Static Air Pressure; Condensate Losses; Table 15. Air Pressure Loss In Ahu/Duct - Nortec NHPC Engineer's Manual

(6) Absorption Distances:
3" centers = 7" (18 cm)
6" centers = 9" (23 cm)
9" centers = 12" (31 cm)
12" centers = 18" (46 cm)
(7) Reference Figures 19, 20, 21 and 22 to determine the center-to-center spacing
required.
1. The absorption distance data is based on 55°F (13°C) minimum temperature
before humidification.
2. Data is based on velocities between 200 fpm (101 cm/s) and
2500 fpm (1270 cm/s).
3. Absorption distance: This is the distance between the SAM-e and the first
obstruction (coil, elbow, damper, etc.) and the first obstruction steam may hit.
Traces of steam may pass this obstruction, but will not condense, leaving
obstructions dry.
4. If any of the duct AHU conditions are changed, the absorption distance may
change due to increase or decrease in duct temperatures, amount of fresh air,
various outside conditions, set point requirements, etc. If this occurs, re-calculate
the absorption distance, and determine if the SAM-e needs to be modified or
relocated.
C. STATIC AIR PRESSURE
(1) Table 15 shows the static pressure loss created by a SAM-e in various velocities.
Air Velocity fpm
(cm/s)
500 (255)
750 (383)
1000 (510)
1250 (638)
1500 (765)
1750 (893)
2000 (1020)
D. CONDENSATE LOSSES
(1) The SAM-e will condense some of the steam generated by the NORTEC humidifiers.
To compensate for this loss in capacity, we must increase the calculated humidification
load accordingly. Refer to Table 16.
10-10
Page 44
2008-10-01
NOTES

Table 15. Air Pressure Loss in AHU/Duct

Air Pressure Loss (inches of water column)
3" (7.6 cm) 6" (15.2 cm)
0.01 (0.02) 0.01 (0.02)
0.03 (0.08) 0.01 (0.02)
0.05 (0.013) 0.02 (0.05)
0.07 (0.18) 0.03 (0.08)
0.09 (0.23) 0.04 (0.10)
0.10 (0.25) 0.06 (0.15)
0.12 (0.30) 0.08 (0.20)
SAM-e Tube Spacing
9" (22.7 cm)
No measurable data
0.01
0.01
0.01
12" (30.5 cm)
0.01
0.01
0.01