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 FOREST PRODUCTS LABORATORY t FOREST SERVICE 
 U. S. DEPARTMENT OF AGRICULTURE 
 
 SMALL SAWMILL IMPROVEMENT 
 
 PRACTICAL POINTERS TO FIELD AGENCIES 
 
 BURNING M JASTE MATERIAL 
 
 Green slabs, edgings, and trims can be burned without a forced draft if 
 such material is in a loose pile. Sawdust, either with slabs and edgings, or 
 separately, usually requires a forced draft. The destruction of waste should 
 occur as fast as it is produced. 
 
 The destruction of accumulated piles of sawdust can be speeded by using a 
 blower powered by a l-l/2 to 5 horsepower unit. About 2^ feet of outlet pipe 
 having a diameter of 6 inches or more permits locating the blower away from 
 fire hazard. A steady, diffused flov; of air is effective, a direct and intense 
 draft on the burning zone is not; hence, outlet pipes of relatively large diam- 
 eter are used, the fans are run at slow speeds, and the air stream is directed 
 to hit the ground at the base of the pile on the windward side. The blower is 
 moved as wind direction changes and as the pile is consumed. Anchoring to 
 skids provides a firm base and ready 'mobility. 
 
 The waste disposal method chosen for use at a small mill should be deter- 
 mined by comparing the capacity and the installation, upkeep, and depreciation 
 costs of the various methods. That requiring a minimum installation cost is to 
 convey the sawdust to the pile with a conveyor chain or a blower, and slabs and 
 edgings by hand labor. One man can keep up with a production rate of S00 board 
 feet per hour if the carry is within ^>0 feet. Slabs and edgings are picked off 
 the rolls or ground near the rear of the edger on the trick side and carried 
 directly away from the mill to the pile. The fire should be at least ^0 feet 
 from the tracks, and preferably be located so that prevailing winds blov; from 
 the mill to the fire. The work can be lightened or the distance lengthened by 
 installing skiels leading to the fire so that waste material can be placed across 
 them and pushed. Slabs will slide by gravity if the slope is one foot vertiefl 
 cally to two horizontally. This method is illustrated in a previous paper of 
 this series (.*+S2221, Flan No.l, I.:imeo.R899-10). With some additional install - 
 tion cost, slabs and edgings can be conveyed to the fire on a slab car. This 
 raises the one-man capacity to about 1,000 board feet per hour or increases the 
 carry to 100 feet (.1+S2221, Flan No. 2, Mimeo.RS99-10). 
 
 An alternative method involving more ec uijpHeJr^'^ir^ifiJji^iiWvant installa- 
 
 tion cost, but requiring less manpower and jr 
 sists of a conveyor-burner combination. Th: 
 production and to considerable distance. 
 
 :J»M«: 
 
 hazard, con- 
 rate of 
 
 s can be adapted to any 
 
 OCT 11 1972 
 
 be shown by balancing t le yearly 
 
 The wisdom of using such equipment can 
 cost against the cost of labor saved. A conveyor system will save ;he labor of 
 at least one man for capacities up to l,000|^AS.fe4ii~ 1 ^iTjf^Orida' 5 to three 
 for higher production rates, and permit pa okagu" piling in lords . Ifetajls of the 
 conveyor are given in another paper of this series (A3222^, Kimeo.RS99-21 ). 
 
 ^o. No. R399-22 
 
 t Maintained at Madison, Wisconsin in cooperation with the University of Wisconsin 
 
 •See outline in Small Sawmill Improvement Working Plan, March 1930, for explanation of indexing system proposed 
 
The burner should be located at least "JO feet from the mill and so that 
 prevailing winds blow the smoke away from the mill. If forced draft is needed, 
 a small fan type of blower is used, A 20- gage pipe about £ inches in diameter, 
 preferably housed in a wood casing and sunk below ground level, carries the air 
 from the fan to the burner. The fan can be powered from the saw mandrel or by 
 a separate power unit ranging from l-l/2 to 3 horsepower. The separate unit 
 permits a draft when the mill is not operating. Various types of outlets are 
 used to diffuse the draft under the burning material. 
 
 In a simple burner, the pipe outlet centers the pit. Rocks or fire bricks 
 are loosely heaped to give a base about k feet across and a peak 2-1/2 feet 
 high. The overhead conveyor should discharge the refuse on this heap; the re- 
 quired draft results from the air forced through the openings in the pile 
 (fig. 1). 
 
 Another relatively inexpensive burner-L (fig* 2) provides for greater 
 diffusion of the draft. If slabs and edgings are burned, a shield of rocks, 
 laid alongside and over the bricks but leaving the vents unobstructed, insures 
 that the bricks are not displaced by falling pieces. More expensive variants 
 are grates (fig. 3 )i-^r- perforated piping (fig. 4)— • Perforated piping func- 
 tions well on sawdust, but is less suitable for slabs. 
 
 A simple type of enclosure wall is shown in fig. 5* F° r more permanence 
 the iron pipe posts of fig. 6— can bo used. 
 
 Contributed by 
 
 C. J. TELFORD 
 
 Small-mill Specialist 
 
 October 19*14 
 
 -Region 2 Construction and Maintenance Handbook, U. S. Forest Service, 
 Denver, Colo. 
 
 Mimeo, Mo. R899-22 -2- 
 
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