Storage cabinet

Gas storage cabinets were originally developed for the semiconductor industry in the 1970s. These early storage cabinets consisted of a box that enclosed the tank and connections they were operated under negative pressure and exhausted to the outside. Gas storage cabinets have become more sophisticated, adding gas detection, fire sprinklers, alarms, and pneumatic controls. " Some cabinets have point-of-operation air cleaners such as scrubbers. 

Many building and health and safety codes require the use of gas storage cabinets, exhausted enclosures, and/or separately ventilated gas storage rooms for toxic gases. These controls are also recommended for flammable and corrosive gases. 

Gas storage cabinets consist of a box that encloses the tank(s) and all connections. Many include change out capabilities and an access door. The cabinets are exhausted to remove any contaminant that may leak into the cabinet and to maintain the cabinet under negative pressure relative to the... 

Gas storage cabinets are used to contain compressed gas cylinders containing toxic, flammable, or corrosive gases. 

Gas storage cabinets are designed to contain one to four gas cylinders. The cylinders are connected to a gas distribution system which is also contained in the cabinet. Very sophisticated systems are available from cabinet manufacturers. These may include automatic or semiautomatic change-over capabilities, fire sprinklers, purging systems, and gas detection systems which may include alarms and automatic shutoff. Point-of-use scrubbers may also be incorporated into the design, depending on the gas being used (see Fig. 10.43). 

Gas storage cabinet use may be required by local, state, or national codes. These codes vary by location and the designer or user of the cabinet is referred to these codes for further information. One source of building code information in the U.S. is the Uniform Building Code and the Uniform Fire Code. ... 

FIGURE 0.43 Typical designs for gas storage cabinets (Matheson Gas Products, used with permission)... 

Burgess et al." describe a study of gas storage cabinets. In the study, coefficient of entry (CJ for various inlet/outlet configurations was measured. A tracer gas study is also described. The tracer gas study involved releasing sulfur hexafluoride (SF ) at 0.032 L s" at a critical leak position in the cabinet and measuring SFg concentration in the exhaust stream. The tracer gas was turned off when a steady exhaust stream concentration was observed and the time for the concentration to decay to 5% of steady state was measured. 

The study found that the slot-type inlet at the bottom of the cabinet door resulted in higher pressure losses (lower CJ than the diffuser or perforated plate inlet. The exhaust configuration had little effect on Q or tracer gas clearance time. The study also concluded that an exhaust rate 0.118 m s for a two-cylinder cabinet was sufficient as little improvement was seen with an increase to 0.165 m s F" The slotted inlet took longer to clear a leak than either the perforated plate or diffuser inlet. Measured coefficients of entry for a two-cylinder gas storage cabinet are shown in Table 10.9. 

There is more to a laboratory than work benches and the instruments mounted on them. Free-standing equipment must also be considered. This includes refrigerators, safety storage cabinets for chemicals, safety shower, desk space, typewriter stand or computer terminal, or any other equipment that is not bench-mounted. File cabinets, which are real space-robbers, must not be forgotten. In one laboratory, much space was saved by placing two-drawer file cabinets beneath the large table used for sorting samples. 

Laboratory storage cabinets and shelves are available in different widths and are usually 12 inches deep. A depth of more than this is not recommended unless large, bulky items are to be stored. Narrower shelves, six to nine inches deep, have been found more practical for reagents and other small items. If shelves and cabinets are to be mounted on walls above work benches, possible interference with work performed there must be considered. Three feet or more should be allowed for aisles. 

Gradually all things that are to go into the laboratory, such as work benches, refrigerators, safety storage cabinets, floor-mounted equipment, desks, file cabinets, balance tables, and a myriad of other items, are in place. Now is another good time to check on traffic patterns. Will a piece of equipment stick out too far Will a desk chair cause obstruction Will the refrigerator door cause problems when open These are just a few of the questions that should be asked again. 

Small quantities [1 gal (4 I) or less] of flammable or combustible paints, solvents, or cleaning materials, including aerosol cans, should be stored in approved flammable liquid storage cabinets. Large quantities [more than 1 gal (4 I)] of these materials should be stored in separate, remote, or fire-rated... 

Chemicals should be stored properly. For example, flammable chemicals (e.g ethanol, methanol, acetone, methyl ethyl ketone, petroleum distillates, toluene, benzene, and other materials labeled flammable) should be stored in approved flammable storage cabinets, and flammable chemicals requiring refrigeration should be stored in explosion-proof refrigerators. Oxidizers should be segregated from other chemicals, and corrosive acids (e.g., sulfuric, hydrochloric, nitric, perchloric, and hydrofluoric acids) should also be stored in a separate cabinet, well-removed from the flammable organics. 

A coarse texture may also develop as a result of heat shock, which involves alternate thawing and freezing of the water in the ice cream owing to temperature fluctuations in the hardening and storage cabinet. This results in a reduction of the textural quality of the ice cream. 

To test the melt-down properties, a rectangular block of ice cream of defined size is taken from the storage cabinet (e.g., at -20°C) and is placed on a wire gauze (mesh size, e.g., 4 mm) at a controlled temperature between 15 and 25°C. The melting may be followed... 

Approved flammable storage cabinets should be used for flammable liquid storage. 

You may store up to 10 gallons of flammable liquids outside of approved flammable storage cabinets. 

An additional 25 gallons may be stored outside of an approved storage cabinet if it is stored in approved safety cans not to exceed 2 gallons in size. 

Return all radioactive and chemical materials to their place of storage. This may simply mean returning the radioactive materials to the laboratory instructor and the chemicals to their storage cabinets. 

Storage facilities meet minimum fire regulations. Most containers carry name of contents. Approved equipment generally is used. Supply at work area is limited to one-day requirement. Containers are kept in approved storage cabinets. 

Determine which of the following liquids used in the laboratory could form flammable air-vapor mixtures if spilled in a storage cabinet and allowed to reach equilibrium. 

Modern life requires a mind-boggling array of materials, some natural but many man-made. A simple drinking cup, for example, might be made of Styrofoam or paper or glass. Consumers can choose the container that fits their needs at the moment— Styrofoam for hot coffee, paper for a sip of water at the gym, glass for a soft drink on the porch. Home storage cabinets can be made of metals or wood or plastic. Space shuttles are assembled from silicon and steel—and hundreds of other materials. All of these items owe their properties to the chemical bonds between the atoms that make up the substance. 

Do not store paper, cardboard, or other combustible material in or on a flammable liquid storage cabinet. 

Elammable liquid storage cabinets are not intended for the storage of small cylinders of compressed or liquefled gases. 

The manufacturer establishes quantity limits for various sizes of flammable storage cabinets do not overload the cabinet. As a general rule, not more than 120 gal (454 L) of class 1, class 2, and class 3A liquids may be stored in a storage cabinet. Of this total, not more than 60 gal (227 L) may be of class 1 and class 2 liquids, and not more than 3 storage cabinets should be kept in a single room. 

Corrosive chemicals should be kept in cabinets specifically designed to hold them. A wooden storage cabinet or metal cabinet treated with a corrosion-resistant coating is... 

Store acids and bases in separate storage cabinets. 

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