Air handling in explosive environments
An explosive atmosphere can be created during normal operation or in the event of an accident or incident.
In Europe explosive atmospheres are governed by the ATEX Directive, in force since 2003. The requirement related to the level of protection varies and is defined according to a number of different criteria which in turn impose different demands on the product. One of the requirements contained in the User Directive is drawing up an explosion protection document for the facility, this includes a classification plan. The classification plan then indicates the requirement imposed on the equipment that is to be used in the area.
The manufacturer of the equipment shall meet the classification requirement in accordance with the Product Directive. This must include a risk analysis of any potential risks.
FläktGroup has many years’ experience of developing solutions for Air Handling Units used for gas and dust in categories 2 and 3.
Typical fields with a possible risk of explosion:
- The mining industry
- Waste management & recycling
- The chemical & petrochemical industry
- Grain silos
- Marine & offshore environments
- Industries that handle fibre
When air becomes explosive
When air is not just air but a mixture of air and combustible substances... Adding a source of ignition such as an electrical or mechanical spark, or heat from friction for example, poses a major accident risk – with consequences that could be anything from minor to devastating!
The function of an air handling unit is to transport air, it is therefore vital that the unit has been designed so that it does not risk igniting that air if it is explosive. On its way through the unit the air passes filters, heat exchangers and fans – components that must be incorporated in an explosion-proof manner. This must be taken into account early in the design stage.
Examples of ignition sources include mechanical sparks, heat, friction or electrostatic discharge. Preventing these from occurring is one of the most important principles in the design of such units. The character of the air and potential risks in the environment vary with each application. FläktGroup has a project department that handles the supply of products that have customer-specific requirements. The application in question is reviewed and analysed, after which a customised product is developed. This means that a safe solution can be offered for each unique installation.
1. Primary protection:
Prevent a hazardous environment arising
2. Secondary protection:
Prevent accidents occurring.
3. Tertiary protection:
If an accident occurs, limit the adverse effects
In Europe explosive atmospheres are governed by the ATEX Directive, in force since 2003, which consists of two parts:
- User Directive (99/92/EC); for users and operators
- Product Directive (2014/34/EU); for manufacturers placing products on the market
These two parts constitute the entire ATEX Directive, governing the measures that must be taken to avoid hazards by specifying the basis of design, implementation and operation.
ATEX is an acronym for the French “Atmosphères Explosibles” – Explosive Atmosphere.
CAIRplus AIR HANDLING UNIT
- CAIRplus is the tailor-made premium range of modular air handling units for every customer requirement
- Environmentally-friendly design means an energy recovery system with high efficiency is available for every configuration
- Clean surfaces and ease of cleaning guarantee hygienic standards to VDI6022
- All units can be supplied with FläktGroup integrated controls ISYteq 4.0
- T2/TB2/L1/D1 Eurovent certified casing