steam pipes

At 100 psig steam pressure, CS pipes specs are as follows:

1. Pipes, A53 Gr.B Seamless, Sch.40, 2.5" dia. and above.

2. Pipes, A53 Gr.B Seamless, Sch.80, 2" dia. and below.

Note: Pipe spec such as A53 Gr.B, A106 Gr.b API 5L Gr.B are in the same level of classification. These spec's mostly is stencilled on the external surface of the pipe for visual inspection purpose.

3. for Flanges, A105 C-150 Raise Face (RF) Weld-Neck or Slip-on Type

4. Fittings: A234 wpb sch.40 / sch.80 (butt-weld)

Regards

A. For steam pipe material : we have to use ASTM A106 Grade B instead of ASTM A53.

B. For pipe wall min. thickness, t : it depends on pipe outside dia. D_o, design pressure P, allowable tensile strength of material at design temp. S, joint efficiency E, and corrosion allowance C .

C. By substituting into equation from ASME B31.1 Power Piping, you can find the pipe wall thickness t.

D. Calculate pipe wall nominal thickness t_m by taking into consideration of 12.5% t as thickness tolerance.

Abdel Halim Galala

Hi, as i mentioned before, ASTM A106 Gr.B, A53 Gr.B & API 5L Gr.B are commercial pipe in the market, which is supplied by International Manufacturing company. These specifications are most common that always stencilled on the pipe. Judgement is that when we take a look the material analysis based on the specifications compare to the actual Mill Certificate of the materials, it is on the range for the above specs.

However, as you mentioned ASME B31.1 reference, please detail your calculation and let us compare to Schedule 40 category if it fall on the limitations.

Do i need to detail these calculation to arrive in Schedule 40 / class-150 rating, as my recommendations?

I do a basic design of steam system and hot water system for almost 9 years, installation, start-up and commissioning with full warranty for materials and workmanship according to intrernational standards.

Fortunately, i havent recieved any negative feedback with these system...

Regards,

Jojie_oak

Mr. Abdel,

i am a fresh graduated, could you please inform me where i can find the specification as your mentioned in this thread (i.e. corrotion allowance)..?

i am doing a pipe stressng for existing steam line right now using AutoPIPE, but still need a guidance to start it. did you have a reference (link), where i can learn how to do this pipe stressing...??

i hope you can help me..

Best Regards

Dear Gayanaji

Corrosion allowance C depends on the type of fluid (steam) and type of pipe material (carbon steel) at the design temperature. All of those parameters determine the corrosion rate per year. And by knowing the total life of your piping system, you can define the amount of corrosion allowance.

Corrosion Allowance, mm = Corrosion Rate, mm per Year x Total life, years

Please refer to NACE Corrosion Data Survey (Metal Section, Sixth Edition).

For that case, I recommend to use a corrosion allowance 3 mm.

NACE = National Association for Corrosion Engineers

Please don't forget to add 12.5% as a pipe wall thickness tolerance.

Mr. Abdel,

Thank you so much for your guidance. if i have steam line 250degC and 15 Bar, the installed pipe spec is CS ASTM A53, how much did you suggest for corrosion allowance..??, sorry if my question is confusing, because i am not the designer of this pipeline, i just want to analyze it...

thanks & Best Regards

Dear Gayanaji

Analyzing an existing piping system is differs from designing a new system.

1. For new design of carbon steel piping system with steam as a fluid, take a CA = 3 mm.

2. For analysing an existing corroded piping system to evaluate its fitness for service and its remaining strength or life, its need for repair, alteration or rerating, please refer to ASME B31 G, or API 579.

Mr. Abdel,

thank for your support on this, did you have references (manual, book, etc) regarding Pipe Stressing, could you suggest me where i can find it please..??

regards

jojie oak said all.

Simple : Steam upto 150 psi - Ms Schedule 40 Seamless

All Valves & Equipments PN16/ 16 bar or CLass 150