Chris_Stannard
New member
I now have a large information pack which pyrogen were kind enough to send me. It includes the MCA report - PGUK: 9-12/99 dated 29 Dec'99. I do not know if you can access this on the web.
First Halon - The EU has ruled that for 2002 Halon from existing sources may be used to replenish current systems. No new Halon can be manufactured for new or exisitng systems. From 1 Jan 2003 this practice will no longer be allowed and from 31 Dec 2003 Halon extinguishers will be illegal. I guess this means that anyone with Charter or Sailing school boats, that need MCA approval, will have to change to an alternative. There are exempt categories, such as aircraft, but pyrogen is being tried for them and the rules state that, as alternatives become available, the exempt categories will be closed off.
How does Pyrogen work - in essence it has a small pyrotechnic charge which fires a fine aerosol of chemicals through a cooling filter into the engine space. Therefore there is no tank of pressurised gas, or anything like that. The chemicals released put the fire out in two ways. The charge releases potassium-bicarbonate and a mixture of nitogen, carbon dioxide and water vapour. The potassium bicarbonate is in vapour form and combines with 'chain carriers' to kill the flame (it all gets a bit technical in the report). This is similar to the action of Halon but it is said to be three times as effective. The other affect is heat removal. The gas has a long hang time so it continues to act as a supressant if there are any hot spots which tend to cause re-ignition.
The MCA report shows the result of 7 tests. In each case the fire was allowed a period of time, usually 2 minutes to get going, before the extinguishers were fired. All tests were judged a success as the fire was extinguished in each case.
The temparture had fallen from about 600-700C to below 200C in 2 minutes in most cases. In the worst case senario, an open pool of diesel, a hidden pool and a hidden diesel spray it was a bit longer. This would equate to you continuing to run the engine, with an injector line broken and spraying diesel every where, throughout the fire.
The MCA approved the use in vessels up to 24 metres load line but with some requirements for commercial vessels such as the installation has to be approved by a surveyor.
Life - The MCA states the system should be replaced in accordance with the manufacturers instructions. This gives it a 10 year life, so although it might be costly to start with on a through life costing basis it is probably cheaper than alternatives which require servicing.
Safety - The Institue of Naval Medicine looked at the safety aspects. Small amounts of Carbon Monoxide, ammonia and nitrous oxides may be released. They recommended a maximum exposure to the gas of 5 minutes. The MCA states that for manned compartments there should be a remote firing system with a 20 second warning before the extinguisher fires, and for unmanned compartments it should be possible to deactivate the extinguisher before going in.
Personal thoughts. SWMBO insisted on an Avon liferaft on the basis of it is a 'one time life saving' device. In that situation she wants the best. I think this is the system I will be fitting as it seems to me to be a 'fit and forget' device which could be a lifesaver.
Chris Stannard
First Halon - The EU has ruled that for 2002 Halon from existing sources may be used to replenish current systems. No new Halon can be manufactured for new or exisitng systems. From 1 Jan 2003 this practice will no longer be allowed and from 31 Dec 2003 Halon extinguishers will be illegal. I guess this means that anyone with Charter or Sailing school boats, that need MCA approval, will have to change to an alternative. There are exempt categories, such as aircraft, but pyrogen is being tried for them and the rules state that, as alternatives become available, the exempt categories will be closed off.
How does Pyrogen work - in essence it has a small pyrotechnic charge which fires a fine aerosol of chemicals through a cooling filter into the engine space. Therefore there is no tank of pressurised gas, or anything like that. The chemicals released put the fire out in two ways. The charge releases potassium-bicarbonate and a mixture of nitogen, carbon dioxide and water vapour. The potassium bicarbonate is in vapour form and combines with 'chain carriers' to kill the flame (it all gets a bit technical in the report). This is similar to the action of Halon but it is said to be three times as effective. The other affect is heat removal. The gas has a long hang time so it continues to act as a supressant if there are any hot spots which tend to cause re-ignition.
The MCA report shows the result of 7 tests. In each case the fire was allowed a period of time, usually 2 minutes to get going, before the extinguishers were fired. All tests were judged a success as the fire was extinguished in each case.
The temparture had fallen from about 600-700C to below 200C in 2 minutes in most cases. In the worst case senario, an open pool of diesel, a hidden pool and a hidden diesel spray it was a bit longer. This would equate to you continuing to run the engine, with an injector line broken and spraying diesel every where, throughout the fire.
The MCA approved the use in vessels up to 24 metres load line but with some requirements for commercial vessels such as the installation has to be approved by a surveyor.
Life - The MCA states the system should be replaced in accordance with the manufacturers instructions. This gives it a 10 year life, so although it might be costly to start with on a through life costing basis it is probably cheaper than alternatives which require servicing.
Safety - The Institue of Naval Medicine looked at the safety aspects. Small amounts of Carbon Monoxide, ammonia and nitrous oxides may be released. They recommended a maximum exposure to the gas of 5 minutes. The MCA states that for manned compartments there should be a remote firing system with a 20 second warning before the extinguisher fires, and for unmanned compartments it should be possible to deactivate the extinguisher before going in.
Personal thoughts. SWMBO insisted on an Avon liferaft on the basis of it is a 'one time life saving' device. In that situation she wants the best. I think this is the system I will be fitting as it seems to me to be a 'fit and forget' device which could be a lifesaver.
Chris Stannard
