Copper alloy for breathing Oxygen

[israelkk]

What bare without coating copper alloy (Bronze or Brass) can be used for breathing Oxygen?

 

[jsummerfield]

Plagiarization? Not exactly but someone wlse prepared most of this reference list for xxygen service materials. I pasted into a document and saved it without credit to the original reference.

ASTM Committee G04 on Compatibility and Sensitivity of Materials in Oxygen-Enriched Atmospheres has published many standards on material for oxygen service. If you purchase a component for oxygen service, the mfr. Should certify compliance with applicable ASTM and CGA standards as well as NFPA articles. Note also cleaning requirements; new & maintainence. Some of the ASTM standards:
G63-99 Standard Guide for Evaluating Nonmetallic Materials for Oxygen Service
G94-92(1998) Standard Guide for Evaluating Metals for Oxygen Service
G88-90(1997)e1 Standard Guide for Designing Systems for Oxygen Service
G93-96 Standard Practice for Cleaning Methods and Cleanliness Levels for Material and Equipment Used in Oxygen-Enriched Environments
G94-92(1998) Standard Guide for Evaluating Metals for Oxygen Service
G114-98 Standard Practice for Aging Oxygen-Service Materials Prior to Ignitibility or Flammability Testing
G121-98 Standard Practice for Preparation of Contaminated Test Coupons for the Evaluation of Cleaning Agents
G127-95(2000) Standard Guide for the Selection of Cleaning Agents for Oxygen Systems
G128-02e1 Standard Guide for Control of Hazards and Risks in Oxygen Enriched Systems
G131-96(2002) Standard Practice for Cleaning of Materials and Components by Ultrasonic Techniques
G136-96(2002) Standard Practice for Determination of Soluble Residual Contaminants in Materials by Ultrasonic Extraction
Abstracts of the above can be viewed, and the documents purchased, at

http://www.astm.org

NASA compiled a bibliography of references of interest to practitioners of oxygen compatibility. It includes every reference in Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: Eighth Volume, ASTM STP 1319, William T. Royals, Ting C. Chou, and Theodore A. Steinberg, Eds., American Society for Testing and Materials (1997), plus several hundred more. Last updated October 22, 2002. At

http://www.wstf.nasa.gov/Oxygen/ASTMG4/ref.htm

A selection of possible interest:
[57] "Oxygen," Pamphlet G-4, Compressed Gas Association, Inc., Arlington, VA, 1987.
[59] "Oxygen System Cleaning Requirements," Cryogenics & Industrial Gases, November/December, 1973.
[124] American National Standard for Medical Gas Regulators and Flowmeters, June 22, 1990 Proposed Update of CGA Pamphlet E-7, 1990.

Also
try NFPA 53: "Recommended Practice on Materials, Equipment, and Systems Used in Oxygen-Enriched Atmospheres, 1999 Edition"
from Nat'l Fire Protection Assoc.

http://www.nfpa.org/catalog/product.asp?category_name...

John

 

[israelkk]

jsummerfield

Thank you for the detailed post. I managed to find MIL-DTL-2/41 specifically dealing with Oxygen valves for medical use. The requirement there is that the valve should be chromium plated.

 

[btrueblood]

Urg. When I worked for a rocket company, we routinely piped LOX and hi-pressure gas oxygen. We avoided any kind of plating at all costs - the risk is that a flake of plating could dislodge, be carried thru a sonic orifice and impinge on a downstream surface at high velocity -- the resulting impact then sparking a fire.

I seem to remember that Monel was recommended as a Cu alloy for LOX. There is a NASA-GSFC or possibly -MSFC document somewhere with detailed recommendations for oxygen piping...can't remember the title, sorry.

 

[macvalsa]

Depends a little on the pressure but in gas service generally you can use bronze to BS LG2 or AS 1565 I think the ASTM code might be B62

Do not forget if its a medical breathing application it must be cleaned to medical gas levels

 

[kenvlach]

Hi,
Most of the references are from the earlier thread
Materials for Oxygen gas duty
thread404-77772
Note the newer NASA reference below.

israelkk, you should be aware that MIL-DTL-2/41 is only an additional requirement to the many general valve requirements of MIL-DTL-2F. I give a few samples of these requirements below, with relevant highlighted (bold). Especially note: You must use a forged brass body; Forging brass shall conform to ASTM B 124/B 124M, CDA Alloy Number C37700.

btrueblood, chromium plating is required per MIL-DTL-2/41. I'm sure it would risk CTE problems in LOX service, but for present situation, only needs testing from -60 to +160^oF (see below). I agree that Monel is superior to brass & steel in many respects, so probably wouldn't need the chromium plating, but the government standardized on a set of less expensive alloys.


MIL-DTL-2/41 - VALVE, CYLINDER, GAS: OXYGEN, OUTLET 540, MEDICAL
(PRESSURES THROUGH 3000 psig (20680 kPa) AT 120 ºF (48.9 ºC)).

“REQUIREMENTS:
TYPE DESIGNATION: V41-540-2
TABLE I. Valve requirements. [I omitted everything except composition]
Composition: A”

“SPECIAL REQUIREMENTS:
1. The valve shall be chromium plated.
2. Mark the valve body: OXYGEN MED.
3. A valve outlet cap shall be supplied.”


MIL-DTL-2F VALVES, CYLINDER, GAS (FOR COMPRESSED OR LIQUEFIED GASES), GENERAL SPECIFICATION FOR

“1.2 Classification. The valves are of the following styles, classes, compositions, inlet sizes, and pressure relief device (PRD) types.” [note: I am only listing composition as example]

“Composition A - Forged brass body. [specified in MIL-DTL-2/41D]
Composition B - Forged steel body.
Composition C - Forged bronze.
Composition D - Machined brass (medical post).”


MIL-DTL-2F lists a large number of 'APPLICABLE DOCUMENTS' with which you must comply:
“2.2.1 Specifications, standards, and handbook. The following specifications, standards, and handbook form a part of this document to the extent specified herein.”

I will give one since its requirement appears in Paragraph 3.4.11.8:

“NATIONAL AERONAUTICS AND SPACE ADMINISTRATION (NASA)
NASA-STD-6001 - Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion.

(Application for copies should be addressed to NASA Technical Standards, EL01 MSFC,
AL 35801 (Phone: 205-544-2448). Electronic copies of NASA publications may be obtained
from

http://standards.nasa.gov/.)”

“3.4.4 Brass.
3.4.4.1 Castings. Brass castings shall conform to ASTM B 763, CDA Alloy Numbers C83800, C84200, or C84400.
3.4.4.2 Forging. Forging brass shall conform to ASTM B 124/B 124M, CDA Alloy Number C37700.
3.4.4.3 Free-cutting. Free-cutting brass shall conform to ASTM B 16/B 16M, CDA Alloy Number C36000.
3.4.4.4 Naval. Naval brass shall conform to ASTM B 21/B 21M, CDA Alloy Number 48500.
3.4.4.5 Strainer wire. Brass strainer wire shall conform to ASTM B 134/B 134M, CDA Alloy Number 27400.”

Note: Specifications for bronze, steel and other materials are also given.

“3.4.11.8 Medical valves. The material used in all medical valves shall be in accordance with the latest revision of NASA-STD-6001 (see 6.2).”


Construction details and other requirements are given. For example,

“3.7.6 Combustibility. When intended for use with oxygen or oxidative gases, organic components of the valve, such as packing, seals, and lubricants, shall be stable when exposed to oxygen. The material shall not react, discolor, or show any evidence of change in appearance under the following conditions:
a. Exposure for 1 hour to oxygen at a pressure of 2000 psig (13790 kPa) and a temperature of 302 °F (150 °C) ±2 °F (1.11 °C).
b. Instantaneous exposure to oxygen at a pressure of 2000 psig (13790 kPa) while heated to a temperature of 160 °F (71 °C) ±2 °F (1.11 °C).”

“3.8.1.2 Storage. The valve shall withstand storage at the maximum service pressure specified herein, for 8 hours at a temperature of -60 °F (-51 °C) ±2 °F (1.11 °C) without leaking, when closed at a closing torque not greater than that specified in table III and without damage or permanent deformation of any components.”

I hope this clarifies things. Get all relevant specs. The government has already decided what alloy to use, etc.
Ken

 

[israelkk]

kenvlach

Thank you for the detailed post. I was aware of the additional requirement to MIL-DTL-2F. I also managed to download NASA-STD-6001. However, I still have no answer if a stainless steel such as AISI 302, 304, 303, 321 or others can be used. Do you have any information concerning the use of stainless steels for medical oxygen systems?

 

[kenvlach]

SS is suitable in general, but not per MIL-DTL-2F & MIL-DTL-2/41D.