Oil & Gas Equipment Cases: ATEX, IECEx, NACE MR0175 Protection

A Cameron SL-T wellhead assembly ($85,000-$350,000) shipped from Houston to a drilling platform in the North Sea arrived with a 3mm crack in the API 6A flange face. The cause? A standard wooden crate with 25mm of loose-fill polystyrene that shifted during 12-meter swells on the North Sea, allowing the 180kg assembly to move 15mm inside the crate and impact the crate wall. The repair cost $28,000, delayed the well completion by five days, and the operator’s day rate for that rig was $420,000.

Oil and gas equipment transport is one of the most hazardous and technically demanding categories in industrial logistics. Equipment ranges from $5,000 pressure transmitters to $2 million subsea control modules, and every shipment faces three converging threats: explosive atmosphere compliance (ATEX/IECEx), sour service corrosion (NACE MR0175/ISO 15156), and extreme mechanical shock from offshore lifting and sea transport.

ATEX and IECEx: What “Explosion-Proof” Actually Means for Packaging

ATEX 2014/34/EU and IECEx are the two primary standards for equipment used in explosive atmospheres. For Zone 1 (gas) or Zone 21 (dust) applications, equipment must be certified to Ex d (flameproof), Ex e (increased safety), Ex i (intrinsically safe), or a combination. But here’s the critical point most buyers miss: the ATEX/IECEx certification applies to the equipment’s operational state, not its transport state. During transport, the equipment is de-energized, so ATEX compliance isn’t legally required—but the packaging must protect the certification-critical features.

What does that mean in practice? The flameproof gaps (typically 0.08-0.15mm for Ex d enclosures per IEC 60079-1) must not be damaged during transport. A 0.05mm deformation of a flameproof flange can invalidate the Ex d certification, requiring re-certification testing that costs $15,000-$40,000 and takes 6-12 weeks. Our cases protect these critical surfaces with CNC-cut foam cavities that hold the equipment in its exact operational orientation, with 3-5mm of foam compression on all non-critical surfaces and zero contact on flameproof gaps, sealing faces, and instrument displays.

NACE MR0175 / ISO 15156: Sour Service Corrosion

NACE MR0175/ISO 15156 governs materials for oil and gas production environments containing H2S (sour service). For equipment that will be used in sour service, all wetted components must be resistant to sulfide stress cracking (SSC), hydrogen-induced cracking (HIC), and stress-oriented hydrogen-induced cracking (SOHIC). But again, the transport case has a specific role: it must prevent the equipment from absorbing hydrogen during transport, because hydrogen charging can occur even at room temperature if the equipment is exposed to H2S-contaminated environments or certain cleaning chemicals.

Our cases use 316L stainless steel hardware (latches, hinges, handles) rather than carbon steel or zinc-plated steel, because 316L is NACE MR0175-compliant for most sour service environments. We include desiccant pouches (molecular sieve type, 33g units) to maintain internal RH below 40%, which prevents moisture-induced corrosion during storage and transport. For equipment with carbon steel components that require VCI (volatile corrosion inhibitor) protection, we offer VCI film liners or VCI foam (Cortec VpCI-126 or equivalent) that provides up to 24 months of corrosion protection without leaving residue on equipment surfaces.

Offshore Transport: Lifting, Sea Fastening, and Salt Spray

Offshore transport is where most packaging failures occur. Equipment is typically shipped by supply vessel (PSV) to the platform, then lifted by the platform crane (typically 50-200 ton capacity) from the vessel deck to the platform. During this operation, the case experiences: lift acceleration (1.5-2g at pickup), pendulum swing (up to 15° from vertical), impact on the platform deck (2-5g vertical shock), and exposure to salt spray (5% NaCl solution, 35°C, per ASTM B117).

Our offshore-rated cases address each of these. Lifting points are certified to DNV 2.7-1 or EN 12079, with proof load testing at 2x the rated load (test certificates provided). For cases over 50kg, we include four corner lifting points (rather than two center points) to reduce pendulum swing and allow balanced lifting. Sea fastening points (8mm or 10mm holes at each corner) allow the case to be secured to the vessel deck with 10mm chain or 50mm webbing straps. Salt spray protection is provided by Type II anodizing (15-25μm) plus polyester TGIC powder coating (60-80μm), providing 1,000+ hours of ASTM B117 salt spray resistance.

Pressure, Temperature, and Humidity: The Subsea Challenge

Subsea equipment (ROVs, control modules, chemical injection skids) faces additional transport challenges. A subsea control module ($500,000-$2,000,000) contains precision hydraulic components, electrical connectors (SEacon or Oceaneering-style), and fiber-optic terminations that must be protected from: pressure changes during air freight (cabin pressure equivalent to 2,400m altitude, causing 25% volume expansion of trapped air), temperature extremes (-40°C cargo hold to +50°C tarmac in the Middle East), and humidity (condensation on cold components when moving from cold cargo to warm humid tarmac).

Our subsea equipment cases include: pressure equalization vents (Gore-Tex or Poron, 50-200 ml/min at 7 kPa) that prevent pressure differential-induced seal damage, thermal insulation (25-50mm closed-cell foam lining) that maintains internal temperature within ±10°C for 12 hours in -40°C to +50°C ambient, and desiccant + humidity indicator cards (reversible, 30-40-50% RH color change) that allow inspectors to verify internal humidity without opening the case. For hydraulic components, we offer oil-absorbent foam (polypropylene oil sorbent) that captures any leakage during transport and prevents cross-contamination.

Testing and Validation: Prove It Before It Goes Offshore

Every offshore-rated case design undergoes a validation protocol before production. This includes: vibration testing per ISTA 3A (random vibration, 0.52g rms overall, 2 hours per axis), shock testing (10g, 11ms half-sine, 3 drops per face per edge per corner), compression testing (stacking load, 2x the rated stack weight for 24 hours), lifting test (2x rated load, held for 5 minutes, permanent deformation <1mm), and salt spray (ASTM B117, 500 hours minimum, 1,000 hours for offshore-rated). For IP-rated cases, we perform IP65/IP67 testing per IEC 60529 (dust chamber 8 hours, water jet 12.5L/min at 3m distance for 3 minutes, or 1m immersion for 30 minutes).

Test reports are delivered with each production batch, including raw data, pass/fail criteria, and photographic evidence. For DNV 2.7-1 certified cases, we provide the full DNV type approval certificate and individual unit test reports. For projects requiring third-party verification, we can coordinate with SGS, Bureau Veritas, or ABS for witness testing and certification.

OEM/ODM Solutions: Built to Your Equipment’s Exact Specifications

Every oil and gas equipment case we build is custom-sized to your equipment’s exact dimensions, with CNC-cut foam cavities that hold each component in its operational orientation. We don’t sell stock cases for oil and gas applications—because a 5mm gap means 5mm of potential movement during offshore lifting, and that’s where damage starts. Typical lead time is 15-25 working days for first article (including design, prototyping, and customer approval), then 20-30 working days for production batches of 10-100 units. MOQ is 5 units per design.

Pricing depends on size, complexity, and certification requirements. A typical pressure transmitter case (400×300×200mm, 5kg payload, CNC foam, basic IP65) ranges from $120-$220 FOB Changzhou. A subsea control module case (1200×800×600mm, 150kg payload, DNV 2.7-1 lifting, IP67, thermal insulation) ranges from $1,800-$3,500 FOB. Volume discounts of 15-25% apply for orders over 50 units.