BVNO 50 Blast Valve with Optional Prefilter: Automatic Blast Protection for Shelter Ventilation Systems
Modern civil defence shelters, safe rooms and protected facilities require ventilation components capable of maintaining normal airflow while automatically protecting the interior during blast events. According to the manufacturer, the BVNO 50 Blast Valve is a normally open, dual-action automatic blast valve designed to close automatically under blast wave pressure while allowing unrestricted airflow during standard operation. The valve is available either as a standard unit or with an optional integrated prefilter for dust particle removal.
Official product page:https://www.shelter-shop.com/product-page/safe-360-abv-54-cmh-air-valve
Product Overview
According to Shelter-Shop, the BVNO 50 Blast Valve is intended for installation in:
civil defence shelters;
bunkers;
safe rooms;
protected containers;
industrial facilities;
ventilation systems requiring blast protection.
The valve allows air to move freely into and out of the protected space during normal operation while automatically closing when exposed to blast wave pressure. According to the manufacturer, this protects the protected space from both the positive and negative phases of a blast wave.
Operating Principle
The manufacturer describes the BVNO 50 as a normally open, dual-action automatic blast valve.
During normal ventilation, air passes through the valve with minimal restriction. When subjected to blast pressure, the valve automatically closes the ventilation opening, helping protect the interior against the effects of a blast wave.
The valve is designed to automatically return to its normal operating position after the blast event, allowing ventilation to resume.
Installation Applications
According to Shelter-Shop, the BVNO 50 can be installed:
in ventilation wall openings;
as part of shelter air ducts;
on pre-installed wall sleeves;
retrofit flanges;
ventilation ducts;
other compatible ventilation connections.
The manufacturer also states that the valve can be supplied with an optional prefilter for removing dust particles before air enters the protected space.
Main Technical Specifications
The following specifications are published by the manufacturer:
Specification | Value |
Valve type | Normally open, dual action, automatic |
Practical pressure durability | >900 kPa (9 bar) |
Nominal airflow | ≈50 m³/h |
Pressure drop at nominal airflow | 200 Pa |
Mechanical shock resistance | >12 g |
Wall connection | 4-inch flange |
Available configurations | 4Y – valve only / 4X – valve with prefilter |
Mechanical Characteristics
According to the manufacturer, the BVNO 50 provides:
automatic blast protection;
continuous airflow during normal operation;
resistance to high blast pressure;
mechanical shock resistance;
corrosion resistance;
operation across a wide temperature range.
These characteristics are intended for long-term use in protected ventilation systems.
Certification
Shelter-Shop states that the BVNO 50 Blast Valve has been:
tested;
certified according to SI4570.
These statements are published by the manufacturer on the official product page.
Optional Prefilter
One available configuration includes an integrated prefilter.
According to the manufacturer, the prefilter is designed to remove dust particles before air enters the ventilation system. The valve is available in two standard configurations:
4Y — valve only;
4X — valve with integrated prefilter.
Typical Applications
Based on the manufacturer's description, the BVNO 50 is suitable for:
civil defence shelters;
bunkers;
safe rooms;
protected containers;
industrial facilities;
blast-protected ventilation systems.
Conclusion
According to Shelter-Shop, the BVNO 50 Blast Valve is a compact automatic dual-action blast valve intended for professional shelter ventilation systems. The published specifications include approximately 50 m³/h nominal airflow, practical pressure durability exceeding 900 kPa, 200 Pa pressure drop, mechanical shock resistance above 12 g, and a 4-inch flange connection. The valve is available either as a standard model or with an integrated prefilter and is certified to the SI4570 standard for use in protected facilities.
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