Piping hazardous material

Wet wire-pipe ESPs have the additional advantages of reducing "sneakage" by passing the entire gas stream through the collection field, and the ability to be tightly sealed to prevent leaks of material, especially valuable or hazardous materials. 

Review the layout to minimize the length of piping containing hazardous material. 

Is process equipment located to minimize length of hazardous material piping ... 

Division 2 Locations where hazardous material exists only in the case of a fault situation (leaky valve, burst pipe, faulty equipment)... 

Every explosive operation that requires conveying hazardous material by enclosed pipelines should be considered a candidate for cleaning the pipes by this method. 

Locating process equipment to minimize the length of hazardous material piping runs... 

Maintenance. Good plant maintenance (qv) obviates the crash shutdowns that could follow failure of critical components. Maintenance in the chemical industry differs from that in other industries because of the nature of the materials, processes, and types of equipment used. Because much chemical work involves the movement of fluids, gases, and powdered solids from one piece of equipment to another, many pipelines (qv), conveyors, forklift tmcks, and other material-handling devices are used. Containers are more likely to be tanks, drums, or some form of closed container than in other industries. Prior to maintenance inside equipment, all lines and equipment containing hazardous materials should be effectively separated, disconnected, blanked, or purged in order to minimize the possibility of release of harmful materials. Maintenance personnel must make sure that all equipment and piping is so prepared. 

Simplify—Design processes and facilities that eliminate unnecessary complexity and that are tolerant of human error. Example Design piping to permit gravity flow of hazardous materials in a plant, eliminating the need for pumps, which can leak. 

Inventory of hazardous material in pipes can also be minimized by using the hazardous material as a gas rather than as a liquid. The Dow Chemical Exposure Index (14) is a tool that can be used to measure inherent safety with regard to potential toxic exposure risk. Table 2 shows the reduction in the Chemical Exposure Index that can be realized by handling a number of hazardous materials as a gas rather than as a liquid, assuming that the same-size pipe can deliver the required flow rate. Figure 6 shows the decrease in the hazard zone (toxic cloud footprint) that resulted from relocating a chlorine vaporizer from a production building to... 

When considering the application of foam to hazardous material spills, key requirements include an adequate water supply, the foam concentrate, appropriate proportioning equipment, piping, foam makers, and discharge devices and protective equipment for the personnel involved. Activation may be automatic, but in most cases it is manual. There are four types of application systems. They include fixed, semifixed, mobile, and portable (NFPA 11, 1988). 

Figure 5.1 is a simplified schematic drawing of a double-wall pipe. The hazardous material flows in the inner pipe. The annular space is purged with a flow of nitrogen gas. The discharge of the nitrogen from the annular space is analyzed to detect a leak of the inner pipe. Note that the inlet and outlet valves for nitrogen to the annular space are car-sealed-open (CSO) or locked open (LO). 

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