Efficient Ways to Deploy Hazardous Area Wi-Fi Networks

Why do process industries represent a wireless networking challenge? The first thing to understand is that sites can cover vast areas often with large outdoor spaces. The outdoor areas vary from areas—such as tank farms and storage yards—to busy processing units packed with dense metallic structures. It is also significant that hazardous areas are likely scattered throughout these outdoor environments away from the main office buildings. Hazardous area wireless networks are difficult enough to deploy without the requirement of spanning multiple disparate locations.

Deploying Wi-Fi in process areas like this is no easy task. Each project is different due to the nature of the environment and the intended use case in each area. Hence custom wireless solutions are often the go-to solution for hazardous area wireless networking.

But where do you start with a custom hazardous area wireless networking, and won’t a bespoke solution lead to increased costs? There are steps and methods you can take that will help dramatically reduce cost and increase efficiency when planning a Wi-Fi deployment for a large processing site.

Complete a Wireless Networking Deployment Survey

Any large-scale industrial infrastructure deployment should start with robust planning, and the first thing you should prepare for is the difference between indoor and outdoor Wi-Fi.

Indoor Wi-Fi deals with the short distances between four walls. Outdoor Wi-Fi deals with open spaces and lots of potential obstacles that can impact efficiency. A few challenges hazardous area wireless signals face include:

• Materials, such as metallic metals in the working environment
• Sharp operating temperatures
• Variations in elevation
• Density of obstacles

The right combination of these factors can make some proposed use cases extremely challenging. So, it is essential that you employ the services of a trained system architect who fully understands how open spaces in process industries can impact Wi-Fi network outputs. They will not only help you determine if the use case is possible, but they will give you insights into how much Wi-Fi infrastructure you will need.

How to Drive a Wireless Networking Survey

Your survey should be driven by your use case, and it should define exactly what your expectations are for each area on your site. For example: VoiP for applications like remote maintenance support require high bandwidth capacity than simple Wi-Fi location tracking. Therefore, higher density wireless connectivity would be required to achieve the desired result.

A properly defined use case plan will not only save time when deciding how much connectivity you need but will save time when working on your survey. Knowing in advance that you want VoIP capability in these areas will allow your survey professional to quickly gain an idea of how much Wi-Fi will be needed to achieve your use case.

Without this approach you run the risk of installing more wireless networking components than you need in some areas, and too little in others. This means costly changes later down the line and further downtime.

Connectivity measurement devices such as the Ekahau Sidekick, can be used by system architects to fully understand the specific requirements of your environment.  Having this level of visibility will help you clearly determine where to put your Wi-Fi access points and design in the overlap factors that you need to ensure seamless connectivity form point to point.

Do you Need Hazardous Area Wireless Connectivity?

Process industry Wi-Fi deployments often require some crossover into Zone 1 or Zone 2 hazardous areas. It is not uncommon for customers to jump straight to hazardous area wireless solutions before carrying out a full site survey. At Extronics, we routinely speak with customers asking for Zone 1 or Zone 2 certified devices who have not yet surveyed their site.

It is critical to carry out that initial survey as it can help you clearly define the extent of hazardous area wireless connectivity that you really need. How many access points need to be certified for use in hazardous areas? This is difficult to say without a full survey.

Taking this approach to your planning opens the door to using standard, off-the-shelf Wi-Fi devices that can be certified via encapsulation using relevant Zone 1 or Zone 2 protection concepts. This is often a much cheaper and quicker alternative for the end users that does not limit them to a small spectrum of certified access points.

Top Tip

Step 1: design your Wi-Fi network using standard access points  

Step 2: work with specialists to ensure any access points that need installing in hazardous areas can be done safely and to the required certification level.

Once your site Wi-Fi survey is complete, you can overlay it with the hazardous area map of your site. That will quickly tell you where any potential access points fall into a hazardous area and what level of certification you may need.

Below are a simple set of hazardous area definitions for ATEX, IECEx and US NEC to help you determine what level of certification you will need based on your hazardous area Wi-Fi requirements.

Hazardous Area Definitions

ATEX and IECEx Haz Area Definitions

Gas Zones	Dust Zones	Definitions
0	20	A place in which an explosive atmosphere is continually present.
1	21	A place in which an explosive atmosphere is likely to occur in normal operation occasionally.
2	22	A place in which an explosive atmosphere is not likely to occur in normal operation, but if it does only occur for short periods.

US NEC500 Table Definitions

Divisions	Definitions
1	A place in which an explosive atmosphere is normally present.
2	A place in which an explosive atmosphere is likely to occur in normal operation occasionally.

Class Definitions Table

Class I	Gas
Class II	Dust
Class III	Fibres

Intrinsically Safe Does Not Mean Explosion Proof

There is often a lot of confusion when it comes to defining the hazardous areas on a wireless networking project, and what is needed to ensure compliance with global standards for wireless devices.

It is important to understand that not all hazardous areas are created equal, and the terminology changes from region to region around the world. At Extronics, we often hear the phase intrinsically safe used to define a Zone 1 or Zone 2 certified devices. To put it another way, we often get asked this question…

“Can you provide an intrinsically safe wi-fi access point for my hazardous area?”

When what is really meant is…

“Can you offer a Zone 1 or 2 Wi-Fi access point solution with intrinsically safe RF outputs?”

Determining your Wi-Fi requirements before deciding if you need hazardous area wireless certified products will allow you to plan your network efficiently and cost-effectively. Once you know how many devices need to sit inside a hazardous area, then you can then work with a specialist like Extronics to ensure successful deployment.

Key phrases

Intrinsic safety or intrinsically safe: This means that the RF output will not cause a spark in hazardous area conditions. It does not mean explosion proof or flame proof. Hazardous area standards for use of wireless devices state that each RF output must be under a certain threshold for the area in question.

Explosion proof: or Ex d is a protection concept that contains an explosion and stops any flame escaping the enclosure that could ignite the surrounding atmosphere. It is typically used in Zone 1 Div 1 hazardous areas.

Restrictive breathing: or Ex nR is a protection concept that stops any gas permeating inside the enclosure, therefore removing any chance of an explosion occurring. This protection concept is often used in Zone 2 Div 2 hazardous area environments.

Extronics: Hazardous Area Wireless Experts

At Extronics, we provide wireless Ex certified wireless enclosures systems for use in hazardous areas. Our vendor agnostic position means we can work with most global wireless devices including most Wi-Fi access points sold on the market.

This approach gives you the flexibility to design your W-Fi network in the most efficient way possible, reducing upfront cost, installation cost and cost of ownership into the future.

We do this using our innovative iWAP range of hazardous area wireless enclosures for reliable wireless networking.

The unique chassis design is purpose built to house most wireless devices and provide intrinsically safe RF outputs using our iSOLATE technology. The iSOLATE technology further drives cost down for the end user by allowing standard non-hazardous area antenna to be used.

If you would like to learn more about our range of iWAP hazardous area wireless enclosures, please contact us.