CHAPTER XIV.Specifications.
Before the engineer begins to prepare his specifications for a proposed vacuum cleaning system, he will naturally consider carefully the conditions to be met in the particular installation contemplated. Having considered these conditions, he can readily determine the type of system that will operate most efficiently and economically under such conditions. It is, therefore, natural to assume that the best interests of his clients can be obtained by confining his specifications to apparatus of the type giving the most efficient results for the special conditions to be met. However, it is also necessary to study the apparatus on the market to determine if there is a sufficient number of manufacturers producing the particular type of apparatus specified to insure healthy competition and reasonable bids.
It becomes necessary, therefore, to examine the various systems offered by the manufacturers in order to determine what competition can be obtained.
Apparatus for Class 1 or Class 2, if confined to the positive displacement rotary exhausters of the two-impeller type, can be obtained from at least seven manufacturers. If the centrifugal fan is included, at least three other manufacturers can be considered and in either case a healthy competition be had.
If apparatus of Class 3 is desired, it can be obtained from at least three manufacturers. A few years ago more manufacturers of systems of this type were in the market. Some of these have dropped out, owing to the comparatively limited field for this apparatus. However, there are still enough manufacturers in the field to insure competition.
Apparatus of Class 4 has been especially manufactured by one company. However, any of the manufacturers of centrifugalfan type of apparatus can easily meet the specification requirements for apparatus of the character.
It is, therefore, evident that the specification of apparatus of the type best suited to any particular installation will not result in lack of competition, and such a procedure would apparently be justified.
There are installations, such as those for public buildings, where it may be advisable from an administrative standpoint to allow the widest competition possible. In such cases the engineer can secure the best results for his clients by so drawing his specifications as to include all types of apparatus, fixing carefully the test requirements to be met and requiring each bidder to state in his proposal the amount of power required to operate his apparatus under full load, three-quarter load and half-load conditions, and to base the award of the contract on an evaluation basis.
To determine what the basis of this evaluation shall be it is first necessary to ascertain the length of time the plant will be operated at each of the loads specified and find the annual cost of a unit of power to operate the plant. Assuming the plant has a life of ten years, we can charge 10% depreciation, add to this 5% for interest on the investment and 1% for insurance. We can capitalize the saving in power at 16% and use this amount as a basis for evaluation.
As an example, assume one bidder guarantees a power consumption of 1 K. W. less at full load, 1.25 K. W. less at three-quarters load and 0.75 K. W. more at half load than a lower bidder. Assume the plant will operate 500 hrs. per year at full load, 200 hrs. at three-quarters load and 300 hrs. at half load. The total kilowatt hours saved by the more economical plant will be:
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 inChapter XIIand a specification permitting the widest competition, with evaluation and penalty clauses.
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.
5. All parts of the exhauster shall be rigid enough to retain their shape when the machine is working under maximum-load conditions.
6. The impellers must be machined all over and must be of such shape and size that they will revolve freely and not touch each other, the follower, or the casing (cylinder) in which they are placed, but the clearance must be of the least possible amount consistent with successful operation.
7. The shafts must be of steel with the journals ground to size.
8. The journal boxes must be long and rigidly supported by the headplates and placed far enough from the headplates to allow the placing of proper stuffing boxes on the shafts.
9. The shafts of two impeller exhausters must be connected by wide-faced steel gears, cut from the solid and securely fastened to the shafts. Follower shaft on single impeller exhauster to be connected to impeller shaft by crank and connecting rod. The gears shall run in suitable oil-tight gear boxes that shall be fitted with adequate and suitable means for lubrication.
10.Centrifugal Fan Type.The centrifugal fan exhauster to be so proportioned and constructed as to handle the volume of air required at the specified vacuum with the least possible loss. The housing shall be of cast iron or aluminum, made in sections. The housing must be air-tight.
11. The fan wheels to be constructed of steel or other metal of high tensile strength, properly reinforced, and, if cast, mustinclude hub and arms complete in one piece. If the fan wheels are built up, they must be strongly riveted to cast-iron, steel or brass hubs or spiders.
12. The fan wheels are to be secured to shaft with a feather and set screws, or with left-hand screw.
13. The shaft of fan exhauster may be vertical and the wheels so mounted that their weight will equalize or partly equalize the end thrust, or the end thrust may be balanced by the magnetic pull of the armature. Shaft may be horizontal and end thrust taken care of with ball-bearing thrust rings.
14. The journal boxes for all of the above named types of exhausters shall be of the design best adapted for the purpose and must be fitted with first-class approved continuous lubricating devices, either sight feed, ring oiler, or any other kind best suited for the work or design of apparatus used.
15.Cooling.The rotary type of exhauster must be provided with the necessary water connections to properly seal and cool the pump. Fan type of exhauster must be designed to operate continuously without a rise of temperature over 100° F. above room temperature.
16.Speed.Rotary exhausters shall not exceed a peripheral speed of 1,100 ft. per minute at tips of impellers.
17. Centrifugal fans shall not exceed peripheral velocity of 22,000 ft. per minute when running under specified full-load conditions.
18.Mounting.The exhauster, motor and separators shall be mounted as a unit on suitable cast-iron base plate, either mounted on legs or resting on the basement floor.
19.Drive.The exhauster shall be driven by an electric motor, which may be direct connected to the exhauster shaft or be operated with an oak-tanned leather belt, or by cut gearing. Belt and gearing are to be of ample size and strength for their work and must run without undue noise or wear. Means shall be provided to take up the slack of the belt. Furnish and place a suitable metal guard over belt and pulley wheels that shall prevent oil being splashed outside of the base plate and prevent clothing being caught.
20. If the exhauster is operated through cut gearing, the gearingmust be inclosed in an oil and dust proof case, which shall be fitted with means for copious and continuous lubrication of same.
21.Finish.The air exhauster and motor and the base plate shall be finished in a first-class manner, filled, rubbed down and painted at least one coat at the shop, and after installation shall receive two more coats, finishing tint to be as directed.
22.Electric Motor.Motor to be of such size that when operating under test conditions it will not be under less than three-fourths nor more than full-load condition. It is to be of standard make, approved by the architect.
23. Motor to be wound for .... volts direct current.
24. Armature to be of toothed-core construction, with windings thoroughly insulated, and securely fastened in place, and must be balanced both mechanically and electrically.
25. Commutator segments must be of drop-forged or hard-drawn copper of highest conductivity, well insulated with mica of even thickness and proper hardness to insure uniform wear, and shall run free from sparking or flashing at the brushes under all conditions of speed. It must be free from all defects and have ample bearing surfaces and radial depth as provision for wear.
26. Brushes to be of carbon, mounted on a common rocker arm for motor, and to have cross-sectional area of not less than 1 square inch for each 35 amperes of current.
27. Brush holders to be of a design to prevent chattering, with individual adjustment in tension for each brush.
28. Bearings to be of an approved self-oiling or ring type.
29. There must be an insulation resistance between motor frame and field coils, armature windings and brush holders of not less than 1 megohm.
30. Motor must be capable of standing a breakdown test of 1,500 volts alternating current. Either or both of the foregoing tests to be applied at the discretion of the architect’s agent at the time of shop tests.
31. The maximum rise in temperature of the motor at a continuous run (after installation at building) at full speed and full-rated load for a period of eight hours must not exceed 50°C. in windings and 55° C. on commutator above the surrounding atmosphere.
32. Motor to be finished in a first-class manner, filled and rubbed down and painted two coats at the shop, and after installation to have two more coats; finishing tints to be as directed by the superintendent of the building.
33.Tablet.Furnish and mount where directed a polished slate tablet not less than ³⁄₄ in. thick, having mounted thereon one 30-ampere, 250-volt, double-pole knife switch, with enclosed indicating fuses, and, if displacement exhauster is furnished, one automatic self-starter having butt contacts, cutting out starting resistance in not less than two steps, starter to be controlled by the vacuum in separator, and shall stop motor when vacuum rises 2 in. above that required to meet test requirements and start motor when vacuum falls to that required for working.
34.Electrical Connections.This contractor shall run feeders from vacuum cleaner panel in switchboard where shown to the motor panel and make all electrical connections between panel and motor, etc.
35. All wires are to be run in standard steel conduit, except those that are so short as to be self-supporting, and these are to be cord wrapped or otherwise protected. No wire smaller than No. 8 to be used.
36. All material and workmanship to be strictly first class. Electrical work must show an insulation resistance of at least 1 megohm, and to be in strict accordance with the latest edition of the “National Electrical Code.”
37.Dust Separator.There shall be one dry separator located where shown on plans, having a volume not less than 3 cu. ft.
38. The interior arrangement of the separator shall be such that no part of same will receive the direct impact of the dust. Cloth bags or metal screens if used in this separator shall be so placed that nothing but the very lightest of the dust can lodge thereon, and that same may be easily cleaned without dismantling the separator. It must be so constructed that it shall intercept not less than 95% of the dust entering same.
38a. Separator tank shall be constructed with steel shells, with either cast iron or steel heads, and be fitted with suitablebases or floor stands for support and proper openings for cleaning same. Separator shall be fitted with iron-column mercury gauge reading 50% in excess of operating vacuum.
39.Pipe Lines.All pipe lines shall be of the sizes and run as indicated on drawings.
40.Pipes.All pipe conveying air is to be standard black wrought-iron or mild-steel screw-jointed pipe, and is to be smooth inside, free from dents, kinks, fins, or burs. Ends of pipe to be reamed to the full inside diameter and beveled. Bent pipe to be used in mains where necessary and where shown on plans.
41. Care must be taken in erecting pipe to maintain as nearly as possible a smooth, uniform bore through all pipe and fittings.
42.Fittings.All fittings to be tough gray cast iron, free from blowholes or other defects; smooth castings in all cases.
43. All fittings on vacuum lines must have inside diameter through body of same size as pipe bore, and all fins, burs, or rough places must be removed.
44. Fittings on vacuum lines are to be black or may be galvanized.
45. Where space permits, all tees and elbows must have a radius at center line of not less than 3 in.
46. Horizontal overhead pipes to be supported with substantial pipe hangers spaced not more than 10 ft. apart.
47. The hangers must have an approved form of adjustment and the instructions of the superintendent in regard to securing hangers to floor construction, etc., above must be carefully followed.
48. Where exposed pipes pass through walls or floors of finished rooms they must be fitted with cast-iron nickel-plated plates.
49.Clean-Out Plugs.Brass screw-jointed clean-out plugs are to be provided in lines at all turns where indicated on the drawing. The clean-out plugs to be 2 in. diameter, except in the 1¹⁄₂-in. lines, where clean-outs are to be same diameter as the lines.
50.Exhaust Connection.Exhaust pipe from the exhausteris to be run up to the basement ceiling and along same into the smoke breeching beyond damper as directed.
51.Sweeper Inlets.The following number of inlets are to be provided: Subbasement , basement , first story , second story , attic .
52. The sweeper inlets are to be fitted with hinged covers or caps with rubber gaskets arranged to be self-closing when hose is removed, and those in corridors and lobby arranged to be opened with a key.
53. Inlets coming through finished walls or partitions are to be flush pattern.
54. Inlets on risers run exposed against walls are to be set close up against bead of fittings.
55. If contractor desires to use other form of connection than above described which is equally satisfactory, same must be submitted to the Architect for approval after award of the contract.
56. In this specification the word “renovator” is used to mean that portion of the tool which is in contact with the surfaces cleaned; the word “stem,” that portion connecting the renovator and hose; the word “cleaner” is used to mean a complete cleaning tool.
57. The following cleaning tools are to be furnished:
One carpet renovator, with cleaning slot ¹⁄₄ in. by 12 in. long.
One bare floor renovator, 12 in. long, with curved felt-covered face.
One wall renovator, 12 in. long, with cotton flannel curved face.
One upholstery renovator, with slot ¹⁄₄ in. by 4 in.
One corner cleaner.
One radiator cleaner.
One hat brush.
One long curved stem about 5 ft. long.
One extension tube about 5 ft. long.
58. The renovators for carpets, bare floors and walls to be arranged with adjustable swivel joint, so that same can be operated at an angle with stem from 45° for regular use to an angle of about 80° for use under or back of furniture and other similar places. This movable joint to be so arranged that lipsof cleaning tool will always remain in contact with surface cleaned, and constructed so that fitted surfaces are not exposed to dust, and the air currents when deflected to impinge only upon surfaces which are of heavy metal and where such wear as occurs will not affect the operation and handling of the tool.
59. All renovators and stems are to be as light as is consistent with strength and ability to withstand cutting action of dust.
60. The lips of carpet renovators and upholstery cleaner to be of such proportions and form as will prevent injury to the fabric, and such widths as will reduce to a minimum the sticking of renovator face to the material being cleaned.
61. Stems to be not less than 1 in. outside diameter. Air passages in swivels to be same diameter as inside of stem. Stem for use with floor renovators shall be curved near upper end to form handle and provided with swivel to permit hose hanging vertical.
62. Stems to be drawn-steel or brass tubing, not less than No. 21 United States standard gauge thick if steel and not less than No. 16 Brown & Sharpe gauge thick if brass.
63. Carpet renovators to be made preferably of pressed steel, as light as possible, or may be made of cast iron, brass or aluminum with iron wearing face.
64. Bare floor renovators shall have renewable elastic wearing face curved in direction of motion when cleaning.
65. All renovators and brushes must be provided with proper rubber or other approved buffers to prevent marring the woodwork.
66. Upholstery cleaners are to have inlet slots or openings of such size and form as to absolutely prevent drawing in loose covering of furniture.
67. Upholstery and corner cleaners are not to be arranged for use with stems, but are to have their own handles permanently attached and be provided with hose couplings.
68. All metal parts of renovators and stems are to be finished, and all except aluminum parts nickel plated.
69.Hose.Furnish 75 ft. cleaning hose in three 25-ft. lengths.
70. The hose to be 1¹⁄₄ in. inside diameter best quality rubberhose, 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. Couplings for hose to be either slip, bayonet-lock or all-rubber type, with smooth bore of practically same diameter as inside of hose. The couplings to have least possible projection outside of hose dimensions and be well rounded, so as not to injure floors, doors, furniture, etc.
72. Bayonet joints may have packing washer, and slip joints to have permanent steel pieces on ends of hose and brass slip coupler. All ends of hose at couplings to have outside ferrules securely fastened in place, or pure gum ends glued to coupling. Simple conical slip joints slipped into ends of hose without ferrules will not be acceptable. All joints must fit together so that they will not be readily pulled apart.
73.Tests.All piping to be tested with air pressure equal to 5 in. mercury before being concealed in walls and other spaces. Mercury must not fall more than ¹⁄₄ in. in one-half hour.
74. On completion of plant the pump will be operated with all outlets closed and, under these conditions, there must be an interval of not less than 10 min. between the stopping and starting of the motor by the automatic control, if pump system is used. And if fan system be used, the power required to operate the exhauster must not be more than 65% that required in capacity test.
75. To test the capacity of the separator, a mixture containing 6 lbs. of sand, passed through a 50-mesh screen, 3 lbs. of common wheat flour and 16 lbs. of Portland cement shall be spread over 50 sq. ft. of floor and picked up with a renovator attached to the end of 50 ft. of 1¹⁄₄-in. hose. The machine shall be stopped and the material removed from the separator spread on floor and picked up. This procedure shall be repeated until the material has been handled four times. If the separator contains a bag, the same must not be disturbed until after completion of the capacity test, which will be made with the material in place in separator, after being picked up the fourth time.
After completion of capacity test, the contents of separator shall be weighed and if same be a partial separator it must contain 95% of the material picked up. If a displacement machine is used as a vacuum producer, the separator must prevent the passage of any dust through separator, which will be determined by holding a dampened cloth over pump outlet during test of apparatus. Said cloth must not show any dust lodged thereon at end of test.
76. To test the capacity of the plant a standard vacometer, attached to the end of 75 ft. of cleaning hose shall show a vacuum of 2 in. mercury with ¹⁄₂-in. diameter orifice open.
77.Test of Cleaning Tools.The plant shall be operated by the Contractor in the presence of the Architect’s representative, and a test made of each kind of cleaning tool furnished. The tool shall be attached to a 50-ft. length of hose attached to an outlet selected by the Architect’s representative, and under normal working conditions each tool must satisfactorily perform the work for which it was designed. Dust and surfaces to be cleaned shall be furnished by the contractor.
78.Painting.After the completion of the specified tests, all exposed iron work except galvanized iron or tinned work in connection with this apparatus, not specified to be otherwise finished, shall be primed with paint suitable for surfaces covered, and then given two additional coats. Machinery shall be painted as already specified, and all other work shall be given finishing tints as selected or approved by the architect. Black iron pipe, etc., shall be given two coats lead and oil of tint directed.
—When alternating current is available, instead of direct, modify specifications as follows:
23. Motor to be wound for .... volts, .... cycle, .... phase alternating current.
24. Motor to have rotor of the squirrel cage type.
Omit 25, 26 and 27.
28. To remain as for direct current.
29. There must be an insulation between the starter or primary windings and the frame of not less than one megohm.
30, 31, and 32. Same as for direct current.
33.Tablet.Furnish and mount where directed a polished slate tablet having mounted thereon a 30 ampere, 250 volt, .... pole knife switch with enclosed indicating fuses and, if displacement type exhauster is furnished, an automatic starter of the “across the line” type, operated by vacuum in the separator which will stop motor when the vacuum in the separator rises 2 in. above that required to meet test conditions, and start exhauster when vacuum reaches working range.
1. Same as for Class 1.
2. Omit centrifugal fan.
3 to 9. Same as for Class 1.
Omit 10 to 13.
14 and 16. Same as for Class 1.
15. Omit centrifugal fan.
Omit 17 and 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. Motor shall be subject to shop test to determine efficiency, heating, insulation, etc. Manufacturer’s certified test sheets of motor giving all readings taken during shop tests, 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 made, designed for the particular duty it has to perform. It must have an automatic no-voltage and overload release. All resistance for rheostat 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 iron frame, so placed that there will be a space of not less than 4 in. between the wall and back of resistance. Mount on this tablet one double-pole, 250-volt knife switch, with two 250-volt inclosed 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 inclosed with a removable diamond-mesh grill of No. 10 iron wire in channel frame.
34, 35, 36. Same as for Class 1.
36a.Automatic Control.Suitable means shall be provided in connection with the 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 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 there shall be placed in the suction pipe to the exhauster an approved positive-acting vacuum breaker havingopening equivalent to the area of 1-in. diameter pipe and set to open at 10 inches vacuum.
(If plant is to be run for long periods without much load, as in a hotel, omit 36a, b, c, and substitute):
36d.Automatic Control.An approved type of controller for maintaining practically a constant vacuum by varying the speed of the motor driving exhauster arranged to permit the operation of the motor continuously at any speed between full speed and stop, so long as there be no change in vacuum and which will increase speed whenever vacuum falls and reduce speed whenever vacuum rises, must be provided.
37.Dust Separator.There shall be one dry separator located where shown on plans, having a volume of not less than 3 cu. ft. for each sweeper of plant capacity.
38. The interior arrangement of the separator shall be such that no part of same will receive the direct impact of the dust. Cloth bags or metal screens, if used in this separator, shall be so placed that nothing but the very lightest of the dust can lodge thereon, and that same may be easily cleaned without dismantling the separator. It must be so constructed that it will intercept all of the dust entering same.
38a 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 shall contain the following:
One carpet renovator, with slot ¹⁄₄ in. by 15 in.
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 connections at end, 8 in. long, 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 extension tube 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 noncollapsible hose in three 25-ft. lengths.
70 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.Test of Separators.At each of —— points, near —— outlets on different risers selected by the architect’s 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 6 lbs. of Portland cement.
75b. Fifty feet of hose shall be attached to each of the —— outlets, and the surfaces prepared for cleaning shall be cleaned simultaneously by operators provided by the contractor until all of the sand, flour and Portland cement has been taken up, when the exhauster shall be stopped and the dirt removed from the separator and spread on the floor again, and the operationof cleaning repeated until the mixture has been handled by the apparatus four times.
The bag contained in the separator must not be disturbed until after completion of the capacity test, which will be made with material in place in the separator after being picked up the fourth time. After completion of the capacity test the contents of separator will be removed. During test of separators a dampened cloth will be held over the exhaust from pump. If such cloth indicates dirt passing through the separator, same will be rejected.
76. To test the capacity of the 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 vacometers 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.
77 and 78. Same as for Class 1.
—When alternating current is available, instead of direct, modify specifications as follows:
23. Motor to be wound for .... volts, .... cycle, .... phase alternating current.
23a. Bidders must name efficiency and power factor of motor at one-half and full load.
24. Motor to have phase-wound rotor with collector rings for insertion of starting resistance.
Omit 25, 26 and 27.
28. Same as for direct current.
29. There must be an insulation between the starter or primary windings and the frame of not less than one megohm.
30, 31, 32, 32a. Same as for direct current.
33.Rheostat.Furnish and install an approved hand-starting rheostat for inserting resistance in rotor circuit in starting, of proper size to insure the starting of motor in not exceeding 15 seconds without overheating.
33a. Same as for direct current, except that switch must be either three- or four-pole, according to current available.
Omit 36d with alternating current machine.
1. Same as for Class 1.
2. Exhauster shall be of the reciprocating piston 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 device shall be employed to minimize the effect of large clearance.
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; machineshaving an extended piston rod for guide purposes will not be acceptable.
Omit 9 to 13.
14. Same as for Class 1.
15. Reciprocating piston 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.
16.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.
Omit 17 and 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 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 80% at half load and not less than 85% at full load.
24 to 32. Same as for Class 1.
32a. Motor 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, togetherwith 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 rheostat 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 this tablet one double-pole, 250-volt knife switch, with two 250-volt inclosed 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 inclosed with a removable diamond-mesh grill of No. 10 iron wire in channel frame.
34, 35 and 36. Same as for Class 1.
37.Dust Separators.There shall be one dry and one wet separator located where shown on drawings. Each separator shall have a volume of 3 cu. ft. for each renovator of plant capacity.
38. The separator first receiving the dust shall be a dry separator, the interior arrangement of which shall be such that no part of same shall receive the direct impact of the dust. No screens or cloth bags shall be used in this separator and it must be so constructed that it will intercept 95% of the dust entering same.
38a. The second separator must be a wet separator which may be contained in the base of the machine or consist of a separate tank.
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 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, through which the interior of the same may be observed, and an iron-case mercury column reading 50% in excess of operating vacuum, attached to the dry separator first receiving the dust.
38g. The wet separator 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 pipe 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 line 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. The exhaust pipe is to be fitted with an approved first-class exhaust 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 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 shall contain the following:
One carpet renovator, with slot ¹⁄₄ in. by 12 in.
One bare floor renovator 12 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 andsecond 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 to be 1 in. inside diameter of 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, 72 and 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 the plant, .... hose lines each 100 ft. long will be attached to outlets on the system and each hose fitted with a standard vacometer. .... vacometers shall have ¹⁄₂-in. opening and .... vacometers shall have ⁷⁄₈-in. opening. Under these conditions 4 in. vacuum must be maintained at vacometers having ¹⁄₂ in. opening.
75a.Test of Separators.At each of —— points, near —— outlets on different risers selected by the architect’s 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.
75b. Fifty feet of hose of size required by the system 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 above run, any dust or mud is found in the cylinder, ports, or valvechambers of the displacement exhauster, or if less than 95% of the dirt removed is found in the dry separator, it shall be deemed sufficient ground for the rejection of the separators.
76 and 77. Same as for Class 1.
—When alternating current is available, instead of direct, modify specifications as follows:
23. Motor to be wound for .... volts, .... cycle, .... phase alternating current.
23a. Bidders must name efficiency and power factor of motor at one-half and full load.
24. Motor to have phase-wound rotor with collector rings for insertion of starter resistance.
Omit 25, 26 and 27.
29. Same as for Class 1, alternating current.
33.Rheostat.Furnish and install an approved hand-starting rheostat for inserting resistance in rotor circuit in starting, of proper size to insure the starting of motor in not exceeding 15 seconds without overheating.
33a. Same as for direct current, except switch must be either three- or four-pole, according to current available.
1 to 17. Same as 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 bringthe 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. Motor 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 rheostat 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 iron frame, so placed that there will be a space of not less than 4 in. between the wall and back of resistance. Mount on this tablet one double-pole, 250-volt knife switch, with two 250-volt inclosed 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 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 rotary exhauster 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; whenever the vacuum in the separator rises above the point considered desirable, and throw the exhauster into action when the vacuum falls below the established lower limit.
36c. In addition to control, a positive vacuum breaker having an opening equal to 1 in. diameter pipe net for 6 in. of mercury, must be provided on separator.
36d. If centrifugal fan is used, no control or vacuum breaker will be required.
37. Furnish one separator having a cubic contents of 4.5 cu. ft. for each sweeper of plant capacity.
38 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 shall contain the following:
One carpet renovator ¹⁄₂ in. by 15 in.
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 68. Same as for Class 1.
69.Hose Racks.Furnish and properly secure in place, wheredirected, .... 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 to be 1¹⁄₂ in. or 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. Same as for Class 1.
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.
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 useof 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 enclosedwith 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.