Posted on 30th August 2019
Regulatory bodies are constantly striving to protect seafarers by improving gas detection and measurement onboard ships. Commercial craft must follow the rules set out by SOLAS and IMO or face fines and detentions.
The latest legislation, Regulation XI-1/7, came into force in July 2016. This makes it mandatory for all applicable vessels to carry portable gas detectors onboard and test them regularly:
‘Every ship to which Chapter 1 applies shall carry an appropriate portable atmosphere testing instrument or instruments. As a minimum, these shall be capable to 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 as they represent the biggest threat to crew members on vessels at sea or in port.
Oxygen is essential for breathing so it always needs checking. In addition to this, it supports combustion so it can be dangerous in potentially hazardous working environments.
In gas detection, ‘Flammable gases or vapours’ is usually shortened to LEL which stands for ‘Lower Explosive Limit’ – the lowest concentration of a gas which can produce fire in the presence of an ignition source. When the LEL is 0%, the atmosphere is free of combustible gas and when it’s 100% the gas is at its lower flammable limit. These percentages will differ from gas to gas.
Exposure to Hydrogen Sulphide will result in rapid unconsciousness and death. It’s a colourless and highly flammable gas that’s produced by decaying organic matter as well as numerous industrial processes. Although it has a characteristic smell of rotten eggs, the gas affects your sense of smell so it’s difficult to detect without equipment.
The final gas of the four, Carbon Monoxide, is the one that’s most frequently overlooked. Although Regulation XI-1/7 states very clearly that it must be monitored, there’s a general misunderstanding in the industry about the legal requirements for testing. Because of this – and the properties of Carbon Monoxide – it’s the gas that leads to most deaths onboard ships.
It’s produced whenever organic matter is burned, including carbon-based fuels. It displaces oxygen in the blood, depriving the heart, brain and other vital organs of oxygen. As little as 0.4% concentration in the air can cause victims to lose consciousness and suffocate within minutes. Even if the initial exposure is non-fatal, the delayed effects could result in memory loss, depression, psychosis, difficulties with speech and coordination, blindness and a reduced life expectancy.
Carbon Monoxide is odourless, colourless, tasteless and a non-irritant so it’s impossible to detect its presence without monitoring equipment. Although the dangers of poisoning have been known for centuries, it still causes thousands of deaths every year – in many countries, it’s the most common kind of fatal poisoning. In the US alone, it’s responsible for over 20,000 emergency department visits per year.
Carbon Monoxide collects in poorly ventilated areas, the kinds of spaces that are often used for installing new machinery or storage. On a modern vessel with a complex matrix of pipelines running through each of its parts, there will be even more of these areas so seafarers are more exposed to the dangers of Carbon Monoxide than ever before.
The IMO defines enclosed spaces as having limited openings for entry and exit, inadequate ventilation or a design not intended for continuous worker occupancy. These areas include:
• cargo spaces
• double bottoms
• fuel tanks, ballast tanks
• cargo pump-rooms, compressor rooms
• chain lockers
• and any other area that may be oxygen deficient.
If a crew member enters to carry out repairs or cleaning without taking adequate precautions, the results are usually fatal. There have been numerous instances of Carbon Monoxide poisoning in the last few years alone.
In April, three seafarers died of asphyxiation after being overcome by exhaust fumes on a drilling rig. This prompted the US Coast Guard to issue a Marine Safety Alert to remind operators about the dangers of confined spaces.
But this was just the latest in a long line of similar incidents. Vessels in the UK, Belgium, Malaysia and The Marshall Islands have all experienced fatalities from confined space entries in recent years.
Effective gas detectors and calibration instruments are essential on all cargo vessels. This equipment should also be as versatile and easy to use as possible so that all crew members are protected.
One gas detection system doesn’t necessarily suit all ships – 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.’
Martek Marine is a recognised specialist in marine gas detection with a team of dedicated technical experts that’s renowned within the maritime industry. The world’s major ship operators trust our products to keep their ships and crews safe while also improving their performance and running costs.
We have a range of fixed and portable gas detection equipment that’s designed to cover a variety of different requirements. Our ABC Station will also allow you to perform onboard calibration and produce a tamper-proof certificate that’s acceptable to Class, Port State Control and Oil Majors.
Contact us to find out more about gas detection and equipment.
Download our free guide which gives you all the advice you need to easily and cost-effectively ensure compliance with gas detection regulations.