Overview
In addition to the normal venting capacity provided by Protectoseal’s Pressure / Vacuum Relief Vents and/or Flame Arresters, every large above ground flammable liquid storage tank should be provided with some means of relieving excessive internal pressure caused by exposure of the tank to a fire. Depending upon the strength of the tank structure, a vent sized to handle the normal venting requirements (for day-to-day operations) may be inadequate to handle the abnormal vapor efflux generated by heat from an exposure fire.
When a fire occurs near a flammable liquid storage tank, heat transmitted through the tank wall to the contents will cause the liquid to vaporize readily. In the case of petroleum based products, this vaporization may amount to roughly 30 or more cubic feet of vapor for every gallon of solvent vaporized. This generates a relatively high pressure within the confined area of the tank’s vapor space. In the absence of sufficient emergency relief a tank rupture could occur, with disastrous effect on life and property and the environment.
Explosions caused by such conditions may be readily avoided by providing adequate emergency relief vents which permit the vapors to escape from the tank. These emergency vents usually include pallet assemblies (as illustrated above) which are weighted to stay closed under normal pressure conditions and which open only when a predetermined pressure is attained, thus relieving the abnormal volume of vapor generated under the fire conditions described above.
Emergency Pressure Vents
Protectoseal Series No. 7800 Emergency Pressure Vents are designed to provide emergency relief capacity beyond that furnished by the operating vent on tanks. The Series No. 7800 vents do not provide vacuum relief. Vacuum relief must be supplied by independent operating vents (See Protectoseal Series No. 830, Series No. 8540H, Series No. 6240, Series No. 18540 or Series No. 16240).
Under normal operating conditions, the vent pallet assembly is closed providing an effective vapor seal. In the event of an emergency (fire involvement of the tank), the pallet lifts in response to the increased pressure in the tank’s vapor space. Vapor is expelled, thereby protecting the tank from dangerous over-pressurization. Pallet assembly automatically closes and reseals when the pressure is reduced.
Protectoseal Series 7800 Specifications
Emergency Pressure Manhole Cover Vents
Protectoseal Series No. 53300 Emergency Pressure Manhole Cover Vents provide emergency pressure relief for storage tanks as well as convenient access for tank cleaning, inspection and repair work. They are designed for installation on the manhole openings of tanks and provide a means of relieving large volumes of vapors, beyond the capacity of a normal operating vent, if an emergency fire involvement of the tank should occur. Series 53300 Manhole Covers do not provide vacuum relief. Vacuum relief must be supplied by operating vents (See Protectoseal Model No. 830, Model No. 8540H, Model No. 6240, Model No. 16240 and Model No. 18540).
When properly installed on a flanged tank manhole opening, the Series No. 53300 Manhole Cover Vent provides an effective vapor seal. Under emergency fire conditions, the vent opens fully to allow escape of vapors and prevent damage to the tank due to excessive pressure. The cover must be manually repositioned after venting has occurred.
Protectoseal Series 53300 Specifications
Spring Loaded Emergency Pressure Vents
Protectoseal Series 54000 Spring Loaded Emergency Pressure Vents provide emergency pressure relief for storage tanks as well as access for tank cleaning, inspection and repair work. They are designed for installation on the manhole openings of tanks and provide a means of relieving large volumes of vapors, beyond the capacity of a normal operating vent, if an emergency fire involvement of the tank should occur. Series 54000 Emergency Pressure Vent does not provide vacuum relief. Vacuum relief must be supplied by Protectoseal operating vents (See Protectoseal Model No. 830, Model No. 8540H, Model No. 6240, Model No. 16240 and Model No. 18540).
Even tanks with high design ratings require protection from excesive pressure accumulation in their vapor space. With the set pressures allowed by a spring loaded design, the vents can remain closed at higher pressures and are allowed to open only when the tank structure may be in jeopardy. Vapors can then be relieved to maintain the tank within its design parameters.
The set point is determined by combined spring force and weight of components acting upon the mean seat diameter of the vent. Settings are adjustable within a specified range for any spring combination, by increasing or descreasing compression of springs. Series 54000 Spring Loaded Emergency Vents can be set at 1 PSIG or higher.
Protectoseal Series 54000 Specifications
Emergency Pressure / Vacuum Manhole Cover Vents
Protectoseal Series No. 52500 Manhole Cover with pressure and vacuum relief, provides both emergency pressure relief and vacuum relief when installed on the manhole of a storage tank. In emergency situations (external fire involvement of the tank), normal venting devices may be too small to prevent overpressurization of the tank. The Series No. 52500 provides the necessary pressure relief capacity to maintain the tank in a safe operating range. The integral vacuum vent provides additional protection against tank collapse due to excessive vacuum in the vapor space.
Protectoseal Series 52500 Specifications
Emergency Pressure / Vacuum Vents
Protectoseal Series No. 52600 provides both emergency pressure relief and vacuum relief when installed on the manhole opening of a storage tank. In emergency situations (external fire involvement of the tank), normal venting devices may be too small to prevent overpressurization of the tank. The Series No. 52600 provides the necessary pressure relief capacity to maintain the tank in a safe operating range. The integral vacuum vent provides additional protection against tank collapse due to excessive vacuum in the vapor space.
Protectoseal Series 52600 Specifications
Hinged Emergency Pressure Manhole Cover Vents
Protectoseal Series No. 51600 Hinged Emergency Pressure Manhole Cover Vents provide emergency pressure relief for storage tanks that are exposed to an external fire. They are designed to open and provide pressure relief beyond the capacity of the normal breather vents. The Series No. 51600 design allows for higher pressure relief settings than are available on our Series No. 53300 Manhole & Emergency Pressure Cover Vent. The Series No. 51600 Cover Vent does not provide vacuum relief. Vacuum relief must be supplied by an operating vent (See Protectoseal Series No. 830, Series No. 8540H, Series No. 6240, Series No. 16240 or Series No. 18540).
These vents are mounted on the tank manhole flange. When properly installed, the device provides an effective vapor seal. Under emergency fire conditions, the cover can pivot open on its hinge and provide required relief, preventing damage to the tank due to excessive internal pressure. When tank pressure is reduced, the cover automatically recloses. The hinged design allows the use of a lever principal counterweight so that the pressure settings higher than those available on other dead weight loaded vents of similar size may be achieved. Full open flow capacity and automatic reclosing of vent as tank pressure decreases provide efficient and dependable emergency venting capability while minimizing amount of vapor unnecessarily vented to the atmosphere. The design also allows convenient access through the manhole opening for tank inspection and maintenance.
Protectoseal Series 51600 Specifications
Hinged Emergency Pressure Manhole Cover Vents
Protectoseal Series No. 51700 Hinged Emergency Pressure Manhole Cover Vents provide emergency pressure relief for storage tanks that are exposed to an external fire. They are designed to open and provide pressure relief beyond the capacity of the normal breather vents. The Series No. 51700 design allows for higher pressure relief settings than are available on our Series No. 53300 Manhole & Emergency Pressure Cover Vent. The Series No. 51700 Cover Vent does not provide vacuum relief. Vacuum relief must be supplied by an operating vent (See Protectoseal Series No. 830, Series No. 8540H, Series No. 6240, Series No. 16240 or Series No. 18540).
These vents are mounted on the tank manhole flange. When properly installed, the device provides an effective vapor seal. Under emergency fire conditions, the cover can pivot open on its hinge and provide required relief, preventing damage to the tank due to excessive internal pressure. When tank pressure is reduced, the cover automatically recloses. The hinged design allows the use of a lever principal counterweight so that the pressure settings higher than those available on other dead weight loaded vents of similar size may be achieved. Full open flow capacity and automatic reclosing of vent as tank pressure decreases provide efficient and dependable emergency venting capability while minimizing amount of vapor unnecessarily vented to the atmosphere. The design also allows convenient access through the manhole opening for tank inspection and maintenance.
Protectoseal Series 51700 Specifications
PIN-TECH® Bubble-Tight <500 ppm Pressure Relief Vents
Series No. 56000, Bubble-Tight <500 ppm Pressure Relief Vents are designed
and tested to address concerns about the leakage of fugitive emissions prior
to set point, and parts per million (ppm) emission rates.
Protectoseal’s PIN-TECH vents are mounted to the vapor space flange connection of a storage tank or vessel. The vents utilize a unique technology that employs a buckling pin to hold the vent piston closed with zero leakage up to the relief set point. The pin is an accurately machined, straight metal rod. It is configured to precisely sense transmitted axial forces that are generated as a result of tank pressure. The force required to buckle the pin is governed by Euler’s Law and is a function of the pin’s metallurgy, length and diameter. An exact buckling force can be determined for any specific pin configuration. When the pressure in the tank reaches the vent set point, the axial force is sufficient to buckle the pin and the vent sealing piston is allowed to move to its full open, relieving position. The pin buckles completely and instantaneously.