steam pipe fittings

Jim_64

isn't my point. durability is.
and, "that "cast", "cast iron" and "malleable" should be not be terms used causually. We can get away with it because we are typically dealing with low pressure steam, but they are different materials." is exactly what i'm saying. and i guess we'll agree to disagree. but, look at the specs from ward. and they use 'cast iron' as their descriptor. and of course everyone knows that they're not intending the semantics of ci dwv

cast 90 - http://www.wardmfg.com/PartDescription.aspx?PT=F&MN=2D.BCL

mall 90 - http://www.wardmfg.com/PartDescription.aspx?PT=F&MN=2D.BML

cast = heavier mall = lighter

and it's the same idea behind using sch 80 for steam, and cast condensate receivers

Frank Como

Steam fittings

We are up-grading and extending our existing steam system. ( Residential ) We have gotten several quotes stating that they will be using malleable fittings. We ( I being in the construction industry ) thought that cast / cast iron fittings were to be used ( class ? ) for steam piping. What is the proper material & class that should be used for steam piping. Thank you for your time.

bob young

steam fittings vs. black mal.

I am not 100 % sure but i believe the nyc code now insists on cast iron steam fittings for steam boilers inspections. maybe one of the other lic. plumbers on this forum knows the complete exact ruling. better safe than sorry . sometimes steam fittings are not available in every configuration & rather than mix & match , mallable was an alternate choice. that could be a possible problem now.

BAB

Malleable

Malleable is a term of art, that in the language of the piping industry, plumbing trade, refers to cast fittings to be used with steam. Go to the plumbing supply counter and ask for a 2" 90 degree el for steam and any counter man will give you malleable. Malleable used to refer to only metals that were hammered into shape. That may confuse the layman but not your pipe fitter. Malleable cast iron is the correct term for steam fittings.

"Cast" and "Cast Iron" is the older general term or specification. The cast fittings were and are more brittle than the newer cast products. Smash an old cast fitting with a big sludge hammer & you will see how brittle cast is.

Some terms die hard. People still refer to wide flange beams as "I beams". I beams are hardly made anymore, most beams are wide flange. PVDC used to be high temperature PVC, they now call it CPVC. Cast fittings are ok but the correct steam fitting is malleable cast iron. BAB

bob young

nyc terminology

maybe in some localities but not nyc. steam fittings are cast iron ...period. steel black or galvanized malleable are mainly used for gas & water. no disrespect intended but different parts of the usa have diferent methods for everything. just the way it is.

Jim_64

bab

unless things have made a drastic and sudden change, ci and mallable are not the same fittings, no matter what the supply house says or stocks.
"All Steel Steam Piping - No Copper: When exposed to heat copper expands 45% more than steel pipe. That puts tremendous strain on soldered joints that were never intended for the stresses of steam heat and simply will not last as long as steel pipe with cast iron fittings. In addition, copper piping and cast iron boilers are dissimilar metals and will suffer electrolysis where the two different metals connect. That is why we use only steel pipe and cast iron fittings on the supply and return piping in a steam system."

BAB

In picked a Con Ed spec (NYC) please note that ..."cast iron is not permitted" ...

4.08. All steam stop valves from the POE up to and including the “House” valve(s) shall be ASME/ANSI B16.34 Class 300, cast or forged steel; cast iron is NOT permitted.

A lot of us have been using the term "cast" for years & not really understanding that there has been a change in the old casting industry.

BAB

cast vs malleable

I never said that cast & malleable were the same. I was actually drawing attention to the fact that they are different terms & specifically different materials.

Also I never mentioned copper at all, I do not know how the copper was intejected at all. Copper does not belong in steam piping.

bob young

con ed

that is a hi-pressure spec [ 102 # ] we are discussing low pressure steam ...one or two pounds. two different worlds. con ed has zero authority on house steam piping

BAB

You comment on the high pressure steam spec is right on, agreed. But I gave the spec to show that "cast" is a vague term, and can be a dangerous term if used too loosely.

Jim_64

copper had nothing

to do with anything. it was just in the quote

but, do you see what you said?
"Malleable is a term of art, that in the language of the piping industry, plumbing trade, refers to cast fittings to be used with steam"
that's simply incorrect. malleable isn't a synonym for cast bec it'll be used with steam

BAB

Mike, I do not disagree with you at all. If I mis spoke I stand corrected. I do want to stress however, that "cast", "cast iron" and "malleable" should be not be terms used causually. We can get away with it because we are typically dealing with low pressure steam, but they are different materials. Getting back to the original question of this thread, I say the industry is going malleable in the specifications. You say it is still cast iron. For low presures I think that we can agree to disagree and it will not hurt anyone.

carter_3

bob is right in this neck of the woods (nyc) a steam fitting is strickly cast iron have not heard about the code change yet(guess your talking july's) but there always something new,we dont typically call it mallable just " a black el" and mallable is understood .still use steel welding fitting so do not know how the cast only code will hold up?yes you will come across a "cast mallable" known here as forged steel -good chance some of your biggest suppliers would never write it up as cast mallable con ed we never call it cast and you can feel and see the difference between the two without having to ask. no arguemnet here call it whatever you want .can you use black fittings on a boiler sure whatever tickles your fancy check the bigger well knowns here all black fittings with a 3 " dropped header are they wrong ?

Supply House Rick

Traditionally...

For low pressure residential steam heat, cast iron fittings were traditionally used (e.g. ASME/ANSI B16.4 Class 125 Gray Cast Iron Threaded Fittings), though malleable iron fittings (e.g. ASME/ANSI B16.3 Class 150 Malleable Iron Threaded Fittings) are also used now, and, these days, may be more readily available than cast iron.

On the other hand, malleable iron, not cast, is used for fuel gas piping; high pressure steam is a whole 'nother story

The cast fittings are more brittle, so may be cracked to permit easier disassembly, have heavier/wider wrenching surfaces -- so visually look a little different (more traditional for steam heat), and weigh a bit more.

The cast iron is more brittle due to the graphite (carbon) content being in the form of flat flakes vs. malleable iron where heat treating causes the graphite to form spheres instead.

BTW: Nodular or ductile iron (such as may be used for large water mains and other large castings) also have spherical (or nodular) graphite structures too.

BAB

Malleable cast iron

I think a lot of people walk out the supply shop thinking they are holding "cast iron" fittings when they are actually holding "malleable cast iron", ... and have for years. Scrook explained it better. Look at the cast iron foundry spec sheets, they all show "malleable cast iron", sure there is some "cast iron" around, but it is dying off.

scrook_2

malleable...

fittings are also made by casting, however they are subsequently heat treated so "cast malleable iron..." while technically correct, is potentially confusing.

Side by side the differance will be obvious, also if they're class 125 they're C.I. but if they're class 150 they are malleable iron.

In theory at least both are available in black (plain) or galvanized.

Note also, the following *raw* materials standards:

ASTM A126 for Gray Iron Castings

ASTM A153 for Zinc Coating (Hot Dip)

ASTM A197 for Malleable Iron

In practice either C.I or M.I. should be fine, though the traditionalist in me votes C.I. all the way!

bob young

official ruling from boiler div. nyc bldg. dept.

black steel malleable fittings ok up to 350,000 btu & five family residential. commercial; & larger to be reviewed by chief inspector. official ruling from boiler div. nyc

Charlie from wmass

It is getting to be like looking for blue steam around here asking for cast iron threaded fittings for steam. 2 out of 6 supply houses have no, none, nada for cast iron for steam. only the malleable we use for gas piping. They say the only reason to use cast iron is if you do not own a sawzall and need to alter the piping. I say B******* no own wants to do it right and they can not carry the extra few ounces of weight on a fitting. I also am well aware of the difference in threaded cast iron fittings for steam and Hub and spigot cast iron fittings. I have seen an old green house that had hub and spigot for the steam piping but that is another story. It calls for a road trip and the digital camera.

BAB

Frank's Question

Getting back to Frank's original question on this thread, "...We have gotten several quotes stating that they will be using malleable fittings....". Frank is asking if "cast" or "cast iron" is correct & his bidders are wrong by using the term "malleable". I say his bidders are ok because they mean "malleable cast iron". Frank can double check with each of the bidders. They should use schedule 40 steel pipe, schedule 40 steel nipples, malleable cast iron fittings or malleable black (cast)iron fittings.

Frank the following is not for your ears:

If the pipe fitters are over 40 years old and they insist on using only cast iron fittings they can do so for the following reasons:

They typically make many piping mistakes & breaking fittings makes rework easier (cast iron is brittle).

Looking ahead into the future a good steam job should be changed or updated (say every 30-40 years). They are thinking ahead and breaking fittings makes rework easier (cast iron is brittle).

Cast iron has a lighter gray older familiar look to it whereas malleable cast iron has a graphite, darker, thicker, bulky look, ... it just looks clunky.

Cast iron usually refers to grey cast iron. The color of a fractured surface can be used to identify an alloy. Grey cast iron is named after its grey fractured surface, which occurs because the graphitic flakes deflect a passing crack and initiate countless new cracks as the material breaks.

For steam cast iron is rated to 125 psig whereas malleable cast iron is rated to 150 psig, ... the job is low pressure so who needs or cares about the higher pressure rating.

Supply houses always have malleable cast iron but insisting on cast iron, especially on larger fittings, can get tough.

Some engineering prints & specs can specifically state that they do not want or allow "cast iron" on their steam project.

Malleable cast iron is typically cheaper than cast iron. Let us repeat that for emphasis, ... Malleable cast iron is typically cheaper than cast iron. Makes it tough on extras or time & material jobs.

Before you reply to this, I am only commenting on a trend in the piping/foundry/suppy house industries that, like it or not, is going on. One should be aware & be careful on what you buy, spec or demand. I am not an inspector that you have to worry about, I can not dictate your usage nor do my views really amount to a tinkers damn ... but the terms can cause confusion.

[Deleted User]

C.I. vs. B.M

BAB, you're all wet. (Pun intended)

Cast iron is cast iron. There is no "vagueness." Ace Hardware may not know the difference or HD, but any supply house north of the Mason-Dixon line stocks both, or doesn't sell boilers, steam or hot water.

The cost for C.I. fittings is slightly cheaper in many areas, especially if over 2"- than B.M.

[Deleted User]

What you got over the phone and what the written code is are at odds with each other.

Any NYC official that quotes code over the phone is problematic. Being referred to a written code is how it must be done.

Any questions? Call Bob Daly, Chief of boiler enforcement NYC. He won't quote anything. But he'll send you a copy of the written code. If you ask nicely.

[Deleted User]

Charlie, what did you expect?

Wholesalers are whores. If they have low profit margins on something, it's heavy to lug around, they have to tie up lots of shelving and get few "turns," they think you'll settle for something less, they BS you into believing it is an equal - you and I will buy it!

Same thing with boilers. You ask for brand 'A', they say 'B' is as good, we buy it.

Business 101. Does that make it true?

Hell no!

Charlie from wmass

Mike I have no illusions as to where their loyalty lies. I Have been dealing with wholesalers since before I could drive to get to them. I am above the mason dixon line and only 2 wholesaler houses stock cast iron threaded fittings. out of 6 houses in the 40 miles around our shop. ANd they all sell boilers.

Jim_64

ah yes, don't trust anyone over 40

what a tired, old philosophy
If the pipe fitters are over 40 years old and they insist on using only cast iron fittings they can do so for the following reasons:
They typically make many piping mistakes & breaking fittings makes rework easier (cast iron is brittle).

pure bs. i work with them, and it's the 'youngsters' that make the mistakes

Charlie from wmass

I am also under 40 and I learned real quick what a rule is for and how to read it. Ever had to duck from a flying 2 inch nipple? and know that was your ride home and the person sitting across the potatoes from you who tossed it. The Malleable fittings the try and sell us are malleable not the high pressure fittings. I am in a land of non-pipe fitters who think running 3/4" copper to a three foot section of compak base board and adding a vent on the end is how to heat a bathroom on one pipe steam. I have a customer that a bean can over a bad vacuum breaker on a two pipe steam was the answer for 4 years until the can rusted through.right is not a word used much around here.