The Evaluation of Wood Preservatives 



Part I 



Interpretation and Correlation of the Results of 

 Laboratory Soil-Block Tests and Outdoor Test Plot 

 Experience, with Special Reference to Oil -Type 

 Materials 



By REGINALD H. GOLLEY 

 (Manuscript received September 22, 1952) 



This paper offers a review and interpretation of laboratory and field experi- 

 ments aimed at determining the necessary protective threshold Quantities of 

 wood preservatives. It details the procedure followed in the soil-block tests at 

 the Bell Telephone Laboratories^ Incorporated. Discussion of specific criti- 

 cisms of the techniques involved and replies to these criticisms are included. 

 The paper also presents for the first time a correlation of the results obtained 

 from soil-block culture tests, outdoor exposure tests on stakes and on pole- 

 diameter posts as well as pole line experience. It demonstrates that the same 

 levels for toxicity -permanence requirements (thresholds) are obtained from 

 the three different types of accelerated experimental evaluations. There is 

 every reason to believe that the same limits apply for the outer inch of sap- 

 wood in pine poles in line. 



TABLE OF CONTENTS 



Introduction 121 



A Short History of the Development of Laboratory Evaluation Procedures 124 



Evaluation by Soil-Block Tests. 132 



General Procedures 132 



Inoculation and Incubation Rooms 134 



Soil Characteristics and Moisture Content 134 



Even-Aged Cultures 138 



Standard Test Organisms 138 



The Scope of the Soil-Block Evaluation Test 139 



Preparation of the Test Blocks — Manufacture 140 



Test Block Selection for Density 141 



Average Block Volume 141 



Treatment of the Test Blocks 142 



Retention Gradients 143 



The Amount of Preservative in the Blocks 144 



120 



