Marine Infrared Thermography Inspection Service for Oil Tanker, LPG & LNG Ships

Figure: Infrared thermal imaging survey applied on oil tanker and LNG vessel for hot‑spot and cryogenic leak inspection

1. Industry Background for Oil & LNG Shipping Vessels

Global trade of crude oil, LPG and Liquefied Natural Gas keeps expanding rapidly. More passenger ships, offshore support vessels, oil tankers, container ships and bulk carriers adopt LNG‑fuelled propulsion systems. Compared with conventional petroleum‑fueled vessels, LNG ships face dual hazards: flammable‑explosive risk plus severe cryogenic low‑temperature damage risk.

Mainstream crude carriers include large‑tonnage VLCC tankers. Common tanker classifications are listed as follows:

Common Oil Tanker Types

• Suezmax Tanker: Maximum deadweight approx 100,000‑150,000 DWT, designed to transit Suez Canal under full‑loaded draft limit, also called million‑barrel tanker.
• Aframax Tanker: Deadweight 80,000‑100,000 DWT, optimized for calling most North American ports with economical operational performance.
• VLCC / ULCC: Very Large Crude Carrier / Ultra‑Large Crude Carrier. VLCC: below 300,000 DWT; ULCC: above 300,000 DWT. VLCC widely operates on Middle‑East to Far‑East routes; many ULCC units are converted for floating oil storage.
• Shuttle Tanker: Specially built for crude oil transfer from offshore oil fields to onshore terminals, fitted with dynamic positioning and helicopter deck facilities, deadweight 80,000‑150,000 DWT.

Vessel Hull Structure Requirement (MARPOL Annex I)

Single‑hull oil tankers have been phased‑out globally since year 2015 according to MARPOL Annex I amendment. Modern tankers adopt double‑hull or double‑bottom / double‑side hybrid construction for anti‑pollution protection.

2. Fire & Explosion Hazards on Oil Tankers

Oil tankers contain dense networks of pipelines for oil and water transfer. Once fire breaks out, heavy smoke, poor visibility, toxic gas and high temperature put crew evacuation under great threat. Combustion and explosion propagate rapidly to form three‑dimensional vessel fire and may lead to total vessel loss.

• Steel hull transfers heat quickly; thermal radiation may heat adjacent cargo tanks and trigger successive explosions.
• Post‑explosion oil spill causes large‑scale surface burning and severe ocean pollution.
• Statistical incident data shows explosions occur more frequently in empty / ballast tanks than fully‑loaded tanks. Residual oil vapour inside empty tanks mixes with air to form explosive gas mixture once reaching flammable concentration range.
• Heavy crude oil combustion may exhibit intermittent flame behaviour; boiling‑over and slop‑over risk exists for water‑contaminated heavy oil cargo, causing flame spread.

Root causes for tanker fire incidents include grounding, collision, capsizing, hot‑work welding, electrical short‑circuit and static electricity discharge.

3. Fire & Leakage Prevention Measures for Oil / LPG / LNG Vessels

Combustible gas mixture only ignites within specific concentration range between Lower Flammable Limit (LFL) and Upper Flammable Limit (UFL). Typical LFL value 1% and UFL 10% by volume for hydrocarbon gas. Controlling ignition sources is critical for marine explosion‑proof safety. Open flame and hot‑work welding must be strictly forbidden on tanker decks and hazardous zones.

Electrical Over‑heat Monitoring & Thermal Survey Workflow

1. Install NKTEVA6 thermal array camera on critical marine equipment for continuous real‑time monitoring, capture thermal images / video for over‑heated electrical components and wiring.
2. Carry out annual / periodic full‑scope infrared thermal scanning for all electrical machinery and cabling. Record temperature data, capture thermal snapshots for abnormal hot‑spots and issue formal thermography inspection report.
3. Analyse root causes of thermal anomalies from thermal images, implement maintenance actions: retightening connections, repairing or replacing defective components.

Cryogenic LPG & LNG Leakage Detection via Infrared Thermography

LPG is stored at approx.‑20℃ under 10 bar pressure; LNG (liquefied natural gas) stores at‑162℃ under 1 bar. Both media stay far below ambient environmental temperature. NKTEVA6 thermal imager identifies leakage points by visualizing obvious temperature deviation on pipelines and tank surfaces.

New‑build or retrofitted LNG‑fuelled vessels are normally fitted with temperature sensors, pressure transmitters, level gauges and fixed combustible gas detectors for LNG supply system monitoring. Nevertheless, point‑type thermocouples provide limited coverage area. The NKTEVA6 thermal camera enables wide‑area rapid visual screening over LNG tanks and piping systems for leak location. LNG vaporizes rapidly upon leakage; thermal imager detects temperature variance and pin‑point leak sources efficiently. This non‑contact thermal device can also detect early fire ignition sources nearby LNG storage installations.

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