ENGINEERING STANDARDS // ATEX 2014/34/EU

ATEX Directive Fabric Expansion Joints: Explosive Atmosphere Safety & Conductive PTFE

ATEX 2014/34/EU Directive for Zone 1/21 & Zone 2/22 Environments: Antistatic Surface Resistance (Rs < 10⁶ Ohm) & Bonding Systems

Engineering Authority

BundleTec Engineered Standards

The ATEX 2014/34/EU Directive governs safety engineering for non-metallic fabric expansion joints installed in explosive atmospheres containing flammable gases, chemical vapors, or combustible dusts (coal, sulfur, clinker, biomass).

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ATEX 2014/34/EU Zonation & Equipment Categorization

Fabric compensators operate across explosive gas zones (Zone 1, Zone 2) and combustible dust zones (Zone 21, Zone 22). Equipment categories 2G/2D and 3G/3D dictate strict electrostatic dissipation criteria:

ATEX Criterion Directive Standard (EN ISO 80079-36) BundleTec Specification Safety Function
Surface Resistivity (R_s) R_s < 10⁶ Ω (Antistatic) 10⁴ Ω ≤ R_s ≤ 10⁵ Ω (Conductive PTFE) Safely dissipates static charges to ground before arc flash occurs
Resistance to Earth (R_earth) R_earth < 10 Ω R_earth < 1.0 Ω (Tin-plated copper braid) Ensures absolute electrical continuity across the flexible joint
Applicable ATEX Zones Zone 1, Zone 2 (Gas) / Zone 21, Zone 22 (Dust) Group II, Category 2G/2D and 3G/3D certified Protects pulverized coal mills, chemical scrubbers, and solvent lines
Temperature Class (T-Rating) T1 through T6 (T_skin < T_autoignition) Guaranteed T4 (<135°C) and T3 (<200°C) skin Prevents external skin from igniting ambient explosive vapor clouds
Barrier Membrane Chemistry Sintered carbon/graphite loaded PTFE 100% Carbon-doped virgin cross-film PTFE Supreme chemical inertness against aggressive acids and corrosive vapors

Antistatic Conductive PTFE Membrane Science (Rs < 10⁶ Ohm)

High-velocity gas streams carrying particulate dust generate destructive electrostatic charge accumulation on dielectric plastics. BundleTec ATEX joints incorporate carbon-doped conductive cross-film PTFE gas barriers with surface resistivity Rs < 10⁶ Ω per EN ISO 80079-36:

R_s = (ρ_s · L) / W < 1.0 × 10⁶ Ω  [Surface Resistivity per EN ISO 80079-36]
R_earth = Σ (R_contact + R_braid) < 1.0 Ω  [Equipotential Bonding]
T_skin = T_gas · e^(-k_insulation · t) < T_autoignition (T3 / T4 Rating)

Equipotential Grounding Straps & Electrical Continuity

Non-metallic joint belts electrically isolate adjacent metal duct sections. To eliminate this spark hazard, BundleTec integrates heavy-duty tin-plated copper braids or AISI 316 stainless steel bonding jumpers bridging both duct flanges. Resistance to earth:

Thermal Surface Limitation (T-Class Compliance)

External skin temperatures must remain well below the auto-ignition threshold of surrounding explosive atmospheres. Multi-layer silica and ceramic bolster pillows ensure outer skin temperatures strictly respect T4 (<135°C) or T3 (<200°C) ratings even with internal duct temperatures exceeding 600°C.

ATEX Certified Non-Metallic Expansion Joints

Explore our ATEX 2014/34/EU compliant fabric expansion joint series:

ArminTec Series →
Multi-layer high temp composite up to +950°C.
ChemTec Series →
100% pure PTFE barrier for acid dew point condensation.
FanTec Series →
Heavy vibration dampening & fan intake duct connectors.
FAQ // Knowledge Base

Engineering Standards & FAQ

Why is an antistatic conductive PTFE membrane required under ATEX regulations? +

In combustible coal, sulfur, or solvent ducting, friction from fast-moving particulates creates static electricity. A conductive PTFE membrane (surface resistivity Rs < 10⁶ Ohm) continuously dissipates charge to ground, eliminating incendiary spark discharges.

What is the allowable resistance to earth for an ATEX fabric expansion joint? +

In accordance with EN 60079-0 and ATEX guidelines, the equipotential bonding resistance bridging the expansion joint must not exceed R < 10 Ω. BundleTec bonding straps typically achieve < 1 Ω.

Which BundleTec expansion joint series can be ordered with ATEX compliance? +

Our ChemTec (chemical and acid vapor in Zone 1/2), FlueTec (combustible coal/cement dust in Zone 21/22), and ArminTec (high-temperature ATEX ducting) series can all be configured with full ATEX documentation.