Electric Air-intake Shut-off Valve 8″ ISOV N800-E

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ISOV N800-E air shut off valve is a swing-gate, spring-operated air shut-off valve mounted in the air intake system. It works on impeding airflow into the cylinders and positively stop the engine. It can be installed pre- or post-turbo.

Control/Actuation: Electric
Bore size/Flange Size: 8 in – 203.2 mm

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  • Technical Data

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Although diesel engines are generally considered safer than gasoline engines in hydrocarbon-rich environments, they can pose ignition risks in specific scenarios. Diesel engine speed is regulated by an internal speed governor that controls the fuel supply. When flammable vapors are present in the atmosphere, they are drawn into the intake system alongside clean air, causing the engine to accelerate due to the additional fuel.
This acceleration leads to an increase in engine speed, resulting in the intake of more air and vapors, perpetuating the cycle until the engine starts running on unmetered vapors as its primary fuel source. If this cycle is not interrupted, it can result in engine overspeed or runaway, potentially becoming an ignition source for explosive vapors. This situation may lead to various hazards, including:
• Valve bounce
• Flames emanating from intake and exhaust pipes
• Elevated surface temperatures (auto ignition)
• Sparks
• Severe injury or fatality

The ISOV functions as an air shut-off valve integrated into diesel engine air intake systems, effectively halting airflow into the engine cylinders, thereby immobilizing the engine and ensuring the safety of both personnel and equipment. It offers manual or automatic control options, capable of responding to various fault or hazard conditions.
Having gained widespread adoption globally, the ISOV demonstrates exceptional performance in diverse environments, including challenging locations such as the Canadian Arctic, the Gulf of Mexico, the North Sea, African deserts, the Middle East, and the Pacific Rim, both onshore and offshore. Our product consistently meets or exceeds the stringent standards set by our diverse customer base, which includes leading engine OEMs.

Key Features & Benefits:

  • Manual or automatic controls – Electric, Pneumatic
  • Mechanical Failsafe control option available
  • Used on-shore and off-shore
  • Responds to a variety of fault or hazard conditions
  • Available with 2” (51mm) to 8” (204mm) of unrestricted port
  • Operates safely at ambient and induction air temperatures between 350°F – 400°F (176°C – 205°C)

Typical applications include power generation, rig saver, off-shore platforms, bulk fuel loading facilities, marine engine rooms, mining equipment, refineries, and petrochemical plants.


electric-failsafe air intake valves


Note: There are a wide range of sizes and flange adapters available


Generally, ISOV Air Intake shut-off valves can be installed pre-turbo or post-turbo on turbo-charged engines. For further support on installation, please contact our team here.


ISOV air-intake emergency shut-off valves prevent engine overspeeding by shutting off the air intake line safely. The Electric version is available in sizes from 2″ up to 8″ (50 – 203 mm).

isov electric configuration


Prior to starting the engine, the manual ISOV emergency valve must be latched open by rotating the manual reset hexagon as shown in the drawing(1).

Once latched the reset lever will remain in the latched position until released by activating a linear 12 or 24 VDC solenoid (2).

All ISOV solenoids are optimized to apply the right force to release and close ISOV, in this way a compact overall dimension can be guaranteed. Unlike other suppliers of safety valve all our solenoids are equipped with an IP65 rated junction box which guarantees safe and reliable wiring required in the industry.

All Electric ISOV valves are equipped with the manual pull handle (see drawing) to increase safety in case electric power is lost.

Warning: Solenoid operation time is 1-2 seconds. Do not energize solenoid longer than 5 seconds continuously.

About ISOV Failsafe

We also offer the ISOV Air Intake Shutoff Valves with Mechanical Failsafe actuation. The ISOV Failsafe Series valves have an electrically powered 2/3 valve. This valve supplies the ISOV failsafe with engine oil pressure, which keeps the ISOV Failsafe open during operation.

When the power is lost, the 2/3 valve will shut off the engine oil pressure and the pressure leading to the valve will be vented, causing the pressure in the ISOV Failsafe to drop and the gate to close. This will stop the supply of intake air to the engine, effectively bringing engine to a halt. This is an ideal solution to help control engines in emergency situations where electric supply is lost frequently. To view our Failsafe range, click here.

If you are looking for support in choosing the best air intake shut-off valve for your engine, please do not hesitate to contact us here.


ISOV Air-intake shut-off valves are designed to work with a wide range of engines used in heavy-duty trucks, exploration, production, mobile, and rental equipment. Here are a few examples where ISOV valves could be installed.

You can contact us for support in choosing the best ISOV air-intake valve for your needs.

Heavy Duty Trucks:
Common MakesCommon EnginesActivation MethodBenefits
PeterbiltCummins ISX1512 V electric or


Meet international regulations that require air shutoff valves on vehicles that transport hazardous materials
KenworthPaccar MX Series 11, 13
International TrucksPaccar PX Series 9, 8
Freightliner TrucksCAT C15
Western StarMaxxforce Series 9, 11, 13
VolvoDetroit DD13, DD15, DD16
Mercedes Benz


Exploration & Production Equipment
Common MakesCommon EnginesActivation MethodBenefits
Well servicing equipmentCummins QSK50

Cummins QSK38

Cummins QSK23

Cummins QSK19

Cummins QSK30

24 V electric


These products are designed for high horsepower, heavy duty engines and harsh operating environments.

• High vibration resistant

• IP Rated – Sealed from environment

• Tolerates extreme temperatures

• Corrosion resistant

• Fits a wide range of pipe sizes

Pressure pumpsMTU 4000
Fracturing blendersMTU 2000
Offshore production enginesCaterpillar C18

Caterpillar C15

Caterpillar C13

Cummins QSM 11
Cummins QSL 9
Detroit Series
DD 13, DD15, DD16


Mobile & Rental Equipment
Common EquipmentActivation MethodsBenefits
Portable welders12V electric• Designed to fit small engines

• Compact and lightweight for tight spaces

Light towers
Fork lifts
Boom lifts
Air compressors
Portable generators


Additional information

Weight8 kg

Possible replacements and related products