Oil rigs can evoke a sense of dread, and that fear was tragically realized on January 22, 2018, when an explosion occurred at an oil rig in eastern Oklahoma, resulting in numerous fatalities and injuries. This catastrophic event stemmed from an uncontrolled gas release that ignited, highlighting the critical need for safety measures to prevent such incidents.
To mitigate the risk of accidents, it is imperative to take stringent precautions. The presence of flammable contaminants in the atmosphere is a significant concern, as they can lead to explosive situations. Common culprits include gas and dust, which, when present in sufficient concentrations, can result in devastating explosions from a single spark.
This article examines the necessary certifications and standards that dictate the appropriate explosion-proof camera systems for use in hazardous environments.
Understanding Hazardous Locations
A hazardous location (HAZLOC) is defined as an area where flammable or explosive gases, vapors, or dust are present in significant quantities. Examples of such locations include:
- Oil and gas platforms
- Drilling rigs
- Oil tankers
- Refineries and petroleum terminals
- Pipelines
- Military installations
- Chemical and pharmaceutical facilities
- Food processing plants, where various solid food ingredients like sugar, flour, and spices can generate explosive dust.
It is crucial to note that simply having flammable gases or combustible dust does not automatically classify an area as hazardous; the quantity or concentration must be sufficient to pose a risk. Standards for classifying hazardous areas rely on the likelihood of an explosion occurring, with statistical measures determining risk levels. For instance, areas exposed to hazardous gas or dust for less than one hour per year are deemed less dangerous than those with constant exposure.
Standards for Defining Explosion Environments
Hazardous areas are designated by qualified personnel, such as Fire Marshals or operational risk assessment engineers, known as Authorities Having Jurisdiction (AHJ). Once an area is classified, all equipment, including IP cameras, must comply with protective methods to reduce explosion risks.
Various standards exist to categorize hazardous environments. The United States, Europe, and the UK have similar specifications that differentiate these areas based on CLASS, Division, and Zones. In the U.S., the National Electrical Code (NEC) establishes markings defined by “divisions” and “zones”:
- Division 1: Areas where ignitable concentrations of flammable gases, vapors, or liquids may be present most of the time (over 10 hours per year) during regular operations.
- Division 2: Areas where such concentrations are unlikely to exist under normal operating conditions (under 10 hours per year).
In contrast, the UL60079 specification employs “zones” for a more detailed classification:
- Zone 0: Areas with continuous or prolonged presence of ignitable concentrations (over 1,000 hours/year).
- Zone 1: Areas where such concentrations are likely to occur between 10 hours and 1,000 hours per year.
- Zone 2: Areas where ignitable concentrations are not expected under normal operating conditions (less than 1 hour per year).
Explosion-Proof Enclosures and Camera Systems
Explosion-proof systems can either consist of enclosures housing a camera or complete explosion-proof camera systems that include the IP camera itself. In many situations, opting for a complete system is advisable, as UL guidelines require cameras to be installed in enclosures within UL-approved facilities.
International and European standards do not impose this requirement, allowing for the purchase of an enclosure separately from the camera. However, it is vital to ensure that the chosen camera is also certified for use in hazardous environments.
Essential Features of Explosion-Proof IP Camera Systems
To guarantee protection, explosion-proof IP camera systems should possess the following characteristics:
- The system must prevent sparks from reaching flammable gases or dust. Enclosures must be sealed, ensuring all cable entry points are secure.
- Combustible gases and dust should be barred from entering the enclosure, typically achieved by pressurizing the enclosure with inert gas.
- The camera design should eliminate ignition sources. For instance, it should not have a potentially explosive battery, and the power levels must remain within safe limits.
- Should an explosion occur within the enclosure, it must be robust enough to contain the resulting damage. These enclosures are constructed to be sturdier than standard camera housings.
Verification of Certifications
It is crucial to ensure that the equipment complies with the relevant certifications for the environmental conditions in which it will be deployed. Consider the following when evaluating an explosion-proof camera system:
- The enclosure and camera must adhere to certification standards indicating (Ex d) for explosion-proof housing suitable for potentially explosive environments.
- Ensure dust ignition protection (tD A21) for zones 21–22.
- The enclosure should prevent excessive temperatures that could ignite gases (ATEX: T6).
- In a dust environment, the enclosure temperature must not exceed 85° C.