Wednesday, May 25, 2011

Nitpicking today – hinging of doors and arrows on stairs...

Go into any architectural consultancy employing people from different parts of the world and soon you’ll find two of them arguing about the way hinging of doors must be represented on drawings.

One school of thought says: the dotted lines form a symbolised arrow (symbolised symbol?) and indicate the opening of the door. The ‘opposition’ claims this to be misleading and wrong. The lines should connect the hinges with the door handle. Logical, of course!
Cadimage, the NZ Archicad-tool-developer is wisely catering for all tastes in their Doorbuilder. (see picture).

The above described issue is rather cute, specially when compared to arrows on stairs.
Here too 2 approaches exist:

One says, cut stairs at 1m above main floor level (as with the rest of the building). Allways show direction of rise with the arrow pointing upwards.

The other side promotes the same cutting process but with arrows going from the main floor both up and down. To avoid confusion ‘up’ and ‘down’ words are added.

There is another, third approach to this question that I find really amusing.
This approach advocates arrows pointing always upwards but the words alternating between ‘up’ or ‘down’ depending on the main floor’s relationship to the stair. (see picture);

Actually, not that amusing – having spent the day working on drawings strangely following this third approach – I have to ask: Why???


  1. Wow. What a drag. My comment got eaten.
    I went on at great length about the down side of using text to indicate stair directions and door hardware, my preference for relying on the Floor Plan to convey door swing (and sliding) direction, the problem of upward-acting doors, the revelation from scanning the 'net that the U.S. stair notation standard is Zolna's least favorite, AND unique in all the world, and the difference between graphic conventions (for 2D delivery) and BIM conventions (for multi-D and IFC delivery).
    Then I wrapped up with two questions:
    Why we (including myself) hardly ever reference even one standard in discussions like this? and
    How in the world can we hope to solve the more complex problems BIM has presented us with if we are still quibbling over what lines mean what in door elevations and stair plans?
    I also offered two solutions in a BIM environment. For doors: Reveal the hardware in the door object. It is independent of language, translates to IFC, and clearly indicates the location of the operator (as long as the exit device symbol has a left and right side. Forget the "triangle." For stairs, show two lines at each riser: a solid one for the nosing and a dashed one for the bottom of the riser - slightly beyond (in the direction of travel) the solid one on the UP flight, and slightly behind it on the DN flight. All the same reasons apply as for the door solution.
    This time, I copied the comment in case Google trashes it again.

  2. Sorry about the initial comment disappearing into the air – I tend to write mine in Word first for exactly this reason. The question you are raising somewhere mid comment (How in the world...) is so important. So important in fact that I will use it in my blog (will credit you with it);
    With regards to stairs, I’d say forget spending too much effort on the 2D projection representation of stairs – do not dress them up (if you use even mildly intelligent object to solve the stairs, they will do the nosing thing anyway); Provide axonometric views of stairs – cut at various levels and sectionally. Don’t assume people will work out stairs on site. They may eventually but at great cost in time and materials.

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