SOLAS Insufficient on Gas Detection -WSS
Ship operators must combine vigilance, structure and care with the new SOLAS X1-1/7 - MSC.1/Circ.1477 & MSC.1/Circ.1485 regulations to safeguard crews from the dangers of gas when entering enclosed spaces, warns Wilhelmsen Ships Service (WSS), stressing that just supplying vessels with one portable four-gas detection unit, as stipulated by the IMO, simply isn’t sufficient.
The new regulation, coming into force on July 1, 2016, requires all ships engaged in international voyages to have at least one unit capable of detecting the presence of oxygen, flammable gases or vapors, carbon monoxide and hydrogen sulfide. This is an important step forward, acknowledges WSS, global provider of maritime products and services, but not the end of the road when it comes to safety.
“The regulation mustn’t be seen in isolation,” comments Andrew Sheriff, Business Manager, Marine Products - Safety Solutions, WSS. “It is sound legislating from the IMO, but it comes with a burden of responsibility for operators. However, this needn’t be an issue if you have the correct knowledge, maintenance structure and testing procedures in place.”
Most importantly of all, Sheriff noted the detection units have to be used by individuals entering enclosed spaces or tanks, not forgotten in a drawer. Next, they must be visually inspected regularly, the batteries charged and the units ‘bump tested’ before use. So, an onboard routine needs to be established whereby the crew satisfy these demands.
“It sounds simple, but it’s very serious,” he stressed. “Also, don’t forget the batteries and sensor will need replacing after 30 months to be on the safe side, or when their runtime drops below that of the shortest on-board shift. A failure to do this can cause some units to ‘forget’ they are equipped with a dual range sensor for combustible gasses.
“The unit’s audible and visual alarms must also be checked regularly and must be free of grime and dirt - which can obstruct them – while the housing of the detector should be free of cracks. If it isn’t water can corrode the inner circuit boards and, if the detector isn’t ‘gas tight’, it can actually, in the worst case scenarios, cause explosions.”
Simple visual and functional checks suffice in these respects, but not in all. The sensors that detect the gas are sensitive to contamination, so must be stored carefully to protect them. Testing them with a lighter, as some crewmembers do, is a definite no.
“This is too high a concentration of gas and basically destroys the sensor’s ability immediately.”
With so many potential risks to detector integrity crews should be trained to perform ‘bump’ tests. This consists of exposing sensors to a challenge gas at a sufficient concentration to activate a unit’s alarms at its lower level settings. It proves it works, but not how accurate it is.
This is when, according to Sheriff, it may be time to call in the professionals: “In order to measure the performance of the sensors a ‘calibration check’, using a traceable source test gas at a set concentration, must be done. This involves measuring the sensor’s responses according to the detector manufacturer’s acceptable limits, which can vary from brand to brand. It is much more difficult to perform on board than the other checks.
“Well informed, regimented crew members will be able to safely use and check the basic robustness and functions of a four-gas detection unit. However, personally speaking, if I was in a confined space on a vessel and my life depended on this piece of equipment, I’d want it calibrated by a professional.”
WSS supplies a range of advanced Unitor gas detection units, such as the Unitor Gas Pro, with complete maintenance packages delivered by skilled technicians, thus ensuring optimal standards of operation. This solution dispenses with the need for exchanging units at service centers, or investing in on-vessel calibration kits. WSS’ service engineers can efficiently re-certificate, calibrate and inspect gas detectors on board when visiting to test or inspect other equipment.
All WSS units have been tested with stringent drop and moisture tests, giving them an increased operational lifespan. The Unitor T4 unit is also supplied with an external filter as standard for increased protection.
“This is an essential device, but it needs to be looked after properly to work,” Sheriff concluded. “The regulations must be backed up by the right mix of everyday care and professional maintenance. By doing so this new regulation will really fulfill its potential to safeguard assets, operations and, most importantly of all, lives.”
