Pressure de-rate of pipe fittings, Temperature

[dkelly@rmce.com]

HI all,
My boiler recently passed 300 PSI hydro test with all openings plugged with bronze fittings. I need to add a 1" union, 3/8" street els, and numerous small valves. ASME tables show quite a de-rate for 150 pound fittings based on the temperature of 150 PSI steam. What fitting specification should be used for adding a union and a street el on this boiler? All piping projected thru the bo9ler is schedule 80. Boiler diameter is 12" SA106, with 285 grade C 3/8" flat sheets, and 5/8" A36 stays. I want to do this right the first time, the scrap bin is full! Are the model valves available from the various suppliers ok to use with this pressure?
Dave

[Bill Shields]

1" and 3/8" piping does not fit in the range of what "model" suppliers generally provide. Hence I am not totally sure about how to reply to your query.

Can you define "small" valves?

Is this a code power boiler?

[pat1027]

Use fittings from a known manufacturer like ASC/Anvil or Ward (not the China-Big Box types). Their documentation has pressure and temperature ratings.

For example follow these links.

https://www.asc-es.com/resources-and-do ... nabled%3A1

https://www.asc-es.com/resource/1103%20 ... 0Submittal

[Glenn Brooks]

Any DIY brass or black iron pipe hardware store variety water pipe fittings will do just fine for 3/8 to 1 inch unions, Valves and fittings at 150 psi. (Actually 1/8” NPT to
1” is fine)

Just make sure you buy WOG (water oil and gas) fittings, not air rated stuff (pneumatic).

really the only area of concern is with check valves. Some are rated at 150.Others at 250. Still others at 400. You just want to make sure that your valve is rated for the fluid and the pressure that it controls. PSI and flow direction will be stamped on the body of the valve.

[dkelly@rmce.com]

Thanks everyone, for the fast response. This is a loco boiler, not a power boiler. I want to use 150 PSI steam to avoid a possible water fountain out of the stack. Here in Colorado, the limit for hobby boilers is 100 PSI, so I wanted to build to a boiler code that accepts 150 PSI on model boilers. ie. Washington State. The small globe, three way, safety, and check valves, seeing boiler pressure, will not exceed 5/16" thread size. Mostly turret mounted, except the safety and check valves. Valves for the water glass will be 1/4", remote from the turret.

[Bill Shields]

Thanks for the clarification.

So you are never going to run in Colorado, or you are going to reset the safety valves to run in Colorado?

[dkelly@rmce.com]

Bill,

I'm up in the air on resetting the safeties. I've contacted two clubs for their input about having Colorado raise the pressure limit but so far no response. Anecdotally, I've heard a lot of locos are running above 100 PSI but do not know if that is true. If people want to raise the pressure limit, I would be available to work with the AHJ to see if this is possible. Let sleeping dogs lie and stay under the radar seems to be the attitude.

I'm on the ASTM F24 committee regarding amusement rides which has a subgroup, F24-60, which covers locomotives, track, rolling stock and operating standards for trainsets open to the public from 12" gauge on up. There has been some talk about including smaller gauges, but I do not know where that is heading. PM me if you want details on F24.
Dave

[Bill Shields]

since i am not running in CO, I am not particularly interested in the trail of the discussion....but it does tell me that it is a known item of question (and maybe of record?)

I was just hinting that if CO has a 100 psi limit for model boilers, if you are running at 150 and you do manage to get a club to issue an inspection certificate and run in that state -> then there is always the possibility that if something happens and you are technically 'outside of the definition' for CO and to put it bluntly 'your butt could be hanging in the breeze'.

it is amazing what people looking for a quick $$$ will try to dig up.

All you need is for someone in CO to get burned by something - a lifting safety or even cylinder drain cocks -> nothing to do with a boiler accident -> and the ball starts rolling because the injuree's medical insurance company is looking for someone else to pay the $$ and the shop it out to an investigation group that is working on a commission.

yes...everyone has heard me bring up this point in the past, but I have been dealing with large scale industrial boilers for decades, and rules are rules and once you get into the area of what a state may call a power boiler....even if it is because of the pressure setting of the safety valve(s)... even if the setting of the valves had NOTHING TO DO WITH THE INJURY -> they now have something into which they can sink their teeth -> which can be scary and expensive.

[makinsmoke]

Schedule 80 is equivalent to XH I thought. XH is 300#, and is not 150# service.

And valve and pipe fittings can be rated for WOG, water, oil, and gas, as well as WOGS, water, oil, gas, and steam.
I’ve seen plenty with that cast into them.

I would not buy a valve for a throttle that was not rated WOGS.

Bill, you are the subject matter expert here for full-size boilers. Am I wrong?

Just my two cents, for what that’s worth.

[dkellldog]

Bill,

It will be a 100 PSI in Colorado until the authorities allow for a change. Thank you for the input. Incidentally, I've met the quick buck scammers and have lost in court!

[Bill Shields]

no, not an expert (talk to Marty Knox for that).

I grew up helping my dad inspect boilers and repaired and tested full-size boilers and other pressure vessels for the first 1/2 of my working career.

I am just cautious and do not want any club or individual to inadvertently err in an area that COULD POTENTIALLY CAUSE a legal and $$$ problem for anyone involved in the hobby.

with the way the legal system can be these days, it is better if you are CLEARLY WITHIN the limits of the law in the state where you are operating -> since it tends to help influence the ambulance chasers 'go look elsewhere for the quick $$$'.

"i did not know" can be a very expensive expression these days.

13 years ago, while helping a friend move his boat to a loading ramp -> I took a fall on the dock, and ended up in the emergency room - totally my fault being a dumb-a**. no other way to explain it.

my insurance company turned the claim over to an 'ambulance chasing' group who hounded me for weeks to find out who the boat belonged to so that they could file a lawsuit against them in an attempt to recover the medical $$$.

I flatly refused to give them the name of the boat / owner.

next they wanted to know 'who owned the dock where you fell'. The inference is obvious.

They finally gave up when I informed them that the dock is owned by the State of Delaware and suggested that they call the department of natural resources to pursue their Don Quixote quest.

I never would have thought that such would occur...but then I am a Mechanical Engineer by profession -> what do I know?

[FKreider]

Let sleeping dogs lie and stay under the radar seems to be the attitude.

Yes you will find that is the general attitude in the hobby and for good fairly good reason. It sounds like you have plenty of experience with AHJ's and dealing with them as part of our hobby is something most of us would like to avoid.

That said if you are simply worried about a wet exhaust there are plenty of ways to manage this other than running at a slightly higher steam pressure, proper firing techniques (don't overfill the boiler, etc) will go a long way.