Dew-point

Date 05-29-2013 23:07

They can ask for anything they want, it doesn't mean they will get it unless it was part of the purchase order or project specification.

Suppliers are not typically required to provide written certifications for shielding gases unless they are told in advance certification is required. The purchaser must tell the gas supplier what documentation is required as part of the purchase order.

Just a thought; are you ordering your gases per AWS A5.32?

Best regards - Al

By Milton Gravitt (***)

Date 05-30-2013 00:31

AL, I really don't know if we ordering our gases per AWS 5.32. I ask for an analyses and a certificate of compliance for the argon and helium and we use the 99.999% and the same thing on the welding wire. I know the analyses on the argon shows the moisture level is <3.0 ppm. I thought that was what the gentleman was talking about, but he said it was different. Al what is the dew-point in a cylinder of argon or helium should be? This gentleman is auditing us for future work.

M.G.

By 803056

Date 05-30-2013 01:33

Per AWS 5.32

Gas Moisture    Dew Point
Ar 10.5 ppm   -76 degrees F

CO2   32 ppm -60

O2    NA -82

Best regards - Al

By 99205

Date 05-30-2013 09:59 Edited 05-30-2013 10:04

If your supplier offers it, ask for a document like this. It will cover most everything that's being required from you.

http://www.alspecialtygases.com/Rata_popup.aspx

By eekpod

Date 05-30-2013 11:05

Yes I have been asked this before, only once. It is a requirement of D1.1 and you have to ask your gas supplier for it.
Good luck

By jwright650 (*****)

Date 05-30-2013 11:14

I've been asked to show this documentation also....usually once a year, during an annual AISC audit.

By fschweighardt (***)

Date 05-30-2013 12:23 Edited 05-30-2013 12:35

If you order your gases to AWS A 5.32 (any edition) the supplier is supposed to label the gas as part of complying to the specification. This labeling is just like the requirement for labeling wire. If the product is to fully meet the standard, each container is to be labeled.

From the specification (2011 edition):

10. Marking
the outside of each cylinder or other container (see 3.4) shall be clearly marked with at least the following information:
name of the manufacturer or supplier;
trade name;
designation in accordance with this Standard (see 5.2);
health and safety warnings in accordance with local, national, and regional standards and regulations as required.

Al's specifications above are from the 1997 R2007 edition. The new standard has different impurity limits It turns out that if the Referencing code (D1.1, for example) specifies a document by date or edition, you are to use that version. If the Referencing code used an undated reference, you are to use the most current version of the specified document. Of course, the Contract can change this requirement.

for Milton G, 3PPM moisture corresponds to -92F dewpoint. There will also be tolerances on the accuracy of the mixture, for a 75/25 (either edition) it wil be +/- 2.5% from the nominal 25%, or 22.5% to 27.5%, assuming the gas is to meet A5.32 requirements. Finally, current (2011) purity is 99.99% global purity, and a maximum of 40 PPM H20 on "I" classifications, which covers argon, helium, and argon/helium mixes.

By 803056

Date 05-30-2013 13:34

Good to know. I didn't have the latest edition with me when a responded.

Best regards - Al

By Darrell_B (*)

Date 05-30-2013 21:02

NADCAP will require your shielding gases to be certified, but all those things will have to be a purchase order requirement.

By Milton Gravitt (***)

Date 05-30-2013 22:52

You know D17.1 2010 doesn't ask for the dew-points but D1.1 as for now does. I don't know about D1.2 or D1.6, but I will later on. I sent our supplier and E-mail this morning saying the we need to comply with AWS A5.32 spec.

M.G.

By fschweighardt (***)

Date 05-31-2013 12:00

D17.1:2010
6.2.3 Gases
6.2.3.1 Gas Procurement Specification
Welding and Shielding gases shall be procured to the requirements of Table 6.1 or to the requiremnts of AWS A5.32/5.32M. Gases may be procured to the alternate specificaitons in Table 6.1 with approval of the Engineering Authority
Table 6.1 has military standards as the primary specification, and the alternate specifications are Compressed Gas Association documents

Be aware that the military specifications often have a bunch of odd requirements (like for helium, it specifies BLM sourcing) that can make properly documenting the gas very time consuming (read expensive)

By Milton Gravitt (***)

Date 06-11-2013 22:04

We got finish with the audit today and I think we did well. I ask the auditor if I could use the conversion AWS A5.32 and he said that would be fine. Our gas suppliers came up wit a cert on 75 argon/25 carbon dioxide with a moisture content of 40. I would like to say thanks to everyone's help.

M.G.

By fschweighardt (***)

Date 06-12-2013 10:42

Be glad the auditor accepted the loose document, rather than the full requirement of having a label on each container. I do a fair amount of reviewing supplier WPS's, etc and one of the most common problems is the use of gas that does not comply (at least from a labeling point of view) with the code of construction and/or AWS A 5.32

By BillC

Date 06-22-2013 16:06

Glad the audit went well. A few weeks ago I found CO2 bottles in our shop that were labeled "Food Grade". The gas supplier tried to argue that it was equivalent, but they had no dew point data. For all I know the gas supplier just has one big tank out back they use for all of their CO2 refills.

Regards,