116 



RuEPixG OR Empty Cell Treatment 



In no case is the Rueping or Empty Cell treatment recommended for piling, 

 regardless of its intended use, or for sawed lumber and timber to be exposed to the 

 action of marine borers. 



If sawed lumber and timber are to be treated for uses other than those mentioned 

 above, and empty cell treatment is desired, the following procedure is recommended: 



Following the warming up period in the case of air seasoned material, or the 

 seasoning period in the case of freshly cut or green material, as previously described, 

 and as soon as the treating cylinder has been completely drained, the timber shall 

 be subjected to an air pressure of sufficient intensity and duration to provide for the 

 injection of the preservative necessary to secure the specified final retention of pre- 

 servative. The preservative shall then be introduced, the air pressure being main- 

 tained constant until the cylinder is filled. The pressure on the preservative shall 

 then be gradually raised until it is not less than one hundred (100) pounds per square 

 inch greater than the air pressure at which the treating cylinder was refilled. This 

 pressure must l)e held until sufficient preservative has been introduced to insure the 

 specified final retention after the final vacuum has been applied. 



Pressures in excess of two hundred (200) pounds per square inch will not be 

 permitted. The temperature of the preservative during the pressure period shall be 

 not less than 170° F. nor more than 190° F. Upon completion of the pressure period, 

 the treating cylinder shall be speedily emptied of preservative and a vacuum of not 

 less than twenty-two (22) inches promptly created and maintained for a period not 

 to exceed two (2) hours; this in order that the material may be removed from the 

 treating cylinder free from dripping preservative. 



Inspection of Treated Sawed M.a.terl.\l 



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, warping, 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. 



NET ABSORPTION 



Shall be as specified by the purchaser. Final retention shall be determined by 

 weighing sufficient representative material before and after treatment and making 

 necessary corrections for loss in its moisture content. 



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 con- 

 sidered 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 penetration shown 

 by boring at least twenty-five (25) per cent of the lumber in each charge. The pene- 

 tration for any given absorption shall be based on the surface area exposed. The 

 theoretical depth to be obtained with a specified amount of creosote oil is shown for 

 information on the curves for various sizes of lumber and timber, in fig. 44. 



