环境污染的标准严格执法，已对易燃液体储存罐的巨大影响。而不是驱逐蒸气进入大气，这种趋势已经对连接或多个坦克歧管通过共同管道到一个中央处理单元。这些已关闭的管道系统，或蒸气回收/收集系统，创造了独特的易燃气体的**隐患。管道运行在这些汽体回收系统往往是更长，更复杂。点火的潜在来源，实际上可能是在蒸汽收集系统本身存在。一个管道系统内可以导致点火火焰前面，可以加速非常迅速，并产生极高的压力。低速，低压密闭爆燃可以很容易地进入一个高速，高压密闭爆燃和过渡然后到爆炸，这是一个在火焰前在蒸气/空气混合物的声音速度移动。“爆炸”避雷器是专门设计来阻止和扑灭爆炸，爆燃和潜水承压爆燃。认为是对尾线和排气线/直插式阻火器放置的位置就点火源的限制不适用于引爆避雷器。

FLAME & DETONATION ARRESTERS

Flammable liquids are volatile in nature. As they evaporate, they may produce ignitable vapor/air mixtures. Such hazardous conditions are commonly encountered in chemical, petrochemical, petroleum and pharmaceutical plants where the storage, transfer and collection of flammable liquids are part of their daily operations.

Flame arresters and detonation arresters are passive, mechanical device installed on a storage tank nozzle or in a flammable vapor piping system. The arresters' functions are: (1) to allow the passage of vapor under normal operating conditions and (2) to stop and extinguish any flame front propagating through the flammable vapor/air mixture under emergency conditions. Stopping the flame protects the storage tank, or the equipment located in the piping system, from the catastrophic damage that may result from an uncontrolled ignition. A variety of arrester designs are available. The choice of a proper arrester depends on factors such as the location of the arrester with respect to the ignition source and the flammable properties of the vapor/air mixture.

The Protectoseal Company recommends that the National Electric Code (NEC) Article 500, rankings of various chemicals be used, whenever possible, to determine the suitability of a flame or detonation arrester for use which a particular chemical.

One common flame arrester configuration is mounted at the end of a storage tank vent pipe and is identified as an "END-OF-LINE" flame arrester. This arrester permits normal tank breathing, while preventing the flashback of an unconfined deflagration (the ignition of the vapor cloud in the open atmosphere) from flashing back past the arrester into the piping and the tank's vapor space.

Flame arresters are at times mounted directly upstream of pressure / vacuum relief vents, or are connected to short runs of open vent outlet piping. These devices, known as "VENT-LINE / IN-LINE" flame arresters are designed with flanged or threaded mounting connections on both the inlet and outlet. It is possible for a flammable vapor / air mixture to ignite within the confined space of the short outlet pipe or within the vent body. Such an ignition is referred to as a confined deflagration. The flame speed is slow and pressures within the vent piping are relatively low. The Vent-Line / In-Line Flame Arrester is designed to stop this type of flame front. Note: these arresters have very specific limitations as to where they can be properly located within the system.

Strict enforcement of environmental pollution standards has had a dramatic impact on tank storage of flammable liquids. Rather than expelling vapors into the atmosphere, the trend has been toward the connecting or manifolding of multiple tanks through common piping to a central processing unit. These closed piping systems, or vapor recovery / collection systems, have created unique flammable vapor safety hazards. The piping runs in these vapor recovery systems tend to be longer and more complex. Potential sources of ignition may actually be present within the vapor collection system itself. An ignition within a piping system can result in a flame front that accelerates very rapidly and generates extremely high pressures. A low speed, low pressure confined deflagration can readily transition into a high speed, high pressure confined deflagration and then to a detonation, which is a flame front moving at the speed of sound in the vapor/air mixture. "DETONATION" arresters are specifically designed to stop and extinguish detonations, confined deflagrations and unconfined deflagrations. The limitations that are placed on the location of end-of-line and vent-line / in-line flame arresters with respect to the ignition source do not apply to detonation arresters.