THE NATIONAL CONTROLLED ATMOSPHERE RESEARCH CONFERENCE 



William J. Bramlage 

 Department o£ Plant and Soil Sciences 



On April 5-7, 1977, a National Controlled Atmosphere Research 

 Conference was held at Michigan State University, bringing together 

 nearly 100 persons with professional interests in controlled atmos- 

 phere storage of various commodities. The last such conference 

 was held in 1969, and the main objective of this meeting was to re- 

 view the changes that have occurred since then. The focal points 

 of the meeting were the consideration of new techniques and new 

 problems, and an update on our knowledge of the responses of differ- 

 ent commodities to CA. The full proceedings of the Conference will 

 be available soon, but in this article I will touch on the points 

 that may be of most interest to our readers. 



Storage construction . Probably the biggest concern today with 

 storage construction, is the problem of how to fireproof polyure- 

 thane satisfactorily. Flame retardants have been of limited value, 

 and some of the approaches that are being taken either are not prac- 

 tical in a storage or are of unproven durability. Several speakers 

 concluded that the most reliable way to fireproof urethane is to 

 cover it with one-half inch of cement mortar. Mr. Keith Clarke, 

 of Vineland, Ontario suggested that at a minimum, a urethane-sealed 

 storage should be dealt with as a highly flammable structure: 

 Treat it as a farmer does his haymow, he suggested. Some storages 

 have burned because their owners were using them as workshops! 



Construction methods were discussed by Mr. D.L. Hunter of 

 Yakima, Washington. Of considerable interest today is how to con- 

 serve energy in the storage. He pointed out that large rooms (e.g., 

 40,000 bu capacity) are most efficient, as are large capacity re- 

 frigeration units. However, large units give you less air move- 

 ment per unit. One common mistake in storage is to put fans in 

 front of cooling coils. This arrangement adds the heat from the 

 fan to the room air. 



Mr. Hunter also described the use of a rubber gas seal that 

 can be sprayed on behind the insulation. Rubber gas seals have 

 been very successful where they have been applied carefully. The 

 first storage to use this material was built in 1969 in Kelowna, 

 British Columbia; this storage has been expanded three times since 

 then, always with th-e rubber vapor barrier, and over a million 

 bushels of apples are now stored in it. The operator of this stor- 

 age was at the Conference and verified the successful use of this 

 gas seal. 



