| 94063 FRP Emergency Vent & Manhole Cover |
Is the material in the tank incompatible with Steel? |
Storage tanks holding highly
corrosive acids, caustics or brine where metallic vents would quickly attack.
- Applications that only need pressure emergency relief (no vacuum) but still want man-way access.
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For storage of highly corrosive products like acids and caustics where metallic vents are not viable. |
All-FRP construction (Derakane 470 vinyl-ester, other resins optional) delivers superior chemical resistance and a leakage rate < 1 SCFH at 90 % of set point—capabilities the metal models cannot match. (L&J Technologies) |
FRP Construction: The only model in the list made of Fiberglass Reinforced Plastic (Derakane/Furan resins), ensuring chemical inertness and preventing corrosion-related failure. |
Weight-Loaded |
Teflon Air Cushioned Pallet Seating |
FRP |
Pressure Only |
| 94200 Emergency Relief Vent/Manhole Cover |
Do you need a manhole cover? Is emissions and tightness of seal NOT a factor? |
General-purpose petroleum or chemical storage where low-pressure emergency pressure relief and roof access are required, and emissions tightness is not critical. |
For general-purpose, pressure-only emergency relief on low-pressure tanks where initial cost is a primary driver and minimal leakage is not a critical requirement. |
Best economy: simplest weight-loaded design and widest size range (16-36 in.).
- Ideal when you do not need Expanda-Seal, vacuum relief, or hinged access—so it's cheaper and simpler than all the other metal vents here.
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The Economical Baseline: Provides fundamental, reliable protection at the lowest price point. It's the no-frills, standard option. |
Weight-Loaded |
Standard Diaphragm |
Metallic (Al, CS, SS) |
Pressure Only |
| 94201 Emergency Relief Vent/Manhole Cover with Expanda-Seal |
Is the material in the tank a VOC, high value, odorous or must you minimize vapors for some reason? |
Tanks containing VOCs, odorous, or high-value products where you must minimize vapor losses but still only need pressure relief. |
For applications requiring low fugitive emissions, product conservation, or odor control, representing a cost-effective upgrade from the baseline model. |
Adds Shand & Jurs Expanda-Seal™ diaphragm—balloons tight as set point approaches, giving "near bubble-tight" leakage (< 0.5 SCFH @ 95 % set).
- Same footprint as 94200, so you choose 94201 whenever emissions control or regulatory compliance is tighter.
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Integrated Expanda-Seal™: Offers the superior sealing performance of Expanda-Seal™ (< 0.5 SCFH @ 95% set point) in a pre-packaged, economical model. |
Weight-Loaded |
Expanda-Seal™ |
Metallic (Al, CS, SS) |
Pressure Only |
| 94210 Emergency Relief Vent/Hinged Style |
Do you need frequent access for cleaning, inspection, or dipping? |
Facilities that open tanks often for cleaning, inspection, or dipping and want that access fast.
- Pressure-only emergency vent duty.
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For applications where frequent tank access for inspection or maintenance is required, and minimizing downtime and labor costs is a priority. |
Hinged lid swings clear in seconds—no unbolting or gasket change—cutting maintenance time dramatically.
- Optional proximity switches for remote open indication.
- Choose over 94200/94201 when speed of access outweighs cost/weight. (L&J Technologies)
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Hinged Cover: Allows quick and easy access to the tank interior without unbolting the vent or replacing gaskets, streamlining maintenance operations. |
Weight-Loaded |
Standard Diaphragm (Expanda-Seal™ Optional) |
Metallic (Al, CS, SS) |
Pressure Only |
| 94221 Emergency Vent & Manhole Cover |
Do you need emergency vents under both pressure AND vacuum conditions? |
Tanks that can see both over-pressure (fire case, thermal expansion) and vacuum (product draw-down, cooling) but where hinged access is not mandatory. |
For basic, dual-function protection against both overpressure and vacuum in applications where the standard, interdependent P&V settings are acceptable. |
Single weight-loaded assembly provides dual pressure + vacuum relief; Expanda-Seal is standard for tight sealing.
- Simpler, lighter, and less expensive than spring-loaded 94225 if you don't need hinged access. (L&J Technologies)
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Basic P&V Relief: The most economical option for combined pressure and vacuum protection. Comes standard with the benefit of Expanda-Seal™. |
Weight-Loaded (Pressure & Vacuum) |
Expanda-Seal™ |
Metallic (Al, CS, SS) |
Pressure & Vacuum |
| 94225 Emergency Vent & Manhole Cover (Spring Loaded Vacuum) |
Do you need emergency venting under pressure and vacuum above atmospheric pressure? Do you need tool free tank access? |
Same dual pressure-&-vacuum duty plus a requirement for quick, tool-free tank access—e.g., digesters, wastewater, biogas. |
For applications requiring precise, adjustable, or non-standard vacuum protection that must be independent of the pressure setting. Also benefits from hinged access. |
Combines hinged cover (easy entry) with spring-loaded, adjustable vacuum pallet—most versatile unit in this list.
- Optional Expanda-Seal; no unbolting needed, so downtime is lower than 94221. (L&J Technologies, L&J Technologies)
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Independent, Adjustable Vacuum: The spring-loaded vacuum relief can be set independently of the pressure setting, overcoming the key limitation of the 94221. This is the premium choice for flexible P&V control. |
Weight-Loaded (Pressure) / Spring-Loaded (Vacuum) |
Standard Diaphragm (Expanda-Seal™ Optional) |
Metallic (Al, CS, SS) |
Pressure & Vacuum |
| 94510 Magna Vent, Magnetically Sealed |
Is the product high-value or hazardous, where any leakage below the set point is unacceptable, yet full-flow is needed at the set point per NFPA guidelines? |
Small-to-medium tanks (4-12 in. nozzle) that must meet NFPA emergency venting and demand instant full-open flow at low set points (0.5–2.75 psig). |
For tanks storing high-value or hazardous products where any leakage below the set point is unacceptable, and instantaneous full-flow capacity is needed at the set pressure. |
Magnetic latch snaps wide open the moment set pressure is reached—higher discharge coefficient than weight-loaded pallets.
- Expanda-Seal standard; compact and economical for small nozzles where the larger manhole-style vents won't fit. (L&J Technologies)
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Magnetic Latch & Snap Action: Provides a bubble-tight seal up to the set point and then opens instantly to 100% capacity with no overpressure required. Eliminates "simmering" and product loss. |
Magnetic Latch |
Expanda-Seal™ |
Metallic (Al, CS, SS) |
Pressure Only |
| 94580 Combo Flame Arrester and Magna Emergency Vent |
Is the product high-value or hazardous, where any leakage below the set point is unacceptable, yet full-flow is needed at the set point AND flammable or low-flash point? |
Low-pressure tanks with flammable or low-flash-point liquids where both flame arresting and emergency pressure relief are mandated but only one nozzle is available (2-6 in.). |
For tanks storing flammable liquids with low flash points (NEC Group D) that require both emergency pressure relief AND protection from external flame propagation. |
Integrates flame arrester and magnetically latched emergency vent in one compact device—saves cost, weight, and nozzle count versus installing a separate 94510 plus a 94309 arrester.
- Still includes Expanda-Seal for tight sealing. (L&J Technologies)
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Integrated Safety System: Combines the high-performance magnetic latch vent with a flame arrester in a single unit, reducing cost, footprint, and potential leak paths compared to separate components. |
Magnetic Latch |
Expanda-Seal™ |
Metallic (Al, CS, SS) |
Pressure & Flame Arresting |
