Which is the correct standard to use for specifying buttwelding return type piping components(180 deg elbows)? ASME lists 2 standards as far as i can see:
ASME B16.28 - wrought steel buttwelding short radius elbows and returns
ASME B16.9 - factory made wrought buttwelding fittings (std. lists...
We have a fired heater open for inspection and have observed spiral patterns on the outside of the 5Cr heater tubes in the radiant zone. The patterns can be seen with the naked eye, but cannot be felt. The tubes are of seamless construction. These patterns have not been seen at previous...
Anybody aware of any NDT method that can be used to test for the presence of polythionic acid stress corrosion cracking in heatr pipes in a fired heater ? Are there any methods that can be used to give a 100% picture of the status of the pipes whilst they are mounted in the heater? I know you...
Not sure if i'm in the right forum here (it's not a pressure vessel type question) but i'll ask the question anyway. We have a number of large atmospheric storage tanks (50-80m dia) that we inspect on a 15 -20yr basis. After repairing the tank bottoms all welds are vacuum tested before coating...
We have to do some welding on the inside of an existing pressure vessel that has been in service where there has been hydrogen sulfide in the product. Knowing the problems that can arise through hydrogen cracking after welding, are there guidelines for how long the vessel needs to be warmed up...
We have both 5Cr and 9Cr piping material specifications. ASME B16.48 (steel line blanks) only lists forged material for 5Cr, and no 9Cr material is listed. The forged material is listed i presume because forgings are less susceptible to laminations than plate material. What type of material...
Hi,
Anybody know of or have experience with calculation software for ASME VIII appendix 13 pressure vessels - vessels of non-circular cross section ??
Specifically we have some air coolers with a rectangular section headerbox, with dividing plates that we would like to control ?
Thanks.
ASME B16.5 paragraph 6.4.1 states that 150# & 300# raised face flanges are 'regularly' furnished with 2mm raised face. I take it that there is no minimum value for the raised face height as paragraph 6.3.2 states you can actually remove the whole of the rasied face part as long as the minimum...
I am in the process of expanding a couple of our piping material specifications from 24" NB up to 42" NB. Regarding branch charts, previous companies here have specified use of reinforcing pads and not used weldolets or reducing tees (they had cheap welders from italy). As i would like to...
Hi,
we have to modify some existing 2"/3" 316L liquid ammonia piping. Looking at the existing installation, nearly everything is welded, valves included. I'm presuming that this is to reduce the number of potential leakage points in the system, therefore no flanges. Some of our team are...
I can see that API 590 Steel line blanks is now withdrawn from service and replaced by ASME B16.48. I'm about to specify line blanks in a 9Cr piping materials spec. Does anybody have a copy of B16.48 (i've ordered a copy but it's currently out of stock) who can tell me if plate material A387...
Our dear process people have calculated that they need a 26" line. Isn't 26" a bit like 5" ? It's covered in the ASME standards, but it's one of those sizes you would prefer not to use (normally spring from 24" to 30"). Anybody know if you can get 26" BW components in normal delivery times ?
Is it possible to get seamless pipe and wrought fittings (elbows/tee's) up to 42" ? We normally only concede use of welded pipe/fittings in our tankage areas for raw and finished products where systems are rated to 150#. This area is not classified as sour service. Now our process designers have...
Hi,
developing a new pipe spec in UNS S32750 for use in seawater service. Up to around 8/10" you can get seamless pipe to A 790, after this it seems welded pipe to ASTM A928 is used (better control of the ferrite/austenite levels in the weld i've been told). The welded pipe use plate of ASTM 240...
Are there internationaly recognised guidelines for choice of flange facings ? I have a company guideline that generally speaking indicates that in 600# and above, irrelevant of service, facing is RTJ with temp over 750F and raised face under this. When we are in the 150/300# pressure rating...
We have a requirement for a 42" overhead line from a vacuum tower. Most of our pipe specs only go up to 36". Are there any special requirements to larger than 36" lines or can you just calculate the required wall thickness based on B31.3 calculations?
With respect to lines in vacuum service...
Anybody have any experience with use of P91 (9Cr-1Mo-V)grade materials in piping plants? As part of a visbreaker revamp we've been recommended by our engineering study contractor to change out some of our existing ASTM A335 Gr.P9 piping to P91. Reasons are better resistance to creep in the...
We have the requirement for a 42" diameter overhead line from a 50m high vacuum tower. Our required piping materials specification only goes up to 36" and needs to be expanded to 42". We use graphite reinforced stainless steel flat ring gaskets normally in this material spec. Someone has raised...
Anybody know if there is a guideline/standard on what the minimum differences can be between design and operating conditions ? We have a case where our process dept. wants to increase the gas outlet temperature from a fired heater from it's normal operating temperature of 326degC up to 450degC...
How compatible are NPT threads with BSP threads ? I've heard varying comments where it's not a problem to screw one type into the other, and other sources that say it is not possible. We are only using threaded connection after block valves typically for connecting to instruments/vendor supplied...
