Standardization Dusting

For Clean Rooms (rooms of a very high standard) dust count per unit volume will be specified, but other specifications for room cleanliness are usually in terms of filtration performance against a standard test dust. Other important features are resistance to air flow and dustholding capacity, leading to the fan energy required and filter life. 

Test dusts. 0.5% material + 0.05% pyreth Standard dust. 0.75% rotenone 10 larvae per test. Averages of 12 tests Dosage of dust. 0.283 gram per square foot... 

There are two basic laboratory methods for the preparation of filter standards--dust generation and the liquid suspension technique. Dust generation has a distinct advantage because of the ability to produce atmospheres similar to the workplace which can then be... 

Despite their ease in handling, formulation, and application, dnsts are the least effective and, ultimately, the least economical of the pesticide formnla-tions. The reason is that dusts have a very poor rate of deposit on foliage, nnless it is wet from dew or rain. In agricultnre, for instance, an aerial application of a standard dust formulation of pesticide will result in 10 percent to 40 percent of the material reaching the crop. The remainder drifts npward and downwind. 

Subscript 1 refers to the appropriate explosion characteristics for Pittsburgh seam coal (the standard dust used by the U.S. Bureau of Mines) and subscript 2 refers to the appropriate explosion characteristics for the specific dust present in the plant. 

If ultrafme particles can be agglomerated, the mass of the new entity is equal to the sum of aU particles in the structure and mass related forces as well as inertia increase proportionately. After agglomeration, ultrafine particles, in their new form, can be removed in standard dust collection devices such as cyclones and packed bed filters. 

Standard dust masks to avoid inhalation. In high-exposure situations, other respiratory protection may be necessary, depending on the concentration and length of exposure (consult MSDS for exposure limits). 

ASTM method D 2132 outlines the procedure for determining dust and fog tracking and erosion resistance of electrical insulating materials. The test is carried out in a fog chamber with a standardized dust applied to the sample surface. Failure is characterized by the erosion of the specimen or tracking. ASTM D 2302 also describes the test for differential wet tracking resistance of electrical insulating... 

Sulfur and its compounds are among the oldest and most widely used pesticides. Elemental sulfur is especially effective as a dust for the control of mites attacking citms, cotton, and field crops and as a protectant against chiggers, Trombicula spp., attacking humans. Sulfur also is a valuable fungicidal diluent for other dust insecticides and is used in wettable form as a spray mixture. Time sulfur has been a standard dormant spray for the control of the San Jose Quadraspidiotuspemiciosus and for other scales and various plant diseases. Time sulfur is a water-soluble mixture of calcium pentasulfide,... 

Eactory Mutual Engineering Corp. 1151 Boston-Providence Turnpike Norwood, Mass. 02062 Standards for safety equipment, safeguards for flammable Hquids, gases, dusts, industrial ovens, dryers, and for protection of buddings from wind and other natural ha2ards. 

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. 

It is good practice to keep concentrations of airborne nickel in any chemical form as low as possible and certainly below the relevant standard. Local exhaust ventilation is the preferred method, particularly for powders, but personal respirator protection may be employed where necessary. In the United States, the Occupational Safety and Health Administration (OSHA) personal exposure limit (PEL) for all forms of nickel except nickel carbonyl is 1 mg/m. The ACGIH TLVs are respectively 1 mg/m for Ni metal, insoluble compounds, and fume and dust from nickel sulfide roasting, and 0.1 mg/m for soluble nickel compounds. The ACGIH is considering whether to lower the TLVs for all forms of nickel to 0.05 mg/m, based on nonmalignant respiratory effects in experimental animals. 

BS 3405, Simplified Methodsfor Measurement of Grit and Dust Emission from Chimneys, British Standards, London, 1961. 

Inhalation of crystalline or fused vitreous silica dust, usually overlong periods, causes a disabling, progressive pulmonary disease known as silicosis (84). Amorphous siUcas have not been linked to siUcosis (85), but can cause respiratory irritation. The history and poHtics of siUcosis have been reviewed (86). Standards have been set or recommended for occupational exposures (87,88) and review articles on the health effects of siUca are available (83,89). 

Thorium is potentially hazardous. Einely divided thorium metal and hydrides can be explosive or inflammatory hazards with respect to oxygen and halogens. Einely divided Th02 and other inorganic salts also present an inhalation and irritation hazard. The use of standard precautions, skin covering, and a conventional dust respirator should be sufficient for handling thorium materials. 

Short-term inhalation of PVA dust has no known health significance, but can cause discomfort and should be avoided in accordance with industry standards for exposure to nuisance dust. The dust is mildly irritating to the eyes. There are no known dermal effects arising from short-term exposure to either soHd PVA or its aqueous solutions. 

Cement plants in the United States are now carehiUy monitored for compliance with Environmental Protection Agency (EPA) standards for emissions of particulates, SO, NO, and hydrocarbons. AH plants incorporate particulate collection devices such as baghouses and electrostatic precipitators (see Air POLLUTION CONTROL methods). The particulates removed from stack emissions are called cement kiln dust (CKD). It has been shown that CKD is characterized by low concentrations of metals which leach from the CKD at levels far below regulatory limits (63,64). Environmental issues continue to be of concern as the use of waste fuel in cement kilns becomes more widespread. 

The Eederal Coal Mine Health and Safety Act set standards for mine ventilation, roof support, coal dust concentrations levels, mine inspections, and equipment. As a part of this comprehensive act, miners must receive medical examinations at employer expense, and payments are made from the U.S. government to miners who caimot work because of black lung disease. 

Inhalation of dusts can cause metal fume fever (79,80), and ulceration or perforation of the nasal septum. Mild discomfort has been noted with workplace concentrations as low as 0.08 mg/m. The workplace standard (TLV) for copper dusts or mist is 1 mg/m and 0.2 mg/m for copper fume (81). 

In the 1993 AATCC standard method (re-affirmed in 1988) a standard weight of dye (10 g) is dropped down a funnel into a cylinder of defined si2e. A wet filter paper is placed as a coUar to the funnel 200 mm above the bottom of the cylinder. After 3 min the stain on the filter paper, obtained by the dust created in the funnel dissolving on the paper, is assessed by comparing the standard photographs and the dye given the number of the picture it resembles the most (1 poor, 5 excellent). 

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