Fires, accidental systems

The full title of this standard is, Fire Prevention and Control on Open Type Offshore Production Platforms. It provides recommendations for rninimizing the likelihood of having an accidental fire, and for designing, inspecting, and maintaining fire control systems. It emphasizes the need to train personnel in firefighting, to conduct routine drills, and to establish methods and procedures for safe evacuation. The fire control systems discussed in this recommended practice are intended to provide an early response to incipient fires to prevent their growth. They provide a baseline, and are not intended to preclude the appUcation of more... 

The calculated detonation velocity in room temperature acetylene at 810 kPa is 2053 m/s (61). Measured values are about 1000-2070 m/s, independent of initial pressure but generally increasing with increasing diameter (46,60—64). In a time estimated to be about 6 s (65), an accidental fire-initiated decomposition flame in acetylene at ca 200 kPa in an extensive piping system traveled successively through 1830 m of 76—203-mm pipe, 8850 m of 203-mm pipe, and 760 m of 152-mm pipe. 

Flame Types and Their Characteristics. There are two main types of flames diffusion and premixed. In diffusion flames, the fuel and oxidant are separately introduced and the rate of the overall process is determined by the mixing rate. Examples of diffusion flames include the flames associated with candles, matches, gaseous fuel jets, oil sprays, and large fires, whether accidental or otherwise. In premixed flames, fuel and oxidant are mixed thoroughly prior to combustion. A fundamental understanding of both flame types and their stmcture involves the determination of the dimensions of the various zones in the flame and the temperature, velocity, and species concentrations throughout the system. 

The equipment and systems of the processing phuit are designed to contain tlie chemicals mider processing conditions and to provide tlie controlled environment required for production. This equipment is designed to function under both specific process conditions and upset conditions. Upset conditions tliat are considered in design include fire, explosions, and accidental chemical releases. 

The father of this system was the so-called fault tree that was developed for the U.S. missile program. The developers ran into the problem of testing the electric circuits of the Minute Man missiles. No one wants a nuclear warhead accidentally fired into space. Yet all the electric circuits had to be tested so that in case of an attack the missiles could be relied on. The fault tree was a method of predicting the probability of an unplanned launch as a result of testing. If the probability were high then either another way would have to be found to test the circuits or more safety devices would have to be installed. 

The nonelectric firing system is simple and requires a minimum of equipment. Once initiated, however, it passes from the control of the operator. The electric system can be retained in the control of the operator up to the actual firing. Electric caps also are more waterproof. On the other hand,-the electric system is more complicated, employs more equipment, and may require the operator to remain near the scene at the time of firing. In addition, electric systems can be accidentally activated by static electricity and are hazardous to use in some target situations. 

The risk of explosion or fire associated with the use of mobile telephones in a LPG vehicle is extremely low. First, LPG vehicle fuel systems are closed systems with safety features to prevent accidental release of LPG. The risk of fuel leakage is less than that of a petrol or diesel vehicle. Second, LPG will only bum when mixed with air in proportions within the flammable limits and when there is an ignition source. Working with higher-pressure fuel systems requires special tools and... 

Business continuity procedures, including disaster recovery procedures, should ensure minimal disruption in the case of loss of data or any part of the system. It is necessary to ensure that the integrity of the data is not compromised during the return to normal operation. At the lowest level, this may mean the accidental deletion of a single file, in which case a procedure should be in place for restoring the most recently backed-up copy. At the other extreme, a disaster such as a fire could result in loss of the entire system. For this situation a procedure addressing the following should be in place ... 

Serious Consequences—Class 2. Equipment or the critical instruments serving equipment whose failure could possibly cause, or fail to warn of upset conditions, uncontrolled releases of dangerous materials, situations that could result in accidental fires and explosions. Furthermore these failures could result in serious conditions involving environmental releases, property or production losses, or other non-life-threatening situations. These particular pieces of equipment, the safety shutdown systems and the alarms that serve this equipment are given a slightly lower priority. However, they are also inspected, tested, or prooftested on a regular schedule, but may be allowed to have some leniency in compliance. 

Avoiding the use of zinc, cadmium, or zinc rich coatings on austenitic stainless steels. Even stainless systems operating at low temperatures can accidentally be heated by fire or welding repairs and can cause stress cracking. 

Critical Consequence—Class 1. Safety Critical instruments whose failure would either cause, or fail to inform of, situations resulting in accidental fire, explosion, uncontrolled release of dangerous materials, reportable environmental releases, or major property or production losses. The safety critical instruments assigned a Class 1 include those that have been mandated as such by regulating agencies an in-house technical safety review committee reliability studies and specific shutdown systems and specific alarms deemed critical by operations supervisors. 

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