CENTRAL GB - Ordering Length for Dry Pendent Heads; Flush Type Ordering Length; Recessed Type Ordering Length; Extended Type Ordering Length

2
Figure 2
Model GB and GB-QR Dry Pendent
Flush, Recessed
Figure 1
Model GB and GB-QR Dry Pendent
Extended
Dry Pendent Design Guidelines
To determine the K-factor, follow these steps:
1. Determine the K-factor length (NOT The “A” DIMENSION). The K-factor
is determined as follows:
Flush - “A” dimension +
7
⁄8" (22.2 mm) = length for K-factor.
Recessed - “A” dimension +
3
⁄8" (9.5 mm) = length for K-factor.
Extended - “A” dimension +3
1
⁄2" (88.9 mm) = length for K-factor.
2. Determine the K-factor for that length by using the K-factor table.
3. Use the K-Factor at the tee in the branchline for the calculations.
Finished Ceiling
LIne
1" (25 mm)
Thread
“A”
Dimension
(order length)
Main Tube
2 1/2" (63.5 mm)
±1/8" (3.8 mm)
Ceiling Opening
1 15/16" (49.2 mm)
Inner Cup Dia.
If A is > 3 1/4" (82.6 mm) Dimension is 4 5/8" (117.5 mm) (±1 1/2" (38.1 mm)) If A is ≤ 3 1/4" (82.6 mm) Dimension is 3 5/8" (92.1 mm) (±3/4" (19.1 mm))
Caution: See step one of installation sequence for appropriate fitting requirements.
Ordering Length for Dry Pendent Heads
Flush — The “A” dimension is measured from the face of the tee to the finished ceiling. This is only approximately flush. Order
to the nearest
1
⁄4" (6.4 mm). Minimum “A” dimension is 2" (50.8 mm).
Recessed — The “A” dimension is measured from the face of the tee to the finished ceiling. Minimum “A” dimension is 2
1
⁄8"
(54.6 mm). Adjustment is ±
3
⁄16" (4.8 mm).
Extended — The “A” dimension is measured from the face of the tee to the finished ceiling. Follow one of these two options:
If the “A” dimension is less than or equal to 3
1
⁄4" (82.6 mm), total adjustment is 1
1
⁄2" (38.1 mm) (from the mid point of the
adjustment range ±
3
⁄4" (19.1 mm)). Order to the nearest
1
⁄4" (6.4 mm). Minimum “A” dimension is 0".
If the “A” dimension is greater than 3
1
⁄4" (82.6 mm), the total adjustment is 3" (76.2 mm) (from the mid point of the adjustment
range ±1
1
⁄2" (38.1 mm)). Order to the nearest
1
⁄4" (6.4 mm). Minimum “A” dimension is 3
1
⁄4" (82.6 mm).
Length K-Factor (metric)
2
1
⁄2" (63.5 mm) to less than 10
1
⁄8" (76.4 mm) 5.3 (76.4)
10
1
⁄8" (254.1 mm) to less than 17
5
⁄8" (75.0 mm) 5.2 (75.0)
17
5
⁄8" (447.7 mm) to less than 25
1
⁄4" (73.5 mm) 5.1 (73.5)
25
1
⁄4" (641.4 mm) to less than 32
3
⁄4" (72.1 mm) 5.0 (72.1)
32
3
⁄4" (831.9 mm) to less than 40
3
⁄8" (70.7 mm) 4.9 (70.7)
40
3
⁄8" (1025.5 mm) to less than 48" (1219.2 mm) 4.8 (69.2)
K-Factor Table
Finished Ceiling
LIne
1" (25 mm)
Thread
“A”
Dimension
(order length)
Main Tube
2 1/2" (63.5 mm)
±1/8" (3.8 mm)
Ceiling Opening
1 15/16"
(49.2 mm)
Inner Cup Dia.
OBSOLETE