Need Advice: Autoclave Based on ASME BPV Sec. VIII Div. 1 2

[hanabie]

Hello,

My employer has a new project, a small autoclave sterilizer. It's actually a 5-6 gallon sterilizer. We have no experience in the mechanical design.
We also have no experienced mechanical engineers specialized in BPV. Do you think we should hire consultants? Or is there any guide/book that I can look at it? Is there any training provided out there? I want to learn as well. It is a very interesting project.

The sterilizer will be built based on ASME BPV Sec. VIII div.1. Do I need to look for a certified manufacturer? Is it too expensive to establish a new certification?

Any recommendation how I should start this project?

Thank you very much

hanabi

 

[Duwe6]

Incredibily too expensive to obtain an ASME Code-stamp for 1 vessel.

Just contact 2 to 4 Vessel Shops that hold current U-stamp certifications, and give them the size and shape you want, plus the Maximum temp and pressure you feel it needs -- NOT the 'normal operating' temp & pressure. They will give you pricing based on them completing the design, certifying the design calculations, fabricating the vessel, and obtaining the Code Stamp certification.

A 'rule-of-thumb' for establishing a reasonable MAWP/MAWT is to add 30-50% to the pressure and temperature that the vessel will actually operate at.

 

[SnTMan]

Concur w/ Duwe6, you don't wnat to go thru what it takes to get a stamp for one vessel. Are you to mass produce? That may be different.

Otherwise, put it in a Code shop. Get drawings and calculations from them for your review, and edification.

Couple of things: 1) Check with your insurer, it may not need stamped, based on its volume. 2) If it has a quick opening closure, its not likely that the average shop can design / build that part of it, kind of specialzed.

Regards,

Mike

 

[hanabie]

Hello,

Thank you for your responses. Yes, I'm glad the quick opening closure is not required for the design.
The design parameters are 29 psig and 135 degrees Celcius.

Based on the design parameters, do we still need the product code stamped or certified?
We are looking for about 100 units per year for the start.

Thanks

 

[hanabie]

I'm sorry I did not do enough research before posting my questions. It's correct that the stamp is required.
Thank you. Any recommended code shop?

 

[metalonis]

Try here:

http://caconnect.asme.org/CertificateHolderSearch.aspx

 

[Duwe6]

With that pressure, you MAY be exempt -- if your interior volume is 5-ft³ or less, ASME Sect VIII Div. 1 U-1(j)(1) allows exemption.

 

[hanabie]

Hello,

Thanks for promptly responses. I notice that ASME has training courses for BPV Sec VIII div. 1 this coming September.
There were two courses available. One is just PD442: Design and Fabrication of Pressure Vessels. Another one is a more comprehensive course which includes Inspection, Repairs and Alterations of Pressure Equipment.

Has anyone attended this courses before? How is your experience?
Do I really need the combo courses?

Is there any material which can assist me before taking the courses? I have ordered ASME Sec VIII Div 1 standards. Is there any other good material to support my research?
To help me to get a better understanding designing a pressure vessel based on ASME code.

Thank you very much

 

[SnTMan]

hanabie, "Pressure Vessel Design Handbook" by Bednar is pretty good, as is "Pressuer Vessel Design Manual" by Moss

Regards,

Mike

 

[fegenbush]

SnTMan, I would also throw in "Pressure Vessel Handbook" by Megyesy.

 

[SnTMan]

Agreed, no doubt there are others as well.

 

[jtseng123]

I wouldn't agree with Duwe6 to set MAWP/MAWT 30%-50% above operating condition for hundreds of pressure around the world passing my hand.
First, find out your normal operating condition, then set the design condition with certain margin. Each comapany has their own criteria.
Second, check if you have upset or sudden surge condition. Code allows allowable stress to be increased (33% if I remember correctly). You need to let fabricator to know this condition and make calculation.
For past 20 years, I only see one project that client requested to calculate MAWT. Since you are making your own product, you definitely do not want to go into that trouble. Once you have set reasonalbe design temperature ( 50F or 25C above operating temperature is very common, though no harm to go a little higher), just ask fabricator to "calculate" MAWP per code. Fabricator will check every parts, head, shell, nozzles, flange, cone, and then pick the smallest one as the stamped MAWP at your design temp. If you do not request fabricator to do MAWP calcualtion, you open the option that fabricator can set MAWP = design pressure.
The final thing you need is the MDMT. You can set the MDMT or let fabricator set for you based on the materails he purchased (not preferred to do tis way). You need to check the ambient enviroment where your product will be operated in those regions, north pole or south africa, indoor or outdoor, and set the MDMT that can cover most of the regions. MDMT will have impact on your cost if it is set too low that special material may be needed. For sure you can custom build for each individual user on specific MDMT instead of mass production with one MDMT.
One more, do you have any vacuum condition that can possibly happen ? Even steam out to claen the vessel will generate vacuum condition due to steam condensation, watch out.

 

[steris]

Assuming that you are in the US, there are only a few companies in the US that manufacture steam sterilizers. If there is no conflict of interest, perhaps they would be willing to contract out this work. Also, your vessel is really small - if you only need a few you may be able to purchase an off the shelf sterilizer. It sounds like your vessel may be similar to what dentists use.

 

[hanabie]

Thank you guys. I will definitely try to do it.

Is it recommended to participate ASME BPV sec viii div. 1 training?

 

[Duwe6]

Yes. Go to the NBIC training at their home in Columbus OH "New Construction Commission and Authorized Inspector Course",

or get tutored by an Authorized Inspection agency, like Zurich or Hartford Steam Boiler.

To pass your Code Stamp audit and receive your Stamp, at least one person in your company will HAVE to be very knowlegable on the Code to pass the audit.