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r6155, ASME B31.3 2022 page 35

r6155, I'm on working with Category D and Normal service fluids. K308.2.2 is for High pressure Fluids if I'm not wrong

ASME B31.3 also states that slip on flanges can be used where severe erosion, crevice corrosion is expected and for toxic, flammable services as well if double welded.

Hi, Is it technically a bad option to go for SS EFW pipes for all sizes from 15NB and higher. I've referred few Pipe material Specifications where Seamless pipes are used upto 200NB and above 200NB they're generally EFW pipes. Is it possible to 100% radiograph small size EFW pipes for SS and...

Hi, What is a stronger connection between Half Coupling and a Stub in for branching of a pipe? For Stub in we get a butt weld connection which is stronger in branch as opposed to 2 welds in half coupling? Why do we still use half coupling as we have to anyways make a hole in the run pipe in...

1503-44, I'm using weld neck for normal fluid services now. Just for cooling water, Potable water, Nitrogen, Fire water I'll be using Slip on flanges. Slip on flanges are generally from 50NB to 600NB in sizes.

GD2, r6155 As mentioned by you I'll refer B31.3, hopefully it will help me make a decision.

How about CS and socket welded fittings? We are using CS for caustic lye, alcohol and phthalates with design conditions below 200 degree Celsius and 6 bar. Would it cause problems if we use CS socket welded fittings as well?

TugboatEng, Thanks. I will check the flash point and take preventive measures. I will also check other normal fluid service that are operating above flash point and make sure the I avoid socket welded fittings.

r6155, I'm sorry but SS socket welded fittings have been used in the industry for decades. Should it be absolutely avoided in all design conditions?

GD2,r6155 Hot Oil service will also be normal fluid category, I mentioned it separately because it has the highest design temperature with the fluids I'm working. All other fluids have at the most around 100 to 150 degree Celsius operating temperature and 6 bar pressure.Even with such low...

r6155, Thanks for you response. What temperature range do you suggest for socket welded fittings?

LittleInch, TugboatEng, Thanks for your reply, I'm leaning towards using weld neck flanges for 50NB and higher sizes for process lines and slip on flanges for utilities like cooling water. For 15Nb to 25NB, socket welded flanges seems my only option.

r6155, The temperatures I'm working with is 200 degree Celsius design. Can you please share your thoughts why can't we use sockets for SS?

Thanks TugboatEng and LittleInch for the reply. I will be using socket welded fittings and flanges for 15NB to 40NB for CS and SS as well and for Hot oil service will use Butt welded fittings and casted flanged valves to avoid bottom out issues. Hopefully, I'll be able to convince my client.

Heaviside1925, Thanks for your reply. I agree with you Butt welds will require more end preparation time, additional welds, gasket and flanges which will add to overall cost and time required for the contractor for completion. Surely socket welds will require a lot less time for completion on...

TuboatEng, Thanks for your reply. We hope Site contactor takes care of Socket welded bottomed out issue as a quality control. However, for Hot oil service with 350 deg celcius temperature I would refrain from using socket welds and go for butt weld even for 15NB for the reasons mentioned by...

akpipelineengr, Thanks for your reply. I think I better discuss this with client itself mentioning possibilities of errors in Slip on flanges as compared to weld neck flanges.

XL83NL, Thanks for the reply. I belive the temperature and pressure range from GD2 is from 16.5 pressure temperature ratings from 300# ratings.

GD2, Thanks for your reply. I agree with you Material slection is based on fluid service and conditions which in my case is A106, SS304 and SS316. Regarding small bore for let's say 15NB SCH 80 has 3.77mm thickness which is enough for butt welding as per my knowledge. For larger bores 50NB and...