Explosion doors

Rupture disks or explosion doors may be used as venting devices. Safety valves are not suitable for this purpose. Obviously, the static-activation overpressures Ps at of he venting devices have to be equal to or smaller than the strength of the equipment to be protected (c-orre-sponding to the Pred.max)-... 

Explosion doors open in case of an explosion, thereby releasing the vent area. Depending on the application, explosion doors may be selected which remain open or close automatically after releasing the explosion. 

The inertia, the opening behavior of the movable cover of the explosion door, and its arrangement (horizontal, vertical) can affect the venting efficiency EF. This results in a higher maximum explosion overpressure Fred,max Iri he protected vessel (see Fig. 26-39). 

The venting capabihty EF and therefore the effective vent area of the explosion door is normally smaller than the capabihty of a plastic or aluminum foil rupture disk with the same area. Therefore, such devices need testing to determine the mechanical strength before actual use, and the venting capability or the pressure rise, respectively. 

FIG. 26-39 Definition of the venting capability EF of an explosion door in comparison with a plastic foil rupture disk. 

When using explosion doors that close the vent area after the explosion, the coohng of the hot gases of combustion may create a vacuum in the vessel, resulting in its deformation. In order to prevent this from happening, vacuum breakers have to be provided. 

Obviously, the best plan is to prevent an explosion from occurring, but appropriate plans should be made in the event one should occur. For example, it is recommended that all personnel be located away from the furnace during light-off in case there is an incident. It may also be advisable to have some type of relief system built into the furnace, for example pressure relief doors (sometimes referred to as explosion doors) that can open in the case of overpressurization. 

The relative advantages of an indirect firing system against a direct firing system focus on the consistency of PF feeding to the burner, the effect of primary air quantity on the process and emissions, and the effect of water vapor. For safety, the indirect firing system needs more safety measures to be implemented to reduce the risk of fire or explosion to an acceptable level by installation of the explosion doors and inertization system with carbon dioxide or nitrogen. 

In potentially gassy or gassy operations, wherever mine-type ventilation systems using an offset main fan installed on the surface are used, they shall be equipped with explosion-doors or a weak-wall having an area at least equivalent to the cross-sectional area of the airway. 

Explosion doors In the event of an explosion in a furnace, doors specifically designed to blow out and protect against a major structural failure are provided they aa like safety valves in a piping system. 

Explosion doors These are now standard in the industry. Use mechanical door stops to close the doors, rather than chains, which tend to break. 

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