BOILER INSURANCE, FUSIBLE PLUGS AND THE PLUG RIOTS OF 1842

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BOILER INSURANCE, FUSIBLE PLUGS AND THE PLUG RIOTS OF 1842

Post by Stanley » 18 Oct 2013, 04:39

BOILER INSURANCE, FUSIBLE PLUGS AND THE PLUG RIOTS OF 1842
One of the nice things about pursuing local history is that you have to range across the whole spectrum of the divisions we make in how history is studied. In order to tell the story you have to understand every circumstance you encounter. This means that you arrive at situations where you recognise what is being presented but you have no detailed knowledge.

I found myself in this position the other day when I was collating my research on the watermill at Lothersdale, near Cowling in the West Riding. There was a reference to the mill escaping the attention of the ‘plug drawers’ during the industrial unrest in the area in 1842 because it was in a remote valley. I knew of a mill in Earby which had been attacked and stopped by the same mob, presumably because it was more accessible. But how much did I actually know about the Plug Riots? I decided to search my books and go out onto the internet and see what I could glean.

I found little that I wasn’t aware of, I was reminded of the progression of unrest from the Luddites in 1812 through the Plug Riots in 1842 to full blooded Chartism in 1848. There was an interesting cotemporaneous reference to the origin of the name ‘Ned Ludd’. The writer, shortly after 1811, said that it started with a lad called Luddlam being told by his father to tidy up his stocking frame, he took umbrage and smashed it with a hammer. I am always wary of these convenient explanations but the date of the writing and something about the story combined to make it ring true. So I was happy to take this snippet of information on board, file it away in the memory and be content with it until I learned anything better.

Further on in my search I came across a definite statement which said that the boilers were disabled by ‘removing the fusible plug’, hence the name ‘Plug Drawers’. I’m afraid that this is completely wrong. The author had knowledge that boilers had something called a fusible plug, had added two and two together, but unfortunately made five.

I’d never really focussed on the origin of ‘Plug Drawers’ because I didn’t have to do this. My experience with boilers and old technology meant that I knew exactly what plug drawing is, how it was accomplished and what the results would be. As I went through this thought process I realised that anyone who had read the article containing the spurious reference to fusible plugs would go through the rest of their lives labouring under a mild but nevertheless important misapprehension. So I thought I’d put the story straight. Then I thought no, this is verging on arrogance. Then I had another re-think and decided to throw caution to the winds. Here is the result.
Fusible plugs.
At first sight, the easiest way to deal with the fusible plug theory would be to prove that they didn’t exist in 1842. This presents a problem in itself because search as I might, I couldn’t find any evidence for a date of the invention of them. Here again, practical knowledge came to the rescue. I knew that the most common source for fusible plugs was a firm called NABIC at Manchester. The name NABIC derives from the National Boiler Insurance Company who started a manufacturing arm of their organisation to ensure that this valuable safety device was easily available to their customers. I found my evidence in a conversation with one of their engineers but before we examine that I think a slight digression might be useful.

The inspection and insuring of land based steam boilers.
The practice of boiling water in enclosed vessels to produce pressure ether deliberately or by accident is very ancient. There can be little doubt that the unfortunate consequences of any failure in the vessel were learned very quickly. Eventually the mechanism which led to the explosion was recognised, water under pressure was capable of storing energy which was controllable as long as the integrity of the enclosing vessel was perfect and pressure was maintained. However, any sudden drop in pressure inside the vessel due to a rupture of the shell allowed the superheated water to release its energy immediately in the form of steam. At relatively low pressures this meant that the volume of the water increased 10,000 times as it flashed off, this was instantaneous and had the same effect as the explosion of a charge of explosive.

For hundreds of years this was simply an esoteric fact of interest only to alchemists, natural philosophers and chemists. It was the introduction of steam boilers on a large scale to provide the motive force for steam engines that introduced knowledge of this danger to the general public.

On November 16th 1815 the 2000 gallon boiler supplying high pressure steam to a 6hp engine at the sugar refinery of the Constadt Company of Well Close Square, Wapping exploded causing six deaths and the destruction of property estimated in value as £25,000. On May 18th 1817 the boiler of The Yarmouth Steam Packet exploded on the River Yare at Norwich and killed eight people. This latter event led to the establishing of a Select Committee of the House of Commons to investigate the best means of preventing such explosions on steam boats. In the course of their discussions the Wapping explosion was brought to the Committee’s attention and it took explosions in land boilers ‘in manufactories and other works’ into consideration.

The Committee reported on 24th June 1817 and made recommendations which, although they did not lead to legislation and were primarily concerned with marine boilers, were the first rules for the regulation of the use of steam boilers ever brought before Parliament. Some idea of the size of the problem that was accumulating can be gained from the fact that in 1870/1871 there were estimated to be 100,000 boilers in operation in the United Kingdom excluding domestic, locomotive and marine installations.

By 1850 the industrial heartland of England from Cheshire across to the West Riding of Yorkshire had the biggest concentration of steam boilers in the world. Increasingly, Coroners found themselves conducting inquests investigating boiler explosions. It was the attendance at these inquests, as expert witness, by Sir William Fairbairn that eventually triggered action to reduce the chance of accidents because Fairbairn’s consistent recommendation was that a system of boiler inspection was required to ensure adequate maintenance and safe working of land boilers. In 1854 he was consulting with Henry Houldsworth and Sir Joseph Whitworth in Manchester with a view to forming a scientific association to conduct experiments on boilers and engines, investigate explosions and inspect boilers.

On the 9th of September 1854 there was a boiler explosion at Bridgefield Mill in Rochdale which killed ten people. The inquest found that the accident was due to neglect in that one safety valve was inoperative and the other had been over-weighted to ‘stop the boiler blowing off’. This triggered public reaction, the Manchester Guardian weighed into the fray on September 16th and the upshot was the formation, by Fairbairn and others, of the Manchester Steam Users Association on the 19th September.

The new association did much useful work in terms of experiments on boilers and raising public awareness but took a long time to really get into its stride as an inspecting and insuring body. In evidence given to the Select Committee on Boiler Explosions of 1870, William McNaught, a prominent engineer in Rochdale, stated that it was his impression that Sir William Fairbairn’s main interest was to be seen to be doing something, even if it was short of full insurance, in order to ‘prevent government interference’.

This inactivity resulted in a vacuum which was partially filled in 1858 when, on June the 8th, a group of men met in the office of Jonathan Cox who had an agency for the Medical, Invalid and general Life Insurance Company and started the process which led to a new company, The Steam Boiler Assurance Company. This company was probably the first in the world to start an efficient inspecting and insuring company devoted entirely to steam boilers. This company prospered and carried on under various names following takeover and reorganisation and for many years traded as the Vulcan Boiler and General Insurance Company Limited. I believe it is now incorporated in the Royal Sun Alliance grouping. It was a success and this led to the formation of rival companies, one of which in 1864 was the National Boiler Insurance Company

Image

This brief outline of the birth of steam boiler insurance is culled entirely from two rare books. The Manchester Steam Users’ Association published ‘A SKETCH OF THE FOUNDATION AND PAST FIFTY YEARS ACTIVITY’ on the occasion of their jubilee in 1905 and a very good history of the Vulcan Insurance Company was written by W H Chaloner and published privately in 1959. Chaloner acknowledges that one of his major sources was the 1905 Sketch. These are the best sources I know on this subject and there is much more of interest if you care to go and do some digging.

The two major consequences of this series of events and the formation of the inspecting and insuring companies were firstly, that they employed competent engineers for the boiler surveying and trusted them entirely. Secondly, they accepted the entire responsibility for the risk and government legislation followed the insurance companies’ lead in developing standards and enforcing them. This framework is still in place and I think has much to recommend it in other fields. In effect, Fairbairn attained his objective.

As they were carrying the risk, the insurance companies were always open to suggestions or new inventions that made boilers safer. Steve Cooper of NABIC’s technical department tells me that in 1863 a London engineer called John Smith patented a fusible plug for boilers and the National Boiler Insurance Company bought the rights to the new device in 1864 for £2,000, used it as the foundation of the firm and started manufacturing it on their own account. This was the formation of NABIC, a firm which is still in business manufacturing fusible plugs and other steam boiler accessories. Through NABIC, the insurers supplied their customers with the new device and offered them a 10% reduction in premiums if they fitted them. Fitment of the plugs rapidly became universal as they were obviously so effective. All the other companies followed the National’s lead and interestingly, recommended their customers to go to NABIC for their requirements. Eventually firms like Hopkinson’s at Huddersfield started manufacture of fusible plugs but the industry standard was always NABIC. The last plugs I bought were from them.

Right; I think we’ve nailed insurance and fusible plugs down now. Let’s apply what we’ve learned to the ‘fusible plug theory’.

There is a trap here, we’ve proved to my satisfaction that the fusible plug as we know it today was patented in 1863 but this doesn’t mean that there were no fusible plugs before that date. Farey’s ‘Treatise on the Steam Engine’ Vol I, 1827 and the unfinished Vol II of 1851 have no reference to fusible plugs. In ‘The Steam Engine’ by John Bourne, published in 1876, page 216, there are two paragraphs on the subject. In the first he refers to plugs of fusible metal based on mercury but says that ‘though ingenious, [it] has not been found of any utility in practice’. In the second paragraph he refers to lead rivets being inserted in the crowns of locomotive boilers and some others. He says that ‘the plug is most conveniently inserted into a brass nipple tapped into the boiler and it will thus be melted out before the water falls so low as to occasion injury’. Essentially, this was the basis of Smith’s patent in 1878.

So, if we’re talking about a technology as simple as a lead rivet in the crown of the boiler it is quite possible that such a simple idea was known and used in the mid eighteenth century. The problem here of course is that we do not know, we have no evidence.

However, there is a much stronger argument against the theory.

In 1842 there were no two flued or Lancashire boilers, William Fairbairn didn’t take the patent out for it until 1844. There were single flued shell boilers and Cornish boilers but these were quite rare as they were new technology. So most of the boilers attacked by the plug drawers would be ‘Wagon’, ‘Haystack’ or cylindrical boilers which usually had one thing in common, very few had an internal flue and it is very doubtful if any of these were ever fitted with a fusible plug. So, even if the fusible plug theory was right, it wasn’t there to draw.

The other flaw with the fusible plug theory is the clincher. Fusible plugs are fitted in the water space of the boiler, screwed into the crown of the firetube over the fire from the inside. They were usually made of gunmetal with a fusible insert made of lead that melted at 330 degrees C. The action of the plug was that as long as it was immersed in water the temperature remained low and the plug intact. If the water level became dangerously low there was a danger of the metal of the flue becoming red hot, losing its strength and either bulging in or rupturing. However, before this condition was reached the fusible plug was exposed, the fusible insert melted and water and steam rushed out into the furnace. This dampened or even extinguished the fire and alerted the boiler attendant.

It will be seen from this description that in order to remove this plug the boiler would have to be blown down through the blow-off cock at the lowest point to get rid of the water, the manhole in the boiler top opened, the boiler cooled down enough to allow entry and then the plug removed. However, these plugs were scaled up and even removal from a cold boiler can be a problem.

So, even if a fusible plug existed, it was too big a job to take it out. Besides, there was no need, there was another plug that existed on all boilers which was easily accessible and once removed disabled the boiler.
The blow down valve.
I should think that every boiler ever made had a blow-down valve at its lowest point. It was used to empty the boiler for maintenance but even more importantly it was a useful way of getting sediment and scale out of the boiler when it had settled in the bottom during the night when the boiler was at rest. All boiler water contains solids which separate out in the course of what is in effect a distillation process inside the vessel. For this reason the cock was always easily accessible, either mounted on the front face of the boiler or on a swan neck connection from the front of the shell.

In the early days of boilers, all the valves were ‘plug cocks’. Even when improved valves became available, plug cocks were retained for blow down because of their simplicity and reliability until improved valves were available, c.1890 onwards.

Image

The illustration above is of a modern plug cock but shows the essential features. There is a body connected at each side to the pipework it controls. A perfectly fitted plug fills the hole in the body and has a hole, the same diameter as the pipework, drilled through it. When the plug is positioned so as this hole is in line with the pipes the liquid can flow. If the plug is turned 90 degrees using the square on top the hole in the plug has no connection with the pipework and the flow is stopped. In the older valves the plug was cone shaped so that it could be ground into the body from time to time to maintain a good seal. The only seal in this type of valve is the quality of the fit between the plug and the body. This means that every cock had its unique size and shape and the plugs were not interchangeable.
The Plug Drawers.
I think you may have realised where I am going with this argument. All the plug drawers had to do to stop the mill was draw the fires, open the blow down cock to empty the boiler and then when the flow had stopped and the steam abated, withdraw the plug from the cock.. This was quick and safe and I should say would take about twenty minutes to half an hour depending on the size and condition of the boiler. The boiler was then useless and if the plug was taken away by the mob it was quite a complicated task to machine a new plug and grind it to a mating fit with the body. It would be easier to simply fit a new cock.

So there you have my version of the origin of the name ‘plug drawer’. All I can say is that I am absolutely certain that this was the way boilers were disabled. This is based on many years of practical experience and research into the much neglected field of steam boilers.

Conclusions about the Plug Drawers.
The thing that interests me about my recent foray into the activities of the Plug Drawers is that I think we can draw some conclusions as to their aims and objectives.

From the evidence I have seen, the mobs of plug drawers relied on the intimidatory affect of a large body of people carrying clubs and other weapons, and stopping factories working by emptying the dams and disabling the boilers by drawing the plugs from the blow down cocks and possibly stealing them. [I favour stealing because, being made of gunmetal usually, they were readily weighed in for beer money.]

The crucial difference between these activities and the earlier Luddite attacks was that the plug drawers were not destructive, simply obstructive. I think this is important and gives some clues to their leader’s thinking.

These were very sophisticated attacks clearly designed by people with technical knowledge to make their point by temporary stoppage of works and not long term destruction. In this way they minimised the impact of loss of wages on the workers. I have read a contemporary account where the leader of the plug drawers persuaded his followers not to empty the mill dam at one factory because it would mean the works would be stopped for many days while it filled up again. He had evidently realised that the mill had a bad water supply and the possible consequences.

These were people whose aim was to shake the employers out of their lethargy without destroying their supporters livelihood. In effect a lightning strike that didn’t depend on organised labour. I am very wary of interpretations that describe these activities in terms of a nascent ‘general strike’. 1842 was a bad enough time for the workers without adding the burden of wholesale loss of work. Besides, I think we are dealing with intelligent and practical people here who knew they hadn’t got the organisation necessary to do this even if they decided it was a good course to pursue.

No, the Plug Drawers knew the perfect way to stop a steam mill with no danger and without causing any damage. If someone were to ask me now what was the safest way to disable a steam driven factory I would come up with the same technique, empty the boiler and drain the condensing pond. It was a brilliant strategy.

There was an example of pure Luddite behaviour Barnoldswick in 1895. In the LTP transcript 78/AB/05, page 1, Billy Brooks talked about Bradley Brothers of Monkroyd Shed at Butts Mill having warps slashed. This was a simple but very effective way of causing partial destruction in a weaving shed. Properly done, warp stabbing or slashing costs the manufacturer time and money but does not totally destroy the warp. I see this as a half way house between outright machine breaking and simple withdrawal of labour.

One last thought about the memory span. During the 1932 strikes in Barnoldswick brought about by low wages and the threats to future earnings from the introduction of the ‘More Looms System’, police were stationed in the engine houses of some mills to protect the plant and boilers. In the case of Long Ing Shed they slept there for almost two years. Some echo of the plug drawers still lingered in the corporate and governmental mind but in the event there was no trouble. Nobody attacked the steam engines or boilers. Things had changed, organisation of labour under the union system was seen to be sufficient, the workers had come of age.

SCG/10 December 2003
3,493 words.
Stanley Challenger Graham
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Re: BOILER INSURANCE, FUSIBLE PLUGS AND THE PLUG RIOTS OF 18

Post by Stanley » 12 Jul 2016, 05:56

bumped....
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Re: BOILER INSURANCE, FUSIBLE PLUGS AND THE PLUG RIOTS OF 18

Post by chinatyke » 13 Jul 2016, 00:15

Stanley wrote:BOILER INSURANCE, FUSIBLE PLUGS AND THE PLUG RIOTS OF 1842

I found little that I wasn’t aware of, I was reminded of the progression of unrest from the Luddites in 1912 through the Plug Riots in 1842 to full blooded Chartism in 1848.
3rd paragraph, shouldn't that be 1812? Only pointing it out so that you can correct it if necessary.

I agree with your conclusion that they were not drawing fusible plugs. If anyone wants to see what this would be like then try removing the weight from a pressure cooker when it is up to working pressure (15psi) and imagine what it would be like at 150 psi and 1000 times the size.

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Re: BOILER INSURANCE, FUSIBLE PLUGS AND THE PLUG RIOTS OF 18

Post by Stanley » 13 Jul 2016, 03:15

You are right of course, Thanks, I've changed it I think. I say that because I have an idea I have attempted to edit it before but failed.
{I think I've succeeded.....}
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