Signs, signs, everywhere there are signs

I am sure some of you have noticed the little white signs with a red border and the letters ‘’BMZ’’ on the outside wall of some commercial buildings. Sometimes it is accompanied by an arrow. So what the heck does it mean? There is a ''BMZ'' newletter that appears monthly in my e-mail @ work. It is from the ''Bundesministerin für wirtschaftliche Zusammenarbeit und Entwicklung (BMZ?)''
(The Federal Ministry for Economic Cooperation and Development) are these two related?

it's for the fire dept.

It's short for Brandmeldezentrale. I believe it means that the place has a sprinkler system or a smoke detector system. I'm a bit fuzzy on the details. And they drove me crazy when I first moved here too, wondering what they meant.

do this dont do that...cant you read the signs???

I've actualy seen this one in Munich.

.

I'm not sure which would be worse:

- Having the sign there 100% of the time and zero hundescheiss

or

- Not having the sign there, and having hundescheiss now and again

On a related matter, on the sides of many roads there are round yellow signs with one or more arrows in each direction and a number, possibly a speed limit. Does anyone know what these are for? I've asked several Germans but they have no idea themselves.

That could be a sign to indicate a B-road.

Don't think so, it's not a general sign for all motorists. They're pretty low to the ground. The best suggestion I've had so far is that it's for the military.

They signify weight limits on bridges.

Edit: found this (in German)

This has been covered before. Signs

Thanks guys

The BMZ area/signs at larger building areas tell the fire dept. where to hook/up the water and park the trucks should there be a fire.. The signs are also to mark the entrance to this area, thus they should not be blocked (Parked cars etc)

Thanks all! On to the next quandary!...