Foam extinguishers fitted on trucks
 

Good Day All,

I thought it might be good to find a 2 gallon Foam extinguisher to put in the holder which came off my F15-A Battery Staff vehicle.

I picked one up on Gumtree today. i realize it was dated 1950 so not 100% period correct but looking at the various Simplex Wormald extinguishers online it seems the desigh hadn't changed at all from the thirties through the fifties. At least 1950 was the closest one to WW2 I could find and only one of two foam type amongst the dozens of water type ones being offered. Once they are paint stripped and polished the price also goes through the roof!

Perhaps military ones has some other differences such as a DD mark so would be interested to know if there was any differences between a civie and a military Foam extinguisher.

The other question is colour. I water blasted the robin egg blue paint off to reveal a lot of the original dark blue colour which is the colour used to denote foam extinguishers. Water type ones are painted red. Since they are exposed on the outside of the vehicle would the Army leave them in that dark blue colour or slap Khaki Green over them?

It didn't cost too much so if I got it wrong I will just polish it up and use it as a brolly stand to remind me to do more research before buying things!

Cheers,

Does it really operate just by turning it upside down ? If so wouldn't the movement of the truck set it off - or is that why it is stowed on the outside of the truck rather than in the cab !

It is rather a nice thing in its own right so would look good in the hall as a brolly stand.

David

Internally, at the top, is a small container of 'something' which when tipped upside down, spills into the main container which holds 'something else' - the resultant chemical reaction creates a foam which is discharged via the hose thingo.

PS That exhausts my technical knowledge of those things. So I guess that violent vehicle movements might see some accidental discharges.

Edit: It's coming back, I think. The small container near the top I think was somewhat bottle shaped (perhaps even made of glass??), with a lead stopper to prevent accidental spillage, so needed to be tipped upside down to displace the stopper. Wikipedia probably has a story on them.

Allan,
You have just brought back a bad memory to me. Over 30 years ago when working in an army workshops, a fire occured in the section I was working in and as an appointed fire team member I was straight on to it. The fire extinguishers were the type you describe and must have been old then. Every one of the extinguishers on the nearby fire point failed to work and I was running around grabbing others. We got the blaze out before the brigade arrived but it was touch and go. After this there was an enquiry and all the extinguishers were updated and regularly checked and recharged. Until you described it I was not aware of the lead stopper, so thinking back it must have stuck.

A fire extinguisher tale
 

On the lighter side. It's a little off topic but it does relate to fire extinguishers.
For putting out engine fires the DC3/C47 used two CO2 extinguishers installed in the cockpit behind the first officers seat with plumbing out to the engines. I was working on a company aircraft in Lae, PNG that required both bottles to be changed for being time expired. The engineer doing the job thought he would give the crew working on one of the engines a bit of a surprise and pulled the appropriate fire handle. Unfortunately he had forgotten that he had already undone the pipe connection or someone beat him to it. The cockpit instantly filled with a dense white fog as he damn near extinguished himself.
You could say that the joke backfired on him.

David

Rather than Water, the Red ones are actually Soda Acid. They contained 2 Gal solution of Bicarb Soda dissolved in water. There was a glass bottle of 50% Sulphuric Acid in the top, which when upturned reacted with the Soda solution to produce Hydrogen Gas and this expanded to expel the water under pressure. I'm not sure of the chemistry that was used with the foam types.

Richard's experience of the non-working extinguishers was a lucky one. The extinguishers were supposed to be emptied, cleaned and refilled every 12 months, as vapours off the sulphuric acid could corrode the copper internals, resulting in big green flakes of crud blocking the hose. If not cleaned out and left sitting for long periods, when activated the expanding Hydrogen gases would have no route of escape past the crud blockage and the cylinder would rupture explosively. The Cylinders were tested to 300psi.

Simplex also made "Marine" versions of these extinguishers for boats. These had a sprung-loaded T-handle through the cap. This shaft of the handle bore down on the cap of the bottle and prevented it from splashing about prematurely (I think that's the term). The instructions reminded users that the handle had to be pushed down and turned anti-clockwise, then turn the extinguisher upside down.

The "Marine" type may have been the version fitted to trucks.

Hi Tony,
I distinctly remember these old extinguishers were cream in colour, where they a foam type? Long time ago and they quickly disappeared after the incident and we had more user friendly ones. When the newer ones were due for a refill we used them on practice sessions.

The extinguisher fitted to Battery Staff, Office etc was described as:

'Extinguisher, Fire, 2-gallon, Foam Type' in most instances.

The Vocab number was LV6-MT1 0879-Z.

In one instance I have, the nomenclature was extended to include 'MT Type', which I take to mean 'Mechanised Transport' or 'Mechanical Transport' or 'Motor Transport' - the abbreviation has multiple meanings.

The 15 cwt fire tender had one each of:

'Extinguisher, fire, 2 gallon, Foam (marine or transportation type)'
'Extinguisher, fire, 2 gallon, Soda-Acid (marine or transportation type)'

The Vocab numbers are: KG 2063 and KG 2067.

The latter ones mentioned would appear to be the same or a similar design to that detailed by Tony, but I'm not sure about the first one above, which lacks the 'marine or transport type' descriptor, and has a different vocab number. Common sense would suggest the extinguisher would have some means to prevent unintended initiation during cross country travel, but in only one description I have does it indicate that it was specifically for 'MT Transport'.

Mike

Foam Fire extinguishers
 

Thank you all for the many inputs to my questions.

I have attached photo of the tube and lead weight cap fitted inside the foam extinguisher.

As an aside:
it was quite an effort to loosen the cap. When I got it open there was still a remnant of foul liquid inside. I purchased the Foam along with a Soda Acid type as a package from a photographer who only bought them for a fashion photoshoot. He obviously never opened them up! May also explain the fresh light blue coat of paint on the Foam one and fresh red paint on the Soda Acid.

As Tony mentioned the Soda Acid had a glass bottle inside for the acid. A lead stopper sat on top of it. That type were never used on my ships but instead stored pressure water type were used hence my describing them as water and painted red.

Richard jogged my memory and I remember the Foam extinguishers on my ship were also cream in colour. I believe modern standards now have all extinguishers red in colour with just colour bands determining the medium inside them.

I think Tony's description of a Marine Version would most likely be a version also specified for vehicular use. A rough day at sea can be as bad as a cross country trip so a means of keeping the two chemicals from mixing would be a priority.

Early foam ones we used were called chemical type where two chemicals were kept isolated by the tube and cap shown in the photo. Later on we changed to mechanical type which had a CO2 charge to expel the chemical into plain water inside the extinguisher.

So I will probably still keep the extinguisher so something can sit in the bracket until something else comes along. It looks good and looks close, to my tired eyes, to the one shown in a photo Keith posted of a F15-A battery staff vehicle.

Cheers,

Hi Tony,

I think the gas created in the reaction was CO2 and not hydrogen.
The "Hindenburg" seems to spring to mind! The Germans wanted Helium but were embargoed from it. Bad call.

Cheers,

From a source who knows this stuff professionally:

"The main container is filled with sodium bicarbonate solution and a long inner polythene container is filled with aluminium sulphate. The inner container is sealed by a cap held in place by a plunger. When the plunger is unlocked by turning it, the cap is released. The extinguisher is then inverted for the two liquids to mix. Carbon dioxide is produced by the reaction which pressurises the container and forces out the foam.

Al2 (SO4)3 + 6 NaHCO3 -> 2Al (OH) 3 + 3Na2SO4 + 6 Co2

The chemicals react to form Co2 which serves as propellant, but the action is slower than the Soda Acid type, giving time for bubbles to form. Foam-making substances added to the sodium carbonate determine the nature of the foam formed. The ratio of the foam produced to liquid is in the order of 8:1 to 12:1. The chemical foam extinguisher may be slow, and the range of jet spray less than the Soda Acid type. Agitating can increase the amount of foam and range.

Because the extinguisher has to be inverted for operation, no internal pipe is fitted. When being recharged the cap seal should be examined and the pressure relief holes in the rim checked."

And yes, Carbon Dioxide. :doh:

Different national marking standards. In the UK (and Europe?), Foam extinguishers are painted cream, or red with a cream band, while the AU/NZ Standard says Foam cylinders should be blue, or red with a blue band.

Foam Extinguishers for vehicles
 

Hi Tony,

Just looking at Keith Webb's photo of the F15-A battery staff vehicle with the foam extinguisher on the side and wondering if he has the photo number of it so I could purchase a higher resolution one of it from the AWM.

I might be able to then see if there is a raised cap for the T handle you mentioned for the marine version of the extinguishers.

In the low res photo it looks flat but it is anyone's guess.

Cheers,

Good Day all,

A late follow up to the info in this thread:

Backtracking a bit I contacted the Fire Service Museum of Victoria last year and they kindly provide me with the attached information.

I just obtained a Transport or Marine type Soda Acid extinguisher based on the info they supplied.

The soda acid type has the glass bottle attached to the top in a cage and the foam type extinguisher lacks that cage and perhaps has a different stopper for the foam tube. Other than that I believe both types of caps are the same.

Hope this is of some interest.

Cheers,

Transport Type Foam Fire Extinguisher
 

Good Day,

Well I finally found a transport type foam fire extinguisher. Picked it up today since some travel is now allowed under the lockdown. I felt one on one with an old gentleman at arms length is still safer than half an hour at Woollies' or Coles with dozens of others.

The major difference between a Soda Acid Transport type and Foam Transport Type extinguisher is the cap. The Soda Acid has a basket to hold the acid bottle and stopper but the foam type just has a pin to hold the foam tube cap down.

Hope this is of some interest.

Cheers,