Flammable material

Some larger institutions build special explosion-proof rooms for storage of flammables. These must conform to all official rules with respect to design, construction, and location. 

Work with flammables should be confined to areas where other work that could cause ignition is not performed. This practice must be carefully policed. Extra ventilation may be needed for such an area. Knowing that most flammable fumes are heavier than air, one laboratory installed an explosion-proof exhaust fan at floor level below the bench where flammables were used. To make the area for working with flammables easier to identify, it could be marked off with red lines on the floor. 

Laboratories working frequently with flammables, such as in extraction processes, may set aside a separate room for such work for maximum safety. Ideally, this room should have explosion-proof electrical equipment and special ventilation. Rigid work rules should be enforced, such as requiring workers to leave matches and lighters on a shelf outside before entering. Installation of conductive flooring should be considered, and steel tools should be prohibited at times when work is in progress. 

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Low pressure. Low pressures are not in general as hazardous as the other extreme operating conditions. However, one particular hazard that does exist in low-pressure plants handling flammable materials is the possible ingress of air with the consequent formation of a flammable mixture. 

Storage of Flammable Materials. The preferred storage for flammable Hquids or gases is in properly designed tanks. Floating roof tanks frequently are used in the petroleum industry for flammable cmdes and products (see Tanks and pressure vessels). The vents on cone roof tanks should either be equipped with flame arrestors or the vapor space above the contents should be inerted with a nonflammable gas or vapor, unless the flash point is weU above the maximum ambient temperature, the contents are not heated above the flash point, and the tank is not exposed to other tanks containing flammable Hquids. 

Sealant Manufacturing. Most sealants use mineral-based fillers which may contain small amounts of crystalline siHca. If crystalline siHca is present, dust control is important to prevent inhalation of these particles. Crystalline siHca is a known cause of siHcosis, a debiHtating disease of the lung. Another common safety concern in sealant manufacturing is the use of flammable materials. Not all sealants use flammable ingredients, but for those that do, proper inerting and grounding are needed to prevent potential explosions. 

Chlorates are strong oxidising agents. Dry materials, such as cloth, leather, or paper, contaminated with chlorate may be ignited easily by heat or friction. Extreme care must be taken to ensure that chlorates do not come in contact with heat, organic materials, phosphoms, ammonium compounds, sulfur compounds, oils, greases or waxes, powdered metals, paint, metal salts (especially copper), and solvents. Chlorates should be stored separately from all flammable materials in a cool, dry, fireproof building. 

Commercial ethyl alcohol is shipped in railroad tank cars, tank tmcks, 208-L (55-gal) and 19-L (5-gal) dmms, and in smaller glass or metal containers having capacities of 0.473 L (one pint), 0.946 L (one quart), 3.785 L (one U.S. gal), or 4.545 L (one Imperial gal). The 208-L dmms may be of the unlined iron type. If a guarantee of more meticulous quaUty is desired, the dmms may be lined with phenoHc resin. AH containers, of course, must comply with the specifications of the U.S. Department of Transportation. Both 190 proof and 200 proof ethyl alcohol are considered red label (flammable) materials by the DOT, as both have flash points below 37.8°C by the Tag closed-cup method. 

It is for these reasons that pneumatic equipment is especially suitable for processing heat-sensitive, easily oxidized, explosive, or flammable materials wriich cannot be exposed to process conditions for extended periods. 

Process Hazard Analysis (PHA) (Dowell, 1994, pp. 30-34.) The OSHA rule for Process Safety Management (PSM) of Highly Toxic Hazardous Chemicals, 29 CFR 1910.119, part (e), reqmres an initial PHA and an update every five years for processes that handle listed chemicals or contain over 10,000 lb (4356 kg) of flammable material. The PHA must be done by a team, must include employees such as operators and mechanics, and must have at least one person skilled in the methodology employed. Suggested methodologies from Process Safety Management are listed in Table 26-1. 

The results of the Flixborough investigation made it clear that the large inventory of flammable material in the process plant contributed to the scale of the disaster. It was concluded that limitations of inventory should be taken as specific design objectives in major hazard installations. It should be noted, however, that reduction of inventoiy may require more frequent and smaller shipments and improved management. 

Conclusions The use of an inert atmosphere can virtually eliminate the possibility of explosions and fire with flammable materials. However, inerting systems can be quite expensive and difficult to operate successfully and can be hazardous to personnel. Before using inert systems, alternatives should be explored, such as using nonflammable materials or operating below the flammable range. 

Introduction Gas dispersion (or vapor dispersion) is used to determine the consequences of a release of a toxic or flammable material. Typically, the calculations provide an estimate of the area affected and the average vapor concentrations expected. In order to make this determination, one must know the release rate of the gas (or the total quantity released) and the atmospheric conditions (wind speed, time of day, cloud cover). 

Operating equipment is opened, cleaned, emptied, or charged frequently. Operator exposure to toxic or flammable materials during normal process operation. 

Install fire safe bottom valves Install fire safe valves on major solvent lines Install remote shut off of fuel sources Eliminate points of leakage (flanges, hoses). Replace with fixed/welded pipes Move flammable material storage away from vessel (e.g., pallets, etc.)... 

Degradation of hose results in leak and release of toxic/flammable material. 

Ignition of combustible or flammable material with filter closed or filter box lid closed. 

Specification for elecirosiaiic hand held spraying equipment for non flammable material for painting and finishing BS EN 50059/1991 ... 

Substitute with less volatile/flammable material where possible (i.e. higher flash point/autoignition temperature, lower vapour pressure)... 

Oxidation Feedstocks generally hydrocarbons Hazard of fire/explosion arises from contact of flammable material with oxygen Reactions highly exothermic equilibrium favours complete reaction... 

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