SHX-UN
Universal Pressure Relief Vent for Inert Gas
Product details
- Single direction vent for positive pressure relief.
- Applicable with inert gas fire suppression systems.
- Available in 3 standard sizes.
- Can be adapted for ceiling mounted applications.
- Operates at 80 Pascals and fully opens at 95 Pascals.
- Constructed from Steel Zintec and powder coated in RAL-9003 white (color change available for additional cost).
- Manufactured to ISO9001 and Russian GOST certification
- The products carry a 3-year warranty.
- Same day shipping if order is processed before 1:00pm EST
Kit: The kit includes a wall liner, wall liner extension and fitting kit. This standard kit can be installed into walls from 4" to 15" thick. For thicker walls, additional wall liner extensions are required.
SHX-UN | Universal pressure relief vent
The SHX-UN Universal Pressure Vent has a unique design (pat applied) offers users the industry’s best solution for blast protection and gas suppression pressure relief for all inert gases. With the largest verified Free Vent Area (FVA) on the market, these third-generation products are effective not only with gas suppression systems, but also handling much higher energy blasts that can occur within electrical switchgear and transformer installations.
The SHX-UN range is the only pressure vent on the market to have the largest true value FVA available correctly 3rd party verified to AFP/BRE live discharge test 122084. VDA calculated vent dynamic co-efficient (vDc) of 1.15 (for gas suppression systems only. The vDc changes with the rate of pressure increase. This is different for switchgear units. Call for advice). The SHX-UN is discharge tested for cascade venting scenarios. Operates at 80 Pascals and fully open at 95 Pascals.
Certifications & Testing
The SHX-UN pressure relief vent has undergone extensive testing to ensure superior performance and compliance with industry standards. Below is a summary of the key certifications and tests this vent has successfully passed. Detailed certificates and test reports are available upon request.
- Performance certification: Witnessed and verified by the Building Research Establishment (BRE), UK. Live inert gas and FM-200 discharge test – Report No. 112084.
- Fire rating certification:
- European approval: Tested by BM Trada to BS EN 1363-1 / BS EN 1364-1, achieving a 4-hour fire integrity rating – Report No. BMT/E=FEI/F15056.
- US approval: Tested by Guardian Laboratories USA to UL555 & ASTM 119-08a, achieving a 2-hour fire integrity rating – Report No. GL 10010.
- Blast and explosion testing: Successfully tested with AFP’s blast simulator to ensure resilience against high-pressure events.
Type of gases
The SHX-UN is specifically designed for use with inert gaseous fire suppression systems. These systems effectively extinguish fires without leaving residue or causing damage to sensitive equipment. Examples of commonly used inert gases include:
- IG-55 (a blend of nitrogen and argon)
- IG-541 (a blend of nitrogen, argon, and carbon dioxide)
- IG-100 (pure nitrogen)
- IG-01 (pure argon)
Benefits of certification
Testing and certification are essential to ensure that products like the SHX-UN pressure relief vent meet the highest safety and performance standards. Certified vents, such as the SHX-UN, are proven to function reliably in critical scenarios, including inert gas discharges, fires, and blast events, minimizing risks to both personnel and infrastructure.
Certification to industry standards ensures seamless compatibility with gas calculation software models, allowing for precise performance predictions. This helps prevent dangerous pressure fluctuations during live suppression system activations, ensuring the safety and integrity of protected spaces.
Fire testing has demonstrated that the SHX-UN vent maintains its role as an effective fire barrier when installed in approved wall systems, with a 4-hour fire resistance rating under European standards and a 2-hour fire resistance rating under US standards. Additionally, blast resistance testing confirms the vent’s ability to endure high-pressure events, preventing structural damage and maintaining enclosure integrity under extreme conditions.
Integrity room tests
The SHX-UN pressure relief vent does not require calibration from a pressure integrity test. It has been fully certified through the BRE Live Discharge test, ensuring compliance with stringent industry requirements.
For any building application, the unit’s size should be selected based on the Free Vent Area (FVA) specified by the gas suppression system supplier’s calculations or an integrity test report.
Unit selection
The SHX-UN vent is a standard stock model, available in a number of standard sizes for installation in both internal and external walls.
Video
The SHX-UN pressure relief vent is designed to regulate maximum room pressure by opening when positive pressure builds up, allowing excess air to escape. Once the discharge is complete and the pressure stabilizes, the vent automatically closes to maintain room integrity.
Evolution through HXD and SHX-UN pressure vent designs
The SHX-UN design, introduced in 2008, is a refinement to AmVentco’s steadily-evolving pressure vent technology. The SHX UN is the latest enhancement to the original HXD design, using innovative lightweight double-skinned louvre blades and offset pivot points. It proved far better at keeping the vent blades closed under the 20 pa required for a fire test, while providing greatly improved pressure relief for gas suppression systems where risks require peak pressures between 250 and 500 pa.
Download Data SheetDownload Installation Guide
The SHX-UN enhances the HXD design. It features:
- a top weight to counterbalance the blade for opening
- a curved trailing edge interlocking blade which maximises the passing air acting on the blades at the point of most mechanical efficiency.
These features allow the vent to achieve 100% of its free vent area at very low pressures.
All these free vent area figures have been obtained using the correct test protocols and live discharge testing with full data logging. This allows the exact position of each vent blade over time, and hence the vent’s FVA, to be proven. Predictions of back pressure and therefore peak pressure to be expected in a building can be made accordingly.
All testing is carried out in-house by AFP using their own equipment and test protocols to BRE Live Discharge Test 122084, and is third-party verified. The standard, verified by BRE, clearly quantifies the rate at which the vent opens relative to the rate of pressure increase as well as the size of the vent specified; so that the role of both factors in controlling the peak pressure in the room is fully recognised.
By contrast, testing for HVAC applications typically involves vent blades being held open, or a constant flow of air; providing no indication of how efficiently they would open if subjected to a blast.
Add-ons
DWL DYNAMIC WEATHER LOUVER
The DWL Exterior Dynamic Weather Louver complements the SHX-UN universal pressure relief vent offering superior wind and weather protection. It does this without restricting the internal vents Free Vent Area (FVA). DWL provides about twice the free vent area of fixed vane weather louvers used as standard within the HVAC market. Accordingly, specifying DWL can halve the number of units needed to deliver the required performance.
Z-Frame
For mounting the DUX in narrow walls, doors, and cladding of less than 4" thick.
Wall Liner Extension Sleeves
For internal wall depths that exceed 15" thickness.
Downloads
Access detailed technical information on the SHX-UN universal pressure relief vent, including data sheets, installation guides, and technical drawings, by downloading the available resources below.
- Technical specifications
- SHX-UN 14 technical drawings
- SHX-UN 22 technical drawings
- SHX-UN 30 technical drawings
- Technical data sheet for one-way venting for Novec FK-5-1-12
Get in touch
For more information on the SHX-UN universal pressure relief vent, including standard vent size options or bespoke sizes, and guidance on typical installation scenarios, feel free to get in touch with our team. We’re here to help you find the perfect solution tailored to your specific needs.
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Below are some related products from the Amventco product range.
DUX | 2-way Pressure Relief Vent
More advanced than single top-pivot designs, the DUX is a compact, highly durable, and efficient two-way pressure relief vent, specifically suited for chemical gases. As the world's first double-action two-way pressure relief vent for halocarbon gases (patent pending), it delivers unmatched performance in its category, setting a new standard for this application.
