Precautions, safety

The precautionary safety principles are fairly simple and comprise  

Under the New Roads and Street Works Act 1991 the local authority has to keep a register of information concerning the apparatus in the streets and coordinate the activities of excavators digging them up. The excavator should therefore be able to obtain all the details of the buried services from the local authority without the need to approach all the undertakers before excavating. 

There is a variety of cable locators readily available, varying in sophistication but of three generic types  

Cable locators should be used only by personnel trained in their use. It is good practice to use them from time to time as the excavation work proceeds until the cable is exposed. Quite often, and particularly in urban areas, there may be more than one cable laid at the same or different depths. Care in the use of the cable plans and locators is needed to ensure that the location of all the cables is determined and that cables located in close proximity to other cables, including above other cables, are properly resolved. Cables are not always distinguishable by sight from other services, but the use of a locator should enable the operator to be sure. 

On paved surfaces the cable route and danger zone lines can be chalked or painted, but elsewhere it will usually be necessary to delineate with pegs driven into the ground. Wooden pegs are safer than metal as they are less likely to damage the cable. 

Before this experiment is carried out, the student must read the material safety data sheets (MSDS) for all the chemicals used as well as for the products. The instructor must approve that you have read and understood the MSDS for the safe handling of these materials. 

Please be advised that all chemicals should be considered hazardous and should be handled in a hood and with proper personal protective equipment (lab coat, proper gloves, approved safety glasses, and/or goggles). Avoid inhaling vapors and/or aerosolized materials. Avoid skin/eye contact with all chemicals at all times. Wash hands frequently. See the instructor if you have any questions or concerns. 

Serious personal injury can result if safety rules are not followed. Observe the following safety precautions when installing a chain. 

Other sources of hazard arise from the handhng of such chemicals as concentrated acids, alkalis, metallic sodium and bromine, and in working with such extremely poisonous substances as sodium and potassium cyanides. The special precautions to be observed will be indicated, where necessary, in the experiments in which the substances are employed, and will also be supplied by the demonstrator. The exercise of obvious precautions and cautious handling will in most cases reduce the danger to almost negligible proportions. Thus, if concentrated sulphuric acid should be accidentally spilled, it should be immediately washed with a liberal quantity of water or of a solution of a mild alkali. 

Finally, the student should famiharise himself with tire contents of the Section in the Appendix upon Laboratory Accidents, with the position of the fire extinguisher, buckets of sand, first aid cabinet, and the fireproof blanket. 

APPARATUS WITH INTERCHANGEABLE GROUND GLASS JOINTS 

The commercial development of glass manipulation, coupled with the use of glasses of low expansion coefficient, has made available truly i 

Scientific Glass Apparatus Co. Inc. i Coming Glass Works. For precise details concerning i 

No corks or rubber stoppers are, in general, required. Contamination or discolouration due to these is therefore avoided. Occasionally, a small rubber stopper may be employed, e.g., for the insertion of a thermometer, but, should the very small surface of rubber thus exposed to the action of the organic vapours be undesirable, a thermometer with a ground glass cone can be used. 

The selection, boring, and fltting of corks is largely eliminated, thus resulting in a considerable saving of time. 

The Polaroid Land rapid-process system of photography has been adapted to some kinds of diffraction equipment. The Polaroid film is backed by an intensifying screen (Sec. 5-2) which converts x-rays to visible light that can darken the film. X-ray exposures are about one tenth of those required by x-ray film, and finished prints are available about ten seconds after the x-ray exposure. 

X-ray counters are devices that convert x-rays into a pulsating electric current, and the number of current pulses per unit of time is proportional to the intensity of the x-rays entering the counter. Three types are currently in use proportional, scintillation, and semiconductor. They will be described in Chap. 7. 

Fluorescent screens are used only for the detection of x-ray beams, while photographic film and the various kinds of counters permit both detection and measurement of intensity. Photographic film has the advantage of being able to record a number of diffracted beams at one time and their relative positions in space, and the film can be used as a basis for intensity measurements if desired. Intensities can be measured much more rapidly with counters, and these instruments are more popular for quantitative work. However, most counters record only one diffracted beam at a time. 

The operator of x-ray apparatus is exposed to two obvious dangers, electric shock and radiation injury, but both of these hazards can be reduced to negligible proportions by proper design of equipment and reasonable care on the part of the user. Nevertheless, it is only prudent for the x-ray worker to be continually aware of these hazards. 

There is no excuse today for receiving serious injuries as early x-ray workers did through ignorance. There would probably be no accidents if x-rays were visible and produced an immediate burning sensation, but they are invisible and burns may not be immediately felt. If the body has received general radiation above the tolerance dose, the first noticeable effect will be a lowering of the white-blood-cell count, so periodic blood counts are advisable if there is any doubt about the general level of intensity in the laboratory. 

Phosgene can be obtained on a large scale from Van De Mark (now part of SNPE), located in Lockport, N.Y., who sell the gas on the merchant market. 

Triphosgene can be obtained on a large scale from Dr. Eckert GmbH [2], Germany, Ubichem, UK and Hungary, or Synergetica, PR China/US. 

Phosgenation Reagents Phosgene, Equivalents CAS Reg. No. Source Order No. 

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SAFETY PRECAUTIONS to be observed during Laboratory Work. 

I) Dissolve 2.465 g Na3lrCIg in water and dilute to volume. (2) Transfer 1.000 g Ir sponge to a glass tube, add 20 ml of HCI and 1 ml of HCIO4. Seal the tube and place in an oven at 300°C for 24 hr. Cool, break open the tube, transfer the solution to a volumetric flask, and dilute to volume. Observe all safety precautions in opening the glass tube. 

Most hafnium compounds requite no special safety precautions because hafnium is nontoxic under normal exposure. Acidic compounds such as hafnium tetrachloride hydroly2e easily to form strongly acidic solutions and to release hydrogen chloride fumes, and these compounds must be handled properly. Whereas laboratory tests in which soluble hafnium compounds were injected into animals did show toxicity, feeding test results indicated essentially no toxicity when hafnium compounds were taken orally (33,34). 

Workers in the metals treatment industry are exposed to fumes, dusts, and mists containing metals and metal compounds, as well as to various chemicals from sources such as grinding wheels and lubricants. Exposure can be by inhalation, ingestion, or skin contact. Historically, metal toxicology was concerned with overt effects such as abdominal coHc from lead toxicity. Because of the occupational health and safety standards of the 1990s such effects are rare. Subtie, chronic, or long-term effects of metals treatment exposure are under study. An index to safety precautions for various metal treatment processes is available (6). As additional information is gained, standards are adjusted. 

Health and Safety. Both N-methylpyrrohdinone and dibasic esters have very low vapor pressure which limits worker exposure to vapors. Manufacturers recommend that the same safety precautions be taken as with other organic solvents. Ha2ardous location requirements must be considered if the formula is flammable. Ventilation that reduces vapors to manufacturer s recommended exposure levels should be used. 

Cross-country gas pipelines generally must odorize the normally odorless, colorless, and tasteless gas ia urban and suburban areas, as is required of gas distribution companies. Organosulfur compounds, such as mercaptans, are usually used for this purpose, and code requires that the odor must be strong enough for someone with a normal sense of smell to detect a gas leak iato air at one-fifth the lower explosive limit of gas—air mixtures. The latter is about 5%, so the odorant concentration should be about 1%, but most companies odorize more heavily than this as a safety precaution. 

Environmental awareness is a prime concern in all KOH plants. Safety precautions required in KOH and chlorine operations are well documented in operating manuals and sales brochures pubUshed by all commercial producers. Discharges of waste effluents containing mercury are strictly forbidden. 

Potassium compounds commonly used in ferti1i2ers, eg, KCl and K SO, are not considered to be ha2ardous substances. Detailed information concerning health and safety precautions recommended for a specific, industrially produced potassium chemical can be obtained by contacting a manufacturer direcdy. Principal potassium chemical producers are Hsted in buyers guides pubHshed aimually by chemical trade maga2ines (52). 

The need for skill and experience on the part of sample designers and persoimel cannot be overemphasized in chemical plant sampling. Safety precautions are of the utmost importance. Necessary steps must be taken to document the hazards involved in an operation and to ensure that the staff are weU-trained, informed, protected, and capable. Except for bulk powder sampling, most chemical plant sampling is hazardous and difficult and must be designed with care. The following discussions are based on the assumptions that most of these decisions have been made and a satisfactory sampling procedure has been planned. 

The Shoe grouting system is considered nonhazardous and nonpolluting. Sodium silicate is essentially nontoxic. Formamide is toxic and corrosive, but does not present a serious hazard if normal safety precautions are followed. Shoe chemical grout materials are two to five times more expensive than Portland cement, depending on the sodium silicate to formamide concentration ratios. Installed costs are generally more similar to those for cement grouts. 

Shipment and Storage. Sulfur dichloride, if kept dry, is noncorrosive at ambient temperatures, thus carbon steel and Hon can be used Hi the constmction of tanks, piping, and dmms. However, when water or humidity is present, materials resistant to hydrochloric acid must be used, eg, glass-lined pipe. Teflon, titanium, HasteUoy C, or possibly a chemically resistant, glass-reiaforced polyester. Threaded pipe joHits should be assembled with Teflon tape. Hoses should be constmcted with a Teflon inner lining with the outer tube constmcted of Neoprene or braided 316 stainless steel protected by an adequate thickness of Teflon. Sulfur dichloride should be stored away from heat and away from dHect rays of the sum. Toluene and sulfur dichloride react exothermically when catalyzed by Hon or ferric chloride. Safety precautions should be foUowed when such a mixture is present (165). 

What safety precautions does the person performing the task need ... 

SAFETY PRECAUTIONS ASSOCIATED WITH THE PURIFICATION OF LABORATORY CHEMICALS... 

Experimental chemistry is a very dangerous occupation and extreme care and adequate safety precautions should be taken at all times. Although we have stated the safety measures that have to be taken under specific entries these are by no means exhaustive and some may have been unknowingly or accidentally omitted. The experimenter without prior knowledge or experience must seek further safety advice on reagents and procedures from experts in the field before undertaking the purification of any material. We take no responsibility whatsoever if any mishaps occur when using any of the procedures described in this book. 

Organo-metallic compounds, on the other hand, behave very much like organic compounds, e.g. they can be redistilled and may be soluble in organic solvents. A note of caution should be made about handling organo-metallic compounds, e.g. arsines, because of their potential toxicities, particularly when they are volatile. Generally the suppliers of such compounds provide details about their safe manipulation. These should be read carefully and adhered to closely. If in any doubt always assume that the materials are lethal and treat them with utmost care. The same safety precautions about the handling of substances as stated in Chapter 4 should be followed here (see Chapter 1). 

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