The Work Area

This two sink bench can be made cheaper than you might think. By using PVC piping and PVC valves and buying old used sinks, you can afford to have two or three. 

Your lab should not look this cluttered. I am including this particular work bench to show all the different items and their uses. If you cannot afford all these things, keep with the more simple formulas. I have noted the mandatory things and even simple operations should not be performed without them. 

Notice how the flame operations (generating steam, superheating steam, etc.) are secluded from the flammable vapor reaction part of the work bench. Both of these sections should be made vapor-proof with a generous quantity of silicon sealer (bathtub caulking is OK also). Put your sealer on all mating surfaces and cracks, inside and out. 

The exhaust fan and vacuum can be piped into your sewer main, but valves must be employed to keep this pressure from overcoming your water traps and blowing back into your house through the sink and bathtub drains. Most fans may not be capable of producing this much pressure, therefore you must try to use the valves if necessary. 

The exhaust fan in your reaction box or fumehood must be a sparkless motor. On most all formulas, fume evacuation is a must  

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The highest G-ratios are obtained when grinding with straight oil coolants. Such oils reduce power, increase maximum depth of cut, and produce smoother finishes. Disadvantages include inabiUty to remove heat from the work, oil mist in the work area, fire hazard, and tendency to hold grinding swarf (fine metal chips and abrasive particles produced in the grinding process) in suspension. Reference 51 is an excellent survey article for grinding fluids. 

Lead is absorbed into the human body after inhalation of the dust or ingestion of lead-containing products. Contamination of smoking materials in the work area leads to inhalation of lead fumes and constitutes a main factor in lead absorption. 

Appropriate protective clothing and equipment should be worn to minimize exposure to methacrylate liquids and vapors. Chemically resistant clothes and gloves and splash-proof safety goggles ate recommended. The working area should be adequately ventilated to limit vapors. Should chemical exposure occur, contaminated clothing should be removed and the affected area washed with copious amounts of water. Medical attention should be sought if symptoms appear. Eurther information about methyl methacrylate and other methacrylates is available (141). 

Health and Safety. Protective clothing that is compatible with the remover formula must be worn. Caustic soda baths should be ventilated to remove vapors from the work area. Most caustic removers are corrosive and cause severe bums with minimal contact to the skin. Canister respirators that are compatible with the remover should be worn. 

Standardized techniques atomic absorption (AAA) and photometric (FMA) of the analysis and designed by us a technique X-Ray fluorescence of the analysis (XRF) for metals definition in air of cities and the working areas of plants to production of non-ferrous metals are applied. The samples of aerosols were collected on cellulose (AFA-HA) and perchlorovinyl (AFA-VP and FPP) filters (Russia). The techniques AAA and FMA include a stage of an acid-temperature ashing of a loaded filter or selective extraction of defined elements from filter by approaching dissolvent. At XRF loaded filters were specimens. 

Vapor Pressure The pressure exerted by a vapor above its own liquid. The higher the vapor pressure, the easier it is for a liquid to evaporate and fill the work area with vapors which can cause health or fire hazards. Venting Emergency flow of vessel contents out of a vessel. The pressure is controlled or reduced by venting, thus avoiding a failure of the vessel by overpressurization. The emergency flow can be one-phase or multi-phase, each of which results in different flow characteristics. 

Are emergency self-contained breathing apparatus (SCBA) or escape air packs available in the work areas involved m the ABC Co. processing ... 

For many applications it is found that the technique of free sintering is quite satisfactory. This simply involves heating the preform in an oven at about 380°C for a time of 90 minutes plus a further 60 minutes for every 0.25 in (0.65 cm) thickness. For example a sample 0.5 in (1.25 cm) thick will require sintering for 3.5 hours. The ovens should be ventilated to the open air to prevent toxic decomposition products accumulating in the working area. 

Segregation is a eommon means of eontrolling toxie risks, or restrieting the working area exposed to them. Segregation may be by any, or a eombination, of ... 

Avoidance of eating, drinking, the application of cosmetics, or smoking in the work area. 

Provide adequate number of exits from the work area. 

Provide instant-aeting safety showers and eye-wash faeilities in the loeation of the work area. 

Is a copy of the permit on clear display in the work area ... 

Building maintenance schedules Try to schedule maintenance activities that interfere with HVAC operation or produce odors and emissions (e.g., painting, roofing operations) so that they occur when the building is unoccupied. Inform occupants when such activities are scheduled and, if possible, use local ventilation to ensure that dust and odors are confined to the work area. 

Vapor pressure The pressure exerted by a vapor above its own liquid. The higher the vapor pressure, the easier it is for a liquid to evaporate and fill the work area with vapors that ean eause health or fire hazards. 

The objeet is to inelude suflfieient details of the work area being referred to. For eaeh work area, speeify types of PPE required or levels of proteetion that will be required when doing the tasks in those partie-ular areas. 

In Figure 9-5 the worker is ascending a caged ladder. Notice that the worker s air pack, airline or apparatus could become entangled with the ladder protection. The worker in Figure 9-6 who is using absorbent to soak up a mock spill has no encumbrances pictured near the work area. So, besides the proper level of protection, the type of work being performed and the work area can be important. 

Is the emergeney alarm distinetive and reeognizable as a signal to evaeuate the work area [OSHA Referenee. 165(b)(3)]... 

Before loekout and tagout deviees are removed from maehines or equipment, is the work area inspeeted to ensure that [OSHA Refer-enee. 147(e)(3)]... 

Mobile exhaust or supply systems also include portable systems—for example, the systems consisting of a fan and a flexible tube used in construction work, either for exhausting or supplying air in work areas without any ventilation system. The work area must have some type of connection, such as windows, to the surroundings. 

Booths are often used for work prtKedures with momentum-driven emissions. In such cases the capture devices must be placed to rake advantage of this momentum. For example, a spray paint booth would have the exhaust location downstream of the painting location, most likely at the back of the booth. The capture devices in the back wall should be suitable to reduce the momenriim of the emitted particles in such a way that they are not reflected back into the work area. Floor exhaust should be able to keep the heavier particles dowm so that they cannot be a source for secondary emissions. 

The bench should be supplied with HEPA-filtered unidirectional airflow, having a velocity sufficient to sweep particulate matter away from the working area. Normally a velocity of 0.45 m s plus or minus 20% is adequate. It is important to monitor the air velocity at suitable intervals because significant reduction in velocity or uniformity in velocity can increase the risk of contamination. 

CIlIss HBl In a Class IlBl cabinet, supply blowers draw room air (plus a portion of the cabinet s recirculated air) through the from grill and then through the supply HEPA filters located immediately below the work surface (Fig. 10,96). This particulate-free air flows upward through a plenum ai each side of the cabinet and then downward to the work area through a back-pressure plate. In some cabinets an additional supply HEPA filter removes particulate generated by the b [Pg.987]

Class UB2 The Class 11B2 BSC is a total-exhaust cabinet no air is recirculated w ithin it (Fig. 10.97). This cabinet provides simultaneous primary biological and chemical containment. The supply blower draws in room air or outside air at the top of the cabinet, passes it through a HEP,IV filter, and down into the work area of the cabinet. The building or cabinet exhaust system draws air through both the rear and front grills, capturing the supply air plus the additional amount of room air needed to produce a... 

Partial enclosure An enclosure used for work with toxic dusts, gases, or vapors in which one or more of the sides may be open to the remainder of the work area. 

When the tanks are filled, the vapor is vented to a stack or back to the plant through a vapor return line, which is fitted to the top of the tank. An official report [5] described a fire that occurred because the fillers had not bothered to connect up this vapor return line. Vapors were discharged into the working area. Seven people were injured. 

Before performing any inspection or maintenance on a flame arrester, the associated process eqnipment and piping shonld be taken ont of service or isolated. The work area mnst be proven by test to be free of any harmfnl gases or vapors. It shonld also be verified that all piping is clean and free of obstrnctions and debris. All plant, company, local, state, and federal safety and fire codes and standards shonld be followed. 

All tools and the work area (workbenches and test equipment) should be kept in a clean, dirt-free condition. 

Clean up the work area and account for all tools before returning them to the tool crib. 

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