Posted by Tony Conner on June 01, 2001 at 07:37:39:
In Reply to: Re: Galvanized Pipe in Blowoff-Blowdown Systems posted by Craig on May 31, 2001 at 13:02:29:
All galvanized pipe is, is just A53F or A53B ERW mild steel pipe that has been dipped. I've never seen A106B seamless galvanized, or sch 80 of any grade galvanized, unless somebody had it dipped after they bought it. Once you do that, though, all of the heat numbers are buried under the galvanizing. Galvanized fittings are 150# malleable iron. I have seen 300# MI galvanized, but again, someone had the fittings dipped after they were purchased. Galvanized pipe was originally used for domestic water lines (and still is, occasionally), before copper water piping became popular after WWII. Why anybody still uses galvanized pipe for anything just baffles me, but I suppose it's still required by plumbing codes in some areas.
ASME B31.1 Power Piping Code covers a lot of these applications under the section "Boiler External Piping".