Document 99R55jLp2Zr08bMbzKOqKgmoL

FILE NAME: Koppers/Beazer East (KBE) DATE: 1958 DOC#: KBE010 DOCUMENT DESCRIPTION: Trade Journal Article - Koppers Comp., Inc. - Guide to Air Conataminants Insulation sound KPPERS COMPANY, INC. METAL PRODUCTS DIVISION Sound Control Department - Baltimore 3, Maryland INDUSTRIAL SOUND TRAPS The AIrcoustat b ioaa band sound fctap is a fully effective means of oppressing exi-handling system noises of all fre quencies in the audio range Its design is based on the Soundstieam* principle used to silence a iic ia ft je t engines. AU Aircoustat units are construe led entirely of galvanized j>heet steel and aie fitted with suitable flanges or fHtmgs to make a quick, airtight connection with all ductwork. The guaranteed decibel reduction and pressure drop requiting from installation of Aircoustat units is in eveiy case clearly defined to the satisfaction of the aichitect and the consulting engineer There aie six batnc types of Aircoustat units, each available in many sizes. They piovide appiopnate sound suppression foi the full range of noise ciiten a de mands, from the lowest--such as restau rants and general offices, to the highest --which includes studios and record ing booths. Listed below aie the sound attenuations in decioels for each of the basic Aircoustat units This range of application enables the ait -handling en gined to maintain p a itk u la r design czUcua reductions commensurate with the pcimisslblc loss for given conditions SOUND ATTENUATION FOR AIRCOUSTAT (IN DECIBELS) Octave R and JA F ief| jen cy \ (2') COPS) j 37 5-75 1 73-150 56 15C-300 1 10 300-600 ' 21 6 0 0 - 2 0 0 f 30 1200-2400 33 2 10O-4SO0 ; 34 J 800-10000 32 J ]> t n 1 i & I * U 31 f 40 i 40 37 1 34 ST D A f SA i w i <60 ! t 6 1n 1 22 1t 35S4 57 55 i 50 10 16 * 25 j 47 I 57 ! 60 57 j 53 { STD ! (n ! 12 i 27 1 50 i 6m2 50 55 1s (SO i 2207 j 40 60 0$ ! 70 ; 67 64 * Bee page 101 i if of th is O o m r for tu rth o t snifnm utiou a n eli thles For complete information, data books, and free htezature, u rite or coniaci the Sound Conti ol Depax wnent, Koppers Company, Inc., 203 Scott St., Balli more, Mai yland. 488 ViTCttio71 Control Devices im p The Korfund Company, Inc. 48-01R 32nd Place, Long Island City 1, New York tepresentktves in Principal Cities. Sec "KORFUND** in local phone directory or m "Thomas* Register.*' Specialists la Vibration &Noise Control for Over Half a Century. For a discussion of vibration control theory and chart for determining deflections required, see "Controlling Vibration From Machine Mountings" at end of Chapter 40. If In doubt about product selection, submit data on make, type, rpm and model number of equipment, and type of floor for specific recommendations; no obligation STEEL SPRING VIBRO ISOLATORS provide greater deflec tions with isolation efficiencies approaching 100 percent. Though more expensive than rubber or cork, they are sat isfaction guaranteed and provide maximum overall economy because: they eliminate bolting, speed equipment installation, usually eliminate special foundations, permit trouble-free upper floor installations, and will usually outlast the machine. Series Z* Isolator THE SERIES L VIBRO ISOLATORS contain from one to twelve steel springs of proper stiffness depending upon the loading and deflection desired. Loading: 75 to 23,000 lb. Maximum deflection 2 in. (special designs available for higher loads or larger deflections). Isolators are usually installed directly under machines (occasionally under steel bases or foundations supporting equipment). They have ad justable snubbers to control movement and built-in leveling bolts, a Korfund feature for over 30 years. SERIES V VIBRO HANGERS; load range 20 lb to 3,800 lb. v\bro-Hanger Maximum normal deflection 1 in. (larger deflections on re* quest). For suspended equipment installations, also as vibra tion-absorbing pipe hanger. RUBBER AND CORK provide good sound insulation. How ever, rubber is not very effective as a vibration absorber for disturbances below 1200 cpm, is fair from 1200-1800, and good above 1800. Cork is effective only above 1800 cpm. Maslo-Rib Pod SERIES R RUBBER-IN-SHEAR HANGERS j Similar to spring hanger illustrated but incorporating rubber mountings of varying stiffnesses for loads from 10-1,000 lb. ELASTO-RIB has a core of high-grade cork plate, permanently bonded between two layers of waffle embossed, Neoprene rub ber. Just set-the machine on Elasto-Rib--no fastening to floor is normally required but can be cemented or bolted if desired. Ex cellent sound Insulation characteristics. Loadingup to60 lb per square inch. Also furnished as Elasto-Rib Dampers with load distributing top plate and buih-in leveling bolt. Vibracork ^ ARMSTRONG'S VIBRACORK & KORFUND LIGHT DEN SITY MACHINERY CORK are strong, durable machinery isolation plates made of pure cork granules compressed and baked under pressure with accurately controlled density. Furnished in three densities for loads from 400-8,500 ib per square foot. 1 in., 2 in., 3 in., thicknesses. Plates 12 in. x 36 in. Duplex Base* Motor Base with Built-in Stuie Rails DUPLEX TWIN RAIL FAN & MOTOR BASES; Rugged con struction and built-in chocks to maintain alignment. Rubber or cork isolation. Advantages of separate fan and motor bases: no motor noise transmitted through ducts--complete adjustability permits job-site changes in motor position, belt length, rotation, equipment bolt location--quicker delivery' of drawings and bases--easier handling--lower transportation costs. INTEGRAL TYPE bases also available. FOR ADDITIONAL DATA. SEE SWEET'S FILES OR WRITE . FOR COMPLETE CATALOG DATA 0 489 162 CHAPTER 8 1958 Guide T able 4. L im it s fo b T o x ic D o sts, F u m es and M is t s (Concluded) Substance A.S.A S t a n d a r d s [ T h r e sh o l d L im it M. C. V alues, A ,C G J H. U ran iu m (soluble compounds) (insoluble compounds) . V anadium (VsO* dust) (V*Os fume) (x) W arfarin (3-[a aoetonylbenzylH -hycroxycouro'irm ) Zinc oxide fumes Zirconium compounds (as Zr) 0 00005 0.00025 0.0005 0 0001 0 0005 0 015 0.005 **G ram s of dust, fum e, or m ist per cubic m eter of air. (x) These values appeared on the A .C G .l H te n ta tiv e list, for 105$. R adioactivity For permissible concentrations of radioisotopes in air, see " Maximum Permissible A m ounts of Radioisotopes m the H um an Body and Maximum Permissible C oncentiations m Air and W ater," H and book 52, U S D ep artm e n t of Commerce, N a t e n d S u reau of Standards, M arch. 1053. In addition, see "Perraissiole Dose from External Sources of Ionizing R ad iatio n ," H andbook 50, U S D epartm ent o f Com merce, National Bureau o f Standards, Septem ber 24, 1054. T a b le 4 values rep rin ted by perm ission from A U -A Archives o f Industrial Health, S e p te m b e r 1957, Vo!. 16, p p . 261-265- temperature scale. It may be defined as the temperature to which a com bustible liquid must be heated to produce a flash when a small flame is passed across the surface of the liquid. The higher the flash point, the more safely can the liquid be handled. Liquids with flash points under 70 F should be regarded as highly flammable. Upper and lower limits of flammability of gases and vapors, and the flash points of the corresponding liquids are given in Table 6. Methods for estimating the flammable limits of mixtures of gases or vapors must be applied with caution; the reader is referred to other publi cations for this information.12*n Design of equipment for the control of combustible anesthetics is out lined in Chapter 7. Construction of equipment for handling air contain ing flammable substances, or operating in atmospheres so contaminated, is discussed in Chapter 45. It is customary to report the concentrations of flammable gases or vapors in percent by volume, or volume percent Comparison with concentra tions on the part per million scale used in chemical, medical or industrial hygiene literature is readily made by the conversion: 1 percent = 10,000 ppm (parts of contaminant per million parts of air, by volume, or in other T able 5 L imits foe M ineral D usts S ubstance T hreshold Lim it Values A.C .G I M 195b m ppcfa A lum inum oxide - . Asbestos C arb o ru n d u m ................... Cem ent Portland D ust (nuisance, no free silica) Mica (below 5% free silica) StUca--high (above 59% free SiO s). Silica--m edium (5 to 50% free SiOO . - - Silica--low (below 5% fiee StOz). Slate (below 5% free SiOi) - . Silicon cm bide Soapstone (below 5% free SiOi) Talc 50 5 50 ' 50 50 20 5 20 50 50 50 20 20 * mppcf--million particles per cubic foot of a ir, sta n d a rd light field count Table 5 values rep rin ted by perm ission from A M A Archives o f Industrial Health, S ep tem b er 1957, Vol, 1$, pp 261-205, Air Contaminants 163 words, cubic feet of contaminant per million cubic feet of air). I t will be noted in Table 6 that nearly all of the substances listed have lower explosive limits above 1.0 percent, while the maotimvm allowable concentrations for gases and vapors m Table 3 are below 1000 ppm or 0.1 percent in most cases. Therefore, control of toxic or injurious vapors to levels below their maximum allowable concentrations for health usually requires much more effective ventilation than for the prevention of a fire hazard. COMBUSTIBLE DUSTS A dust explosion is essentially a sudden pressure rise caused by the very rapid burning of airborne dust. The primary explosion often originates from a small amount of dust in suspension exposed to a source of ignition and the pressure and vibration it creates may be sufficient to dislodge large accumulations of dust on horizontal ledges or surfaces of the building and equipment, thereby creating a secondary explosion of great force. Thus the air conditioning engineer is involved for two reasons: (1) to obtain a movement of dust-laden air into exhaust hoods or openings, and through ventilating or pneumatic conveying ducts, in a manner th at will prevent accumulation of highly flammable dust a t points where it could ignite inside the equipment; and (2) to so design process ventilation as to prevent the escape of dust which might settle on horizontal surfaces and become a potential source of disaster at some distance from the dusty operation. (See Chapter 45). Intensity of a dust explosion depends upon: chemical and thermal properties of the dust; particle size and shape; concentration in air; propor tion of inert dust in the air; moisture content and composition of the air; size and temperature of the ignition source; and degree of dispersion of the dust cloud. Investigations on the explosibility of dusts require determina tion of the maximum pressure developed during explosion of a known air concentration, as well as determination of the rate of pressure rise. In vestigators frequently experience difficulty in obtaining dust suspensions of uniform dispersion, and this should be kept in mind when comparing results from several sources.14 Minimum explosive concentrations of airborne dusts already tested range from 0.01 to 0.5 oz per cubic foot, or 10 to 500 grams per cubic meter of air. Maximum pressures generated have been reported as high as 500 psi, although they are more likely to be of the order of 50 psi. Investiga tions on the flammable characteristics of dusts are currently made at 0.1 and 0.5 oz per cubic foot.15"21 ATMOSPHERIC POLLEN Properties of pollen grains discharged by weeds, grasses and trees and responsible for hay fever, are of special interest to designers of air cleaning equipment (see Allergic Disorders in Chapter 7, and Air Cleaning, Chap ter 33). Whole grains and fragments transposed by the air range chiefly between 10 and 50 microns in size, but some have been measured as small as 5 microns, and others over 100 microns in diameter. Ragweed pollen grains are fairly uniform in size within the range of 15 to 25 microns. Pollen grains can be removed from the air more readily than the particles of dust prevalent in outdoor air or produced by dusty processes, since the latter predominate in the range of 0 1 to 10 microns in size. Most grains are quite hygroscopic and therefore vary in weight with the humidity. Illustrations and data on individual pollen grains arc available