OXYGEN COMPATIBLE AIR (OCA): SPECIFICATION
Analysis of OCA is also complicated by the misunderstanding as to what specification is appropriate. The most common specifications for OCA come from AAUS, ANDI, IANTD and the US Navy. Although all agree on lower levels of condensable hydrocarbons (0.1 mg/m3 ), a problem exists regarding particulate.
Expecting an air sample taken from piping in a Dive Shop to be free of 2 microns particles is difficult to achieve. Think about it. Aside from the absence of experimental data to support the 2 micron theory, the specification is even far more stringent than for a Class 100 clean room. It is also more stringent than that used by the world’s best authority on oxygen systems: NASA.
We have designed a specification which utilizes: existing specifications, NASA criteria for oxygen handling equipment, and a knowledge of what is reasonable with current sampling and analysis techniques. We give it here as a draft version, and we have included our rational to allow peer review criticism.
COMPONENT |
|
|
|
|
|
Oxygen %
|
20-22 |
20-22 |
N.A. |
20
-22 |
20-22 |
Carbon Dioxide ppmv |
500
|
500
|
500
|
1000
|
1000
|
Carbon Monoxide ppmv |
2
|
2
|
10
|
2
|
10
|
Total (Volatile) Hydrocarbons Including
Methane ppmv |
|
|
|
|
|
Halogenated
Hydrocarbons Including Freons ppmv |
|
|
|
|
|
Oil Mist + Particulate mg/m3
|
0.1
|
-
|
-
|
-
|
-
|
Condensable HC's mg/m3 |
-
|
0.1
|
0.1
|
0.1 |
0.1
|
Particulate
mg/m3 |
-
|
-
|
-
|
-
|
-
|
Particulate Size microns |
|
2.
|
1.
|
- |
Per NASA * |
Fibers microns |
-
|
-
|
-
|
-
|
Per NASA * |
Dew Point no warmer than |
|
- 50º F |
- 40º F |
Per client |
- 40º F |
Pronounced Odor |
|
|
|
|
None |