In refining, terminals and offshore platforms, the wrong actuator enclosure is not a quality issue — it is a safety incident waiting for a shift change. Explosion-proof selection is therefore certification-first: the paperwork is part of the product.
This note covers the four decisions that matter: certification scheme, zone matching, emergency-shutdown duty and marine corrosion class. Get these right and the rest of the specification is conventional.
Certified Ex protection, matched to the zone
Accept no 'equivalent to' claims without a certificate number. The certificate is the product.
- Zone 1 requires flameproof enclosures (Ex d / Ex db); Zone 2 allows increased-safety (Ex ec) units at lower cost.
- ATEX for Europe; IECEx for most of Asia, the Gulf and Australia. Many projects accept both; confirm with the operator.
- Ask for the certificate number at quotation — not at delivery.
- Temperature class (T3/T4) must match the process area classification, not just the actuator's surface temperature.
Emergency shutdown and partial-stroke testing
ESD and blowdown valves are only useful if they are proven to work — and proving them without stopping the process is the whole point of PST.
- Specify fast travel at your real torque and voltage, including cable voltage drop.
- Partial-stroke testing capability lets operations exercise the valve 10–15% every shift without disturbing the process.
- Fail position (closed for inventory, open for venting) must be documented per valve, not per project.
Marine-grade corrosion protection
Coastal refineries and offshore platforms destroy standard paint in eighteen months.
- Specify C5-M class coating systems with stainless fasteners and shafts.
- Inspect coating thickness certificates, not color charts.
- Combine with double-sealed glands: salt fog finds the gland first.
Oil & gas services mapped to SJMC platforms.
How SJMC fits oil & gas
The JVX-04 explosion-proof line carries certified Ex enclosure options from 50 to 50,000 Nm, with PST-capable logic and C5-M coating available for coastal duty. Documentation ships with certificate numbers your HSE department can verify.
- JVX-04 Explosion-proof — Certified Ex enclosures, 50–50,000 Nm, matched to your zone and temperature class.
- PST-capable logic — Partial-stroke testing for ESD valves — prove the valve moves without stopping the process.
- JVX-01 Quarter-turn — Non-Ex utility duty and C5-M coastal options to 100,000 Nm.
Frequently asked questions
ATEX or IECEx — which certificate do I need?
Follow the operator's specification: ATEX for European installations, IECEx across most of Asia, the Gulf and Australia. Many operators accept both; we ship the scheme your project requires.
Can I use a Zone 2 actuator in a Zone 1 area to save cost?
No. Zone matching is a safety boundary, not a budget line. Zone 1 requires flameproof (Ex d) construction.
Do your Ex actuators support partial-stroke testing?
Yes — PST-capable logic is available on the JVX-04 line, allowing scheduled 10–15% valve exercise without interrupting the process.
What proof of coating do you provide for coastal sites?
Coating thickness certificates accompany delivery for C5-M orders, along with the Ex certificates and standard FAT documentation.