If you work with applications where there is a risk of explosion due to the presence of dust, you should be aware of the need to use specialist equipment which is appropriate for use in these environments. Any lighting installed should be certified to Zone 20, Zone 21 or Zone 22 standards, depending on the level of risk.
Selecting the most suitable luminaire for these applications can ultimately save you money. Before we look at how, let’s take a look between the differences between gases and dusts.
Gas and Dust – What are the Differences?
The different properties of gas and dust affects how testing is carried out as part of the hazardous area certification process. This is why gases and dusts are both classed under separate ‘Zones’.
Gas certification tends to be more complex. Gas can permeate a luminaire’s housing, and the internal components exposed to the gas (regardless of IP rating), so the luminaire must be tested accordingly to ensure it does not present an explosion risk.
In contrast, protecting and certifying against dust is more straightforward. All hazardous area luminaires must carry a minimum IP rating, which will depend on the level and method of protection. An IP rating has two digits (e.g. IP67), the first of which (the 6 in this example) denotes the luminaires protection against dust ingress. A rating of 6 is the highest level of protection which means a luminaire with this rating has complete protection against dust ingress.
As a result, testing for dust certification on luminaires which carry an IP rating of IP6x is focused on the luminaires exterior, usually to ensure the surface temperature of the enclosure does not reach temperatures which could cause a buildup of dust to ignite.
What Does This Mean for My Installation?
When thinking about lighting, the majority of Ex luminaires certified for use in Zone 1 (gas) areas, will also be certified for use in Zone 21 (dust) areas. While some applications may have a risk of gas and dust, in others such as flour mills or grain stores, no explosive gases will be present. In applications such as these, there’s therefore no need to install luminaires with Zone 1 protection. So how does this relate to being able to save money?
Think of it like this. You’re purchasing a new car; one of the options the manufacturer offers you is to upgrade from 2-Wheel to 4-Wheel Drive. You never intend to take the car off-road and you live in a warm climate where there is no risk of snow or severe weather. Upgrading to 4WD will cost you £3,000. The 4WD option may be considered as a higher spec, but with no practical use for it, the 2WD model is the most logical and economical choice.
The same concept applies to lighting. If there is an option of a more cost-effective Zone 21 certified luminaire, why would you pay more for a luminaire which has Zone 1 + Zone 21 certification if your application only requires Zone 21 protection?
At Raytec, we recognise that some projects only require dust protection. A number of our products have been certified with dust applications specifically in mind and provide cost savings compared to Zone 1/21 fittings to reduce the cost of your installation.
Reducing Ownership Costs – Remote PSU Mounting
Reducing the initial cost for dust applications is one thing but selecting the right luminaire can also help to reduce costs in other areas over a longer period. A luminaire with a modular design, which allows the PSU (power supply unit) module to be mounted remotely, can be particularly beneficial for dust applications.
As an example, maintenance in grain storage warehouses (where the grain can sometimes pile up almost to the ceiling) can be particularly challenging, to the extent where the grain may need to be removed first before the luminaires can be accessed. This is likely to be a costly and time-consuming exercise. A modular luminaire, such as Raytec’s High Power Flood or Bay range, is designed with maintenance in mind. The luminaire’s drivers are housed in a separate, removable module, which can be mounted at ground level and accessed easily.
In summary, if you’re working on a project where you need to protect solely against explosive dust, then selecting a luminaire which has been specifically certified and designed for dust applications could help to significantly reduce your initial outlay and long-term ownership costs.
Is this relevant to a project you’re working on? If so, contact us to discuss more about our range of products for dust only applications, call us on +44 (0) 1670 520 055, or email Raytec Global at firstname.lastname@example.org or Raytec Americas at email@example.com.