AODD Pump Hazardous Area and ATEX Design Guide

Why AODD for Hazardous Areas

Inherent Safety Features

AODD pumps are naturally suited for hazardous areas because:

Remaining Hazards

Even though AODD pumps have no electrical ignition sources, these hazards remain:

ATEX Zone Requirements

Zone Classification Review

Required Equipment Category

Temperature Classes

Gas Groups

Static Electricity Prevention

Why Static is Dangerous

Flow → Charge Separation → Static Buildup → Spark → Ignition

In flammable atmosphere:
Spark + Fuel + Air = EXPLOSION

Static Generation Sources

Conductivity Requirements

Material Conductivity Ranges:

Insulator         Conductor
10¹⁴ ohms        10⁰ ohms
   │                │
   │ Static         │ Safe
   │ danger         │
   │                │
   └──────┬─────────┤
          │         │
     Dissipative    │
     10⁶-10⁹ ohms   │
          │         │
          └─────────┘
           OK for hazardous

Material Conductivity

Grounding and Bonding

Requirements

Grounding System

┌──────────────────────────────────────────┐
│        GROUNDING SYSTEM                  │
│                                          │
│   AODD Pump ──┬── Bonding wire ──┐       │
│               │                  │       │
│   Piping ─────┼── Bonding wire ──┼──►Ground│
│               │                  │   Rod  │
│   Structure ──┴── Bonding wire ──┘       │
│                                          │
│   All metallic parts connected           │
│   Resistance to ground < 10 ohms         │
└──────────────────────────────────────────┘

Bonding Requirements

Grounding Equipment

Conductive Materials

Conductive PTFE

Standard PTFE is an insulator (10¹⁴ ohms). For hazardous areas, use:

Conductive PTFE:

• PTFE + carbon black or carbon fiber
• Surface resistivity: 10⁴ ohms
• Chemical resistance preserved
• FDA versions available

Material Options by Zone

Available Conductive Products

Pump Selection for Hazardous Areas

Zone 0/Zone 20 (Continuous Hazard)

Requirements:

• Category 1 certification (II 1G or II 1GD)
• All metal construction (Aluminum, SS, Cast Iron)
• Conductive diaphragms
• Full documentation package
• Notified Body certification

Typical Configuration:

Housing: Aluminum or Stainless Steel
Diaphragm: Conductive PTFE
Balls: PTFE or Stainless Steel
All parts bonded and grounded

Zone 1/Zone 21 (Likely Hazard)

Requirements:

• Category 2 certification (II 2G or II 2GD)
• Metal or conductive plastic housing
• Conductive wetted parts
• Proper grounding provisions
• Technical dossier required

Typical Configuration:

Housing: Metal or conductive PVDF
Diaphragm: Conductive PTFE
Balls: PTFE or Stainless Steel
Grounding lugs provided

Zone 2/Zone 22 (Unlikely Hazard)

Requirements:

• Category 3 certification (II 3G or II 3GD)
• Standard materials acceptable
• Basic grounding provisions
• Self-certification allowed

Typical Configuration:

Housing: Standard PP, PVDF, or metal
Diaphragm: Standard materials OK
Balls: Standard materials OK
Grounding recommended

Installation Requirements

Checklist for Hazardous Area Installation

BEFORE INSTALLATION:
□ Verify pump ATEX marking matches zone requirement
□ Confirm temperature class for process fluid
□ Confirm gas group (IIA, IIB, IIC)
□ Have all certificates and documentation

GROUNDING:
□ Ground connection point on pump identified
□ Grounding cable installed (< 10 ohms)
□ All metallic piping bonded
□ Resistance tested and documented

AIR SUPPLY:
□ Air supply is clean and dry
□ No lubricated air (oil-free)
□ Flame arrestor on exhaust (if required)

COMMISSIONING:
□ Continuity test on all bonds
□ Resistance to ground verified
□ Documentation completed
□ Warning signs in place

Air Supply for Hazardous Areas

Inspection and Maintenance

Regular Inspections

Maintenance in Hazardous Areas

Hot Work Permit Required For:

• Welding
• Grinding
• Any spark-producing activity

Standard Maintenance:

• Diaphragm replacement: Generally safe (no sparks)
• Use non-sparking tools
• Ground pump before opening
• Bond to container before fluid transfer

Documentation Requirements

Required Documents

ATEX Marking Requirements

ATEX Marking Example:

    CE 0081
    II 2G Ex d IIB T4

    CE 0081  = Notified body number
    II       = Equipment group (non-mining)
    2        = Category (Zone 1)
    G        = Gas
    Ex d     = Flameproof
    IIB      = Gas group
    T4       = Temperature class (135°C max)

Specification Template

=== HAZARDOUS AREA AODD PUMP SPECIFICATION ===

AREA CLASSIFICATION:
Zone: □ 0 □ 1 □ 2 □ 20 □ 21 □ 22
Gas group: □ IIA □ IIB □ IIC
Temperature class required: T___
Fluid ignition temperature: ___ °C

PUMP REQUIREMENTS:
ATEX category: □ 1 □ 2 □ 3
Required marking: II ___ G/D T___

MATERIALS:
Housing: □ Aluminum □ SS □ Cast Iron □ Conductive plastic
Diaphragm: □ Conductive PTFE □ Conductive elastomer
All wetted parts conductive: □ Yes □ No

GROUNDING:
Grounding lug: □ Required
Bonding provisions: □ Required
Max resistance to ground: 10 ohms

CERTIFICATION:
□ ATEX certificate required
□ IECEx certificate required
□ Notified body: _______________

DOCUMENTATION:
□ Declaration of Conformity
□ ATEX/IECEx Certificate
□ Installation instructions
□ Technical file

AIR SUPPLY:
□ Oil-free air required
□ Flame arrestor: □ Required □ Not required

Summary

Key Points for Hazardous Areas

1. AODD pumps are inherently safe - no electrical ignition source
2. Static electricity is the main hazard - use conductive materials
3. Grounding is critical - <10 ohms resistance required
4. Zone determines requirements - Zone 0 strictest, Zone 2 least
5. Documentation is mandatory - certificates, marking, records
6. Regular inspection required - verify grounding, check bonding