Explosion Protection Cheat Sheet

Explosion Protection Cheat Sheet

A quick-reference guide for engineers, technical sales, and product managers working with explosion-protected equipment. For full details on any topic, follow the links to the detailed files.

Quick Qualification Questions

When evaluating whether equipment is suitable for a hazardous area, answer these six questions in order:

  1. What zone is the area? (0, 1, 2 / 20, 21, 22) → Zone Classification
  2. Gas or dust? (or both?) → Site hazard assessment
  3. Required gas/dust group? (IIA/IIB/IIC or IIIA/IIIB/IIIC) → Gas Groups
  4. Required temperature class? (T1–T6 or specific °C for dust) → Temperature Classes
  5. Regional approval required? (ATEX / IECEx / NEC / other) → Standarder
  6. Which protection method? (Ex d, Ex i, Ex e, Ex p, Ex n, etc.) → Protection Methods

High-Level Mapping

Zone → EPL

Zone EPL Required Protection Level
Zone 0 / 20 Ga / Da Very high (2-fault safe)
Zone 1 / 21 Gb / Db High (1-fault safe)
Zone 2 / 22 Gc / Dc Enhanced (normal operation safe)

See EPL for full details.

Hierarchy Rules

These "covers" rules simplify equipment selection:

  • Gas groups: IIC covers IIB and IIA — one IIC-rated device works everywhere
  • Dust groups: IIIC covers IIIB and IIIA
  • Temperature: T6 is the most restrictive and covers T5 through T1
  • EPL: Ga equipment can be used in Zones 0, 1, and 2

Protection Method → Zone Suitability (Quick Reference)

Method Zone 0 Zone 1 Zone 2
Ex ia ✅ ✅ ✅
Ex d ✅ ✅
Ex e ✅ ✅
Ex p ✅ ✅
Ex n ✅

See Protection Methods for the complete matrix including dust zones.

Onboarding Reference

For someone new to explosion protection, read in this order:

  1. Grunder — what makes an area hazardous
  2. Zone Classification — how areas are categorized
  3. Gas Groups and Temperature Classes — fuel properties
  4. Protection Methods — how equipment is made safe
  5. EPL — connecting zones to equipment requirements
  6. Ex Markings — reading equipment labels
  7. Standarder — the regulatory landscape
  8. Certification — how equipment gets approved
  9. Installation & Inspection — keeping it safe in the field