In an ATEX zone, choosing the wrong connector material doesn’t just compromise compliance; it can create real safety risks. Along with the product being processed and your operating conditions, two of the most critical factors are the surface resistivity of the connector material and its overall length.
The Science of Safety: Resistivity and Length
These two characteristics play a major role in determining connector safety in ATEX environments:
- Surface Resistivity: Indicates how effectively a material dissipates electrostatic charge generated during product flow.
- Connector Length: A longer connector has more surface area, increasing its potential to accumulate electrostatic charge.
Pro Tip: Use the shortest practicable connector length, especially in strongly charge‑generating processes.
Standard Processes (Low Risk)
For processes that are not strongly charge‑generating (ie, free‑fall lengths under 3 metres and no pneumatic transport), most standard BFM® connectors are suitable.
Recommended: All standard BFM® connectors
Exception: Teflex NP Opaque: This insulative material is not recommended for any ATEX zone.
Strongly Charge‑Generating Processes (High Risk)
Processes involving pneumatic transport or free‑fall lengths over 3 metres require stricter material selection.
1. Seeflex 040E
A widely used option for ATEX dust zones when the following conditions are met:
Max Length: 200 mm
Product Resistivity: Processed materials must have low (<10⁶ Ω) to mid-range (<10¹⁰ Ω) resistivity
Humidity: Transport air must remain above 25% relative humidity
2. Seeflex 040AS (Anti‑Static)
Manufactured with an anti‑static infusion, offering greater tolerance in variable environments.
Max Length: 200 mm
No Restrictions: No humidity or dust resistivity limitations
3. Teflex NP Black
The highest-performing material in the BFM® range for electrostatic control.
Max Length: Up to 1,000 mm (1 metre)
Versatility: Suitable for any ATEX environment, including gas zones and high‑charge dust processes, with no restrictions
The Bottom Line
Your connector must be matched to your process. While the Seeflex range covers most dust applications, Teflex NP Black is the definitive choice for gas zones and high‑intensity dust environments.
For full zone‑specific requirements, refer to the BFM® ATEX Declaration of Compliance or contact your local BFM® Distributor.
