Rugged, explosion-proof computers safeguard offshore rigs

PAUL SHU, Arista Corporation 

Offshore oil and gas rigs are among the most demanding environments for industrial computing systems. Positioned miles from shore and constantly exposed to corrosive salt air, these platforms contain drilling systems, production modules and fuel skids that can release flammable gases and vapors, even under routine operating conditions.  

HAZARDOUS ZONE CLASSIFICATIONS 

As a result, regulators classify certain areas of a rig as hazardous locations. In these zones, even a small spark or hot surface could ignite a gas–air mixture and trigger a catastrophic explosion. Any computer or electronic device installed in these zones must comply with strict international and national safety standards to prevent ignition hazards. 

Hazardous locations are classified based on the type and frequency of flammable gases or vapors present. In North America, hazardous areas are primarily defined, using the Class/Division system, and regulations related to the design and manufacturing of industrial equipment are formulated by the NEC, CEC, OSHA and NFPA (National Fire Protection Association). Internationally, most installations follow the ATEX or IECEx Zone system. 

Under the NEC and CEC systems used in North America, Class I areas involve flammable gases or vapors, with Division 1 indicating that such hazards are present during normal operation and Division 2 meaning they are only likely under abnormal conditions.

Fig. 1. Due to the harsh marine environment, computing systems on offshore oil rigs must be engineered to withstand salt spray, constant vibration and high humidity.

Computing and control systems are typically not installed in Class I, Division 1 areas, due to the continuous or frequent presence of flammable gases or vapors. Instead, such systems are typically located in Class I, Division 2 areas, where hazardous materials are present only under abnormal conditions. 

On offshore rigs, Class I, Division 2 areas commonly include spaces adjacent to production equipment, such as the open areas surrounding production modules, compressor skids and separation trains. Even exterior decks and ventilation intakes may be classified as Division 2, since drifting vapors can occasionally accumulate there when wind or ventilation is insufficient. 

COMPUTER DESIGNS CERTIFIED TO OFFSHORE CONDITIONS 

To create a safe and secure working environment in hazardous areas, the computing systems at the worksite must be designed and certified to meet explosion-proof standards and withstand corrosive marine conditions.  

In these environments, computer systems must be either intrinsically safe, explosion-proof, or housed in purged or pressurized enclosures, depending on the zone and frequency of hazardous substance presence. Every enclosure, connector and touchscreen must be tested and certified by a recognized authority, and temperature limits must remain below the ignition point of the gases present. 

Due to the harsh marine environment, computing systems on offshore oil rigs must also be engineered to withstand salt spray, constant vibration, and high humidity, Fig. 1. As a result, offshore computing systems typically require enclosures rated as IP66 or IP67 to ensure adequate environmental protection. Materials, such as 316 stainless steel, are often used for their corrosion resistance in offshore applications. 

Long lifecycles, revision control, electromagnetic compatibility, and strict documentation are also critical, as industrial rigs demand predictable, stable platforms that can be supported over many years. 

TOUCH-PANEL PCs AND THIN CLIENTS

Fig. 2. Any computer or electronic device installed in these zones must comply with strict international and national safety standards to prevent ignition hazards.

To meet these requirements, a wide range of panel PCs and thin clients, certified for Class I, Division 2, hazardous locations, are available. 

Touch-panel PCs in various sizes are routinely deployed as HMI workstations in hazardous industrial operations. For this type of application, panel PCs are certified for Class I, Division 2 locations in the oil and gas industry. These units feature explosion-proof designs and are built with NEMA 4X stainless steel enclosures, providing robust protection against harsh offshore conditions. The Panel PCs are installed with a Windows operating system, and the high-resolution touchscreens can be manipulated by operators wearing industrial gloves.  

Fan-less thin client models for hazardous environments are also available. Class I, Division 2–certified thin clients are engineered with 316L stainless steel enclosures and IP66/NEMA 4X protection, ensuring reliable operation in areas exposed to high humidity, salt spray and corrosive substances, Fig. 2. 

As offshore oil rig operators continue upgrading their control systems, Class I, Division 2–certified computing platforms are becoming essential components of modern infrastructure. Combining explosion protection with marine-grade durability, these systems provide the safety, reliability and resilience required to operate effectively in some of the world’s most demanding environments. 

PAUL SHU is president of Arista Corporation, a manufacturer of ruggedized computing and industrial visualization systems for harsh and hazardous environments. He has extensive experience supporting industrial and offshore applications requiring certified explosion-proof and corrosion-resistant equipment.