The Vallen ISAFE3 intrinsically safe acoustic emission equipment is designed and certified for permanent monitoring tasks in hazardous environments with a potential risk of ignition or explosion. The application focus is clearly put on the petrochemical as well as the oil and gas transportation industry and employed for detection of active corrosion and fatigue crack in various test objects.

Vallen’s ISAFE3 sensor options consist of a range of several intrinsically safe acoustic emission sensor variants based on the required frequency range, certified according to ATEX/IEC for installation in zone 0, gas group IIC and a signal isolator which is certified for installation in zone 2. Each ISAS3 sensor model can be mounted in atmosphere or even submerged, e.g., in water or oil.

Intrinsically safe AE sensors (ISAS3)

ISAS3 is an Acoustic Emission (AE) sensor with integral preamplifier based on intrinsically safe electronic design making it suitable for installation in ATEX zone 0 environment.

An AE sensor is employed to detect and locate cracks, corrosion and leakage.

The ISAS3 product range consists of five variants of high sensitive AE sensors covering a frequency range from 25 kHz to 900 kHz. Low frequency variants are suitable for corrosion screening and leakage detection of large objects such as above ground storage tanks and pipelines. Higher frequency variants are suitable for integrity testing.

ISAS3 is equipped with an integral preamplifier that has 20 dB gain. It is suitable for driving long distances (up to 2 km) of coaxial cable. The integral preamplifier supports Automatic Sensor Test (AST) for judging sensor coupling.

ISAS3 can be submerged into oil or water, withstanding pressures up to 12 bar. ISAS3 sensors are designed to be mounted inside crude oil storage tanks of ships and can be operated even in case of rough sea.

All ATEX sensors

Signal Isolator (SIS03)

SISO3 is a signal isolator that electrically isolates the intrinsically safe circuit from non-intrinsically safe circuit such as a data acquisition system, e.g. AMSY-5 or AMSY-6. A SISO3 is required if an ISAS3 is installed in an hazardous area according to ATEX. The SISO3 itself can be installed in ATEX zone 2 environments. SISO3 requires an enclosure guaranteeing ingress protection class IP54.

SISO3 limits the power, voltage, current and pulse energy supplied to the integral ISAS3 preamplifier to a safe level even in case of two worst case failures in SISO3. Furthermore, it provides an amplification stage to fully utilize the input range of the ASIP-2 signal processor. It also relays the Auto Sensor Test control pulse to the ISAS3 integral preamplifier.

Further Information
ISAFE3 Brochure / ISAS3 Operation Manual


HISO3 provides an enclosure for SISO3 with ingress protection class IP54. HISO3 can be installed in non-hazardous areas and is required for operating SISO3 within specification and meeting ATEX requirements.

HISO3 is available in two different sizes with easy to handle DIN snapon rail.


MAG4IS is a magnetic holder for ISAS3 providing stable acoustic coupling. A magnetic holder allows easy mounting and removing of an AE sensor.

Further Information
ISAFE3 Brochure