It's hard to find monitoring equipment for remote sites that is able to survive the harsh environments. From the lung-gasping cold of the North to the blistering heat of the summer, remote sites must be able to survive a wide range of temperature and weather conditions in Canada.
Electronic,communication and automation equipment have three operation ratings: commercial, industrial & military. Rankings are based on operating temperature range and ensure that the equipment will operate as specified. For most extreme Canadian environments, industrial rated equipment will suffice.
The semiconductor integrated circuits (ICs) used in monitoring equipment can be rated as follows:
- Commercial: 0 C to +70 C
- Industrial: -40 C to +85 C
- Military: -55 C to +125 C
It's the responsibility of the equipment manufacture to determine which components they are using and to give an overall rating for their equipment. Their specification is only as strong as their most vulnerable part.
When used in your mission-critical application, ask for a written guarantee from the vendor stating the recommended operating temperature range. Don't rely on a data sheet listing as it is not a guarantee and can change at the vendor's discretion.
Don't Kill a Fly with a Sledge Hammer
Instead of using more expensive industrial- or military-grade equipment, it's possible to use commercial equipment with a National Electrical Manufacturers Association (NEMA) rated enclosure.
Commercial equipment is more readily available and less expensive and using it makes your application less vulnerable to obsolesces, long lead-times and higher equipment costs.
NEMA enclosures are durable cabinets that are rated for different indoor & outdoor environments. Selecting the correct type depends on
- the application,
- the operating environment
- the risk of extreme events
- the value of the equipment
- the cost of outage.
Ratings are based upon the protection against water, dust & ice ingression and provide security for remote equipment. These units can be connected to power conduits which can then feed heaters and fans to keep the indoor environment within commercial specifications.
Things to Consider
- Is the cost of using a higher rated enclosure offset by the lower cost of commercial-grade equipment?
- Does your system require battery backup in case of a power outage?
- Are you operating in a coastal environment where corrosive salt-fog may degrade metal components?
- Are you operating in an earthquake prone area?
- Does the enclosure need to withstand a shotgun blast?
- What vermin is in the area? Electrical systems are vulnerable to rodents, insects & reptiles can gnaw through conduits & cables.
On Canada's west coast, a large, distributed control network needed outdoor enclosures. It was determined that the commercial-grade equipment had to withstand the extremes of the Pacific weather fronts, an additional requirement separate from the rest of their deployment.
- Each cabinet had to resist salt fog which is common in the winter months
- It had to be well sealed to protect against wind-driven rain during the gale-force storms that strike the west coast. This also prevented the ingress of insects (spiders, slugs& beetles).
- The units had to survive a 7.0 earthquake which is predicted for the area.
- Cooling units were needed in some areas since solar loading in certain urban areas could result in high internal temperatures.
Since it was determined that the use of commercial equipment in harsh environment was acceptable, engineering analysis was required to determine the regional risks across the entire network. By using NEMA rated enclosures, the client was confident that their industrial control system was going to work no matter where the area of deployment.