Designing Displays for Use in Explosive Environments

In building equipment designed for use in hazardous environments, there’s a specific set of standards depending on the level of intrinsic safety required. That’s why you abide by certain standards, such as ANSI/ISA-RP, for all of the equipment you design.

That equipment also includes your LCD displays.

There’s an alternative to purchasing off-the-shelf displays and asking for deviations when they’re used in explosive environments. You have the option of designing custom components for your specific intrinsic safety needs.

Intrinsic Safety Calls for Custom Displays

Off-the-shelf displays, while prevalent and widely used across different environments, do not inherently account for hazardous locations. Given the standardized nature of these devices, there is no intention to abide by hazardous environmental requirements.

There are simply too many applications, even within hazardous environments, to create a one-size-fits-all display. Standard displays are made for mass market and for addressing more general applications. Hence, the need for a custom display design, specific to your product and the intrinsic safety standard required for your market.

Once you understand this concept, it just comes down to working with the design team and developing the ideal design to accomplish function and safety in your custom display design.

Considerations for Design Attributes

Consider the following design attributes when designing your display for intrinsic safety, taking note that they are tied closely together.

Component selection. Selecting the right components is an essential attribute of your design. Consider aspects such as their size, voltage, and material, ability to generate or store energy, maximum surface temperature, operating and failure characteristics, and suitability to work in conjunction with one another as combined parts of the device.

Voltage. The maximum voltage produced throughout the LCD display is another consideration. You want to minimize the voltage to minimize the potential for spark ignition. This ties back into component selection, as you need to either select components that limit the amount of stored energy or limit the number of energy-storing components altogether.

Interconnects. Another design consideration is limiting the number of interconnects. The more interconnects you have, the more complexity present in your display, which raises the potential for arcing or sparking.

Traces. One last design consideration involves traces. Exposed circuit traces pose a risk of spark ignition; therefore, it’s important to encapsulate or otherwise contain them to mitigate this risk. Distance between traces and distance between components are all subject to a specific standard based on your intrinsic safety requirement.

Remember You Have Options

There’s no doubt that intrinsic safety plays an integral part in the design of your equipment. That requirement must be carried through to the LCD display as well.

You aren’t stuck with off-the-shelf displays. You have the option to go custom and design intrinsic safety into your displays. In this manner, you’ll be able to ensure the intrinsic safety level of compliance that you can’t achieve with standard displays.