Tables for pipe support spacing 12

[Tankman650]

Are there published tables for the maximum unsupported run of pipe per given pipe size??? I can calculate the maximun stress values but was wondering if there are standard tables for support apacing based on stress and deflection.

 

[ChasBean1]

1996 International Mechanical Code, Table 305.4 - "Piping Support Spacing."

Also, "Pipe Hangers and Supports - Selection and Application" by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc., MSS SP-69-2002. Table 3 - "Maximum Horizontal Pipe Hanger and Support Spacing."

Neither are available without forking out cash. Since you are a valued guest of this forum, I'd be happy to email you pdf forms of these tables. I can't copy the whole publication for copyright issues, etc., but I don't see a problem with providing just the table info. (hopefully these folks don't either).

-CB

 

[LSThill]

Hi Tankman650 (Structural), cceballos (Mechanical)

ASME B31.1-2001:

TABLE 121.5 SUGGESTED PIPE SUPPORT SPACING
Page 46. Suggested Manimum Span for Water Services and Steam, GAs or Air Service.

Need to read the General Notes on page 46

 

[StressGuy]

You're going to want to be careful with a 30" line, particularly if it is liquid full. Most of these span tables are based on bending stress and deflection. When you gets to pipes that large, local/horn stresses at the support location become a bigger concern that need to be address by the support design (typically a saddle). A common reference in this area is the work of L.P. Zick on the design of support saddles for horizontal vessels. I'm sure others here can suggest more references.

I haven't looked at Isthill's reference since I've not really worked with Power Piping, but I would imagine it probably makes some note of these issues. Edward L. Klein
Pipe Stress Engineer
Houston, Texas

All opinions expressed here are my own and not my company's.

 

[LSThill]

Tankman650 (Structural)

The Piping Engineer will have the SUGGESTED PIPE SUPPORT SPACING in the Piping and Piping Stress Specification.

With the SUGGESTED PIPE SUPPORT SPACING spread sheet calculation for Wt. dead load.

 

[1969grad]

I have calculated the pipe stresses for the given spans in the MSS publication and found that the stresses are usually less than the allowables found in either B31.3 or B31.8. So the problem then becomes how much deflection is acceptable.

I might add that I do not think that the MSS publication includes 30" pipe but I could be wrong as it has been some time since I looked at it.

Does anyone have any deflection guidelines for services other than steam?

 

[DLANDISSR]

Tankman650:
ITT- Grinnell publication "Pipng Design and Engineering" have a table of suggested pipe hanger spacing of Carbon Steel pipe filled with water based on a bending and shear stess not exceeding 1500psi and a deflection between hangers not to exceed .1". as follows:

Nom. Size Span
1 7
1.5 9
2 10
2.5 11
3 12
3.5 13
4 14
5 16
6 17
8 19
10 22
12 23
14 25
16 27
18 28
20 30
24 32
26, 28 33
30, 32 34
34, 36 35
42 36
I have found this to be a good basic guide. These spans are for straight pipe only. Bends, valves and other added loadas will effect the span. If there is any question as to the span a stress analysis should be done.
CaesarII is an excellend stress program which is user friendly and easy to use. A 50 run version can be purchased for about $700. Look on the web.

 

[StressGuy]

Be aware also that the B31.1 table is fairly conservative, particularly for smaller lines. For B31.3 refinery piping, most engineering companies that I know of allow down to 2" diameter piping to span 20ft in standard pipe rack bays. With that table, you need to have a minimum of 10" piping in your pipe racks.

Also, typical deflection criteria is 1/2"-5/8" for ISBL lines. This span translates to a minimum natural frequency of 4Hz which is a suggested minimum to keep your pipe spans from galloping like the Tacoma Narrows Bridge.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

All opinions expressed here are my own and not my company's.

 

[umreng]

Previous replies and responses to the pipe span question have not considered siesmic forces. If the location of the piping installation is in an area with earthquake history, this may lead the engineer or officials to make certain site-specific recommendations or design requirements.

 

[chicopee]

All horizontal pipe support equations that I have seen are based on the fundamental beam equations found in strength of material. Bending stress and deflection are the two main criteria. ASME piping code for power boilers also requests the additional load of water filling the pipes.

 

[Hookem]

Stress Guy: I have many criteria for supports before, but not the 4 hertz. Please advise on background and basis. Thanks.

Hookem
aka TomChesney
chesney@uei-houston.com
bchesnfish@aol.com

 

[StressGuy]

I'll have to do some digging for the documentation. That one comes from my boss, who's been doing pipe stress since before I was born. I'm pretty sure it comes from Kellogg's Design of Piping Systems.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[StressGuy]

I did confirm - the 4Hz criteria comes from the Kellogg Design of Piping Systems. In general, if your piping system sags less than 5/8" between supports, the natural frequency will be above 4Hz. You want it above this to avoid exciting a resonance with the wind blowing across it. (Tacoma Narrows Bridge, anyone?)

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[KernOily]

OK Ed what do I have to do to get you to make me a copy of Kellogg's book? How 'bout lunch at Pappadeaux's?

Thanks!
Pete

 

[StressGuy]

I gladly would if I could, as there is a lot of good information in that book. I've written the publisher to let them know there's interest in a new printing, but they indicate they've no plans to reprint it at this time.

They show up on Ebay about once or twice a year and never go for less that $50.

For now, I have to rely on the library of my boss, Noble Stewart, who thankfully has managed to amass copies of just about everything in his career.

In fact, I'm currently borrowing a 30 year old catalog for a spring manufacturer that went out of business about 25 years ago to evaluate a piping system with some existing springs. It's amazing how much information is simply dissapearing, save for a few pockets that are keeping it alive.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[KernOily]

AARGH! Not good news. What about the 25-years-and-the-copyright-expires/public domain thing?

The web is a good thing for manufacturer's catalogs in most cases. A major excpetion to this is old equipment (as you related) which lots of owners still have in operation, forcing us to keep paper copies around. Worthington pumps is one good example.

Guess I will have to watch ebay... well I'll buy you lunch anyway next time I'm down there, how bout that. Thanks Ed.

Thanks!
Pete

 

[ctink]

Any possibility that I could get a copy of the tables mentioned above?

"Pipe Hangers and Supports - Selection and Application" by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc., MSS SP-69-2002. Table 3 - "Maximum Horizontal Pipe Hanger and Support Spacing."

 

[ApC2Kp]

Manufacturers Standardization Society publications are available from website,

http://www.mss-hq.com

Along with SP-69 for pipe support selection, also consider the SP-58, and SP-89 publications for the loads on the support components.

 

[pipingdesigner]

Hi guys,

Interesting discussion !
On my website,

http://www.pipingdesigners.com

you will find a file under the "tools" section called pipe and vessel data.

It contains a wealth of charts etc on excel, including allowable pipe spans (just tab through the pages).

Just download, unzip and leave on your pc. I use it everyday !!

Hope it helps,

Kind Regards

Anton

http://www.pipingdesigners.com

 

[JohnBreen]

Hello All,

I am surprised that nobody mentioned that the classic "span length tables" always include warnings (in fine print) that these recommended spans are for simply supported piping (no moment connections) and do not address the presence of concentrated loads (valves, strainers, etc). Also, changes in direction add some complexity to the equation.

I wonder if ye olde Grinnell publication on pipe support design is still available through Anvil. EPRI members should look on the EPRI website for a PowerPoint presentation that some olde codger prepared.

Regards, John.