and provided with a complete set of cleaning tools, each securely held in its proper place, and fitted with lock and key, clamps, and conveniently arranged handles.

57. Each case will contain the following:

One carpet renovator, with slot ¹⁄₄ in. by not less than 12 or more than 15 in. long.

One bare floor renovator, 15 in. long, with curved felt-covered face.

One wall brush, with skirted bristles, 12 in. long and ¹⁄₂ in. wide.

One hand brush, with hose connection at end, 8 in. long and 2 in. wide.

One 4-in. round brush for relief work.

One upholstery renovator.

One corner cleaner.

One radiator tool.

One curved stem about 5 ft. long.

One straight extension stem 5 ft. long.

At least one hat brush with the system.

58 to 64. Same as for Class 1.

64a. All brushes to be of substantial construction, with best quality bristles set in close rows and as thick as possible, skirted with rubber, leather, or chamois skin, so that all air entering renovator will pass over surface being cleaned.

65 to 68. Same as for Class 1.

69. _Hose Racks._ Furnish and properly secure in place, where directed, .... hose racks in basement, .... each in first and second stories (.... racks in all). The racks to be constructed of cast-iron, galvanized or enamel finish, and each rack to be suitable for holding 75 ft. of hose of required size.

69a. _Hose._ There must be furnished with each hose rack, 75 ft. of non-collapsible hose in three 25-ft. lengths.

70. Hose shall not be less than 1 in. or more than 1-³⁄₄ in. inside diameter, best quality rubber hose, reinforced in best manner to absolutely prevent collapse at highest vacuum obtainable with the exhauster furnished and to prevent collapse if stepped on. Weight of hose to be not over 12 oz. per linear foot.

71 to 73. Same as for Class 1.

74. On completion of the plant, the pump will be operated with all outlets closed and under this condition the power consumption must not be more than 50% of that required under test conditions.

75. To test the capacity of plant, one hose line 100 ft. long shall be attached to inlet farthest from the separator, with standard vacometer with ¹⁄₂-in. opening in end of hose. Hose lines shall be attached to other outlets, each with 50-ft. hose and vacometer in end of hose, .... vacometers having ¹⁄₂-in. opening and .... vacometers having ⁷⁄₈-in. opening. Under these conditions 4 in. mercury must be maintained in vacometer at end of 100 ft. of hose.

75a. _Test of Separators._ At each of ---- points, near ---- outlets on different risers selected by the .... representative, the contractor shall furnish and spread on the floor, evenly covering an area of approximately 50 sq. ft. for each outlet, a mixture of 6 lbs. of dry sharp sand that will pass a 50-mesh screen, 3 lbs. of fine wheat flour, and 1 lb. of finely pulverized charcoal, if wet separator be used, and 6 lbs. of Portland cement, if bag be used.

75b. Fifty feet of hose of size required by the system used shall be attached to each of the ---- outlets, and the surface or surfaces prepared for cleaning shall be cleaned simultaneously by operators provided by the contractor until all of the sand, flour and charcoal has been taken up, when the exhauster shall be stopped and the dirt removed from the dry separator and spread on the floor again, and the operation of cleaning repeated until the mixture has been handled by the apparatus four times. If, after thoroughly flushing the system at completion of the above run, any dust or mud is found in the cylinder, ports, or valve chambers of the displacement exhauster, or if less than 95% of the dirt removed is found in the dry separator of the centrifugal exhauster, it shall be deemed sufficient ground for the rejection of the separators. If bag is used, same must not be disturbed until after capacity test, which will be made with material in separator after being picked up the fourth time.

76-77. Same as for Class 1.

78. Evaluation of proposal (for 4-sweeper plant): No proposal will be considered which contemplates furnishing an exhauster requiring more power to operate under test conditions than:

Full load, 14 K. W.; three-quarter load, 12.25 K. W.; one-half load, 10.5 K. W.

Test Requirement: Paragraph 75 to be considered full load. To reduce the load to three-quarters, one ⁷⁄₈-in. vacometer opening to be closed; to produce one-half load, one ¹⁄₂-in. opening to be closed in addition to the ⁷⁄₈-in. opening.

Bidders are requested to state in proposal the power consumption required by their apparatus at full, three-quarters and one-half loads, and in case the guarantees of the various bidders differ, they will be evaluated as follows for the purpose of comparison:

For each full K. W. of power consumption or fractional part thereof there will be allowed the following amount or proportionate parts for fractional parts of a K. W. hour at the various loads:

Per Cent. of Full Load 100 75 50
Amount $156.00 $62.00 $94.00

As an illustration, let it be assumed that proposals have been received offering equipment in accordance with specification requirements, and the one offering the most economical apparatus based on guaranteed power consumption names the highest price for the installation.

To determine if the purchaser will be justified in accepting the highest proposal, let it be assumed that he has guaranteed a power consumption of 1 K. W. less at full load, 0.75 K. W. less at three-quarters load, and 0.25 K. W. more at half-load than the lowest bidder. Under these conditions the algebraic sum of the saving of the higher bidder over the lower bidder would be 156 + 46.50 - 23.50 = 179, which is the additional amount in dollars which the purchaser would be warranted in paying for the apparatus of higher efficiency.

In making the economy test to determine if the guaranteed power consumption has been fulfilled, an integrating watt meter, previously calibrated and found correct, will be placed in circuit and a two-hour run made at each load and the power consumption based on the meter readings.

=Penalty.=--It must be distinctly understood to be one of the conditions under which bids are to be submitted for the work embraced in this specification that the apparatus shall meet every requirement of the specification and the guaranty for efficiency under which conditions the contract price will be paid. In the event the apparatus tested fails to meet the specified requirements for capacity or economy, or both, the Architect shall have the right to reject the apparatus, absolutely, and require the installation of satisfactory apparatus, which shall comply with the contract requirements; or if he elects to accept the same, in the event the capacity or efficiency at any load (irrespective of other loads) is less than that named in the proposal, then the contract price shall be the amount named in the contract for a satisfactory plant, less the amount of deficiencies shown by the test based on the following:

=For Capacity.=--$500.00 for each inch of vacuum and a proportionate part thereof for each fraction of an inch below the 4 in. required in vacometer when operating under full load.

=For Economy.=--Deduction for each K. W. or a proportionate part thereof for each fraction thereof required in excess of guarantee.

Percentage of Full Load 100 75 50
Penalty $229.00 $93.00 $141.00

* * * * *

This evaluation was based on the same time of operation and cost of current as that used in illustration under tests (Chapter XII).

The maximum power to be allowed for plants of various capacities should be as follows:

Capacity in 100% 75% 50%
Sweepers of Load of Load of Load
8 24 20 17
6 20 18 15
4 14 12.25 10.5
2 7.5 ..... 6.25

In event that the plant is to be run with vacuum “on tap,” as in a hotel, a guaranteed power consumption at no load should be required and evaluated on the number of hours the plant will probably operate under these conditions. This will be the largest item in the evaluation under such conditions.