pass through a 34-in ring, for concrete in thin sections, or sections with closely spaced reinforcements, to those which pass through a 12-in or 2-in ring, for concrete in foundations.

(4) Crushed rock is bought by the cubic yard or ton. One cubic yard of crushed trap-rock, with 45% of voids, weighs approximately 2700 lb. For reinforced-concrete work the physical qualities of crushed rock should be the same as for gravel.

(5) Steel reinforcing-bars are bought by the hundredweight and shipped from the mill or warehouse either in stock lengths or cut to the dimensions required for the different portions of the work. The maximum length for single car shipments is 40 ft, when it is desired to ship bars of greater length, two cars are loaded as one. The maximum stock length at most mills is 60 ft. Eighteen tons, 36 000 lb, is a minimum car-load for interstate shipment. Prices are computed on a BASE-PRICE which applies to 3/4-in or larger, plain round, plain square, or deformed bars; and the smaller sizes carry standard extras varying from 10 cents per hundredweight for 5%-in bars or rods, to 40 cents for 3⁄4%-in, and to $1.00 for 1/4-in bars or rods. There is also an extra charge for cutting to length. Reinforcing steel should be tied in bundles of 50 or 100 lb and plainly marked. If the bending is done before the steel is delivered to the job, each rod, or set of rods, should be marked in such a way as to identify their location in the building. These matters should be specified in the order. The STANDARD SPECIFICATIONS of the American Society for Testing Materials, or the MANUFACTURER'S STANDARD SPECIFICATIONS applying to the grade of steel desired, are used to define the character of the materials for both steel rods and mesh-reinforcement. In this connection, it should be noted that steel of either a STRUCTURAL OR INTERMEDIATE GRADE is to be preferred to steel of the harder grades when it is planned to do the bending on the job, provided, of course, that the design-requirements are satisfied. In regard to the purchase of rusted steel, it has been found that a slight surface-coating of rust is not detrimental; but when it is contemplated to use material in this condition, it should not be purchased without a thorough inspection in order to be sure that the rust is merely superficial. Spirals for column-reinforcement are shipped in the collapsed form, and the diameters of the steel are expressed in either the values of the standard wire-gauges, or as fractions of an inch, as for ordinary reinforcements. In case partial shipments are made, which is usually the case, the date at which the steel is required for the various parts of the building should be given.

(6) Lumber is bought by the 1 000 (M) sq ft, board-measure, a square foot, board-measure, being 12 in long, 12 in wide, and 1 in thick, except as reduced by the planing of the material. Prices for any particular kind and grade of rough lumber are computed on a BASE-PRICE for certain sizes, to which EXTRAS are added for increased lengths or widths. Rough lumber is used for the supports of the centers, and in fact for nearly all purposes except the forms which come in contact with the surface of the concrete, or when it is necessary to plane the edges in order to make a tight connection between the sides and bottoms of beam-troughs, etc. A good quality of sound lumber should be used, the choice depending upon the local market. In the Eastern States, North Carolina

pine roofers, -in, tongued and grooved are generally used for the decking of the floor-forms supporting concrete slabs and for wall-forms. Formerly, spruce was very widely employed for all the heavier portions of the work, but recently it has been largely replaced by short-leaf yellow pine as a matter of economy. Rough spruce lumber, thoroughly dry, weighs approximately 2 100, short-leaf yellow pine 2 650, and North Carolina yellow pine roofers 2 300 lb per 1 000 sq ft. The order is made up from the REQUISITION, OF LUMBER-SCHEDULE, and should contain a brief specification in regard to the character of the stock which may be expressed as follows:

(1) The sizes given in the schedule for dressed material are FINISHING SIZES, and the manner of planing shall be such that there is no variation between pieces shown to be of the same size.

(2) All boards and timbers shall be approximately straight, and in any case, shall not show a variation from a straight line of more than 1⁄2 in in a 16-ft length; and there shall be the same proportional variation for sticks of other lengths.

(3) No knots other than sound knots shall be permitted; and no knot shall be permitted which decreases the sectional area of the stick more than 20%.

(4) The ends of all sticks shall be sound and free from checks. A small amount of bark may be permitted on the corners of rough lumber, but not on dressed material.

The lumber is usually delivered during the early stages of the work so that the carpenters may make the forms while the excavation is going on.

4. Orders for Fabricated Materials Set by the General Contractor. As in the case of orders for UNWORKED MATERIALS, a BRIEF SPECIFICATION is used to describe the materials to be furnished. The four points to be considered in the order are the same as those given in the former instance, but the description must usually be amplified by so-called SHOP-DRAWINGS, made either in the general contractor's office or submitted by the subcontractor.

In reinforced-concrete construction, much of the work falling under this classification includes items made of cast iron or steel, such as steel doorframes, pit-frames, manhole-frames, etc., and cast-iron door-sills, windowguards, wheel-guards, etc., which are often set when the concrete is placed. The price of such work is based upon the weight of the material and the labor of shearing, punching, and riveting; and is usually quoted as a LUMP-SUM FIGURE for the work covered by any particular order. Unless called for in the general specifications, it is not ordinarily necessary to include a description of the quality of material to be used in these minor elements of the work; but if such description is required, the STANDARD SPECIFICATIONS FOR STRUCTURAL STEEL or FOR CAST IRON, of the American Society for Testing Materials, can be incorporated in the order. The main points to be emphasized in ordering materials of this character are (1) the necessity of strict conformity with the detail drawings, or with contiguous work on the job, and (2) delivery in ample time, so as not to delay the progress of the work, especially when the metal frame, or sill, etc., is to be set in place when the concrete is cast.

MILLWORK is another type of material falling under this classification for

which shop-drawings are necessary. The order should contain a COMPLETE TABULATION, giving the number, size, and type of doors, sashes, frames, etc., and should be completely illustrated by accompanying drawings. The price of such work is ordinarily quoted as a lump-sum. The SPECIFICATIONS FOR MILLWORK are usually very complete in architect's general specifications, and should be copied into the body of the order.

5. Subcontracts. Subcontracts are occasionally used to replace ordinary orders when the materials furnished are WORKED TO A SPECIAL DESIGN, even if no work is done on the job by the subcontractor's men. But although the individual or firm furnishing such materials would, under Article 1 of the GENERAL CONDITIONS OF THE CONTRACT, in the STANDARD FORM of the American Institute of Architects, be considered a subcontractor, the agreement for such services can usually be written as a simple order. When, however, work is actually required to be executed on the job in connection with the furnishing of materials, a SUBCONTRACT-AGREEMENT should be made between the general contractor and the individual or firm intrusted with that portion of the construction. This agreement must contain all the elements of an order, giving the precise scope of the work, with full specifications, prices, method of payment, time of starting and completion of work, and the stipulations of a general nature necessary to insure a proper coordination of the work and a relationship between general contractor and subcontractor consistent with the obligations of the former to the owner. The STANDARD FORM OF AGREEMENT BETWEEN CONTRACTOR AND SUBCONTRACTOR, published by the American Institute of Architects and reprinted on page 423, can be used when the general contract is based upon the GENERAL CONDITIONS OF THE CONTRACT, published by the same authority (see page 411), with any additional articles that may be necessary to guard the general contractor's interest, and with the appropriate changes relative to the basis of payment and the speed-requirements.

6. Supplementary Articles Applying to Subcontracts. As the subcontractor is primarily responsible to the general contractor for the proper execution and coordination of his work, these ADDITIONAL ARTICLES are principally in the nature of AMPLIFICATIONS and EXPLANATIONS of the general stipulations of Article 44 of the GENERAL CONDITIONS OF THE CONTRACT of the STANDARD FORMS of the American Institute of Architects, in which the subcontractor assumes to the general contractor all the obligations and responsibilities that the general contractor has assumed under the contract to the owner. With this end in view it is usually necessary to add to this STANDARD FORM OF AGREEMENT BETWEEN CONTRACTOR AND SUBCONTRACTOR additional Articles relating to the following subjects:

(1) ADDITIONAL DRAWINGS AND SPECIFICATIONS furnished by the general contractor and detailing work to be performed by the subcontractor.

(2) The MATCHING AND FITTING of work covered by any particular subcontract with contiguous work, for which purpose actual measurements should be taken at the job, in case the building has progressed sufficiently to make this possible; and, if not, the obtaining of the general contractor's authority to use the figured dimensions on the drawings.

(3) The obligation of the subcontractor to report to the general contractor any DEFECTS IN WORK not included in his contract, but upon which the accurate performance of his own work depends, in ample time to permit the general contractor to remedy such defects.

(4) The approval of the general contractor as well as that of the architect for ALTERATIONS in the work. The general contractor's privilege of inspection both in the shop and on the job.

(5) The CONSIGNMENT OF FREIGHT-SHIPMENTS of subcontractor's materials in the name of the general contractor.

(6) Compliance with the RULES of the National Board of Fire Underwriters and of all other LOCAL OR STATE LAWS AND ORDINANCES, and a distinct understanding in regard to just what PERMITS are to be obtained by the subcontractor.

(7) The general contractor's RESPONSIBILITY FOR DAMAGE to the work or other loss sustained by the subcontractor, due to fire, water, wind, theft, or other

causes.

(8) The employment of NON-UNION LABOR on union-jobs.

(9) In subcontracts calling for payments on a cost-plus-commission basis, or a cost-plus-fee basis, the questions of NIGHT-WORK and OVERTIME should be clearly covered, especially when there is a penalty time-clause.

7. Basis of Payment in Subcontract-Agreements. Articles 26 and 44 of the GENERAL CONDITIONS OF THE CONTRACT above referred to, are applicable when both the general contractor and the subcontractor receive their remuneration on the same basis, and particularly when partial payments are made on an approved estimate of the value of work accomplished, or on a schedule of amounts due the contractor at certain stages of the construction. Under these conditions it would appear just that the subcontractor receive the total of the monies disbursed by the owner on behalf of the subcontractor's work or, in the general case, the subcontractor receives his proportional share of each of the owner's payments.

If, however, the owner sees fit to make a COMMISSION-AGREEMENT or a FIXEDFEE AGREEMENT with the general contractor, because of the latter's particular qualification for the work, there is no reason why the financial advantage which is thus obtained should be automatically passed on to the subcontractor. Consequently, the majority of subcontracts, except when it is impracticable to make an accurate estimate of cost, are usually written as LUMP-SUM AGREEMENTS, even when the general contractor's remuneration is in the form of a COMMISSION, or of a FIXED FEE. Under these conditions, it is customary to base the PARTIAL PAYMENTS to the subcontractor on the value of his work accomplished, deducting any charges for material or for service furnished by the general contractor, and retaining a percentage until the time of final payment upon acceptance by the architect of that portion of the work.

In order to obviate any misunderstanding between the general contractor and subcontractor in regard to the value, or proportional amount, of the subcontractor's work up to any particular stage of the operation, it is often necessary to DEFINE THE BASIS UPON WHICH THE QUANTITIES ARE TO BE COMPUTED more specifically than required in the general-contract documents.

example, in the case of excavation, when the subcontractor is paid on the basis of yardage measured in place, it should be stipulated that the computation of volumes is to be made from a series of cross-sections taken before and after the work, and which are to be checked by representatives of both parties to the contract. Again, with contracts for such work as heating or plumbing, there are likely to be disagreements regarding the proportion of the whole installation represented by some particular part of the work, and when several partial payments are to be made, the amounts to be paid at different stages of the work should be stipulated.

8. Completion Dates in Subcontract-Agreements. Section 3 of the STANDARD FORM OF AGREEMENT BETWEEN CONTRACTOR AND SUBCONTRACTOR, suggested by the American Institute of Architects, provides space for the requirements in regard to TIME OF COMPLETION. In certain classes of work merely a completion-date is adequate, but it is usually advisable to state, also, dates for the furnishing of materials and for the COMMENCEMENT OF WORK, as well as for the final completion. When it is impossible at the time of signing the agreement, to determine the exact dates for STARTING THE DIFFERENT PORTIONS OF THE WORK, a statement can be made to the effect that each shall proceed within a stipulated period after notification by the general contractor's superintendent that the building is ready for the subcontractor's installation. A definite time should also be set for the FURNISHING OF SHOP-DRAWINGS, when they are not available at the time of signing the agreement. For extensive work, such as plumbing and heating, the subcontractor should be required to keep in touch with the operations on the job, and to start his own work as soon as conditions permit.

9. Specification of Subcontract-Work. Section 2 of this STANDARD FORM OF AGREEMENT BETWEEN CONTRACTOR AND SUBCONTRACTOR provides for a description of the work covered by the subcontract. In some cases an extract from the general specifications, with appropriate references to the drawings is adequate, but usually it is necessary to include a SUPPLEMENTARY SPECIFICATION, not only to cover any technical omissions in the former, but to include those details which are necessary to carry out the general intent of the specifications, and which, although they may not affect the completed construction, are vital to the efficient progress of the work. For example, the SEQUENCE OF THE WORK included in any particular subcontract, the portions to be done first, or any special methods of procedure, are not ordinarily treated in the general specifications; but they may be of the utmost importance in the management of the job as a whole, and may materially influence the resulting cost for which the general contractor is responsible.

There are also many matters which affect only the RELATIONS BETWEEN THE GENERAL CONTRACTOR AND THE SUBCONTRACTOR, such as the use of the general contractor's plant, the furnishing of timbers, runways, and scaffolds, the use of pipe-lines, etc. Ordinarily the preliminary articles of the general specifications cover the use of water, light, and power; but many of these matters often need amplification in order that misunderstandings may be avoided on the job. Another very important consideration, in reinforced-concrete con