Gas Detection: What is a 4-gas detector?

4-Gas Detectors

Effective gas detection is one of the most important safety concerns in the shipping industry. A third of all dangerous incidents that happen offshore are gas related.
Fatalities among seafarers are still occurring despite attempts by regulatory bodies to prevent them.
 

Regulations

SOLAS Regulation XI/1-7 states that:

‘Every ship to which Chapter 1 applies shall carry an appropriate portable atmosphere testing instrument or instruments.
As a minimum, these shall be capable of measuring concentrations of oxygen, flammable gases or vapours, hydrogen sulphide and carbon monoxide.’
 
It’s these gases that a 4 gas detector is designed to monitor. They represent the biggest threat to crew members on vessels at sea or in port.
 
Oxygen (O2)
As well as being necessary to breathe, oxygen also supports combustion. So, monitoring its presence is vital in hazardous working environments on board ship.
 
Flammable gases (LEL)
LEL is short for ‘Lower Explosive Limit’.
LEL is the lowest concentration of a gas or vapour capable of producing fire in the presence of an ignition.
 
Concentrations lower than the LEL are too lean to burn, those above, too rich. The LEL is displayed as a percentage with 0% showing a combustible gas-free atmosphere and 100% when a gas is at its lower flammable limit.
The percentages will differ from gas to gas.
Methane, for example, is too lean to burn between 0% and 5% but is highly flammable between 5% and 17%. Over 17% and the atmosphere is too rich for methane to ignite.
 
Hydrogen Sulphide (H2S)
Known as ‘sewer gas’ or ‘swamp gas’, Hydrogen Sulphide is colourless and highly flammable.
It’s produced by industrial processes and/or decaying organic matter and has a characteristic odour of rotten eggs.
However, this may not be detected until it’s too late as exposure to the gas affects your sense of smell.
It’s heavier than air, so hydrogen sulphide accumulates in enclosed and poorly ventilated areas.
 
Inhalation produces extremely rapid unconsciousness and death.
 
Carbon Monoxide (CO)
CO is produced whenever a fossil fuel is burned and collects in poorly ventilated areas. CO displaces oxygen in the blood, depriving vital organs of oxygen causing victims to lose consciousness and suffocate.
 
Because it’s odourless and colourless and can overcome you in minutes, it kills thousands of people every year.
 

Fixed gas detectors

Fixed gas detection systems are a requirement for some vessels but are recommended for a much wider range of ships. These can be placed in vulnerable locations to monitor gases at all times, issuing alerts at the first sign of potential danger.
 
However, one gas detection system doesn’t necessarily suit all vessels. You have to make sure that you have the correct equipment for your vessel’s particular needs.
SOLAS guidance states:
It should be noted that, given a ship’s specific characteristics and operations, additional atmospheric hazards in enclosed spaces may be present that may not be detected by the instrument recommended to be selected by these Guidelines, and in such cases, if known, additional appropriate instruments should be carried.’
 
That’s why at Martek, we have a team of expert engineers. They build our fixed detection systems in-house so that we can ensure that the equipment is tailored to your specific requirements.
 
Our MM2000 system tests for toxic and flammable gases in a wide variety of situations and is guaranteed to be SOLAS and ISGOTT compliant.
 

Portable gas detectors

Worn by seafarers entering spaces where dangerous gases may be present.
This equipment should be as versatile and easy to use as possible so that all crew members are protected.
 
We have a range of the best portable gas detection equipment designed to cover a variety of requirements, including:
 

A robust and accurate portable gas detector, the Marine 4™ provides unrivalled protection in confined space applications with audible and visual alarms in the event of exposure to flammable or toxic gases.

Detecting and displaying up to 4 gases simultaneously, it is suitable for a host of applications in a variety of industries. The Marine 4™ can be configured to detect a combination of:

    • Methane
    • Oxygen
    • Carbon Monoxide
    • Hydrogen Sulphidea
  • and other flammable gases.

MGC Simple+

NO CALIBRATION. NO CHARGING. NO COSTS.

A WORLD FIRST IN PORTABLE GAS DETECTION.

From Zone 0 to inert atmospheres – with the Marine Triple-C you’re always good to go.

Innovative 3-year battery life and cutting-edge infrared technology remove the need to calibrate, meaning no unproductive maintenance breaks and no expensive sensor replacement.

This all-in-one solution guarantees compliance and reduces risk whilst saving time and money – all at the touch of a single button.

 

Discover how we can help to keep your crew safe on board ship.

Kivu Ebola Outbreak – What you need to know

The current Ebola Virus Disease (EVD) outbreak in the Democratic Republic of the Congo was declared on the 1st August 2018 and has grown to become the second biggest EVD outbreak to date.

This recent outbreak followed on from the earlier Équateur province Ebola outbreak which occurred May to July 2018.

Previous Epidemic

The West African Ebola virus epidemic was the largest to date with 28,616 reported cases and 11,310 deaths – although it was suspected that 17-70% of cases went unreported.

This epidemic saw reported cases outside of Africa in the United States, United Kingdom, Italy and Spain.

It was believed to have started in December 2013 when a one-year-old boy in Guinea died from the disease. Later, his mother, sister and grandmother died from the same symptoms.

The village was close to a large colony of Angolan free-tailed bats, which have been thought to spread Ebola, yet none of the bats tested were found to carry the disease.

World Health Organisation (WHO) Update

As of 26th December 2018, a total of 591 EVD cases, including 543 confirmed and 48 probable cases, have been reported.
These reported cases have come from 16 health zones in the two neighbouring provinces of North Kivu and Ituri (Figure 1).

Of these cases, 54 were healthcare workers, of which 18 died. Overall, 357 cases have died (case fatality ratio 60%).

In the past week, ten additional patients were discharged from Ebola treatment centres; overall, 203 patients have recovered to date. The highest number of cases were from age group 15‒49 years with 60% (355/589) of the cases, and of those, 228 were female.

Confirmed and probable Ebola virus disease cases by week of illness onset, data as of 26 December 2018. Source: WHO
Confirmed and probable Ebola virus disease cases by week of illness onset, data as of 26 December 2018.
Source: WHO

Travel Restrictions

WHO advises against any restriction of travel and trade to the Democratic Republic of the Congo based on the currently available information.

Currently, no country has implemented travel measures that significantly interfere with international traffic to and from the Democratic Republic of the Congo. Travellers should seek medical advice before travel and should practice good hygiene.

Direct Transmission

Ebola’s transmitted through close and direct physical contact with infected bodily fluids. The most infectious being vomit, blood, and faeces.

There have also been cases of Ebola detected in breast milk, urine and semen; with studies detecting the virus 70 days after the patience had recovered from symptoms.

There have also been studies showing the virus to be present in Saliva and tears, but the sample size was limited.

If coming into contact with those who may have Ebola, you should ensure protective equipment is worn.

Indirect Transmission

Ebola can be transmitted indirectly through contaminated objects and surfaces.

If you are frequently in contact with objects, materials or surfaces that could carry infection, it’s recommended to regularly clean and disinfect. Wearing protective equipment will decrease the risk of transmission.

There is no evidence that Ebola can be transmitted via airborne means. The virus could be transmitted through large wet droplets from a heavily infected individual coughing and sneezing at close distance, but no study has confirmed this.

Again, if you are in close proximity with people who may be in contact with the virus disease, ensure thorough cleaning procedures are in place and consider safety equipment.

Vaccination

There is currently no licensed vaccine to protect people from the Ebola virus. Therefore, any requirements for certificates of Ebola vaccination are not a reasonable basis for restricting movement across borders or the issuance of visas for passengers leaving the Democratic Republic of the Congo.

Summary

The latest Ebola outbreak is the second biggest to date, behind the West African Ebola virus epidemic 2012-2016.

There are currently just short of 600 cases, with around 10% of those being healthcare workers.

Ebola is passed through direct contact with infected bodily fluids and can survive for 70+ days after the symptoms have passed.

Although there is currently no cure, the risk of spread can be greatly reduced though personal and surface cleaning procedures, and further reduced with protective equipment.