Is There a Standard for Symbol Sizes that are Not to Scale?

[David_Feynman]

Let's say I'm working on a floor plan for a typical residence that is scaled to 1/4" = 1' on a 36 x 34 sheet. Is there a standard size for symbols that are not to scale, such as phone, televisions and light switches? And if so, what is it?

 

Also, if I receive a floor plan that is scaled to 1/8" = 1', do I scale the symbols to half of the size to whatever the answer is to the above, at which point they are pretty much unreadable?

 

I am not an architect (obviously), but I'm trying to gain an understanding of this. I searched online and while I can find tons of standards for architectural plans, I could not find any reference for a standard for symbols that are not to scale.

 

Thanks

[bass_mark00]

David, there aren't any standards for sizes of symbols. In the old days we used to use stencils which used to regulate the sizes but now there's no convention. The main intention of any drawing is clear communication and so your primary aim should be legibility. Fortunately, this is still one area that the nannies haven't got their hands on, and it's up to draughtsman to decide the size of symbols.

 

Regarding scaling of symbols; your CAD blocks should be scaled up or down depending on the output scale of your drawings. I work in metric so I'll give metric examples: all of my electrical blocks are sized for use on drawings to be printed at 1:100. If I need to produce a drawing at 1:50, I then halve the scale of the blocks otherwise they would print out at double the intended size when printed at 1:50. For 1:10, reduce by a scale of 10. For 1:20, reduce by a scale of 5 etc. By using this method, the symbol should print out at the same size regardless of the output scale of the drawing.

 

If you are working regularly between different scales and need to use the same symbols, it would be worth considering converting them to dynamic blocks and including a number of visibility states which would allow you to simply click through different sizes of each block. There's also the option of using annotative blocks but that's likely to open up other cans of worms and is probably best avoided. If you have all of the symbols together in a Key, a simple solution is that you could just scale the whole lot up or down at once and then simply copy them into place where needed.

 

Hope that helps.

[ReMark]

You should not be drawing anything to scale in model space. Draw everything full size. If a room is 10'x12' then draw it to those dimensions. If a doorway is 36" wide then draw it that way. The time to worry about scale is when you switch to your paper space layout and start creating your viewports. Each viewport you use is assigned a scale.

 

I see symbols used mainly in electrical layouts for such things as outlets, lights, and switches. If these were drawn at full size they would still be so small as to be virtually useless.

 

You might consider buying a good architectural drafting/design book to help you sort out some of your questions. Books of this type almost always contain samples of the drawings one would encounter in an architectural practice such as foundation, floor plan, roofing plan, electrical layout, plumbing, elevations, sections and details.

[David_Feynman]

bass_mark00 thanks, perfect answer, that tells me exactly what I needed to know.

 

ReMark, thanks as well. In fact I was just looking at all of my options on Amazon yesterday to decide what reference book I should buy on the subject. I found some very good ones but it was my inability to find any standard (which I now know is because there isn't one) for this particular issue either there or on Google that prompted my question.

[ReMark]

The bible: Architectural Graphics Standards.

[Quagga]

Everything is 1:1 light switches are 160mm[6"] dia.

 

Hope this helps

Sheet-A103-NEWOFFICES-FloorPlan-CalloutofLevel2.dwg

[bass_mark00]

Another good recommendation for a book is a UK publication called Architect's Pocket Book by Charlotte Baden-Powell. Obviously it's specific to the UK but one that's worth looking into.

[David_Feynman]

Thanks for all the answers. Quagga, thanks for the file, am downloading it so I can check it out now.

[SuperCAD]

Most of my electrical blocks (i.e. switches, outlets, lights, etc) fall within a 9" circle in model space. This allows them to show up decently at 1/4" scale and not take up too much room.

[harrison-matt]

There are two types of symbols:

Scale-Dependant:

Symbols that change size dependent on the scale factor of the viewport.

 

Scale-Independent:

Symbols that stay the same size regardless of the scale factor of the viewport.

I.E. Doors, Windows, Large Mechanical Equipment, Columns, etc.

 

Concept:

Think of relationship between modelspace and paperspace much like a sheet of paper with a hole in the middle (paperspace), a table below the paperspace (modelspace) and the distance between the paper and the table is the scale, as you move the paper further away from the table the scale increases and the range of the view increases.

 

Now the relationship between modelspace and paperspace can be calculated equating to a scale factor. When you don't know what factor the scale is for your viewport run this equation.

 

1/4" = 1'-0"

1'-0"=12" & 1/4"=0.25"

12/0.25=48

48=The viewport scale factor.

 

Take this example a bit further:

Lets say your target size of text on paperspace is 1/8" Height and you want the text to be present in modelspace so you simply multiple 1/8" by 48 which equals 6". So text drawn in modelspace in a viewport that is 1/4"=1'-0" needs to be 6" high to be presented as 1/8" on paperspace.

 

This works fine for text however the same can be applied to symbols. Now most electrical and plumbing symbols are Scale Dependent so there size purely rely on how they are represented on paperspace. You should consider when you create a symbol how that symbol will look on paperspace. So a good practice is to draw the symbol on paperspace change the sizes to your liking. Then create a block of the entities. If you created the block while it was on paperspace then the block's scale factor would be 1 allowing you to change the scale factor of the block to match the factor of the viewport to achieve the same scale represented on paperspace.

 

Considerations:

1. The block properties should be set to Scale Uniformly. You will see why.
   
2. Placing the base point of the block where, say, the point at which the switch is placed on the wall. The reason of which you can simply change the scale of the block and the switch will remain on the wall!
   
3. These steps are great for creating what I call hard scale situations, hard scale meaning with direct relationship to scale factors. You should consider looking into Annotative blocks to experiment with soft scales where blocks interact with annotation scales on their own rather than you having to change the scales your self.
   

 

Kind Regards,

 

Matt