The importance of Gas Detection in the Marine Industry 

Gas detectors for vessels is a device that detects the presence of gases in ships, often as part of a safety system. SOLAS regulations XI- 1/7 requires that vessels have at least one portable gas monitor on board for oxygen and flammable gas detection. This type of equipment is used to detect a gas leak and interface with a control system so a process can be automatically shut down. 

Why is gas detection required? 

Gas detection equipment measures a gas concentration against a calibration gas which acts as a reference point. Some gas detection monitors only can detect a single gas, some gas detectors can detect several toxic or combustible gases and even combinations within one device. 

Marine applications often generate high humidity and dirty conditions. Detection is required from O2 monitoring in cargo room exhausts, to monitoring flammable and toxic gases within various void spaces, to pump room or cabins, fixed systems with sampling are all commonly used in marine settings. 

Gas detection is required within the marine industry due to the high temperature surfaces housed in an engine room, as well as the short circuit in the electrical system. Both factors combine with smoking or other domestic sources of fire or a reaction in the cargo, leave ships extremely vulnerable to fires. Gas detection is therefore a vital piece of equipment in protecting the lives of those who work on these vessels. This is key as many seafarers lose their lives every year due to the toxic working environment, they work in. Therefore, detecting such hazards before they become fatal, is essential to contain the damage which can take the form a disaster, meaning gas detection is one of the most important pieces of equipment on a marine vessel. 

What are the gas hazards? 

There are several different gas hazards, dependant on the vessel type, such as FPSO (floating, production, storage, and offloading), tankers, ferries, submarines, general or cargo tanks.  

FPSO and tankers house flammable gases and hydrogen sulphide. Therefore, there is a gas hazard risk of flammable gas leaks within the pump rooms. Gas hazards in confined spaces are another hazard, as there may be inerted tanks or voids, which therefore may be too much or too little oxygen in these confined space environments and where inerting gases are stored. There are also hydrocarbon oxygen risks during the purging of tanks (from %Volume to %LEL (Lower Explosive Limit)).  

  • Carbon monoxide (CO) and nitrous oxide (NOx) are housed on ferries as a result of the accumulation from vehicle exhausts, as both are poisonous gases, they are both gas hazards to be aware of.  
  • Submarines house hydrogen within battery rooms. Along with CO2 leaks from air conditioning systems. 
  • On general vessels, CO and NOx are present engine rooms. Along with hydrogen sulphide (H2S) and O2 being depleted in bilges, that arise from the on-board sewage treatment plant. Vessels that carry food produce, such as grain, will sometimes be at risk of H2S. 
  • Cargo Tanks house vapour emission control systems which are used to analyse waste vapour gas for oxygen gas content. The system includes a pressure transmitter to monitor the pressure on the waste vapour line. 

Marine standards 

Products installed on any marine vessel must comply with internationally recognized regulations. Therefore, the international standard that applies to a vessel depend upon where it is registered. It is essential that products sold for use on a vessel comply with the standards relevant to the country in which the ship is registered. For example, products fitted to a European-registered vessel undergoing a re-fit in Singapore must comply with the European MED (Marine Equipment Directive) directive. 

There are several different standards that comply to different regions: 

  • EU (European Union) countries: MED (Marine Equipment Directive 96/98/EC). 
  • North America: US Coast Guard (USCG) regulations. 
  • Other countries: SOLAS (Safety of Life at Sea) regulations provide the minimum requirements, however individual countries will require compliance with the standards of their chosen marine insurance body (e.g., BV, DNV etc). 

Why use detectors? 

Gas detectors measure and specify the concentration of specific gases within the air via different technologies. 

Gas meters are also used on-board ships to measure the hydrocarbon content, explosion hazard risk, and the oxygen analysers. Under the current guidelines cargo tanks or any enclosed space on-board the ship must be tested to ensure that the space is gas-free along with ample amount of oxygen for any required personnel to work there. These circumstances include; prior to starting any repair work or before loading as quality control. 

To find out more about the Marine industry, visit our industry page.  

What’s so Important about my Monitors Measuring Range?

What is a Monitor Measuring Range?

Gas monitoring is usually measured in PPM range (parts per million), percentage volume or percentage of LEL (lower explosive limit) this enables Safety Managers, to ensure that their operators are not being exposed to any potentially harmful levels of gases or chemicals. Gas monitoring can be done remotely to ensure that the area is clean before a worker enters the area as well as monitoring gas through a permanently fixed device or body worn portable device to detect any potentially leaks or hazardous areas during the course of the working shift.  

Why are Gas Monitors essential and what are the Ranges of deficiencies or enrichments?

There are three main reasons why monitors are needed; it is essential to detect oxygen deficiencies or enrichment as too little oxygen can prevent the human body from functioning leading to the worker losing consciousness. Unless the oxygen level can be restored to a normal level the worker is at risk of potential death. An atmosphere is considered to be deficient when the concentration of O2 is less than 19.5%. Consequently, an environment that has too much oxygen in it is equally dangerous as this constitutes a greatly increased risk of fire and explosion, this is considered when the concentration level of O2 is over 23.5%. 

Monitors are required when Toxic Gases are present of which can cause considerable harm to the human body. Hydrogen Sulphide (H2S) is a classic example of this. H2S is given off by bacteria when it breaks down organic matter, due to this gas being heavier than air, it can displace air leading to potential harm to persons present and is also a broad-spectrum toxic poison.  

Additionally, gas monitors have the ability to detect flammable gases. Dangers that can be prevented through using a gas monitor are not only though inhaling but they are a potential hazard due to combustion. gas monitors with an LEL range sensor detects and alert against flammable gases.  

Why are they important and how do they work?

Measurement or Measuring Range is the total range that the device can measure in normal conditions. The term normal meaning no overpressure limits (OPL) and within maximum working pressure (MWP).  These values are usually found on the product website or specification datasheet. The measuring range can also be calculated by identifying the difference between the Upper Range Limit (URL) and the Lower Range Limit (LRL) of the device. When trying to determine the range of the detector it is not identifying the area of square footage or within a fixed radius of the detector but instead is identifying the yielding or diffusion of the area being monitored. The process happens as the sensors respond to the gases that penetrate through the monitor’s membranes. Therefore, the devices have the ability to detect gas that is in immediate contact with the monitor. This  highlights the significance of understanding the measuring range of gas detectors and highlight their importance for the safety of the workers present in these environments.   

Are there any products that are available?

Crowcon offer a range of portable monitors; The Gas-Pro portable multi gas detector offers detection of up to 5 gases in a compact and rugged solution. It has an easy-to-read top mount display making it easy to use and optimal for confined space gas detection. An optional internal pump, activated with the flow plate, takes the pain out of pre-entry testing and allows Gas-Pro to be worn either in pumped or diffusion modes. 

The T4 portable 4-in-1 gas detector provides effective protection against 4 common gas hazards: carbon monoxide, hydrogen sulphide, flammable gases and oxygen depletion. The T4 multi gas detector now comes with improved detection of pentane, hexane and other long chain hydrocarbons. Offering you compliance, robustness and low cost of ownership in a simple to use solution. T4 contains a wide range of powerful features to make everyday use easier and safer. 

The Gasman portable single gas detector is compact and lightweight yet is fully ruggedised for the toughest of industrial environments. Featuring simple single button operation, it has a large easy-to-read display of gas concentration, and audible, visual and vibrating alarms.  

Crowcon also offer a flexible range of fixed gas detection products that can detect flammable, toxic and oxygen gases, report their presence and activate alarms or associated equipment. We use a variety of measurement, protection and communications technologies and our fixed detectors have been proven in many arduous environments, including oil and gas exploration, water treatment, chemical plants and steel mills. These fixed gas detectors are used in many applications where reliability, dependability and lack of false alarms are instrumental to efficient and effective gas detection. These include within the automotive and aerospace manufacturing sectors, on scientific and research facilities and in high-utilisation medical, civil or commercial plants. 

What are Area Monitors and how do I use one?

Outdoor leaks from storage tanks or pipelines are a particular kind of hazard. With many outdoor areas not housing permanent, fixed detectors. If you’re relying solely on a personal monitor, by the time it alarms, there is a possibility that you may be engulfed in a hazardous gas cloud. Therefore, a temporary early warning system between you and the potential source of a gas hazard has the ability to alert you to trouble coming your way.

What are Area monitors and where would they be used? 

Temporary Area monitors are usually rugged units that can be placed, stand-alone to monitor a small area or multiple units can be linked together via wired or wireless networking to create a perimeter defence of a larger area. Area Monitor devices help safety personnel protect their workers from gas hazards in situations, in addition to—or sometimes in substitution of—personal, portable gas monitors used as Personal Protective Equipment (PPE). Area monitors can be positioned to produce a guard between potential hazards and workers, to notify what they are heading into or what potential hazards are coming their way.  This occurs most often when work takes place outside of normal operations where the risks are higher and/or different such as special projects, construction, maintenance, shutdowns, temporary sites or rigs, etc. In this way, they can be used to form a barrier around a tank or along a portion of pipeline close to the location of work being carried out. Portable units can be easily deployed to provide fence line monitoring during maintenance, shutdowns or turnaround. The objective is to ensure that the devices are not so far apart that gas could pass between them undetected.  If a fixed system is being taken offline for maintenance a network of fast to deploy temporary area monitors is an ideal option to use in place of the fixed system until maintenance is complete and the system is brought back online. 

How do you use one? 

Units can be connected by cables. However wireless connection between individual area monitors is also available and avoids introducing a potential trip hazard. This could add significantly to an already risky task, for example, if working at height. Some wireless systems create a “self-healing” mesh network. In this case, should the wireless connection between two devices weaken, the network will automatically re-route communications via alternate enabled devices, creating a mesh type network allowing a more robust and efficient wireless network. 

The benefit from a wireless connection is that it is practical to use repeaters or extra units to relay alerts directly to the control room. Besides the gas alert signals, some detectors will transmit other faults i.e., the loss of signal, or “battery low” alarm. This programmed alert mode is often conveyed by a specific sequence of signals, such as the beacon and lights will flash for 3 seconds followed by 5 second pause which will be repeated until an operator acknowledges the alarm. 

Wireless temporary area monitoring allows for quick deployment whilst ensuring a high level of protection for workers in circumstances where the risks are tricky to monitor. Personnel working at height can be alerted to any gas hazards on the ground, or vice versa and the same alarm can be relayed to the control room by having an additional detector in the control room. The audible alarm is significantly louder than a standard portable and light sequence is brighter and flashes faster on the Detective+ unit when gas is detected. , whilst the sequence on other units in the network is slower. This differentiates the unit nearest the gas from the rest, so everyone is alerted to the location of the hazard. In contrary, to the benefits of this products, the configuration tends to be straightforward without additional hardware. The batteries in Detective+ are larger and last longer than conventional portables. All in all, these units offer a simple yet effective solution for protecting workers outside of normal operations. 

Crowcon’s Detective+ is ideal for temporary area monitoring while workers carry out a repair. Detective+ is portable and can be easily deployed to provide fence line monitoring during shutdowns or turnaround. If working on a cooling tower fin fan, Detective+ units are connected to other units (up to 70m away) via Detective Wireless modules, which eliminate the need for cabling between units. Detective Wireless uses the proven RICOCHET mesh network. In the unusual circumstance that the wireless connection between two devices weaken, the network will automatically re-route communications via alternate RICOCHET enabled devices and so ‘self-heal’. In essence, this creates a mesh type network allowing a more robust and efficient wireless network.

Read more about Area Monitoring