Leaks sources

Use instruments judiciously more instruments can lead to more leak sources... 

Airborne particulates include dust, fume and aerosols. Many such particles are invisible to the naked eye under normal lighting but are rendered visible, by reflection, when illuminated with a strong beam of light. This is the Tyndall effect and use of a dust lamp provides a simple technique for the rapid assessment of whether a dust is present, its flow pattern, leak sources, the effects of ventilation, etc. More sophisticated approaches are needed for quantitative data. Whether personal, spot or static sampling is adopted will depend upon the nature of the information required. 

Ensure that fresh air movement is from worker to leak source and not vice versa. 

Fired equipment will have penalties, if the material in process unit near the air intake of fired heater could be released above its boiling point, if the material is a combustible dust, or if the material could be released above its boiling point. The penalty depends on the distance from the possible leak source and it varies between 0.1 and 1.0. For instance the distance of 15 m gives the penalties 0.27 (above the flash point) and 0.60 (above the boiling point). Any situation involving a material processed below its flash point receives no penalty. 

IR beams are typically provided as a special gas detection applications. They offer a direct view and surveillance over a large area rather than a point source origination of gas. The most frequent use of these is verifying whether a gas release would be carried offsite from the facility. Other possible applications would be overall monitoring in area of several possible leak sources but within a line of sight arrangement such as a pump alley or an offshore module. 

A network of chlorine detectors is positioned at points close to potential leak sources (such as close to the chlorine vaporiser, compressor flanges and drum, cylinder and tanker filling connections) as well as along the perimeter of the site. Many chlorine detectors are interconnected with automatic plant responses and initiation of chlorine scrubbing where a chlorine release occurs within a contained building. 

The base of the jet flame is usually not attached to the release point, due to the high velocity and richness of the fuel near the heat source. This lift-off distance has been measured on flares to be 20% of jet length. This effect is important in reducing the predicted radiation level on the leak source, which might otherwise cause a small leak to escalate to a full-bore failure. 

Local or point-of-release coverage—based on fire protection system judgment to predict possible leak sources. Detection should be located in proximity to release source near specific individual equipment items. 

Refinery employees observed a noticeable leak on a 1-inch (2.5 cm) connection above a discharge header in a refinery. While carefully removing insulation around the leak to better observe the leak source, the mechanic aggravated the situation, and a threaded nipple and valve blew off. A stream of hot oil slurry (670° F (354° C)) sprayed the area and produced a dense cloud of heavy hydrocarbon mist. Oil sprayed over 90 ft. (27 m) into the air and the mist covered an extensive area of the refinery. [9] Immediately after the oil mist cloud formed, operators initiated a shutdown of the unit, and the alert team started the fire-water monitors. The hydrocarbon mist ignited about 10 minutes after the threaded nipple blew off. Responders extinguished the blare within about 90 minutes. Luckily, only a portion of the total volume of escaping oil burned. 

In some other instances, engineers have counted flanges on long and complicated piping networks to help estimate potential leak sources. Their time would have been better spent getting an estimate on the maintenance mind-set so as to determine what programs were in progress to reduce leaks by the ever-present threats of external corrosion. 

All Teflon stopcocks and valves must remain free of particulate contamination so the surface will not be scratched or damaged. Any abrasions, or distortions, of the central shaft are likely to be leak sources. In addition, do not place any filled container closed with a Teflon stopcock (or valve) in a refrigerator. Just as Teflon expands in heated environments, it contracts in cooled environments. Thus, what was a good seal at room temperature may leak in a cold environment. Do not try to compensate for the cold temperature by overtightening the shaft for two rea-... 

Steam leak signal data recrived fiom IAEA for developing noise analysis technique to detect and localise the leak source was analysed using the cross corrdafion and cross power spectral density methods. The transit time delays betwemi the leak source and the dififerent sensors were estimated based on the above methods. 

PHT system pressure control is achieved through feed and bleed and a pressuriser has been added to improve performance during operational transients. System components are protected from over pressure by instrumented relief valves and suitable regulating system and protective system action. Potential heavy water leak sources are kept to a minimum by using welded construction wherever practicable, and bellow sealed valves. Heavy water leakage collection and recovery systems are connected to the locations where potential leak sources exist. 

Unfortunately investigators do not agree on the exact reason for the massive loss of containment. There are two significantly different theories of the exact leak source from the piunp within Block 23. Block 23 is one of the tank farm areas in the huge complex. 

Petroleos de Venezuela (or PDVSA) leak source study... 

When hazardous materials are handled, these sources of leaks should be located in curbed or diked areas to localize spills. If a permanent curb or drain can not be provided around the leak source, a temporary curb should be provided, using barriers or absorbent materials. 

If the seal on the source is breaehed and removable radioactive material is detected, the leaking source should be immediately removed from service and returned to the manufacturer. The area around the leaking source needs to be surveyed with a G-M counter, and points of leakage ( hot spots ) are wiped clean. The area must be rechecked to ensure all contamination has been removed. Employees should be notified of the incident. 

Use water spray to reduce vapor dispersal. Caution, resultant liquid is corrosive. Isolate area. If possible, remove leak source to ventilated enclosure and direct to scrubber. 

As a precaution, hot surfaces should be insulated, cooled, or relocated when they pose a threat of ignition to combustible gas or liquid potential leak sources. Required equipment that contains hot surfaces should be rated to operate in such environments. 

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