Welcome to GH Gordon.
I also do a lot of drafting in my day job. So I definitely get the need for a full board. I currently have a Razer Blackwidow that I bought as my entry board. I also have a Filco Ninja Majestouch 2 and a Leopold FC700R which is TenKeyLess. I'd recommend not going TKL at work. I have the Blackwidow sitting at work but I'm going to be bringing in my Filco soon. Filcos are nice because they're simple looking. That goes the same for a Leopold. They have a simple design and really good quality. The Razer is a bit flashy (in case you care about what people think of your board) and I'm starting to not like how it feels when I type on it as compared to my other boards.
All three of my boards are blue and I don't think they're terribly loud. And at work, only one co worker has said anything. My office is filled with frustrated engineers blasting away at their rubber domes, people on the phone/in meetings, and the hum of computers/heaters/air conditioners. All the black noise seems to mask the noise of my keyboard. In fact, I know that some of the people I work with mash their RD boards and are louder than my BlackWidow or Filco.
Blues feel really really nice to type on. And if you're like me, you're typing A LOT all day between emails and drawings. If you're a bit skeptical on the sound of blues, I'd say order a
WASD Sampler Kit. Look on Youtube for videos on the switch sounds. Like inteli722 said, they all make a lot of noise. More than a rubber dome board would.
If you're determined to get a brown or a red board, I'd stick with a browns. I prefer Filco Majestouches or Leopold FC500s. Filco's can be found on Amazon. Leopolds at Elitekeyboards.
If you have any more questions, feel free to ask or PM me ^_^