Minor leaks

Less than a year later, a small leak from a passing drain valve on a pipeline caught fire. It was soon extinguished by closing the valve. But an investigation disclosed that  

There should have been two valves in series or a single valve and blank. 

The valve was made of brass and was of a type stocked for use on domestic water systems. It was not the correct pressure rating for LFG. 

The valve was screwed onto the pipeline, though the company s codes made it clear that only flanged or welded joints were allowed. 

It was never discovered who installed this unauthorized substandard drain point. An attempt had been made to publicize the lessons of Feyzin, the company s standards, and the reasons for them. However, this did not prevent the installation of the drain point. Note that a number of people must have been involved. Besides the man who actually fitted it and his foreman, someone must have issued a work permit and accepted it back (when he should have inspected the job), and several persons must have used the drain point. Many must have passed b. If only one of them had recognized the substandard constmction and drawn it to the attention of those responsible, the fire would not have occurred [10]. 

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Rflto pf T p rstura Ris6 b. Minor Leak Through... 

Existing installations may not meet the requirements laid down for new installations because of minor leaks that have developed. It is necessary to relate such leak rates to the pipe environment. 

I. Leakage—joints and packing this factor accounts for the possibility of leakage from gaskets, pump and other shaft seals, and packed glands. The factor varies from 0.1 where there is the possibility of minor leaks, to 1.5 for processes that have sight glasses, bellows or other expansion joints. 

Finally, A contains acceptor fluorescence (/jj) and two usually very minor leak-through components that of the (partially quenched) donor population inappropriately excited at acceptor wavelength and leaking into the acceptor channel (lf) s), and the small amount of sensitized emission that stems from FRET after inappropriate excitation of donors at acceptor wavelength (/ ). 

Some operations will include a scrap soap reboil to recover reclaimed soap. The soap reboil is salted out for soap recovery and the salt water is recycled. After frequent recychng, the salt water becomes so contaminated that it must be discharged to the sewer. Occasional washdown of the crutcher may be needed. The tower is usually cleaned down dry. There is also some gland water that flows over the pump shaft, picking up any minor leaks. This will contribute a very small, but finite, effluent loading. 

Stop-leak compounds are effective in closing minor leaks. After leaks are closed, a reserve of stop-leak material in the coolant is usually necessary to reseal old leaks opened up by vibration, corrosion, etc., and also to seal any new leaks that may develop. Stop-leaks should be considered as adequate only for short term band-aid uses. As soon as practical, the leak should be properly repaired. 

All joints must be well greased and securely clamped. Even a minor leak is a fire hazard. 

Accidental release of MIC can happen wherever the chemical is stored. A minor leak occurred from the Union Carbide plant in West Virginia only a few months after the Bhopal disaster and a nearby school had to be evacuated. Exposure to MIC at higher concentrations and for a longer duration than happened in Bhopal can also occur and can be fatal to a substantially greater percentage of population regardless of where it happens. The fact that MIC is heavier... 

If animal experiments were solely performed to answer questions relating to the Bhopal disaster, the use of excessively high concentrations of MIC (Dodd et al, 1987 Troup et al, 1987 Fedde et al, 1987 Fowler et al, 1987) and repeated exposures would not have much relevance. However, workers are likely to encounter repeated exposure to MIC indeed, anecdotal reports suggest that the impending disaster was not expected because workers were used to minor leaks and consequently eye irritation in the Union Carbide plant. Although no worker died inside the plant in Bhopal, because MIC spewed outside the factory, an accident worse than Bhopal cannot be ruled out, especially in an enclosed space. 

Materials incompatibility is one of the most frequent causes of process incidents. Degradation of seals and gaskets that have become softened by solvent effects can lead to minor leaks or major loss of containment, and hence to fires, explosions, or more serious accidents. If seal or gasket leakage is identified in a process, then the plant engineer should consult with the manufacturer to confirm the material is suitable for the service. If necessary, all the seals or gaskets of that material should be replaced with something more resilient to the process conditions. 

Answer by Author Sufficient escape area to relieve a minor leak, say 100,000 cfh, as part of the primary system, and full area to relieve a gaseous-insulation mixture of at least the full plant compression capacity for the secondary system. 

Some minor leaks of acids/gases from reactor are yet to be attended,... 

There are two fundamental modes of release for a chemical to the environment routine or accidental. Routine emissions are those which are expected to occur and are frequently the subject of a permit or control procedures. Accidental emissions are much more difficult to quantify since they are usually isolated occurrences and can range from minor leaks in a process unit to spills or explosions. The materials balance process most thoroughly describes the routine releases. 

The general procedures discussed in Chapter 5, section 5.C, can be used for relatively minor leaks, when... 

The system (Figure 4.8) basically consists of a fore-pump which provides the high-pressure and low-pressure section with water from a condensation chamber. In case of a minor leak in the reactor cooling circulation, water loss must be compensated by means of the high-pressure pump (HP pump) feeding water from the condensation chamber to keep the reactor continuously cooled. In case of failure of the high-pressure feed, reactor pressure can be reduced by means of the subsystem automatic pressure relief (not shown in Figure 4.8, but included in Table 4.5 as. Yu) to such... 

Figure 4.11(a) Incident sequence diagram of a case of a minor leak in a cooling system part I). 

Expected accidents are those which probably will occur frequently throughout the reactor life. Examples of expected accidents are fuel failures and minor leaks In Instrument lines. Such accidents have little Importance from a reactor hazards viewpoint and are... 

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