When Did Boiler Safety Get Serious?

[PenrithBeacon]

Stewart, I don't suppose that you happen to have any images of those Crown Exemption discs do you? I could do with one for my GPO Moggy van......

 

Andy G

The Post Office Museum might be able help.

 

Regards

[PatB]

It's interesting to note that Curly Lawrence tended to specify boiler pressures for his miniature locomotives that would make a modern public liability underwriter's hair stand on end .

[Bernard Lamb]

Going back to the question.

The earliest I know of is in the USA where the American Society of Mechanical Engineers introduced a boiler testing code in 1884.

This was followed by a Boiler and Pressure Vessel code in 1915 that was adopted into state and federal law in the next few years.

In the UK the earliest reference I have heard re boiler standards was by James Paxman in 1870 where he demonstrated the quality of his boiler construction. The inference being that there were no national standards at that time and he was showing an example of what he considered to be a safe and efficient boiler. ASME in the USA or Lloyds in the UK could probably provide a lot more information. I was authorised to examine welds and test welders, but never got onto testing the finished article, so only have a very general knowledge of the history.

Bernard

[Joseph_Pestell]

Using compressed air isn't much better than steam/water!  Less energy but still compressed. water can't be compressed, hence no energy storage.

 

NHS vehicles didn't have tax or insurance either.

Water can be compressed. Pressure into this building from the main is about 14 bar. Gave our plumber a few problems.

[jjb1970]

Water is pressurised, not compressed. Very different.

[Oldddudders]

I believe the terrifying power of a boiler explosion is well-told in this report.

 

http://www.drgw.net/info/ICC3489

[PenrithBeacon]

Water is pressurised, not compressed. Very different.

Not sure what the difference is, I'd be grateful for an explanation.

 

Why is water at the sea floor not compressed? It's certainly at a very much greater pressure.

 

Regards

[bertiedog]

It's interesting to note that Curly Lawrence tended to specify boiler pressures for his miniature locomotives that would make a modern public liability underwriter's hair stand on end .

Let's be fair to LBSC,(Curly Lawrence), his designs are safe if built to his specification, but methods have changed, and people began to complain about his methods when they had mixed in things like unthreaded stays. I note the comment comes from Australia, and the standards there are very stringent indeed, especially in connection with crown stays, and spacing of all rod stays, and even suggestions that copper boilers are unsafe.

 

Much comes from larger gauge work than common in the UK, and the standards here are pretty strict for smaller boilers anyway.

Several Australians approach the safety issue from the design end, whilst in the UK the designs tended to be conservative, and the testing was not to query the design, but to weed out the bad builders, wrong materials, and corner cutters.

 

The late Ken Harris despite commenting om some LBSC design, did say they were safe to build, passing his calculated safety margins quite easily.

 

All the main LBSC designs pass the margin testing, but can be improved. None are unsafe, unless corners are cut like using brass instead of bronze. Some of his fittings are now classed as bad practice, threading direct to copper sheet, but anybody building a boiler will usually be a club member and have these issues pointed out, and the up grades are easy to do.

 

One thing Curly did know was the pressure required to get his designs to work, but again later valve design etc., has increased efficiency, and comparison with his style of fairly limited running sessions and modern track use is difficult. We don't even have the same coal these days.

 

Stephen

[bertiedog]

Not sure what the difference is, I'd be grateful for an explanation.

 

Why is water at the sea floor not compressed? It's certainly at a very much greater pressure.

 

Regards

The volume of the water under compression barely alters, whereas the air will be compressed,( and store energy), with the increasing pressure. In theory a one pint boiler and a main line loco boiler, both filled with water could be tested on the same simple hand pump. Any leaks would be greater with the bigger boiler, but a burst would be no worse, but in practice a bigger boiler has an elastic structure as it is pressurised, so that energy is added to the expelled water, but it is usually safe! just a bigger rush of water escaping. This is not to say a fitting popping out would not be violent with only water.

it's the steam tests that begin to get exciting..............

Stephen.

[Arthur]

Compressed means squeezed into a smaller volume than something was originally, you can compress a gas. e.g. Calor gas bottles contain a volume of gas which would be considerably larger once out of the container, if one ruptures the gas expands massively.

 

Like a solid, you cannot squeeze a liquid into a smaller volume. You can apply pressure to it and it will 'hold' that pressure but you cannot, and do not, reduce its volume. That is how and why hydraulic systems work. You push a liquid from one cylinder to move another, the volume remains the same.

 

If a pressurised vessel bursts the liquid is forcibly ejected until pressures equalise but the volume of liquid remains constant.

 

Edit: post crossed with Stephens reply.

[Edge]

From what I recall, Boiler safety on steam engines became a source of concern after a massive explosion at Paddington station where a broad gauge engine's boiler exploded causing an awful lot of damage. From what I recall from the story there were not too many casualties, but the stationa dn surrounding area suffered tremendous damage and the general feeling in the air was that everyone was fortunate that it didnt happen at peak times.

[Nearholmer]

Bernard

 

See my post 19.

 

In a sense, the ASME were actually quite late to the game. There was the Manchester Society from 1854, a US insurer with a code and inspection/test regimes (Hartford, I think) from 1866, and there was GB boiler legislation from 1882. I have a vague idea that India had legislation very early too. Germany and France etc I haven't delved into.

 

I think that the major contribution of the ASME was to establish national practice in the US, whereas there had been a patchwork of state legislation and nothing before. The earliest states in the game were those along major rivers, I think, because paddle steamers kept going off pop.

 

But, the basic answer to the question posed is: "1854 among non-engineer users/owners; and, among competent engineers, a long time before that."

 

The 'watershed' among engineers was probably the time of the "strong steam" debate, prompted mainly by Trevithick. There was huge worry about the safety of high pressure boilers then, and safety valves started to be taken very seriously. Non-engineering users/owners took a very long time to catch-up, and weren't really whipped into line until either insurance premiums or legislation bit.

 

Railways are an interesting case, because many, although not all, had highly competent engineers on the staff, but a large number of the users, the drivers, didn't really get it, and tampered with safety valves, and because engineering practice wasn't always up to scratch away from the eye of the few highly competent engineers. But, blowing your passengers to kingdom come was bad for business, so Boards took the matter pretty seriously from quite early-on. The incidence of locomotive boiler explosions fell very steeply once the risk was understood.

 

Kevin

[AberdeenBill]

I believe the terrifying power of a boiler explosion is well-told in this report.

 

http://www.drgw.net/info/ICC3489

 

Indeed.   Was it normal practice for American boilers to not have fusible plugs?    No clear conclusion seems to be made in the report as to why the water level dropped to a dangerous level -- inattentive crew or faulty pump/ga(u)ge glasses?

 

Bill

[Happy Hippo]

Indeed.   Was it normal practice for American boilers to not have fusible plugs?    No clear conclusion seems to be made in the report as to why the water level dropped to a dangerous level -- inattentive crew or faulty pump/ga(u)ge glasses?

 

Bill

Another issue with many early boiler explosions was the loco crew increasing the boiler pressure by screwing down the safety valve(s) so the boiler was working at more than it's designed pressure.

 

Early safety valves would often be a just a weight hung on a beam which held a plug in place.

[Oldddudders]

The fusible plug does not indeed seem to have crossed the Atlantic. Barmy. 

[TheSignalEngineer]

I believe the terrifying power of a boiler explosion is well-told in this report.

 

http://www.drgw.net/info/ICC3489

'Twas a rather large boiler 

Sister loco 3705

http://www.drgw.net/gallery/v/DRGWSteamContainer/L105s/DRGW3705/drgw-3705-grandjunction_ut-_may-1941_-000.jpg.html

[PatB]

Let's be fair to LBSC,(Curly Lawrence), his designs are safe if built to his specification, but methods have changed, and people began to complain about his methods when they had mixed in things like unthreaded stays. I note the comment comes from Australia, and the standards there are very stringent indeed, especially in connection with crown stays, and spacing of all rod stays, and even suggestions that copper boilers are unsafe.

 

Much comes from larger gauge work than common in the UK, and the standards here are pretty strict for smaller boilers anyway.

Several Australians approach the safety issue from the design end, whilst in the UK the designs tended to be conservative, and the testing was not to query the design, but to weed out the bad builders, wrong materials, and corner cutters.

 

The late Ken Harris despite commenting om some LBSC design, did say they were safe to build, passing his calculated safety margins quite easily.

 

All the main LBSC designs pass the margin testing, but can be improved. None are unsafe, unless corners are cut like using brass instead of bronze. Some of his fittings are now classed as bad practice, threading direct to copper sheet, but anybody building a boiler will usually be a club member and have these issues pointed out, and the up grades are easy to do.

 

One thing Curly did know was the pressure required to get his designs to work, but again later valve design etc., has increased efficiency, and comparison with his style of fairly limited running sessions and modern track use is difficult. We don't even have the same coal these days.

 

Stephen

My comment was somewhat tongue in cheek and I fully agree that LBSC's boilers were and are safe designs. Were they not I'm sure we'd have heard something over the last 90 years.

 

Regarding my Australian perspective, over the 20 Yeats I've been here I've found Australians to be easily frightened and to have a liking for over restrictive regulation. I found myself working with some imported Germans a while ago and they couldn't believe how over regulated we were.

[Oldddudders]

'Twas a rather large boiler 

Sister loco 3705

http://www.drgw.net/gallery/v/DRGWSteamContainer/L105s/DRGW3705/drgw-3705-grandjunction_ut-_may-1941_-000.jpg.html

 

Indeed. I have pics of the remains in a book, but have failed to find an accessible pic online. 

[roythebus]

there was a boiler explosion in the USA fairly recently, a road traction engine's boiler exploded at a rally causing several deaths. ISTR there was also a loco boiler explosion in recent times caused by a fusible plug that had been welded in place!

[Arthur]

 

This is the US incident, 2001, 5 deaths and several injuries.

 

https://www.farmcollector.com/steam-engines/tragedy-at-medina-county-fairgrounds

 

It's an early report about the incident but mentions that a fusible plug had been welded up.

[jjb1970]

I believe the Lloyd's Register of Shipping rules first incorporated boiler rules in 1877. Class rules (such as LR, ABS, DNV etc) are a bit different from simple test and inspection requirements as they also provide design, materials & manufacture rules.

[jjb1970]

In todays world ASME requirements are basically a de-facto international standard for many applications.

[Siberian Snooper]

Just for the book the volume of steam is 1600 times greater than the equivalent volume of water and so creates a very big bang when something fails.

[laurenceb]

As some people may know, there's a book entitled 'Locomotive Boiler Explosions' (http://www.ebay.co.uk/itm/Locomotive-Boiler-Explosions-Hewison-Christian-H-New-Book-/121878039762 ), which covers the history of the topic, mostly from an engineering rather than a legal perspective.    There are various accident reports of boiler explosions on the Railways Archive website, where they seem to have been taken very seriously.  

 

Bill

This book is supposed to list all loco boiler explosions in Britain but misses out L M S 6399 Fury, witch makes one wonder what else is missed out

[Reorte]

Just for the book the volume of steam is 1600 times greater than the equivalent volume of water and so creates a very big bang when something fails.

An easy not too dangerous example - fill a balloon with water and another with air. If the balloons are identical they'll both burst at the same pressure, but the air-filled one will make a loud bang and send bits of rubber flying (you don't want to be inflating it by mouth when that happens!) and the water-filled one will just make a puddle.