Detection of gas leakage in Maritime and Shipbuilding Industries

According to maritime regulations, each vessel should be equipped with at least one handheld gas detector on board, which can measure explosive gases or oxygen gases. In some higher requirements, the machine needs to measure both toxic gases (e.g., H2S). Most regulations require additional backup equipment on board, which means that each vessel needs two gas detectors. Applications on board are mostly harsh, where temperature, humidity, dirt and hard surfaces create a harsh environment where RAE gas detectors operate in these places.

Detection of gas leakage in maritime and shipbuilding industries
Detection of gas leakage in maritime and shipbuilding industries

Common places to use

  • Boat
  • Ferry
  • Navy
  • Offshore oil rigs
  • Shipyards – repairers and manufacturers
  • Marine chemistry
  • Customs Inspector
  • Coast Guard
  • Lifeboats and fiberglass boat manufacturers


The main application of gas detection tools in the maritime field is to check the tunnels, tanks, safes on board. These cellars and tanks often have complex spaces, easily forming gas traps. All types of vessels have cellars – tanks, which often have to enter for repair, cleaning or overall inspection. These cellars and tanks are divided into 4 different groups and are considered “standard into limited space”:

  • 1. Cargo bunkers (only on tankers and rem upid vessels)
  • 2. Deposit box (only available on tankers and res resed vessels)
  • 3. Fuel tanks (types of ships)
  • 4. Ballast (vessels)

What do we need to monitor?

The configuration of the gas measuring instrument is selected depending on the type of cellar – tank and type of vessel. There are 3 main groups that are commonly used as follows:

  • Monitoring oxygen levels
  • Monitoring of explosive gas concentrations
  • Monitoring toxic gas concentrations based on environmental sanitation characteristics

Oxygen and explosive gases are relatively easy to identify, but for toxic gases it is more difficult because it depends on the type of cellar – tank and type of vessel.

Oil and chemical cargo bunkers

Onboard cargo bunkers are often used to transport a variety of liquids depending on the ship’s classification according to the IMO (International Maritime Organization). There are 3 common types of ship decentralizity. Decentralized 1 consists of vessels carrying mainly corrosive liquids or poisons while decentralized 3 can carry most types of corrosive substances and toxins.

  • IMO 1 – Vegetable oil tanker, LEL and O2 explosive gas measurement are recommended
  • IMO 2 – Carrying crude oil and oil into gas, measuring LEL, O2, and H2S is recommended
  • IMO 3 – Carrying chemicals (BTEX to MTBE), gas detection tubes are often used for these spaces. But PID gas detectors are more commonly used because they are more economical and safer while providing a continuous gas measurement solution. In RAE’s gas measuring equipment system, the MultiRAE model can simultaneously integrate PID together with the LEL, O2 and H2S teams, which is a comprehensive solution for this application

Deposit box

The deposit box is often used to store water to wash the bunkers, to get into this space, at least equipped with a tool that can measure oxygen gas. Sometimes the deposit box is also used as a cargo vault to increase the storage space, when at this time, all conditions of the deposit box are exactly the same as the vault.

Fuel tank

Fuel tanks, of course, should be equipped with the least gas detection tools for LEL and Oxygen flammable gases.

Ballast water tank

Ballast water is sucked into the vessel to serve the balance and navigation of the vessel. It can have either rotting organisms or leaks from the adjacent area. Therefore, entering this space needs to be equipped with lel, oxygen and H2S explosive gas detection machines.

Container Ship

Container ships account for a large amount in the maritime sector. Basically, the gas detector for the Container vessel only needs to measure lel and oxygen for cleaning, repairing and checking for fuel tanks and ballast water tanks. However, there are some chemicals in methyl bromide, ammonia, and many other applications on board that require both basic gas detectors (LEL, O2, and H2S) and wide range for chemicals (PID).


The choice of gas detectors for seagoing vessels is relatively complex because each vessel is differently required. Meanwhile, crew members can often rotate between ships, so standardizing equipment between ships to ensure that every crew member understands the equipment is essential. The Rae system has most types of gas detectors in response to all of the ationed applications, and each gas detector has a similar usage.


RAE Systems offers reasonable prices, compact sizes, high performance, and ease of use, but more importantly, services worldwide. If the instruments do not work, there is a risk that the ship cannot enter the harbor. Because delays are a big cost, trains can’t wait 72 hours for a new sensor. With RAE Systems’ worldwide distribution network, new instruments can be ordered at any port. Due to “classification” and decentralizity, spare parts and sensors must be from the same company. This makes the worldwide distribution network RAE Systems a valuable resource.


Denmark, the world’s top 7 largest maritime markets, is a country full of ship owners, construction contractors, shipyards, operators and offices of the RAE system. RAE system has been very successful in selling in this country to the shipbuilding industry. The top 3 shipbuilding industries such as Greece, Import and Norway along with countries in the top 10 such as Sweden and the US are also quite interested.

Remance ships and rigs

The basic configuration of gas gauges for service vessels and gas detectors for rigs is oxygen, explosive gas and H2S gas with integrated suction pumps. These tools are often used for deck areas and rigs where there is an H2S gas hazard, in limited space areas where pumps such as ballast water tank, fuel tank, cargo bunker and deposit box are used.

Chemical tanker

We also have success with gas detectors for chemical tankers configured with O2, LEL, H2S, and PID with integrated suction pumps. It is used for inspection in tanks and decks in the manufacture of chemical products.

Ferry (RoRo Train)

We are also quite successful in supplying ferries, the configuration in this area is O2 gas measurement, LEL explosion, CO and suction pump. Another important application is measuring no gas released from vehicles.

Gas tanker

We have seen that MultiRAE Pluses configured with O2, LEL, NH3 (ammonia), Cl2 (chlorine) and PID integrated pumps are very actively meeting the needs of oil and gas tankers. They were used on deck during loading and unloading, a process that took up to 30 hours. Note: This is a good idea to have two additional batteries and an external batterery charger to be able to monitor expansion during prolonged processes.


  • 1. MiniRAE 2000 for Esso, Canada, in unloading 50 and 100 ppm detection of gasoline and diesel vapor in Halifax, Canada.
  • 2. ToxiRAE O2 monitors swedish ice breakers in Stockholm harbour.
  • 3. ToxiRAE PID to track vinyl chloride in Dow, Louisiana, and Maersk gas pipeline, Houston.
  • 4. H2S measuring tubes for suppliers off the coast of North Africa and Middle East markets.
  • 5. UltraRAEs to determine the benzene content of oil rig products off the coast of Louisiana.
  • 6. ToxiRAE PID contact test styrene for Sun Ray, Arizona electric train manufacturer, and Norwegian lifeboat manufacturer.
  • 7. Experience in Denmark for Oto/truck and MultiRAE Plus ferries for simultaneous NO measurement of Maersk shipping line using MultiRAE LEL/O2/H2S
  • 8. MultiRAE LEL/O2/H2S for customs and taxation in the UK.
  • 9. ToxiRAE PID for customs for methyl bromide smoked gas.
  • 10.MiniRAE, ToxiRAE II, and MultiRAE Plus for marine chemical scientists measuring toxic gases and THCs.
  • 11.VRAE and MultiRAE for US shipbuilders.

Special thanks to Michael Jorgensen of Instrumatic in Denmark for his knowledge and advice.


Application Note AP-215 (07/99)

by TES Industry team

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