Exposure limits limit values

Health and Safety. Halosilane vapors react with moist air to produce the respective hydrohalogen acid mist. Federal standards have not set exposure to halosilanes, but it is generally beheved that there is no serious risk if vapor concentrations are maintained below a level that produces an irritating concentration of acid mist. The exposure threshold limit value (TLV) for HCl is 5 ppm, expressed as a ceiling limit. Because most people experience odor and irritation at or below 5 ppm, HCl is considered to have good warning properties. 

USA Occupational Safety and Health Administration permissible exposure limit ceiling value of 5ppm (15mgm ). 

Non-enforceable guidelines have also been established for formaldehyde. The American Conference of Governmental and Industrial Hygienists (ACGIH) has established a ceiling limit for occupational exposure (Threshold Limit Value [TLV]) of 0.4 ppm. NIOSH has a recommended exposure limit for occupational exposure (8-hour TWA) of 0.016 ppm, and a 15-minute ceiling limit of 0.1 ppm. 

For some chemicals, the material safety data sheet Material Safety Data Sheet (MSDS) show a short-term exposure limit (STEL) value. STEL is defined as the 15-minute average that should not be exceeded even if the average value for an eight-hour day is below the PEL. STEL values are related to short term effects while PEL values apply to chronic exposures. The following are some definitions used by OSHA ... 

Temporary Emergency Exposure Limit (TEEL) Value... 

TABLE 18-8 Permissible Heat Exposure Threshold Limit Values (WBGT readings in °C/°F)... 

For monitoring occupational exposures, the following biological exposure limits (BAT values) for Hg-B are recommended [102,103] ... 

Work air impurities are followed up through regular measurements of occupational exposure limit (OEL) values 0.46 0.38 0.20 0.17 0.42 1.72... 

The physical properties of the Isopar grade of isoparaffinic solvents produced by Exxon chemical are shown in Table 15.2. The Isopar series of eight solvents cover a distillation range of 98-3H°C, have flash points from 18°F to a high of 239°F, have low surface tensions in the range of 20-30 dynes/cm, and recommended allowable vapor exposure threshold limit values (TLV) of 300-400 ppm. The isoparaffinic solvents have inherently low solvency for most resins and plastic materials (no Hansen polarity or hydrogen... 

Table 2. Lower and upper action values, and daily exposure noise limits values for workers.

Various short-term exposure limits (STELs) values are in use. They include the following ... 

The limits for prolonged exposure are expressed as the threshold limit values. These are essentially acceptable concentrations in the workplace. There are three categories of threshold limit values ... 

Exposure limits (threshold limit value or TLV) are those set by the Occupational Safety and Health Administration and represent conditions to which most workers can be exposed without adverse effects. The TLV value is expressed as a time weighted average airborne concentration over a normal 8-hour workday and 40-hour workweek. 

Material Safety Data Sheets (MSDS) issued by suppHers of acetone ate requited to be revised within 90 days to include new permissible exposure limits (PEL). Current OSHA PEL (54) and ACGIH threshold limit values (TLV) (55) ate the same, 750 ppm TWA and 1000 ppm STEL. Eot comparison, the ACGIH TWA values for the common mbbing alcohols are ethyl, 1000, and isopropyl, 400 ppm. A report on human experience (56) concluded that exposure to 1000 ppm for an 8-h day produced no effects other than slight, transient irritation of the eyes, nose, and throat. 

The OSHA permissible exposure limit (11) and the American Conference of Governmental Industrial Hygienists (ACGIH) estabHshed threshold limit value (TLV) (12) for fluorides is 2.5 mg of fluoride per cubic meter of air. This is the TLV—TWA concentration for a normal 8-h work day and a 40-h work week. 

The threshold limit value (TLV) for cyclohexane is 300 ppm (1050 mg/m ). With prolonged exposure at 300 ppm and greater, cyclohexane may cause irritation to eyes, mucous membranes, and skin. At high concentrations, it is an anesthetic and narcosis may occur. Because of its relatively low chemical reactivity, toxicological research has not been concentrated on cyclohexane. 

Magnesium vanadates, as vanadium compounds in general, are known irritants of the respiratory tract and conjunctiva. The threshold limit value (TLV) for vanadium compounds in air recommended by the National Institute of Occupational Safety and Health is 0.05 mg/m based on a typical 8-h workday and 40-h workweek (7,147). Chronic inhalation can lead to lung diseases such as bronchitis, bronchopneumonia, and lobar pneumonia. These dust-related effects can be avoided by use of individual respirators in areas where exposure is likely. 

Maleic Anhydride. The ACGIH threshold limit value in air for maleic anhydride is 0.25 ppm and the OSHA permissible exposure level (PEL) is also 0.25 ppm (181). Maleic anhydride is a corrosive irritant to eyes, skin, and mucous membranes. Pulmonary edema (collection of fluid in the lungs) can result from airborne exposure. Skin contact should be avoided by the use of mbber gloves. Dust respirators should be used when maleic anhydride dust is present. Maleic anhydride is combustible when exposed to heat or flame and can react vigorously on contact with oxidizers. The material reacts exothermically with water or steam. Violent decompositions of maleic anhydride can be catalyzed at high temperature by strong bases (sodium hydroxide, potassium hydroxide, calcium hydroxide, alkaU metals, and amines). Precaution should be taken during the manufacture and use of maleic anhydride to minimize the presence of basic materials. 

Value is a PEL C, ie, permissible exposure limit ceiling exposure limit. 

The dB/d/is limited to 6 T/s out of concern that larger values could cause nerve stimulation. The r-f exposure is limited to a specific absorption rate (SAR) of 0.4 W/kg for the whole body, 0.32 W/kg averaged over the head, and less than 8.0 W/kg spatial peakia any one gram of tissue. These numbers are designed to limit the temperature rise to less than 1°C and localized temperature of no greater than 38°C head, 39°C tmnk, and 40°C ia the extremities. 

Because naphthalene vapors can cause eye irritation at concentrations of 15 ppm in air and because continued exposure may result in adverse effects to the eye, a threshold limit value of 10 ppm (50 mg/m ) has been set by the ACGIH (45). This amount is about 30% of the air-saturation value at 27°C. 

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