CONTENTS Losses incurred in seasoning lumber_.. Seasoning of lumber in sawmill yards_ Sawmill yard arrangement and layout_. Width and spacing of lumber piles___ Page Steam-heating equipment of dry kilns__. Why the final kiln-drying stage needs more heat and less humidity. ILLUSTRATIONS 1. Scheme of pile and alley numbering for sawmill yard. 2. New longitudinal pile foundations on concrete piers_ 3. Old foundation contrasted with improved form_. 4. Two views of foundations on concrete piers_---. 5. Foundations too low and handicapped by weeds_. 6. A typical foundation bent_-. 7. Short lumber piles on longer stringer foundations_ 8. Foundation supported on wooden blocks----- 10. Double-ranked piling of Red River Lumber Co. served by locomotive 18. Elevated tramcar helps in piling lumber.. 21. Diagram of arrangement of tiers in box piling- 22. Yard alleys showing common form of pile roofs_. 23. Cross section of side-piled lumber pile--- 24. Pile shield for end of pile of 3-inch cypress- 25. Pole stacking for reduction of blue-stain damage_ 26. Samples showing checking and honeycombing- 45. Kiln load piled with narrow vertical vents___ 46. Kiln load piled with liberal vertical air vents__. 47. Kiln load mechanically piled of package units_-- 48. Convenient form of control chart for progressive kilns- 49. Conventionalized cross section of compartment kiln_- 50. Edge-stacked kiln load collapsed by shrinkage in kiln 51. Study of two kinds of spacing between boards_ 52. Use of form for shaping chimney in kiln load. 55. Kiln load with flared chimney reaching part way up. 56. Piling frame with sticker spacing racks---- NATIONAL COMMITTEE ON WOOD UTILIZATION R. P. LAMONT, chairman. R. Y. STUART, Forester, United States Forest Service, Department of Agriculture, vice chairman. AXEL H. OXHOLM, director. DUDLEY F. HOLTMAN, construction engineer. EDWARD EYRE HUNT, secretary. The National Committee on Wood Utilization, established by direction of President Coolidge, comprises over 150 members, representing manufacturers, distributors, and consumers of lumber and wood products. Its object is to work for closer utilization of our country's timber resources. The committee, whose headquarters are in the Department of Commerce, Washington, D. C., works in close cooperation with a number of official and private organizations, notably the Bureau of Standards of the Department of Commerce and the Forest Products Laboratory of the Forest Service, Department of Agriculture. SUBCOMMITTEE ON SEASONING, HANDLING, AND CARE OF LUMBER B. F. DULWEBER, president Kraetzer-Cured Lumber Co., Greenwood, Miss., chairman. WALTER ROBINSON, vice president Pickering Lumber Co., Kansas City, Mo., vice chairman. MANUFACTURERS' SUBCOMMITTEE A. TRIESCHMANN, chairman; Crossett Watzek Gates, Chicago, Ill. C. R. JOHNSON, president Union Lumber Co., San Francisco, Calif. W. M. NICHOLS, resident manager, the Pioneer Lumber Co., Elrod, Ala. J. M. PRITCHARD, hardwood operating manager, Kirby Lumber Co., Silsbee, Tex. CARL L. WHITE, president, the Breece-White Manufacturing Co., Arkansas City, Ark. FOREWORD Probably no other measure will so greatly increase the usefulness of lumber as its proper seasoning-not only because the seasoned stock is increased in strength from one to three times as compared with green lumber, but also because its lasting qualities are enhanced and charges for freight, and handling costs, are greatly reduced. For this reason modern or efficient wood-utilization practice must have for one of its most important parts efficient methods for the seasoning, handling, and care of lumber. In modern business to-day the old adage "Check the evil at its source applies, and particularly in this instance. It is natural and logical that lumber should be seasoned before it leaves the mill, hence the responsibility of the manufacturer in supplying to the consumer, the fabricator, and the distributor well-seasoned stock. This edition is the fourth of a series of four bulletins covering the seasoning, handling, and care of lumber. The facts and findings are largely based upon the replies to questionnaires sent to manufacturers of practically all the commercial wood species of importance in the United States and represent a summary of the methods which they employ. This report is intended to point out in a purely suggestive way the various methods of producing properly seasoned lumber. Yard layouts, methods of handling, and yard seasoning are also discussed. The report has been prepared for the subcommittee by the late Albert Benjamin Cone, of the committee staff. Acknowledgment is made of the valuable services and assistance given by the United States Forest Service through its Forest Products Laboratory; from the Division of Building and Housing, Bureau of Standards; from the Agricultural Engineering Division, Bureau of Public Highways, United States Department of Agriculture; from the National Lumber Manufacturers' Association and its regional organizations; and from all those whose plant facilities were inspected in the field surveys, or who have cooperated in supplying material for questionnaires which form the basis for this report. Appreciation is also due to C. J. Hogue, Albert Hermann, and Phillips A. Hayward, for their valuable assistance in the compilation of this publication, and to those others who have assisted in criticizing and revising this report. APRIL 15, 1929. AXEL H. OXHOLM, Director. SEASONING, HANDLING, AND CARE OF LUMBER FOR MANUFACTURERS INTRODUCTION This report on the seasoning, handling, and care of lumber by the manufacturer is in no sense an instruction manual. There is already a liberal amount of instruction text on various phases of the subject, and the report attempts to review this text and ascertain how far its details are reflected in the general practice of lumber manufacturers. This is imperfectly accomplished, because of the lack of adequate survey of the subject at the mills in the various lumber manufacturing regions; the information used has been secured largely from studies made and reported by others, and chiefly by the experts of the Forest Products Laboratory or other branches of the United States Forest Service, some of them in cooperation with various lumber manufacturers' associations. Considerable additional information has been brought in by replies to questionnaires sent out, for the purpose of securing information for this report, to representative manufacturers in all species of wood and in all lumber-manufacturing regions. These replies give a fair view of the main features of practice in respect to the subjects embraced in the report. As an adequate personal field survey of the entire sawmill industry was impossible, touch was established with approximately 700 manufacturers by the mailing out of elaborate questionnaires on air-drying and on kiln-drying. There was some misgiving in sending this out because of its size, and had it been simple more would doubtless have taken the time to answer it, but the replies would not so completely have covered the subject. It is a matter of some significance that 73 mills, or a little more than 1 in 10, did return replies, most of them very complete. The mills replying were fairly representative of all the commercial species of lumber and reported an aggregate annual production of 3,231,500,000 feet of lumber, or about 8.3 per cent of the total annual production, or an average of 44,050,000 feet per mill, thus indicating that the largest manufacturers were most strongly represented in the replies received. In one respect this is somewhat unfortunate, in that the information compiled from these replies represents seasoning practice somewhat better and more progressive than the general average used in the industry; but this result could be expected. Those who pay most attention to the subject of seasoning will be most apt to reply to a questionnaire on the subject and also will be most apt to have made most progress in their own seasoning practice. The effort of the report is to be of use to the individual manufacturer-to offer suggestions which he may test and discard or adopt |