Safety explosive limits

Health and Safety Factors, Toxicology. Because low molecular weight phosphines generally are spontaneously flammable, they must be stored and handled in an inert atmosphere. The upper explosion limit is 1.6% and the upper limit is near 100% (93). The higher and less volatile homologues are more slowly oxidized by air and present less of a problem. 

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. 

Tables 16 and 17 Hst tke analytical test methods for different properties of interest. The Manufacturing Chemists Association, Inc. (MCA) has pubUshed the Chemical Safety Data Sheet SD 63, which describes in detail procedures for safe handling of use of toluene (46). The Interstate Commerce Commission classifies toluene as a flammable Hquid. Accordingly, it must be packaged in authorized containers, and shipping must comply with ICC regulations. Properties related to safe handling are autoignition temperature, 536°C explosive limits, 1.27—7.0 vol % in air and flash point 4.4°C, closed cup.

Explosive limits are expressed in percent by volume of vapor in air. LELs and UELs have been determined in fire and safety, and health laboratories for all substances likely to be found in industry. Typical values for some solvents and gases are given in Table 3. 

Packed full of useful information, this volume helps you solve field engineering problems with its hundreds of common sense techniques, shortcuts, and calculations. The safety chapter covers lowers explosive limit and flash, flammability, as well as static charge. 

Explosions emergency relief, 450 Explosions, vapor cloud, 520 Explosive limits, 485 External fires, see fires Factors of safety, llow, 56 Fiber bed/pads impingement separator, 254, 255... 

GP 11] [R 19] Based on an analysis of the thermal and kinetic explosion limits, inherent safety is ascribed to hydrogen/oxygen mixtures in the explosive regime when guided through channels of sub-millimeter dimensions under ambient-pressure conditions [9], This was confirmed by experiments in a quartz micro reactor [9],... 

Hazard, i.e. the potential of the material to cause injury under certain conditions (flammability, explosion limits in air, ignition and autoignition temperatures, static electricity (explosions have occurred during drying due to static electricity), dust explosion, boiling point, fire protection (specification of extinguishers, compounds formed when firing), R S (nature of special risk and safety precautions). Table 5.2-5 lists hazards associated with typical chemical reactions. 

The primary objective of gas odorization is safety. Odorization serves as a warning in the detection of natural gas in air before it reaches combustible levels. Certain federal pipeline safety regulations require that combustible gases in pipelines be detectable at one-fifth of the lower explosive limit by a person with a normal sense of smell, either by the natural odor of the gas or by means of artificial odorization [574]. Therefore the proper odorization and odorants are integral parts of safety [813,1753]. 

For a dust ignition to occur, the suspended solids concentration must lie between lower and upper limits which vary from material to material and are influenced by subtle factors such as particle shape and size distribution. From the standpoint of assessing safety hazards in commercial and industrial operations, the lower explosive limit is the more important one. The rationale of this statement is that, if the possibility of exceeding the lower limit in a powder-handling operation can not be completely ruled out, then a hazard must be recognized and appropriate measures taken. Over the... 

Another consideration is whether all the factors can be changed independently through their range of possible values, or whether there are limits on the possible values. The most obvious limiting situation is the case of mixtures, where all the components of a mixture must sum to 100%. Other limitations might be imposed by the physical (or chemical) behavior of the materials involved solubility as a function of temperature, for example, or as a function of other materials present (maximum solubility of salt in water-alcohol mixtures, for example, will vary with the ratio of the two solvents). Other limits might be set by practical considerations such as safety except for specialized work by scientists experienced in the field, few experimenters would want to work, for example, with materials at concentrations above their explosive limits. 

Class II safety explosives must fulfil new conditions when tested in an angle-shot mortar 350 g of explosive fired in this mortar at a distance of 65 cm from the wall and at an angle of 40° must not ignite a 9% methane-air mixture. The charge is increased by increments of 25 g. The charge limit should not give an ignition in any of five consecutive shots. 

Class III safety explosives must be safe in a 9% methane-air mixture when fired with the maximum number of cartridges that can be placed in a row in the 2 m long groove of the angle-shot mortar. The experiment starts with 1800 g charge. It is increased by 200 g increments. The charge limit is determined this should not give any inflammation in five consecutive shots. 

In bulk chemicals manufacture economic considerations usually dictate the use of molecular oxygen as the oxidant. In fine chemicals, on the other hand, other oxidants may be commercially feasible (see table 1). Indeed, other oxidants (e.g. 30% hydrogen peroxide) may even be preferred for reasons of selectivity and ease of handling, i.e. it is not a question of price per se but price/performance ratio. Although molecular oxygen is the least expensive oxidant it requires elaborate safety precautions, and the associated costs, in order to avoid working within explosion limits. 

---