The classification of a space as Zone 1 or Zone 2 is directly dictated by the effectiveness of the ventilation system.
Under MS IEC 60079-10-1, ventilation is categorized by its "Degree" (High, Medium, or Low) and its "Availability" (Good, Fair, or Poor).
Zone 1 (High Risk): An area where an explosive atmosphere is likely to occur occasionally in normal operation. Compliance requires High Availability ventilation. If mechanical ventilation fails, the area may quickly become a Zone 0 risk.
Zone 2 (Lower Risk): An area where an explosive atmosphere is unlikely to occur, and if it does, it will persist for a short time only. Often, providing Adequate Ventilation (typically $>12$ Air Changes per Hour) allows an area that would otherwise be Zone 1 to be downgraded to Zone 2, significantly reducing equipment costs.
| Parameter | Zone 1 Requirement | Zone 2 Requirement |
| Air Changes (ACH) | Typically 12 to 20+ ACH depending on chemical release rate. | Minimum 12 ACH is often the benchmark for "Adequate Ventilation." |
| Availability | High: Requires duty/standby fans with automatic changeover. | Fair/Good: Single fan may be acceptable if monitored. |
| Monitoring | Mandatory: Airflow switches interlocked to process power. | Recommended: Visual/Audible alarms on fan failure. |
| Certification | Equipment Category 2G (e.g., Ex d, Ex e, Ex p). | Equipment Category 3G (e.g., Ex nA, Ex ec). |
In Malaysia, any mechanical ventilation used to control hazardous chemicals is classified as Local Exhaust Ventilation (LEV). To stay compliant:
Design Approval: The system must be designed by a JKKP-registered Professional Engineer (PE) or a competent person.
Annual Testing: Under USECHH Regulation 17, the system must be inspected and tested by a Registered LEV Tester at least once every 12 months.
Static Pressure Monitoring: For Zone 1, we install manometers or digital sensors to prove the hood is maintaining the required "Capture Velocity" to prevent gas escape.
We utilize Variable Frequency Drives (VFDs) to ensure the system remains compliant even as filters clog or air density changes:
Constant Volume Control: The VFD automatically increases fan speed to compensate for "filter loading," ensuring the JKKP-mandated airflow is always met.
Emergency Ramping: When gas sensors detect a leak (e.g., at 10% LFL), the VFD ramps the fan to 100% capacity to move the area from a "stagnant" state to a "diluted" state.
Vibration Safeguards: Since mechanical friction is an ignition risk, we use the VFD to monitor motor load and perform Vibration Analysis to prevent bearing failure in Zone 1.
EPCC Specialist: We handle the Engineering, Procurement, Construction, and Commissioning of hazardous area HVAC systems across Kuala Lumpur and Selangor.
Certified Competency: Our team is trained in IECEx/ATEX installation standards, ensuring that your "Ex" equipment stays safe and your JKKP audits pass without findings.
Risk-Based Design: We can help you optimize your ventilation to downgrade a Zone 1 area to Zone 2, saving you significant capital expenditure on explosion-proof electricals.
Malaysia
