Magnet-Schultz of America Blog

Electrohydraulic Solenoid Coils for Hazardous Locations (HAZ-LOC®)

Posted by: David Stockwell, Magnet-Schultz of America, CEO

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Fri, Mar 07, 2014 @ 02:00 PM

Engineered for Safety Critical Markets


Magnet Schultz of America (MSA) offers the patented HAZ-LOC® product family

The potential for loss of life and enormous damage to the environment that can occur as a result of fire and/or explosion on oil rigs, in petroleum processing plants, in explosive dust environments, and in volatile chemical manufacturing process has greatly increased global interest in reducing the risk of such disasters that might be caused by the equipment that is operated throughout these hazardous locations.

One way to reduce the risk of fire/explosion is to keep the surface temperature of the machinery and equipment below the ignition point of the gases and dust that are present. Equally important is to ensure that small explosions which might occur inside the components of the machinery is not allowed to propagate into surrounding atmosphere, thereby creating a conflagration that may rapidly get out of control.

Toward this end, global government agencies have developed strict guidelines defining the operating surface temperatures and the explosion propagation characteristics of electrical components that are integral to such equipment.


Specifications and Features
The electrical coils that are mounted on, and which actuate hydraulic valves, are just one of the many electrical components found on the equipment used throughout all industrial and commercial processing facilities. In the course of normal operation, conventional coils can pose a risk of over-temperature, and poor connection techniques can produce electrical sparks. The presence of volatile gas or dust within the environment these coils operate provide the potential for fire and/or explosion.

To help mitigate such risks, Magnet Schultz of America (MSA) has developed a specialty line of Electrohydraulic Coils called HAZ-LOC®. Electrohydraulic Solenoid Coils for hazardous locations (HAZ-LOC®) are designed, tested and certified:

1) to operate below 135 degrees C, which is identified as a T4 rating
2) to offer explosion proof capability


HAZ-LOC is worldwide certified for relevant global location surface applications above ground and sea:

NEC 500—Safety ratings in the US are governed under the National Electrical Code (NEC). There are two separate classification systems (NEC 500 and NEC 505)

NEC 505—Mandatory for Gulf of Mexico Class and Zone Rating

CEC/CSA—Canadian safety ratings are regulated by the Canadian Electrical Code (CEC), closely following the US-NEC Standards

ATEX—European markets, similar to NEC 505 gas and dust ratings

IECEx—International (excluding above locations), similar to ATEX gas and dust ratings


HAZ-LOC Technical Details
The reference designs of MSA HAZ-LOC coil family can be mounted on any manufacturer’s valve, which utilizes actuator pressure tube diameters of 13mm, 16mm, 19mm and/or 22mm. Standard voltages are 12 and 24 VDC, and 120 and 240 VAC. An internal bridge rectifier enables the use of AC voltage(s). An integrated junction box provides ease of electrical connection, while maintaining explosion proof characteristics. All HAZ-LOC coils are rated IP 66, NEMA 4X for water and dust ingression.

If the reference design HAZ-LOC coils do not satisfy all of the hazardous location requirements of your application, through MSA’s Collaborative Innovation approach, we can design and achieve certification for customized derivatives of this unique product family, thereby enabling the resulting custom coil to perfectly interface with your actuator tube diameter(s) and valve configurations.


As a leading manufacturer of standard and specialty Solenoids for hazardous locations, Electromagnetic devices—Electrohydraulic and Electromechanical—MSA provides advanced engineering, innovative design and lean manufacturing capabilities to our customers that simply outperforms the competition. If you’d like to discuss how our collaborative innovation business process might help your organization create a product with a distinct market advantage, Contact MSA Today

Topics: Electrohydraulic Solenoid Coils, Specialty Solenoids, Hazardous Location Solenoid Coils