The History of Fire Extinguishers as we know it – follow up
Regular readers of our Blog pages may remember a post entitled “The History of the Fire Extinguisher as we know it” back in April of 2009.
The piece received quite alot of attention and drew comments from readers regarding old and obsolete fire extinguishers amongst other things. Recent comments and responses made reference to the restoration of an old Minimax Frowave fire extinguisher possibly dating back to the 1930’s. The gentleman responsible for restoring the extinguisher has provided us with some fascinating before and after photos which can be seen below.
Avoidable Risk
The news this week has been dominated by the “fallout” from the volcanic eruption in Iceland, pushing the General Election jamboree into second place. At least one silver lining perhaps. We live close to an airport so the lack of engine roar and vapour trails in the sky has been noticeable and welcome for us but not I guess for the thousands trapped abroad on sun drenched beaches.
The inquest will now no doubt begin into whether the risk was overstated. Surely that is the thing about risk assessment. If you are at 30000 feet in a glorified cigar case then any clear and present danger should be taken seriously until proved otherwise. To fall from that height is akin to dropping raw eggs off a cliff. None survive.
Despite a withering Northerly wind the sun was shining yesterday so we stepped out for an amble along the river bank to give us and the old dog a bit of exercise. Half way through the walk, high in the sky we saw the tell tale vapour trail of a jetliner so even before the Evening News confirmed it could be surmised the sky’s over the UK were once again open for business.
More encouraging for those not able to head for warmer climes we also spotted the first Swallows of summer skimming low over the sink pools in the flood basin. Those that know birds will be encouraged that, not before time, warmer southerly winds cannot be far away. Swallows ride these winds on their annual migration up from Africa and even for savvy Hirundininae the risk of getting that judgement wrong are fatal.
The arrival of warmer weather will also trigger the annual scramble to dust down the sun loungers, bring the barbeque out of hibernation and stock the fridge with sausages and canned beer. Cars are loaded up with all but the kitchen sink for alfresco family picnics and thermal vests discarded in favour of fuller exposure to the warming Sun.
A risk assessment of these activities often comes low in our priorities but statistically the arrival of summer presages an increase in domestic fire related accidents and injuries.
I have given advice before on how to mitigate these risks but the basics are or should be obvious. Be prepared for the unexpected. Invest in a small powder fire extinguisher to smother an errant barbeque or picnic fire, keep the kids away from both and make sure the flames are out before you leave the scene. Like the Swallow risk preparedness and avoidance is a skill worth learning when lives may depend on it.
Tony
Fired up for Summer
This Sunday last was a pleasant day, summer had arrived with the clocks moving forward on Saturday night and as if to underline the event we had a good measure of sun albeit with a fairly brisk south westerly, ideal in fact for some garden maintenance. It always amazes me just how prolific nature is and once fallen branches, leaves and dead plants were collected we had built a sizeable rubbish heap.
The prevailing wind direction provided a safe opportunity to light a garden fire as the smoke and ash would blow harmlessly across the open fields. And so it proved. When we called it a day and swapped rakes and hayforks for slippers and a cup of tea all that remained was a low hot glowing pile of white ash.
Shortly after seven in the evening as dusk drew in I took the dog out and glancing down the garden to the rubbish fire I was surprised to see fairly boisterous flames flickering in the gathering gloom. I knew immediately what was amiss. On the dyke edge around 10 feet from the fire is a big old willow tree. The centre of the tree has gradually disintegrated over the years and it is hollow to the extent you can see through parts of the lower trunk. Although literally not in the line of fire the gusting wind had clearly blown a hot ember into one of the dry hollows and now the tree was well alight with flames licking out up to 8 foot from the ground.
The fire was burning the core out of the tree and despite copious buckets of dyke water I could not douse the upper reaches within the tree itself.
The wife then remembered we had a couple of fire extinguisher samples in the store that we “borrowed” to safeguard a garden marquee two summers ago. Sure enough we had a 9litre water and a 9litre Foam extinguisher. I was loath to use the foam as the tree like many willows sits on the dyke edge so contaminating the water course was inevitable.
I picked up the 9 litre water and headed for the tree. It was a fair weight and I thought at the time that a lighter 3litre water additive extinguisher would have been as effective and much easier to manoeuvre. The flexible discharge hose allowed me to reach inside the tree and direct the nozzle upward toward the hidden fire. I pulled the pin and squeezed the trigger.
The fire was out within the 20 or 30 seconds it took to discharge the extinguisher. Pretty impressive compared to the gallons of water I had bucketed on previously with little result. It was only the second time in my long association with fire safety that I had used a fire extinguisher in anger. There is no doubt in my mind that as a first line of offence they have no equal.
I put out what was left of the original fire, something I should have done in the first place, and headed back to the house berating myself and feeling somewhat foolish. That’s the third bloody time that’s happened!! Willow ever learn.
Tony
The difference between water and water additive extinguishers
What are Water Additives in Fire Extinguishers
Chemical additives (like butyldiglycol, pronounced butyl-di-gly-col) when mixed with water increase the effectiveness of a water fire extinguisher by up to 300%. Water additive fire extinguishers, often referred to by the brand name of Hydrospray, are smaller and lighter than standard water fire extinguishers for the same fire rating.
A 3 litre Water additive extinguisher should have the same 13A rating of an ordinary 9 litre water extinguisher. The rating is the maximum volume of combustible materials the extinguisher can manage. It follows that if a 3litre Water Additive has the same 13A rating as 9 litre water it is 3 times as efficient – 300%
A 6 litre water additive will normally have a 21A rating which rather proves that a 6litre with additive has more fire fighting power than a 9 litre water without additive. Many office premises only need a 13A extinguisher which has made the smaller easier to handle 3 and 6 litre more popular.
How Water Additive Fire Extinguishers Work
The additives work by removing water’s natural surface tension, making the water ‘wetter’ or ’stickier’, so it adheres to and soaks into the burning materials more effectively rather than the water “running off”. Glycols also have a high evaporation temperature so can soak up more heat. There are usually other additives in the mix that enhance performance like alkyl surfactants (soaping agents) that also lower surface tension and are also used in foam extinguishers. It is therefore wrong to say the additives do not improve the fire suppression performance of the water
Spray Nozzle and Electrical risks
The special spray nozzle on water additive extinguishers atomizes the water (and additive) and spreads it in a more effective arc than a conventional jet nozzle. In addition, the nozzle enables safe use in the vicinity of (but not directly on) electrical equipment. What this means is they have passed the 35KV electrical conductivity tests to BSEN3-7:2004. Although Water Fire Extinguishers are not designed to put out electrical fires, with additives they are safe to use near live electrical equipment provided the nozzle is no closer than 1metre. Passing this test needs the combination of the special high pressure atomizing nozzle and the additive. This is also true for many foam extinguishers that also pass this test.
Of course the best advice is to isolate any electrical equipment before tackling the fire, irrespective of the extinguisher being used. Using a light weight 3 litre water additive extinguisher on solid combustible fires is easier than using a heavier 9 litre Water, live electricity or not.
Tony
Construction Sites under the spotlight
The fire performance of modern methods of construction used in timber frame buildings came under the spotlight at an insurance industry event earlier this month. The insurance industry has a pretty significant influence on what can and can’t be built given that being refused insurance would make the building unsellable.
The RISCAuthority (“The Risk Insight, Strategy and Control Authority”, formerly InFireS), who organized the Seminar, represents many UK insurers with a remit to research and develop risk mitigation measures against fire and security risks. It publishes extensive guides and recommendations for risk mitigation in the areas of Fire and Security. The Risc Authority’s seminar was held in the wake of recent large fires in timber frame buildings and construction sites in London.
I am quite a fan of Timber Frame houses particularly the more aesthetically pleasing homes I have seen featured on Grand Designs. The Timber framed constructions at the centre of this story were more pragmatic multi occupancy affordable housing that utilized the twin benefits of using environmentally sustainable materials and being quick and presumably cheaper to construct than the usual concrete and steel methods.
As far as I can make out timber framed buildings present no greater risk from fire than conventional constructions and pretty detailed industry standards and building regulations are in place to ensure it stays that way. The evidence suggests the greatest fire risk is during construction rather than in completed buildings.
This begs the question as to how the Regulatory Reform (Fire safety) Order applies to construction sites. Clearly it must but by their very nature the potential fire risks on construction sites will be a constantly moving target, giving the Responsible Persons quite a headache to ensure conformity during every stage of the process.
There is also the cost factor. Economic reality dictates that although site safety is clearly paramount it is impracticable to be conducting interminable Risk Assessments and implementing fire measures that are quickly redundant.
The fire safety industry has come up with some solutions. Standalone and linkable fire call points and alarms like the Howler range can be installed to suit the site conditions and adapt to changing size. They have the benefit that at the end of construction they can be quickly dismantled and moved to the next site.
Wheeled mobile fire extinguishers are also ideal for this application and can be quickly deployed to counter a fire in any area of the site. Again once the job is done they can be easily moved to a new site location. They also have a far higher fire rating than the smaller portables with capacities up to 100litres.
The RRO also requires specialist construction site signage. This can get expensive if using the corrugated plastic and foam board versions as they are easily damaged and vandalised. The new TUFF Site Signs are virtually indestructible and despite being more expensive they work out cheaper in the long run as they can be used time and time again. The site safety manager therefore has the means to put together a mobile package of fire and safety equipment that can be deployed to suit individual site conditions.
Tony
