SHX-UN MOT
Motorised Pressure Relief Vent for Inert Gas
Product details
- Largest verified Free Vent Area (FVA) on the market.
- Single direction venting for positive pressure.
- Applicable with gas fire suppression systems using inert gases.
- Motor Spring return when required e.g. fire alarm signal.
- Operates with a vDc factor of 1.15 for gas suppression applications.
- Fully opens within 13 ms.
- Available in 4 standard sizes.
- Constructed from Steel Zintec and powder coated with RAL 9003 white.
- 5 year warranty.
- Available off the shelf on next day delivery.
Kit: The kit includes a Belimo motor, wall liner, wall liner extension and fitting kit. The standard kit can be installed into walls up to 380 mm. For thicker walls, additional wall liner extensions are required.
Note: For external walls the EXP Expander Box Weather Louvre is required.
SHX-UN MOT | Motorised Pressure Relief Vent
The SHX-UN MOT is AFP’s advanced motorised pressure relief vent, designed to deliver exceptional performance in gas suppression systems and demanding blast protection applications. Building on the trusted SHX-UN range, this vent combines automatic pressure relief with motorised functionality for ventilation and multi-room cascade venting.
Always Full Pressure Relief
A key feature of the SHX-UN MOT is its ability to provide full pressure relief, even when the vent appears fully closed. Unlike traditional dampers, the motor is not mounted on the blades themselves. This means that the system can respond immediately to sudden pressure increases at any point during operation, including while the blades are in motion or fully sealed. In an emergency situation, there is no delay and pressure is released instantly, maintaining the integrity of the protected space.
High-Speed Blast Response and Verified Performance
The SHX-UN MOT has been independently tested and proven to fully open in as little as 13 milliseconds. The vent’s blades have undergone rigorous blast testing, successfully withstanding simulated internal pressures above 350 kPa. In addition, the SHX-UN range is the only product of its kind on the market with a Free Vent Area (FVA) that has been correctly verified by a third party. This confirms that the vent performs not only under controlled conditions but in real-world scenarios involving live inert gas discharge.
Applications
This vent is particularly well suited to protecting critical equipment such as electrical transformers, where continuous natural ventilation must be combined with protection from gas discharge or blast events. With its pressure rating above 10 kPa, the SHX-UN MOT provides a safety buffer for high-risk enclosures.
For large-scale suppression systems, the vent can be used alongside our BSV IN Insulated Blast Vent or BSV F-INS Blast Vent with Fire Rated Insulation, to create a sealed gas-tight space that still allows safe and rapid depressurisation. This makes it a go-to solution for multi-room venting systems or any application where performance, compliance, and safety are non-negotiable.
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Certifications & testing
Tested using Propane/Oxygen & Acetylene/Oxygen ignition mix to potential 350Kpa discharge.
- 4 Hour Fire Resistance, rated by Exova to BS EN 1363-1 and BS EN 1364-1.
- UL-555 conformity, according to Guardian Fire.
- Live discharge test 122084, including vent area validation, certified by BRE.
- Blast and Explosion tested with AFP's blast simulator.
Types of gases
The Motorised SHX-UN can be used with gaseous fire suppression systems using any inert gas. Inert gases are non-reactive and leave no residue, making them ideal for protecting sensitive equipment and critical spaces. Inert gaseous agents include:
- Nitrogen (N₂)
- Argon (Ar)
- Carbon Dioxide (CO₂)
- Inergen® (Blend of N₂, Ar, and CO₂): IG-55, IG-100, IG-541
- Argonite® (Blend of N₂ and Ar)
Benefits of certification
Testing and certification are essential to ensure that products meet strict safety and performance standards. In real-life applications, this means that certified vents, like the SHX-UN MOT, reliably perform in extreme conditions such as gas discharges, blasts, or fires, significantly reducing the risk to personnel. Certification to standards such as the BRE Live Discharge Test ensures that the vents are compatible with industry gas calculation software models. This allows for precise performance predictions and preventing dangerous over-pressurisation during a live gas discharge — mitigating the risk of blockage and ensuring safe operation.
Fire testing guarantees that the vents act as an effective fire barrier when installed in a block wall, providing essential protection in high-risk environments. Extensive blast resistance testing proves their ability to withstand extreme pressures, preventing structural damage and safeguarding the integrity of the enclosure. By undergoing thorough certification, the SHX-UN MOT vent ensures consistent and reliable performance when it matters most, offering peace of mind in critical situations.
Integrity testing calibration
The AFP range of universal pressure relief vents do not require calibration from an integrity test, as they are fully certified to the BRE Live Discharge test of 2008 (room leakage 3,43 cm3 for SHX-UN-500).
Unit selection
The SHX-UN pressure relief vents are offered in a number of standard sizes for installation in both internal and external walls.
| Product Code | SHX-UN300 MOT | SHX-UN500 MOT | SHX-UN700 MOT | SHX-UN1000 MOT |
| Free Vent Area | 0.077m2 | 0.212m2 | 0.416m2 | 0.85m2 |
| Overall WxHxD | 420x420x120mm | 620x620x120mm | 820x820x120mm | 1120x1120x120mm |
| Hole cut out WxH | 355x345mm | 555x545mm | 755x745mm | 1055x1045mm |
| Wall Mounted Weight | 18kg | 29kg | 44kg | 70kg |
Add-ons
EXP
The EXP offers superior wind and weather protection for external walls, without restricting the internal vents Free Vent Area (FVA).
Grilles
The AFP product range offers several security grilles to mount on vents in outside walls for different levels of protection.
Z-Frame
Powder coated steel stub duct for mounting the SHX-UN into thin walls, doors, and cladding of less than 100 mm thick.
Wall liner
A wall liner is an extension for internal wall depths that exceed 15" thickness. With extra wall liners, minimal leakage and FVA will still be applicable.
Downloads
Access detailed technical information on the SHX-UN, including data sheets, installation guides, and technical drawings, by downloading the resources below.
Get in touch
Get in touch for a quote, more information, assistance with correct sizing, or bespoke solutions tailored to your needs.
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