120 RADIOISOTOPES IN BIOLOGY AND AGRICULTURE 



Where there is a greater possibiHty of contamination, strippable films are 

 recommended, preferably a vinyl type. Care must be taken to provide 

 a good base for the strippable film. Cracks between wall panels may be 

 sealed by using polyethylene or vinyl tapes. 



The usual laboratory utilities such as gas, air, vacuum, water, and elec- 

 trical outlets will be required. Adequate circuits should be available to 

 provide for hot plates, water baths, heat lamps, and muffle furnaces, 

 which require considerable current. Fluorescent lighting is generally 

 recommended because of lower operating cost and less heat production. 

 It is advantageous to use a voltage-stabilizing unit for the counting room 

 to avoid errors due to fluctuations in the line supply, and a ground wire 

 should be installed. 



For the most part, conventional laboratory benches may be used, with 

 emphasis on the elimination of dust-catching protrusions or cavities and 

 the use of cup sinks rather than open troughs. The decontamination 

 properties of the bench top are not particularly important, since most 

 operations are carried out over trays bedded down with absorbent paper. 

 Continuous stainless-steel bench tops are not necessary. Drains should 

 be as short as possible and located so as to permit ready access for mon- 

 itoring or repair. The use of flanged joints in the drainage system will 

 permit the easy removal of pipes. Cast-iron drains and piping should be 

 adequate, although silicon iron, at a higher initial cost, will be most 

 acid-resistant. 



Stainless-steel sinks, commercially available, offer certain advantages 

 over those of soapstone or porcelain. The sink should not have sharp 

 corners, which are difficult to clean. In sinks to be used for routine dish- 

 washing, conventional hand controls are preferred. However, in loca- 

 tions where the faucets must be operated intermittently during a period 

 when the hands and gloves are contaminated, elbow or foot controls have 

 been found convenient. Ample drainboard space is very helpful. Peg- 

 boards for drying glassware are not recommended; rather, arrangements 

 can be easily devised so that the glassware can be drained without contact 

 between the inside of the vessel and a supporting structure. Grilles of 

 stainless steel or parallel stainless-steel rods are very handy for this 

 purpose. Small cup sinks are recommended for the reception of radio- 

 active wastes, since they have a minimum of exposed surface to become 

 contaminated. 



Ade(}uate ventilation is of utmost importance and is directly related 

 to the air flow of the hoods. The continuous supply of free air can often 

 be made available by the use of simple door louvers. The removal of air 

 by hoods must also be taken into account in calculating the heating capac- 

 ity required and the placement of the heating units. Unit blowers offer 

 some advantage over radiators in that the latter take up floor space and 



