US State Boiler Code

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Rocket Man

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I live in Murfreesboro TN. There is a business in town called, Boiler Supply Co. they, service, sell, repair boilers. I talked to Dave the owner he gave me a copy of TN State Law. I can build my own boiler if it is smaller than 5 gallons. It does not have to be, inspected, tested, licensed, or anything. I built a 4.9 gallon boiler for my 4"x4" steam engine it ran the engine good.
 
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Awesome, you know what you are doing. Have you looked into the ASME Boiler and Pressure Vessel Code for additional reference? Just a thought.
Kind regards, Al
 

kaolsen1728

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I have uploaded all of the boiler info for the State of Washington on our Kitsap Live Steamer's website at this link: https://kls.clubexpress.com/content.aspx?page_id=22&club_id=96970&module_id=148906
Our state is also more relaxed on hobby boilers than it used to be, but all boilers must be certified, but once this has been done to their satisfaction, they no longer require the annual inspection as in the past.

However, be careful if you are in the market for a live steam locomotive. I have helped others in the state learn how to do the calculations and prepare the documents for boiler inspections, but I have found three hobby boilers that were a disaster! A 1 1/2 gauge pacific with crown sheet stays that had deteriorated so badly that they no longer connected to each other, another 1 1/2" pacific that the boiler was built with no stays, and a third that had girder stays that were not large enough to support the crown sheet and when we cut into this boiler, the welds were not full penetration.

So just because because our hobby boilers are truly "overbuilt" for the allowable working pressure they were designed for, if they are not properly taken care of, they can become a potential problem.

Ken Olsen
 
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A boiler, incorrectly built and maintained, is a ticking bomb. I worked 38 years on oil platforms in the Gulf of Mexico. Boilers and pressure vessels were my livelihood. Our pressure vessels had to undergo periodic non-destructive testing to monitor the wall thickness of the vessel's shell. Boilers have to be removed from service and sent ashore for complete inspection and evaluation by a certified facility. Ken, I agree that you can't stress enough the potential dangers that boilers can pose.
Kind regards, Al
 

wazrus

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As Dan Rowe said, it appears that Australia is the only country which has a miniature boiler safety code. As a model builder, I have built three boilers using the AMBSC (Australian miniature Boiler Safety Committee) code for copper boilers and as Dan's thread suggested, the codes are available through the magazine Australian Model Engineering. The codes are well researched and documented and I do use them as a construction manual. Without looking at them, I think their scope covered boilers up to 12" diameter and I think that was in steel. I think the copper maximum was about 7". I'm a little surprised to see that no Australians have joined the discussion???
Wazrus
 

Brian Hutchings

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The UK also has its own codes for miniature boilers.
The Boiler Test Code 2018VOLUME 1-Boilers 3 bar litres to 1100 bar litres
The Boiler Test Code 2018VOLUME 2 -Boilers under 3 bar litres
Brian
 

TimTaylor

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I'm retired now, but worked with boilers and steam power systems my entire career - everything from low pressure to super-critical utility boilers.

Any boiler failure can be extremely dangerous - even a small hobby boiler. In the absence of any other mandated safety regulations, there are several things that are a must for a hobby boiler.
1. It should be periodically hydrostatic tested to 1.5 times the maximum operating pressure
2. It should have a tested relief valve
3. There needs to be a means to quickly remove the heat source

Something that most hobby boiler operators rarely take into account is boiler water chemistry. As steam is generated, the dissolved solids in the water (typically calcium & sodium) get left behind, and if allowed to concentrate can form scaling that can promote corrosion and lead to potential failure over time. These deposits also reduce the heat transfer and thermal efficiency of the boiler. Commercial and industrial boilers use a combination of water treatment to inhibit scaling & corrosion, and blowdown to limit the cycles of concentration. For a small hobby boiler, the easiest solution is to flush the boiler with clean water after each use.

Just my $0.02.........
 

kaolsen1728

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The US ASME boiler code does recognize what they refer to as "Miniature Boilers" under "Part PMB, Requirements for miniature boilers".
PMB-2 under Scope notes the following:
PMB-2.1 The classification miniature boilers applies
to boilers that do not exceed the following limits:
(a) 16 in. (400 mm) inside diameter of shell
(b) 20 ft2 (1.9 m2
) heating surface (not applicable to
electric boilers)
(c) 5 ft' (0.14 m3
) gross volume,' exclusive of casing
and insulation
(d) 100 psig (700 kPa) maximum allowable working
pressure
PMB-2.2 If a boiler meets the miniature classification,
the rules in this Part shall supplement the rules for power
boilers and take precedence over them when there is conflict.
Where any of the limits in PMB-2.1 are exceeded,
the rules for power boilers shall apply.

However, each state can modify the code. For example note that the ASME code limits for ASME miniature boilers to 100 psi, the State of Washington has set the limit at 150 psi. However, the boiler calculations must show that the weakest component will withstand this pressure. Otherwise, the weakest component will prevail. The exception is that copper boilers are limited to 100 psi.
Ken
 

radial1951

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....The codes are well researched and documented and I do use them as a construction manual. Without looking at them, I think their scope covered boilers up to 12" diameter and I think that was in steel. I think the copper maximum was about 7". I'm a little surprised to see that no Australians have joined the discussion???
Wazrus
*
Ok Wazrus, I'll take the bait! If you are near Sydney, are you a member of a local club? Anyway, as you know, our boiler codes are well researched and documented. They are also used in many parts of the world where live steam builders don't have a suitable local code.

The AMBSC boiler codes are in 4 parts. They are recognised by authorities in all Australian States.

Part 1 Copper boilers 50-203mm dia and 1-25 litres, 100psi, 68pages
Part 2 Steel Boilers (Certified Mild Steel) to 356mm dia and 50 litres, 100psi incl full loco and Briggs types, 66 pages.
Part 3 Sub-Miniature Copper Boilers to 50mm dia and 1 litre, 35psi
Part 4 Duplex Steel Boilers 325mm dia and 50 litres, 100psi, 44 pages

The codes are fully detailed with drawings, charts, plate thickness, flange depth, weld preps, stay dia and spacing, bushes, safety valve design etc etc. No trouble to design and build a complying (safe) boiler or air receiver using these codes, they are very comprehensive.

See Australian Model Engineering Magazine www.ameng.com.au and go to the Shop.
 
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SirJohn

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Alberta, Canada code does not require a boiler to be registered if it is <152mm I.D. and <42.5 litres volume, maximum working pressure <1725kPa which translates to approximately 6" I.D. x 23" long and 250 psi.
Using copper pipe and the maximum pressure is 100 psi.
 

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