gonzalez@bbn.com (08/16/89)
In a recent issue of this digest, Michael Warfield comments on color codes
for gas cylinders. The facts he presented are largely correct, but here is
some more detail. The information below is from 1982 issue of the Airco
Industrial Gases (AIG) Data Book.
AIG markets compressed gases for a variety of applications, including wafer
semiconductor fabrication. Airco Welding Products (AWP) markets the other
equipment needed for gas and arc welding. Both are headquartered at 575
Mountain Avenue in Murray Hill, NJ, directly across the street from Bell
Labs. Lovely neighborhood. Anyway, here's the data:
Oxygen:
USP (medical) oxygen is supplied in green cylinders with green
caps. All other standard grades are supplied in orange cylinders
with orange caps, with an aluminum ("silver") collar to specify
higher pressure.
Specialty grade comes in aluminum cylidner with orange collar.
Nitrogen:
For all standard grades, lower half of cylinder is painted orange.
Upper half is red or aluminum, depending on grade. Blue band in
middle denote prepurified nitrogen. Cap is orange, except for
2485 psig (as opposed to 2200 psig), which is aluminum.
Specialty grades come in aluminum cylinders with with collars.
White shoulder band denotes 6000 psig (3000 or less is normal).
Helium:
All standard grades have brown body with orange collar. Silver
shoulder band indicates 2200 psig, as opposed to 1800 or 2485.
Specialty grades have aluminum cylinder with brown collar. Brown
shoulder band indicates 6000 psig.
Carbon Dioxide:
All grades have aluminum body with orange, green, blue or brown
collar indicating grade (beverage, industrial, welding and "siphon").
Acetylene:
Black cylinder and cap.
Compresed Air:
Only specialty grade is listed. It is aluminum with white collar
and orange shoulder band.
Oddly enough, I had never given much thought to those cylinders by the
telephone poles. You can bet I will, now.
-Jim.roy%phri@uunet.uu.net (Roy Smith) (08/19/89)
For what it's worth, the only nitrogen tanks I've seen on the street
(marked "property of NYTel") are LN2 (liquid) tanks. You can get either
liquid nitrogen or gas out of them, depending on which valve you open. The
newer tanks are stainless steel (or at least they look that way). At the
lab, we get LN2 in either the stainless tanks, or similar sized older tanks
painted white. I've never seen the old white ones on the street.
It always struck me as odd that they left LN2 tanks laying around
where anybody could wander along and have a fast lesson in cryogenics.
--
Roy Smith, Public Health Research Institute
455 First Avenue, New York, NY 10016
{att,philabs,cmcl2,rutgers,hombre}!phri!roy -or- roy@alanine.phri.nyu.edu
"The connector is the network"onymouse@ames.arc.nasa.gov (John DeBert) (08/20/89)
Airco is not the only producer of compressed gases. There are quite a few who provide industrial and medical gases: Matheson, SPecialty Gas Products and Liquid Air Products are three that come to mind. Cylinders from Matheson and SGP differ in the color coding as described in the referenced article (not included because of it's size) quoting Airco's technical manual. As for Liquid Air, aside from the giant dewars used for liquified gases, I haven't seen their cylinders in some time and don't recall what colors they use. There would seem to be no way to be really sure about the contents of a cylinder without knowing who produced it and knowing the color scheme used. That's from a distance - up close, one can look for the DOT mandated labeling on the cylinder. JJD onymouse@netcom.UUCP