INDUSTRIAL FUMIGATION AGAINST INSECTS 43 



be used at the same rate as for the treatment of the large storage 

 sections. 



Furniture 



Insect-infested furniture is usually fumigated in an atmospheric 

 vault, although a vacuum vault can be used and is preferable in cases 

 where infestation is due to wood-boring insects. 



Hydrocyanic acid, ethylene oxide, carbon disulfide, chloropicrin, 

 carbon tetrachloride, the mixture of carbon dioxide with ethylene 

 oxide or methyl formate, and the ethylene dichloride-carbon tetra- 

 chloride mixture can all be used for the fumigation of furniture in 

 atmospheric vaults. 



Hydrocyanic acid and the ethylene dichloride-carbon tetrachloride 

 mixture are used most commonly. A dosage of 8 ounces of liquid 

 hydrocyanic acid or its equivalent, or of 14 pounds of ethylene di- 

 chloride-carbon tetrachloride mixture, per 1,000 cubic feet of space, 

 for a period of 12 to 24 hours will give satisfactory results unless 

 wood borers are involved, when the exposure should be at least 48 

 hours. If any of the other fumigants are used, the following dosages 

 should be applied per 1,000 cubic feet of space: Ethylene oxide, 2 

 pounds; ethylene oxide-carbon dioxide mixture, 20 pounds; methyl 

 formate-carbon dioxide mixtures, 28 pounds; carbon disulfide, 5 

 pounds ; chloropicrin, 1 pound ; or carbon tetrachloride, 30 pounds. 



Furs and Garments 



The protection of furs and fur and other garments in storage by 

 fumigation is becoming more common. The method consists in stor- 

 ing garments in tight rooms (fig. 32) that are so arranged that they 

 can be fumigated regularly. The garments are fumigated in a small 

 vault (figs. 2 and 24) before being placed in the storage rooms (fig. 33). 



CONSTRUCTION OF STORAGE ROOMS 



The large storage rooms may be of any type of construction that 

 is sufficiently tight for fumigation purposes. Usually they are of 

 concrete or of hollow tile covered with Keen's cement. The surface 

 should be finished with two or three coats of good paint, Large 

 shallow evaporating pans are fastened along the walls near the ceil- 

 ing, or are suspended from the ceiling, but so placed that they are not 

 directly over the garments suspended from the racks. These pans are 

 connected by pipes to the storage tank (fig. 34) containing the fumi- 

 gant. If ethylene dichloride-carbon tetrachloride mixture is used as 

 the fumigant, it can be run into the evaporating pans by gravity or 

 by the use of a small compressor. If any of the mixtures of carbon 

 dioxide with ethylene oxide, methyl formate, or methyl bromide is 

 to be used, the evaporating pans are unnecessary, and a piping sys- 

 tem with one or several spray nozzles or cones should be used instead. 

 The cylinders containing one of these mixtures with carbon dioxide 

 are connected to the piping system outside of the room (fig. 23), and 

 the fumigant is applied by merely opening the valve on the cylinders 

 and allowing the required poundage to be discharged. 



The door of the storage room is usually of the safe or refrigerator 



