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whitepiper
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Join Date: Mar 2008
Posts: 7

Allowable Nozzle Loads

03/07/2008 11:01 AM

I have been struggling to get some guidelines for allowable nozzle loads for equipment to ensure it is not overstressed due to connected piping? does anybody has some easy method to check that? WRCs are very tidious..
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Steve S.
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#1

Re: allowable nozzle loads

03/07/2008 4:58 PM

Every equipment OEM will have design load limits for his machine and it is often on the equipment data sheet, but a lot of them just use zero load cause if a give a piper an inch he'll take a mile, and if you give him a pound, he'll assume it is a anchor...
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Abdel Halim Galala
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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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#2

Re: allowable nozzle loads

03/09/2008 8:36 PM

Nozzle standard loadings are varied from equipment to another, also from material to another, also from nozzle size and rating to another.

For example, the max. allowable nozzle loadings for pressure vessels and shell-and-tube heat exchangers shall be as follows:

A. For Carbon Steel:

Force FA = K x 675 x D , FL = K x 1000 x D & FØ = K x 1000 x D

Moment MT = K x 125 x D2 Nm , ML = K x 100 x D2 , & MØ = K x 75 x D2

where, K = 1 for Flange rating 150-300# and K = 1.25 for Flange rating > 600#

B. For Stainless Steel:

Force FA = K x 675 x D , FL = K x 1000 x D & FØ = K x 1000 x D

Moment MT = K x 125 x D2 , ML = K x 100 x D2 & MØ = K x 50 x D2 , where, K= 1

D = Nominal nozzle size (inch), F = Force component (N) and M = Moment component (N-m)

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Neville Tomlinson
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Location: Maryland, USA
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Good Answers: 2
#4
In reply to #2

Re: allowable nozzle loads

03/10/2008 11:40 AM

Can you indicate the reference to these formulas.
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Abdel Halim Galala
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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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#12
In reply to #4

Re: allowable nozzle loads

06/02/2010 11:03 PM

Dear Neville Tomlinson,

The reference book for these formulas is Piping Stress Handbook by Victor Helguero M. (Part 1 & Part 2).

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Anonymous Poster #1
#15
In reply to #12

Re: allowable nozzle loads

07/15/2011 9:45 AM

I went through this handbook twice, but was not able to find the formulae that you listed above for the max. allowable nozzle loadings for pressure vessels and shell-and-tube heat exchanger?

Can you please refer me to the page number or para number in the Piping Stress Handbook by Victor Helguero M where I can locate this formulae?

Thanks
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Abdel Halim Galala
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#16
In reply to #15

Re: allowable nozzle loads

07/16/2011 5:42 AM

Refer to Piping Stress Handbook by Victor Helguero M, Chapter 8 "Design Criteria for Allowable Loads, Moments, and Stresses".

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rajachem
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Join Date: Mar 2012
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#18
In reply to #16

Re: allowable nozzle loads

03/05/2012 2:07 AM

Hi Abel,

I need to calculate the "Allowable nozzle loads" for a pressure vessel and was looking into the forum and referred the "Pipe Stress handbook - Second edition" by Victor Helguero, Chapter 8 "Design criteria for allowable loads, moments and stresses" and could not trace out the formulas. Please help, is iam looking at the right edition?.
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rajachem
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#19
In reply to #18

Re: allowable nozzle loads

03/05/2012 2:26 AM

Hi Abdel,

Also iam dealing with the welded nozzles (BW) and not flanged ones for the pressure vessel. Please say whether i can use the formulas mentioned.
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Anonymous Poster
#5
In reply to #2

Re: allowable nozzle loads

03/12/2008 10:43 AM

Thanks Abdel, for upto 6" or 8" nozzles the rules are fairly matching with the nozzle loads by API 610. but could you suggest allowable nozzle loads for smaller pipes <2" directly welded to the columns/ equipment. Actually i was working on a cryo system where MOC are SS or Al with small piping sizes welded to equipment nozzle directly. due to transients (TAM) the nozzle loads are very high. MOreover how to transform these relations for Al. Could you suggest the reference for these rules?
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Abdel Halim Galala
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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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#6
In reply to #5

Re: allowable nozzle loads

03/12/2008 1:46 PM

Yes, my dear

I still doing my best to find that reference book, it was located on shelf of our company's library. The book may be lost or may be they interchanged its location, but I still lookfor my hardcopy.

For small nozzles < 2" connected to equipment, it must be designed with no loads to be transmitted from piping to vessel and vice versa, since the Al. nozzles are very weak connections.

Please send your e-mail, there are some data related to cast iron and aluminium nozzles and casing of pumps.

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Abdel Halim Galala
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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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#7
In reply to #6

Re: allowable nozzle loads

03/12/2008 2:31 PM

The following data are extracted from the same reference book:

I. DESIGN CRITERIA FOR ALL PUMPS

b. WITH CAST IRON OR ALUMINUM NOZZLES AND CASINGS ALUMINUM PUMP FORCE, MOMENT AND STRESS LIMITATIONS

The following criteria shall apply for pumps with 4-in. discharge nozzles or smaller (suction nozzles may be larger). The forces contained herein are considered minimum criteria and should be adjusted where the vendor has experimental or test data permitting larger reactions.

Suctions and discharge nozzles shall be designed to withstand forces and moments from the thermal expansion or contraction of piping. Piping reactions shall be computed in conformance with ANSI B31.3 : Petroleum Refinery Piping, Section 319, "Code for Pressure Piping", and shall be designed within the limiting criteria set by this standard. The modulus of elasticity shall be adjusted for the operating temperature condition.

♣ Each nozzle shall be capable of withstanding forces from external piping determined by the following formulas :

• For suction nozzles : Frs ≤ 1.6 w ≤ 50 D

• For discharge nozzles : Frd ≤ (2w - Frs) ≤ 50 D

♣ Top suction and top discharge pump nozzles are further limited by :

Frs and Frd = (Fx2 + Fz2)1/2 and the following;

• For suction nozzles

a. Fxs ≤ 1.3 w ≤ 40 D

b. Fys (in compression) ≤ 1.2 w ≤ 50 D

c. Fys (in tension) ≤ 0.5 w ≤ 25 D

d. Fzs ≤ w ≤ 35 D

• For discharge nozzles

a. Fxd ≤ (1.8 w ± Fxs) ≤ 40 D

b. Fyd (in compression) ≤ (2 w ± Fys) ≤ 50 D

c. Fyd (in tension) ≤ 0.5 w ≤ 25 D

d. Fzd ≤ (w ± Fzs) ≤ 35 D

♣ End suction and top discharge pump nozzles are further limited by :

Frs = (Fzs2 + Fys2)1/2 and Frd = (Fxd2 + Fzd2)1/2 and the following;

• For suction nozzles

a. Fxs ≤ 1.2 w ≤ 50 D

b. Fys ≤ 0.6 w ≤ 35 D

c. Fzs ≤ w ≤ 40 D

•For discharge nozzles

a. Fxd ≤ (1.8w ± Fxs) ≤ 40 D

b. Fyd (in compression) ≤ (2w ± Fys) ≤ 50 D

c. Fyd (in tension) ≤ 0.5 w ≤ 25 D

d. Fzd ≤ (w ± Fzs) ≤35 D

Limit tension and compression forces to 500 lb.

Where : F = force, lb.

Subscript r = resultant of forces

Subscript x = axis parallel to shaft

Subscript y = vertical 90o to shaft

Subscript z = horizontal 90o to shaft

w = weight of pump only, lb.

D = diameter, nominal diameter = I.P.S. = iron pipe size, in.

d = discharge or exhaust

s = suction or intake

Fr = resultant shear force in the plane of any specific flange face.

Sh = basic allowable stress for the material of construction at maximum operating temperature (see ANSI B31.3).

Each suction and discharge nozzle shall be designed to withstand the forces described for the specific configuration. Unit stresses in each nozzle shall be limited to :

• One-third of the allowable hot stresses Sh for pipe sizes ≤ 4 in.

• One-half of the allowable hot stresses Sh for pipe sizes > 4 in.

as shown in ANSI B31.1 and ANSI B31.3.

The baseplate and pedestal support assembly on pumps having a discharge nozzle 4 in. shall be adequate to limit the shaft displacement, when measured at the coupling, to a maximum of 0.005 in. in any direction when subjected to the following loads. These loads represent the total effect of all external mechanical forces that may be applied to a fully grouted pump base. They are to be applied to the pump through the suction and / or discharge nozzle.

Mx = 3.0 w* ft-lb

My = 2.0 w* ft-lb

Mz = 1.5 w* ft-lb

where Mx = moment in y-z plane

My = moment in x-z plane

Mz = moment in x-y plane

w = weight of pump only

* Minimum w is 500 lb. in these computations.

For purposes of evaluating computed piping-imposed external moments and forces, they shall be transferred from both suction and discharge flanges to the intersection of the X, Y and Z axes. An algebraic summation shall then be made for comparison with the moment limitation given above.

The vendor shall submit alternative criteria for pumps having a discharge flange 4 in. NPS. It is suggested that these criteria be developed as a result of tests.

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Anonymous Poster
#8
In reply to #7

Re: allowable nozzle loads

03/13/2008 11:04 AM

Dear Abdel,

now thats very useful guidelines, especially the stress control part at nozzle locations w.r.t. size of nozzles. thats a huge help, thanks for the information.
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Abdel Halim Galala
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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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#9
In reply to #8

Re: allowable nozzle loads

03/13/2008 7:44 PM

Dear Guest/whitepiper

Thank you very much and you are welcome.

But for "thats very useful guidelines" & "thats a huge help", may be it is in need to a very huge rate of score..... hahaha

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Abdel Halim Galala
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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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Location: Cairo, Egypt
Posts: 1746
Good Answers: 243
#10
In reply to #9

Re: allowable nozzle loads

03/29/2008 8:25 AM

My friends,

Do you know that 1 + 1 = 0.

That what was exactly happened to my posts #2 and #7, both granted score 1, "almost" Good Answers, and the net score is zero. Can you please prove that 1 + 1 = 1 at least to be added to the total of Good Answers. Nothing to say, just for fun.

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inspectorjoe
Associate

Join Date: Apr 2008
Posts: 54
#11
In reply to #10

Re: allowable nozzle thickness

05/02/2008 10:17 PM

Good day abdel.

What about the nozzle thickness? Can you help on this? We conducted an ultrasonic thickness gauging of nozzles of a pressure vessel. How do i compute if the nozzle thickness are still acceptable?
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Anonymous Poster
#13
In reply to #2

Re: allowable nozzle loads

07/13/2010 4:13 AM

What is k overhere?From where did u got the value of k?

thanks
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Abdel Halim Galala
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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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Location: Cairo, Egypt
Posts: 1746
Good Answers: 243
#14
In reply to #13

Re: allowable nozzle loads

07/13/2010 12:58 PM

See my post #12.

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Rajcs82
Participant

Join Date: Dec 2011
Posts: 4
#17
In reply to #2

Re: allowable nozzle loads

12/04/2011 7:29 AM

I am doing stress analysis for natural gas plant which has part of under ground pipe and connected to above ground equipment( pig launcher), i got output which has the code compliance of 40% of allowable stress and the vertical displacements are with in 5mm but the force and moments are too large of 100000N at pig launcher inlet i really surprise and need help to balancing this force and moments, please some experts can help me?
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ronniehossain
Participant

Join Date: Jun 2013
Posts: 1
#20
In reply to #2

Re: allowable nozzle loads

06/05/2013 9:41 PM

Mr. Abdel,

I am facing a problem with a horizontal tank in my plant. Plant installed a two stage pump weighing approx. 2650 lbs on the top of an 18" manway. My understanding is per ASME code vessel's nozzle is not designed for withstand this load. How can I make sure that this load is ok or I have to add repad? Maybe 1" thickness of the shell will not allow this extra loading. Thank you for your help. Ronnie Hossain

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joarder
Participant

Join Date: Apr 2014
Posts: 1
#21
In reply to #2

Re: allowable nozzle loads

04/16/2014 9:56 AM

Hi Abdel,

I have the book you referred but I can not able to find these formulas in Chapter 8. There is nothing for vessels in chapter 8. What version you are referring to. Appreciate your help.
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zhang.limin
Participant

Join Date: Feb 2016
Posts: 1
#22
In reply to #2

Re: allowable nozzle loads

02/04/2016 6:27 PM

Thanks Abdel,

I check our company standard, It is match your equation that just time 0.8 of K,

very useful,

Thanks

Limin
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Lawrence
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Join Date: Jun 2007
Posts: 67
Good Answers: 5
#3

Re: allowable nozzle loads

03/10/2008 8:55 AM

The WRC 107 method is tedious. However, it is the best analytic method available. The best way around the tedium is to buy a canned program to read all of the tables for you or to go FEA. A recommendation for a program that does both is FE/Pipe by Paulin Research Group (http://www.paulin.com/). This program is a parametric FEA program organized around pressure vessels and piping. One can model the piping and the vessel in a linked analysis that both generates the loads and analyzes the support stresses.
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Users who posted comments:

Abdel Halim Galala (8); Anonymous Poster (4); inspectorjoe (1); joarder (1); Lawrence (1); Neville Tomlinson (1); rajachem (2); Rajcs82 (1); ronniehossain (1); Steve S. (1); zhang.limin (1)

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