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Air Danshin is a Japanese building system that uses earthquake sensors and stored compressed air to lift a house from its foundation interface when shaking is detected. Sansei AIR Danshin System Co., Ltd. says the system activates in approximately 0.5 to 1 second. Its published performance figure—reducing intensity-7 shaking to approximately one-thirtieth—is a manufacturer claim, not an independently verified field result in the sources available.
How the residential Air Danshin system works
The manufacturer describes a sequence in which sensors detect earthquake motion and compressed air stored in tanks is sent between the artificial ground and the house foundation. The air lifts the structure, reducing direct transmission of ground movement into the building. The system is a specialized installed building system, not a portable air cushion or a consumer accessory.
- Detection: sensors detect earthquake shaking.
- Air delivery and lift: stored air is rapidly sent to the space between the artificial ground and the foundation, lifting the house. The company gives an activation interval of approximately 0.5 to 1 second.
- Balancing: the manufacturer describes a mechanism intended to keep the lifted house level.
- Return and correction: after shaking subsides, a position-correction mechanism lowers and repositions the building. The company says a major earthquake can leave the house offset by a few centimeters, which can be corrected with a small hydraulic jack.
These are the manufacturer’s descriptions of the system’s intended operation; they do not establish how it performs under every earthquake, building design, or site condition.
What the one-thirtieth performance claim means
Sansei AIR Danshin System Co., Ltd. states on its residential product page that shaking at Japan’s seismic intensity 7 can be reduced to approximately one-thirtieth. The cited page does not specify a year for this claim. Treat it as the manufacturer’s stated performance figure, not a peer-reviewed result or an independent measurement of a house during a real earthquake. The available sources do not provide an independent field evaluation or a detailed independent assessment of operating limits.
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What the 2026 approval announcement establishes
In an announcement published July 22, 2026, the manufacturer reported receiving a new Minister of Land, Infrastructure, Transport and Tourism approval dated June 30, 2026. The announcement alone does not establish the approval’s technical scope or what it means for a particular home. Anyone assessing a proposed installation should review the approval instrument itself and confirm the applicable requirements for the building and project.
Air Danshin is not the company’s industrial air-isolation product
The residential system lifts a house at the foundation interface during detected shaking. The company also describes a separate air-isolation device for precision equipment, including semiconductor manufacturing equipment. That industrial product is a different application and should not be treated as a homeowner alternative to the residential building system.
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- EARTHQUAKE GAS SHUTOFF VALVE: The Watts Little Firefighter Earthquake Gas Shutoff Vertical Valve automatically activates to shut off gas supply when a seismic event or earthquake of 5.4 magnitude or greater is detected, preventing any hazards during an event.
- LIGHTWEIGHT DESIGN: This shutoff valve features a compact design that allows for quick and easy installation. It includes a bracket and assembly kit for hassle-free setup and is approved for use with both natural gas and propane lines.
- VERSATILE FITTING: This valve is designed to fit a 3/4" NPT connection with a maximum pressure capacity of 10 psi. It also features a manual reset option available on both sides of the valve, ensuring easy reactivation and maintenance.
- ENHANCED SAFETY: This valve reduces the risk of property destruction from earthquake-related gas fires by automatically shutting off the gas supply. It is not a fire or gas alarm or alert system, but a seismically triggered gas auto shutoff valve designed to enhance safety.
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How to evaluate it for a building project
For a Japan-based homeowner or project team considering this system, the manufacturer’s product information and listed installation partners are a starting point, not a substitute for project-specific review. Ask the manufacturer or installer to document the details that determine suitability and performance for the actual building.
- What buildings, foundation arrangements, and site conditions are eligible for installation?
- What does the relevant approval cover, and what design, installation, inspection, or maintenance conditions apply?
- How is the stated intensity-7 reduction defined and measured, and what supporting test or field records are available?
- How does the system respond to prolonged or repeated movement, and what inspection or repositioning may be needed afterward?
- How will the building be returned to position if it is left offset after shaking?
These questions matter because earthquake protection approaches intervene differently: a project may strengthen the structure, damp its motion, isolate it, or use compressed air to lift it. The available sources do not provide enough independent or project-specific evidence to rank Air Danshin against competing systems.
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Earthquake context: long-period ground motion
The Japan Meteorological Agency explains that long-period ground motion can resonate with buildings and produce prolonged movement; in high-rise buildings, furniture and equipment indoors may move or fall. This is general seismic context, not an evaluation of Air Danshin or evidence that the system addresses every kind of earthquake motion.
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- EARTHQUAKE GAS SHUTOFF VALVE: The Watts Little Firefighter Earthquake Gas Shutoff Vertical Valve automatically activates to shut off gas supply when a seismic event or earthquake of 5.4 magnitude or greater is detected, preventing any hazards during an event.
- LIGHTWEIGHT DESIGN: This valve features a compact design that allows for quick and straightforward installation. It includes a bracket and assembly kit for hassle-free setup and is approved for use with both natural gas and propane lines.
- VERSATILE FITTING: This valve is designed to fit a 1" NPT connection with a maximum pressure capacity of 10 psi. It also features a manual reset option available on both sides of the valve, ensuring easy reactivation as well as maintenance.
- ENHANCED SAFETY: This valve reduces the risk of property destruction from earthquake-related gas fires by automatically shutting off the gas supply. It is not a fire or gas alarm or alert system, but a seismically triggered gas auto shutoff valve designed to enhance safety.
- EVERY DROP COUNTS: Water. It's in our name and close to our hearts. Since 1874, Watts Water Technologies has been delivering innovative technologies that make the world's most precious resource safe and accessible. Everything we design is made to keep the Earth's most precious resource safer, cleaner, and more useful for our customers. Our family of brands offers one of the most varied product lines in the world, with world-class, water-related solutions.
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