68 



at least a twenty (20) inch vacuum during the period of artificial sea- 

 soning, until such time as the water accumulating in the hot well of 

 the condenser is not in excess of one-tenth (1-10) of a pound of water 

 per cubic foot of timber in charge, per hour. 



Air Seasoned Sawed Lumber and Timber 



This material, as in the case of green or freshly sawed lumber and 

 timber, shall be treated separately and in no case shall it be mixed 

 and treated together in the same 'ieylinder charge with other material 

 of different moisture content. 



In this case, the period of artificial seasoning may be dispensed 

 with, but the material must be held in the hot oil, under the same tem- 

 perature limits outlined for green lumber and timber until it is heated 

 sufficiently to permit proper treatment. This having been accom- 

 plished, pressure may be applied until the specified absorption has been 

 reached. 



When air seasoned sawed lumber and timbers are found to be case 

 hardened, preliminary steaming will be allowed, at atmospheric pres- 

 sure only, until the case hardening is relieved. 



Inspection of Treated SaVved Lumber and Timber 



Physical Condition'. After the material has been removed from the 

 treating cylinder and allowed to cool in the air for not less than six 

 (6) hours, it shall be free from excessive checking, water bursts, warp- 

 ing, shrinkage, or any other defects due to improper treatment and 

 which, in the opinion of the inspector, would impair its strength and 

 durability for the purpose intended. 



Absorption. Shall be as specified by the purchaser. 



Penetration. The . treated material shall be accepted upon the 

 showing of black or very dark oil penetration, slight discoloration of the 

 wood due to treatment not being considered in determining penetration. 

 If, upon boring the material, it is found that the borings contain free 

 moisture, the inspector shall reject any such material and have the 

 same retreated. The acceptance of lumber shall be based on the pene- 

 tration shown by boring at least twenty-five (25) per cent of the lumber 

 in each charge. 



The penetration for any given absorption shall be based on the 

 surface area exposed. The theoretical depth to be obtained with a spec- 

 ified amount of creosote oil is shown for information on the curves for 

 various sizes of lumber and timber, in Diagram II. 



