Steam fittings and valves

GMcD

Well, our building owner is paying for the steam installation. The steam service is coming from a Campus Steam Plant. The Campus steam plant guys have their standards for their steam distribution system outside the buildings, but the standard for inside the building (low pressure side) is "to Code". Safeties are set at 85 psig on the low pressure side. My side of the work is the High pressure steam into the pressure reducing valve station and then into our mechanical room with 15 psig steam. The high pressure side is protected by 160 psig safety valves in the main steam tunnel. Our valves and fittings are specified to meet code and are 250 psig class rated for steam service , malleable iron and the brass/bronze valves. My real question is : are there any long term operational issues related to the use of the brass/bronze valves in the steam system in general. I'm not worried about the "code" issues as what's spec'd meets the Boiler & PV Code in terms of pressure ratings, and method of assembly, it's the desire for the steam plant folks to ask for higher standards of materials inside the building that is being paid for by somebody else. I'm willing to change to steel rising stem valves if there is a good practical reason for it. So, that's mainly what I'm fishing for- any practical installation issues with the brass/bronze valves, provided everything else meets Code?

GMcD

Steam fittings and valves material

Got a local steam plant rep telling us we "have" to use steel or stainless steel rising stem valves on the 85psig and 15 psig incoming steam we are using into a building for basic heating (to a hot water HEX, max. load = 1800 lbs/hr.). The standard spec we are using allows brass/bronze valves, threaded up to 2", no stipulation on rising stem. Any thoughts from the steamfitters out there as to how I may respond to this? I understand as a specifying engineer that the steel rising stem valves are a nice thing to have, but $$...What are the issues if we dig our heels in and stay with the brass/bronze valves for cost savings?

Tony Conner_2

What's...

... the setting for the safety valves on this system? It runs at 85#, but the safety valves might lift at 300#. Regardless, who spec's the requirements, and who's paying? It's not uncommon for a higher grade than the code calls for, to be specified. Beyond that, whoever is making any arguements one way or another on this, really should referring to the latest copy of the applicable code - probably the B31.1 Power Piping Code, and remember that that's normally considered the MINIMUM standard.

Tony Conner_2

In Some...

...operations, the plant people don't like to see yellow metal components in condensate service for water treatment/chemical reasons. Other than that, as along as they have the pressure/temperature rating and otherwise meet code, then it's not illegal, as far as I can see. However, there are some sections of the ASME B31.1 Power Piping Code, when referring to specific services and/or conditions that state "...shall be steel", but that's normally for things like boiler blowdown lines. There are also lots of jurisdictional spins on codes. If this situation really means a lot to you, then I think you'll have to refer to the code, and talk to the local inspector for the interpretation that is used in your location and application. "ASME" - Always - Sometimes - Maybe - Except.

GMcD

Thanks Tony

Well, we'll see how it pans out. The Campus heating plant guys have the power to turn off the steam valve if they want, so I guess they will push harder than I can. Poor consultant gets in in the end anyway, both the building owner and the steam plant guys just glare at the consultant and say "you should have known...."

The fundamental issue is that the steam plant guys' published "Technical Guidelines" don't cover this, and in spite of our plans and specs being sent to them for review a year ago, no comments were received until the Steam Plant folks came out to check the Contractor's installation to prepare to turn the steam on. Yeah, I "should've known"...

Tony Conner_2

Have...

...you done other work of this kind for these people? If you knew (or should have known) the drill, then the problem could possibly be at least partially yours. However, if you haven't done work for these people before (and therefore couldn't have known about any "special" requirements), AND reviewed their written "Technical Guidelines", AND sent them your plans & specifications (a year in advance), AND there's no code violations, AND the installation functions as the end-user requested, then I'd say that the problem is someone else's - not yours.

GMcD

Previous Work

Worked for them before? Yes, but it was 8 years ago, when the Steam Utilities guys installed the incoming steam service by themselves to the Campus Buildings. Now we have a scenario where they are downloading the design and installations to different outside consultants and Contractors to do the design and B&PV Act Registrations. Our building had 3 different consultants involved to get the steam just to the blind flanges inside the building for our inside Contractor to connect onto. Plus, revisions to Technical Standards have occurred over the last few years to the point where conflicting information abounds. What appears to be enforced is an "outside distribution services standard" for an "inside the building" application.

At least it's not just me, our Contractor tells me he is doing two other buildings on the same overall site and is getting three different directions, all from the same Utilities office....

Tony Conner

This Sounds Like...

... an internal turf war. The Utilities guys are having their patch being dealt-off to outsiders. This will be a real mess - both technically and politically. To me, the bottom line is if they have no clear standards, then the mess is theirs to deal with. They probably won't like hearing that, though. Is there any way that YOU can generate some business for yourself AND help them out by offering to assist in developing some updated technical standards?

seabee570

I thought somewhere in the power boiler code

may years as an operator of high pressure steam plants,On many state exams it was stressed that valves over 2 inches must be rising stem....this is for quick identification in an emergency situation,...I would say that the plant utilities guys are correct,they want rising stem so they can identify position of the valve quickly...not any other reason

Tony Conner

Lots Of...

...local spins on this stuff. For most jurisdictions, there's a boiler & pressure vessel code, a separate code identifying what, if any, qualifications for stationary/operating engineers may be required, and a another code again for piping. There are a number of ASME piping codes, covering a range of plants, installations, and services. The one that deals specifically with district heating installations (among other things) like this one is the ASME B31.1 Power Piping Code.

Unless the campus powerhouse guys can actually POINT to a code requirement, or POINT to their documented internal technical specifications (and it appears that the in-house documentation has been badly re-worded over time, and contradicts itself on several points), I don't think that they have much to argue with. Non-rising stem valves are a perfect example. I don't like them either, but if there's no code clause, or internal specification document that prohibits them, there's not much you can do.

This situation is pretty common, anymore. A LOT of what used to be well run companies and organizations have downsized themselves into a position where there's no continuity anymore. And many will never get it back, since everyone who knew anything about how things are supposed to be, is gone. I think the overall situation will get worse, before it can get better, and that sucks.

seabee570

code

here is the section for valves,it also goes on to say that if working pressure is below 200psig,then bronze valve material is ok,above 200psig,must be steel...so they want the rising stem valves so they can be identified quickly,no other reason





CR-ASME/ANSI
PAGE 1 0L0
POWER BOILERS ASME SECT. I & POWER PIPING ANSI/ASME B 31.1
CODE REQUIREMENTS FOR PIPING, FITTINGS, VALVES & TRIM
I. GENERAL STEAM LINE PIPING AND VALVES
3. Steam Stop valves must be of the rising stem style or, if not, be equipped with a position indicator to
indicate from a distance whether the valve is open or closed. Quarter turn valves shall be equipped
with a slow-opening mechanism. Valves with resilient (non-metallic) seats shall not be used over 150
PSIG (B31.1 Para. 122.1.7).

GMcD

Thanks for the responses.

As the building side systems designer, all I really want to be comfortable with is the long term use of the bronze valves on the building side of the steam system. The max system pressure on the district steam supply side is 85psig, with the pressure reduced into the building to max 15 psig. The low pressure building side has a pressure relief valve set at 85 psig, so if the pressure reducing valve station fails, we don't see more than the main distribution line pressure on the LP building side. The piping system (valves, fittings etc.) is all spec'd at 150 psi rating.

My reading of the B31.1 and B31.9 Codes indicate that the valve material and specific handle/stem type is not specifically regulated on the system I'm dealing with. I have no problem putting in the steel OS&Y valves, but it means a delay to the project (Construction Manager would love that), and additional costs that the Building Owner is whining about. I get to play ham in the sandwich. If I can make the case to leave the bronze valves, then I have a happier Construction Manager and the whining from the Owner dies down a bit.

Tony Conner

Codes

It's great that you can refer to the codes. (It really is, I'm not being sarcastic.) I don't have mine here with me, so I'd just ask you to check to see if you're looking at the "Boiler External Piping" section. That section has more stringent requirements, and is for boiler feedwater, blowdown/blowoff and steam leads from the boiler to the header.

GMcD

Boiler

The main steam plant is about a 1/2 mile away, so I don't believe I have to worry about the "near boiler" piping standards. The section I am connecting to is part of the distribution system.

Tony Conner

Code Stuff

I realize that you're some distance from the main plant, so if (and they may or may not be, I don't have all of this stuff committed to memory) the sections being quoted are for the boiler external piping parts of B31.1, then the less stringent requirements likely apply to you. This stuff can be tricky to understand, and, as always, the inspection authority's interpretation is the one that will count. I'm in Ontario, and the inspection authority doesn't use the building services piping code. They look to the power piping code to cover installations like yours. The other two they look to are the refrigeration piping code, and the process piping code. And depending upon the plant, the process piping code can be used for all kinds of piping, including steam & refrigeration. Where you are may very well be different again. "ASME Codeland" is a tricky bit of real estate to be working in.