• Building width is measured in bays. The maximum width of a ting tang is 9 bays.
  
• Bay width. A bay has one bracket set on the column (a columnar set) and either one or two sets between the columns (intercolumnar bracket sets). The centre-to-centre spacing of bracket sets is 125 fen +/- 25 fen; thus the width of a bay with one intercolumnar set is 250 fen +/- 50 fen, and with two intercolumnar sets is 375 fen +/- 75 fen. This gives a total range of 200-450 fen. The centre bay is often wider. In addition, in most extant examples the two outer bays are slightly smaller than the others.
  

Our sample building is 3 bays wide; the outer bays are 200 fen wide; the centre bay is 250 fen wide. Thus the width of the building is (200 + 250 +200) fen = 650 fen. At the 6th grade, 1 fen = 12.8 mm; thus the building is 650 x 12.8 mm = 8320 mm wide. (See illustration.)