Pipe failures

Low-pressure gas distribution pipeline failures result in leaks that undetected might ignite and cause an explosion. The number of leaks because of corrosion was mains 

864 services 99,024. The majority of the leaks were repaired without major incidents. Only 26 major incidents caused by corrosion were reported during 1984—1999, which resulted in 4,923,000 in property damage, 4 fatalities, and 16 injuries. 

Davenport [1] has listed more than 60 major leaks of flammable materials, most of which resulted in serious fires or unconfined vapor cloud explosions. Table 9-1, derived from his data, classifies the leak by point of origin and shows that pipe failures accounted for half the failures— more than half if we exclude transport containers. It is therefore important to know why pipe failures occur. Following, a number of typical failures (or near failures) are discussed. These and other failures, summarized in References 2 and 3, show that by far the biggest single cause of pipe failures has been the failure of construction teams to follow instructions or to do well what was left to their discretion. The most effective way of reducing pipe failures is to  

Check construction closely to see that the design has been followed and that details not specified have been constructed according to good engineering practice. 

Origin of Leaks Causing Vapor Cloud Explosions 

Pipeline (inci. vaive, 34 Includes 1 sight-glass and 

Vessei 5 Includes 1 internal explosion, 1 slopover, and 1 failure due to overheating 

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This is an important practical problem area, as piping vibration can cause consider le downtime or even pipe failure. 

Category 2. Release of liquid ammonia from pipe failure for two plant-damage states involved the assumptions ... 

B. T. Matusz and D. L. Sadler, A Comprehensive Program for Preventing Cyclohexane Oxidation Process Piping Failures, Paper presented at AIChE Loss Prevention Symposium, Houston, Texas, Mar./Apr. 1993. 

Dead-ends have caused many pipe failures. Water, present in traces in many oil streams, collects in dead-ends and freezes, breaking the pipe. Or corrosive materials dissolve in the water and corrode the line. 

For another failure due to water hammer, see Section 10.5.3. 9.1.6 Miscellaneous Pipe Failures... 

The fire and explosions in Mexico City in 1984, which killed more than 500 people (see Section 8.1.4), started with a pipe failure. The cause is not known, but the pipe may have been subjected to excessive pressure. Earlier the same year, in February, at least 508 people, most of them children, were killed in Cubatao, Sao Paulo, Brazil, when a 2-ft-diameter... 

B. M. Hancock, Preventing Piping Failures, Safety and Loss Prevention in the Chemical and Oil Processing Industries, Symposium Series No. 120, Institution of Chemical Engineers, Rugby, UK, 1990, p. 589. 

Geyer, T. A., Bellamy, L. J., Astley, J. A., Hurst, N. W. (1990). Prevent Pipe Failures Due to Human Errors. Chemical Engineering Progress, November. 

Safety of Interstate Natural Gas Pipelines Power 87 Casualities/Approx. 3000 pipe failures U S. interstate Natural Gas large diameter, high pressure transmission pipelines 43. 

Pipe Break Frequency Estimation for Nuclear Power Plants Nuclear 19 occunences of pipe failures (breaks), supplemented by expert-opinion estimates Leaks of 1 gpm for 2 inches in diameter pipe 50 gpm tor all pipe for 81 nuclear plants 101. 

Characteristics of Pipe System Failures in Light Water Reactors Nuclear Approximately 100 records of pipe failure rates in a wide variety of failure modes Nuclear Power Plant Piping 114. 

NUMHER AND TYPE OF RECORDS 19 occurrences of pipe failures (breaks), ... 

NUMIIER AND TYPE OF RECORDS Approximately 100 records of pipe failure... 

Piping is tlie most important transport facility in an industrial plant. In general, piping failures can result from... 

To maintain the BSR at less than 5.5, the string of drill collars must frequently be composed of different sizes. For severe drilling conditions (hole enlargement, corrosive environment, hard formations), reduction of the BSR to 3.5 helps to reduce frequency of drill pipe failure. 

The simultaneous action of cyclic stress alternating tensile and compressive and corrosive attack is known as corrosion fatigue. Corrosive attack can be in the form of pitting. These pits function as notches, acting as stress risers and initiate cracks. Once a crack is formed, the probability of pipe failure is enhanced by further corrosion as corrosion is accelerated by action of stress. The tip of the crack deep within the fracture, the area under the greatest stress, is anodic to the wider part of the crack. As corrosion progresses, the metal at the tip of the crack goes into the solution, the crack deepens and eventually penetrates the wall of the tube. 

Corrosion fatigue, therefore, is a special case of stress-corrosion cracking and fatigue failure. Figure 4-451 shows an example of pipe failures due to corrosion fatigue. Corrosion fatigue can be prevented or reduced by ... 

Main, W. C., Detection of Incipient Drill-pipe Failures, API Drilling and Production Practices, 1949. 

Hendrickson, J. R., et al., Drill pipe failure in hydrogen sulfide, lADC Drilling Technology Conference, Houston, 1984. 

Scenario 4—Manifold piping failure with VCE consequences... 

Risk management is a continuous process as was highlighted in Chapter 5, the consequences and frequency of an event are highly condition dependent. As a result, managing risk requires that conditions that may increase event severity or likelihood are adequately controlled. For example, if crane safety programs are not followed, the frequency of occurrence of dropped loads or overturned cranes may increase. This could result in substantially increased risk of piping failure and material release. 

USTs release contaminants into the environment as a result of (1) corrosion, (2) faulty installation, (3) piping failure, and (4) overfills.15 17... 

Piping failure can be caused in several ways. A study by U.S. EPA16 has shown that piping failure accounted for a substantial portion of releases at USTs. Spills and overfills are usually caused by human error. Repeated spill can also increase the corrosive nature of soils. 

Determine the pressure required for a pipe to swell and the pressure required for a pipe failure. The pipe is 3-in stainless 316 schedule 40 pipeline for transporting a gas mixture that is sometimes within the explosive composition range. 

Piping failure at compressor due to vibration induced stress. Combustible gas detection system inoperability contributed to loss. 

Safeguarding is the provision of protective measures to minimize the risk of accidental damage to the piping or to minimize the harmful consequences of possible piping failure. 

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