If the distance between the face of two T-rails brackets (DBB) is 8' 11", what is the back-to-back guide (BBG) distance?

To determine the back-to-back guide (BBG) distance based on the given distance between the face of two T-rails brackets (DBB), it's important to understand the relationship between these dimensions. The BBG is essentially the distance measured from the back of one rail to the back of the opposite rail.

For T-rails, there is typically a specific calculation to convert the DBB measurement into the BBG measurement. The standard conversion involves subtracting a certain amount from the DBB measurement. In many elevator systems, the typical reduction from the DBB to find the BBG is around 1 foot and 1 1/2 inches.

Given that the distance between the face of the two T-rails brackets is 8 feet 11 inches, when you subtract the typical reduction (which we can consider to be 1 foot and 1 1/2 inches), you reach the correct BBG measurement.

Calculating this gives:

1. Convert 1 foot and 1 1/2 inches to inches:

• 1 foot = 12 inches

• 1 1/2 inches = 1.5 inches

• Total reduction = 12 + 1.5 = 13