Most likely you want to place one trigger_multiple around the door. It should be long enough so that it stretches throught the door (in this case func_static) to both side of it. So that no matter from what direction you approach the door, the trigger would launch. The just set some wait value to the trigger, like 5 seconds (needs probably to be adjusted), so that the script won't try to launch too many times in too short a time. Target the trigger to a target_scriptrunner.
In the scriptrunner, set "count" to "-1", so that the door can be opened as many times as wanted. Then enter "usescript" key and as the value: "mymapname/hingeddoor". That is of course the path to the script and the actual script name. Naturally you must have under script folder a subfolder named after your map's name.
Ah, the func_static itself. Like I said, you need to have the actual visible door composed of as many brushes as you want. Then just insert the origin brush. It's just a brush covered with system/origin, an ugly orange shader. The exact center of that origin brush is the center of rotation. So if you look the door from above, the center of the origin brush needs to be where your hinges lie. The origin brush won't show ingame, it's just in the editor, and it doens't even need to be inside the actual visible entity. Give the func_static a "script_targetname" key with a value: "hingedoor".
Then you need to launch the good old, trustworthy BehavEd, and make the script. Start it with:
//Generated by BehavEd
affect ( "hingedoor", /*@AFFECT_TYPE*/ FLUSH )
task ( "opendoor" )
rotate ( < 0.000 90.000 0.000 >, 1400.000 );
task ( "closedoor" )
rotate ( < 0.000 0.000 0.000 >, 1400.000 );
dowait ( "opendoor" );
wait ( 3000.000 );
dowait ( "closedoor" );
Now, this script would rotate the func_static to point to the direction of 90 degrees in Radiant definition (in 1.4 seconds). If you don't set any angles to an entity in Radiant, it considers itself to point to 0 (=360) degrees, and so it would turn 90 degrees. In effect this script turns it 90 degrees, waits for 3 seconds, and returns it to point to 0 degrees, that is, to the original orientation. Save the script with a name hingeddoor, compile it and copy the .ibi file to the appropriate folder.
Of course, at some point, you might want to add horrible, rusty grating sound to the door, but I'm sure you are quite famialiar with that kind of procedures already.
That should be it. Most likely I forgot something, but this should give you some impression of the deeds needed to do the trick.