" A window with a minimum width of opening of 20 inches. A window with a minimum height of opening of 24 inches. A window with a minimum net clear opening — the actual opening through which a person must crawl — of 5.7 square feet. A sill height no higher than 44 inches above the floor. "

There's not really a "standard size" per se, however you will need to meet code requirements for egress, and also possibly for natural light depending on the size of the room and some other factors. Typically the most efficient window to install for that would be a casement as when open, most of the window is "clear opening" for egress purposes. Sliders are fine and will let more light in, but need to be larger as only one side can be open at a time so the net clear opening is less than half of the overall window size. For that reason, I actually question if the size that he recommended is sufficient. For 20" of egress on width for a slider, you are probably going to need a window closer to 44-46" wide. If natural light isn't a huge factor for you or based on the size of the room for code, then again, a casement would be a more efficient solution. You can also get them with egress hardware to reduce the size of the window even more.

Shouldn't this be a Google question...??

That window will not work for an egress. A 34" slider only opens to 17" (half the window). Any lumber yard / big box store will show you the windows they sell for egress - they are usually crank outs.

I’ve never seen a slider that opens to a full 50% if we are going to start throwing measurements out here, it would hit locks, lift rail, etc. Comment form HS about 5” or so over is about right. Id also avoid box stores or technical advice from the people that work there

To meet egress window in the basement the clear opening must be 5.0 SQ FT You will also need a window well at least 9 SQ FT with 36" min Horizontal and Width projections.

If you not planning to have a bedroom in the basement you can go with window he suggested.

Good luck

+1 about the slider size comments. 48 x 48 is a pretty common size when sliders are used for egress, although again, a casement with or without egress hardware would get you there more efficiently if that natural light percentage is not a factor based on the room size/usage.