Help w/ Ballast example

Follow

Francis Pham

May 19, 2020 16:46

Hi All,

This is example 10.2 form the Ballast manual., it's killing me why i dont understand it.

 

 

 

 

 

 

 

 

I cant understand why the solution was to solve for gross area first then multiply gross area by LF.

R/U = rentable/useable....where is gross area in this equation? 

Thanks all!

1

• 

  Gang Chen May 24, 2020 06:08 (Edited May 24, 2020 06:16)

  In this case, usable sf is the gross sf. This link may help:

  https://42floors.com/edu/beyond-the-basics/usable-vs-rentable-square-feet

  Gang Chen, Author, Architect, LEED AP BD+C (GreenExamEducation.com)

  0

  Comment actions Permalink
• 

  Francis Pham May 27, 2020 00:04

  Hi Gang!

   

  Thanks for responding. I understand that in this case, the usable sf is the gross sf, however the question for me is still why and how? Ballast and Problem Seeking both define the difference between net, usable, rentable and gross, so i', confused on why 1) we have to solve of Gross, and 2) Where is gross in R/U equation? =)

  0

  Comment actions Permalink
• 

  Gang Chen May 27, 2020 02:02 (Edited May 27, 2020 02:03)

  In this case, usable sf = the gross sf.

  LF = R/U = rentable sf/usable sf = rentable sf/ gross sf

  So,

  rentable sf = gross sf x LF

  Or use the format in ballast:

  A _rentable = A _gross x LF

  Gang Chen, Author, Architect, LEED AP BD+C (GreenExamEducation.com)

  0

  Comment actions Permalink
• 

  Francis Pham May 27, 2020 02:14

  Hi Gang,

  Thanks again for taking the time to help me with this. I have a follow up question, why should we assume usable sf = gross sf when they represent two different types of spaces? Whats included in gross sf is not all included in useable sf.  The website referenced above specifically calls out " total square footage' & "useable square footage".

  Thanks!

  0

  Comment actions Permalink
• 

  Gang Chen May 27, 2020 03:03

  You are right. I guess in this case, usable sf should be used, and the gross sf should not even be mentioned at all. Otherwise, it’ll just confuse people.

  Gang Chen, Author, Architect, LEED AP BD+C (GreenExamEducation.com)

  0

  Comment actions Permalink
• 

  Francis Pham May 28, 2020 01:39

  Thanks for the help Gang. I don't know if it was just their poor word of choice or my lack of understanding. 

  0

  Comment actions Permalink
• 

  Rebekka O'Melia June 11, 2020 16:42

  Overall space would always be 'gross'.  When the insurance company determines the spaces they need, they are simply adding up the sf of required spaces like offices, conference rooms, and break rooms.  They are NOT adding in sf for hallways, or mech rms, so that needs to be added in. That's the .75 factor.  This problem identifies office plan inefficiency and overall building inefficiency (both are in the normal range too, fyi). The 1.2 building load factor accounts for bldg lobbies, lavs, main circulation, bldg loading dock areas, etc.  Work from inside the spaces, out...  HTH.

  0

  Comment actions Permalink
• 

  Francis Pham June 14, 2020 18:48

  Thanks for the help Rebekka ! I understand the break down, I just think it’s was the wrong choice of term that they used. Gross is clearly defined I. Their chapters .

  0

  Comment actions Permalink
• 

  Hang Cho June 18, 2020 23:28 (Edited June 18, 2020 23:29)

  I think gross means usable. (see Book Problem Seeking - page 101 or attachment)

   

  0

  Comment actions Permalink
• 

  Gang Chen June 18, 2020 23:45 (Edited June 18, 2020 23:46)

  I think in this case, Ballast probably meant “usable sf,” but he might have accidentally used the word “gross sf”, which opened a can of worms. The intent of the question was pretty clearly explained by Rebekka.

  Gang Chen, Author, Architect, LEED AP BD+C (GreenExamEducation.com)

  0

  Comment actions Permalink

Please sign in to leave a comment.