Lounge access with purchased upgrade?
 

Yep, your boarding pass will say Class C or similar, and you will get most business class benefits including lounge access. Luggage allowance is based on the original ticket.

If the booking class is "I", you won't get into United Polaris lounges since those require paid business class tickets.
But since there isn't such a lounge at Washington, you'll be fine.
​​​​​​You'll be able to get into the United Club and other Star Alliance Lounges no problem.

EDIT: I cannot find this information anymore so I'm probably wrong and confused it with the Air Canada Signature Room.

Err, where do you have this information from? "I" is used for regular business class awards, as well as *A upgrades to business both of which should give you access to Polaris lounges.
But Plusgrade to business gets you into "Z" on SAS.

I've read in various places that Polaris access is only available with revenue tickets and not award (and iirc upgrades as well).
I also remember reading it on United's site but I cannot find it anymore.
So either I'm wrong or it was changed in the meantime.

EDIT: Since I cannot find it anymore I'll go with "I'm wrong". Sorry!

I know that that's what happens when bidding with cash, is it the same when using miles?

I remember seeing something similar, but I think the restriction were only for pax trying to access using UA loyalty program or flying on UA metal. And I think I saw it on the *A lounge access policy site.

As far as I know the only limitation on the points bids is the amount of points you earn. The rest should be the same.

You have to have an international *A business (or first) same day boarding pass (or arrive on UA international business with onward UA flight) to enter a Polaris lounge. Cards alone won't get you in. But I class gets access. I got access in October on LH C at ORD with bonus tickets booked in I class.

In IAD (any anywhere else) LH and TK will allow you into their lounges with a SAS business class boarding pass. United will too, but in IAD their facilities are impractically far away from the gates that SAS uses.

Either unknowing or lieing agent unfortunately. Haven't been departed from IAD in many years myself so not exactly sure of the location, but the star alliance website confirms there is a "gold track" which business a long with *G does get access to. And with business you'd have access to LH Business, TK lounge (& united club which would be a waste of time as it's far away and a worse lougne).

Upgraded tickets get you fast track at IAD. It is only half fast track, however - it gets you up to document control faster, but from there you are in the regular line. But I have never had to wait more than a few minutes for screening at IAD (unlike the arrival nightmare at the same airport). Lounge access is LH biz and TK, just as mentioned. Is there a United Club in the international terminal? Have to say I have never even contemplated looking for it...

Isn't that the same in almost any other airports in US? At least that's how I recall it last I passed through DTW, ORD, MIA and SFO.

Yes, everywhere I have been too. Just clarifying that it isn't like Europe where you have a dedicated line all the way in most places. Sometimes, of course, this isn't the best option, like ARN T4 between 16:00 and 18:00 weekdays when everyone has status and uses fast track - my experience is that the regular security line is faster most of the time then.

Well, I never saw a fast track lane. However, I have never waited more than a couple of minutes for document check at IAD. The line for screening though is routinely 30+ minutes (and so it was on Monday when I was there). Never mind, I still had some time in the LH lounge and a very nice flight (although I now know that I still only get about 2,5 hours sleep IAD-CPH regardless of how I travel ...).

- DanishFlyer