Friday, 7 February 2014

Boat Alarm

It's winter and a time when we all like to keep the stove running round the clock to keep everything toasty and warm. Every year we read about people who have a few drafts on their boats and block the ventilation holes. The problem is - the holes are usually needed to ensure safe operation of the stove. We have seen boats with plastic containers placed over the mushroom vents and others with, duct or gaffer tape placed over fixed louvre vents. 

There is also the temptation to keep the stove 'banked up' (full) and just ticking over at night to keep the boat aired.  The problem is that the only way to keep a fire ticking over is to restrict oxygen getting to the fire.  If the fire is full of fuel and the fire is struggling to stay alight. The heat will cause large amounts of CO (Carbon Monoxide) to be generated. When a fire has a good supply of oxygen this can help to reduce the amount of  CO being generated.  Never over fill the fire box. On Rosie we just fill the firebox to the point where it will have exhausted most of the fuel by morning and we never burn wood overnight. 

It is a good idea to have a smoke alarm(s) and CO alarms fitted to your boat. They are two different kinds of alarm. One will be triggered by heat and smoke and the other will trigger on detecting small levels of carbon monoxide. Sighting the alarms in the correct position is important.  Heat and smoke and carbon monoxide caused by fire will rise to the roof level.  The smoke alarm should be located as near possible to a source of fire. Such as the kitchen galley or the area where the stove is located. A smoke and CO alarm should also be placed in your sleeping area. You are at greatest risk when asleep than when you are awake.
The Health and Safety Executive (HSE) have a set of guidelines: Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas, oil, wood and coal. Carbon-based fuels and appliances are safe to use if correctly installed and maintained. It is only when the fuel does not burn properly that excess CO is produced, which is poisonous. When CO enters the body, it prevents the blood from bringing oxygen to cells, tissues, and organs.
You can't see it, taste it or smell it but CO can kill quickly without warning. HSE Statistics show every year around 14 people in the UK die from CO poisoning caused by gas appliances and flues that have not been properly installed, maintained or that are poorly ventilated. Levels that do not kill can cause serious harm to health if breathed in over a long period. In extreme cases paralysis and brain damage can be caused as a result of prolonged exposure to CO. Increasing public understanding of the risks of CO poisoning and taking sensible precautions could dramatically reduce this risk.

When you press the test button on a smoke or CO alarm. You are only testing the battery and that their is sufficient power to operate the alarm. Some alarms have a low power sensor and will emit a beep to alert you to the battery being exhausted. Different makers have different testing requirements. I would suggest a CO alarm that has a digital readout. Read and save the enclosed documentation. If you have lost the instructions - download them on-line.

To confirm that a CO detector is detecting carbon monoxide, test it with a substance that will detect low levels of the gas, such as a lit cigarette, match or a smouldering candal wick. As you move the smouldering item  within a few inches of the CO detector, the digital display should change to register the presence of carbon monoxide. If the CO level detected is below 70 ppm (parts per million) the alarm will probably not go off. But the digital readout should read more than zero.  I find it easy to test the smoke alarm in a morning by preparing toast in the galley.

We clear the stove flue with a brush every few months. We have noticed that as soot builds up on the inside of the stove pipe. The flue pipe gets cooler spots to the touch. The flue brush head and three 3ft connecting rods cost us about £20. If you use methane or propane on your boat, it is possible for leaking or un-burnt gas which is heavier than air, to build up in the boat bilge. There are hydrocarbon alarms which can be installed to warn of such issues. We have one installed on Rosie and we only have to change the remote detector head every few years.

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