Enclosures are at the heart of the engineering industry but these vital pieces of kit must continue to evolve if processes are to run efficiently and workers and the plant are to stay protected, writes Robert Smith.
Industrial enclosures are crucial to the process engineering industry and are designed to create a protective environment for installed equipment, such as electronics, PLCs and drives.
Safety is fundamental and is integrated into the design of enclosures, which are regulated by the IEC and UL standards. To fulfil the safety requirements, the enclosures should have no sharp edges and there must be no penetration to the object.
This is according to Fatima El Guemmat, product manager of Universal Enclosures at Schneider Electric, who says additionally, the surface temperature of an enclosure should be within the limit defined by the regulations. Ultimately, they are also designed to protect workers.
“It is the job of the enclosure to protect us from electrical shocks within the Class I and II, as defined by the IEC 61140. When it comes to public applications, often Class II enclosures are a recommended choice when it comes to thinking about safety.
“Certain applications naturally require a higher compliance to safety standards, for example ATEX, seismic and nuclear applications. Under these circumstances specific enclosures and certifications are available.”
Spoilt for choice
Understanding an enclosure’s role also helps to ensure a high level of service and overcome industrial challenges, including reliability, energy efficiency and the continuity of service.
El Guemmat says having a good choice of enclosures “will enable better value for all the actors” within the engineering industries.
This includes management – by protecting the electrical assets from harsh environments, preventing lifetime reduction of the electrical installation and the installation shutdown of machines and operations. “As a result productivity and return on investment are improved,” El Guemmat says.
It also includes operations and maintenance – by ensuring a high level of safety as well as reducing the installation faults generated by the environment and thermal issues. “Hence, preventing recurrent interventions, heavy maintenance and increasing operational efficiency.”
The choice of enclosure typically comes at the end of the design process, El Guemmat adds, after gathering all the requirements generated by customer needs, the application and the environment.
“This requires a versatile range in terms of materials, IP, dimensions, installation systems and thermal management systems. For more flexibility, a bespoke solution can be offered to meet the specific requirements of each customer.”
The world is becoming more digital and the demand for energy is continuing to grow. And that means equipment is under more stress. In fact, 80% of failures in electronic devices are due to unmanaged heat, humidity, and condensation
Fatima El Guemmat, product manager Universal Enclosures, Schneider Electric
According to El Guemmat, the electrical architecture and the environment has segmented the enclosure business into two axes: dimensions and materials.
“Depending on the electrical architecture, we can find three types of enclosures: industrial boxes, wall-mounting enclosures and floor standing enclosures.”
However, the type of material used for each enclosure is largely dictated by the environment and the application.
For example, glass reinforced polyester enclosures are most suitable for outdoor, corrosive, high UV and public area type of applications such as in the water and wastewater industries and in the transport sector.
Stainless steel enclosures, meanwhile, are best suited for food and drink, pharmaceutical, petrochemical or infrastructure industries, El Guemmat says.
“Steel enclosures offer a robust solution for the industrial environment where the protection of electrical and electronic components against dust and mechanical impact is crucial. Some common applications include packaging, conveying, HVAC and buildings,” she comments.
Evolving enclosures
As processes modernise, the role of the enclosure is adapting further. With advances in technology, the interior installation of enclosures is getting more and more complex, says Paul Metcalfe, product manager for industrial and outdoor enclosures at Rittal.
Metcalfe says: “What’s more, vital equipment using wireless technology needs to be protected from any outside interference. Rittal offers a range of enclosures that are electromagnetic compatibility-approved (EMC), for example. These use special materials within their seals to offer an enhanced level of shielding across a broad range of frequencies.”
There are particular design features that can be incorporated into enclosures to suit specific needs. For example, standard locks can be replaced by a padlock hasp, or the lock can be changed to a key system, so that access is only granted for authorised people with keys, adds Metcalfe.
“Rotary isolator switches can be included so that any power inside the enclosure is isolated prior to any of the doors being opened. This [is designed to eliminate] any risk to operators who need to gain access to the enclosures.”
More advanced systems for monitoring within the enclosures can also be employed to measure temperature, humidity, fire/smoke, access, impact, and leaks.
“The systems can be programmed to deliver any one of a range of responses from firing up a cooling unit if the temperature exceeds a certain limit, to having audible and visual alarms, to reporting back to a central control system, or even activating fire suppression equipment,” says Metcalfe.
Schneider Electric’s El Guemmat says enclosures face challenges from digitisation. “The world is becoming more digital and the demand for energy is continuing to grow. And that means equipment is under more stress. In fact, 80% of failures in electronic devices are due to unmanaged heat, humidity, and condensation.”
Therefore, enclosure design must continue to evolve to cut energy consumption, extend equipment life and keep enclosed industrial and electrical distribution equipment running reliably.
Enclosure override leads to worker fatality
Risks from entering enclosed spaces containing powerful equipment, cannot be eliminated entirely.
Earlier this year a man suffered fatal injuries when a conveyor he was conducting maintenance on started moving. An investigation by the Health and Safety Executive (HSE) found the required control measures were not checked before the man started work.
According to HSE, access to dangerous moving parts of the machines at the site was controlled by enclosures, which prevented access to the danger zones.
Access into the enclosure was via a special key system designed to make sure the machinery was isolated and safe to work around if people needed to enter.
In May, Bath Magistrates’ Court heard that when the site was inspected a spare key was discovered, meaning access to machinery in the incident area “was possible without turning off and isolating the machine”.
Speaking after the hearing, HSE inspector Leo Diez said: “This tragic incident, which led to the avoidable death of a man, was easily prevented and the risk should have been identified.
“Employers should make sure they apply effective control measures to minimise the risk from dangerous parts of machinery.”
