23
Ta ble 5 – Filter Media Pressure Drop (Clean) Versus Airflow -- In. W.C. (Pa)
14 x 25 Filter
(356 x 635 mm)
Factory-Accessory
Washable
Factory-Accessory
Media*
Representative After-Ma rket Filter Media*
Fiberglass* Pleated*
CFM L/s (1-in. / 2.5 cm) (4-in. / 10 cm) (1-in. / 2.5 cm) (2-in. / 5 cm) (1-in. / 2.5 cm) (2-in. / 5 cm)
600 (283) 0.04 (12) 0.05 (12) 0.07 (17) 0.10 (26) 0.24 (60) 0.16 (40)
800 (378) 0.06 (15) 0.07 (19) 0.10 (25) 0.15 (39) 0.34 (85) 0.23 (59)
1000 (472) 0.07 (18) 0.10 (27) 0.13 (34) 0.21 (52) - - 0.32 (81)
1200 (566) 0.08 (20) 0.14 (36) 0.17 (43) 0.27 (68) - - - -
16 x 25 Filter
(406 x 635 mm)
Factory-Accessory
Washable
Factory-Accessory
Media*
Representative After-Ma rket Filter Media*
Fiberglass* Pleated*
CFM L/s (1-in. / 2.5 cm) (4-in. / 10 cm) (1-in. / 2.5 cm) (2-in. / 5 cm) (1-in. / 2.5 cm) (2-in. / 5 cm)
600 (283) 0.04 (10) 0.05 (13) 0.06 (15) 0.09 (22) 0.20 (51) 0.13 (34)
800 (378) 0.05 (13) 0.07 (18) 0.08 (21) 0.13 (32) 0.29 (72) 0.20 (49)
1000 (472) 0.06 (16) 0.11 (28) 0.11 (28) 0.17 (43) - - 0.27 (67)
1200 (566) 0.07 (18) 0.15 (37) 0.14 (36) 0.22 (56) - - - -
1400 (661) 0.08 (21) 0.19 (48) 0.18 (45) 0.28 (70) - - - -
1600 (755) 0.09 (23) 0.24 (60) 0.21 (54) - - - - - -
1800 (850) 0.10 (25) - - 0.26 (64) - - - - - -
20 x 25 Filter
(508 x 635 mm)
Factory-Accessory
Washable
Factory-Accessory
Media*
Representative After-Ma rket Filter Media*
Fiberglass* Pleated*
CFM (L/s) (1-in. / 2.5 cm) (4-in. / 10 cm) (1-in. / 2.5 cm) (2-in. / 5 cm) (1-in. / 2.5 cm) (2-in. / 5 cm)
800 (378) 0.04 (11) 0.05 (12) 0.06 (16) 0.09 (24) 0.22 (55) 0.15 (37)
1000 (472) 0.05 (13) 0.07 (18) 0.08 (21) 0.13 (32) 0.29 (72) 0.20 (49)
1200 (566) 0.06 (15) 0.09 (22) 0.11 (27) 0.16 (41) - - 0.25 (63)
1400 (661) 0.07 (17) 0.12 (31) 0.13 (33) 0.20 (51) - - 0.31 (79)
1600 (755) 0.08 (19) 0.15 (38) 0.16 (40) 0.24 (61) - - - -
1800 (850) 0.08 (21) 0.18 (47) 0.18 (47) 0.29 (73) - - - -
2000 (944) 0.09 (23) 0.22 (56) 0.21 (54) - - - - - -
2200 (1038) 0.09 (24) 0.26 (66) 0.25 (62) - - - - - -
25 x 25 Filter
(635 x 635 mm)
Factory-Accessory
Washable
Factory-Accessory
Media*
Representative After-Ma rket Filter Media*
Fiberglass* Pleated*
CFM L/s (1-in. / 2.5 cm) (4-in. / 10 cm) (1-in. / 2.5 cm) (2-in. / 5 cm) (1-in. / 2.5 cm) (2-in. / 5 cm)
800 (378) 0.03 (9) 0.03 (8) 0.05 (12) 0.07 (18) 0.17 (43) 0.11 (28)
1000 (472) 0.04 (11) 0.05 (12) 0.06 (16) 0.09 (24) 0.22 (55) 0.15 (37)
1200 (566) 0.05 (13) 0.07 (17) 0.08 (20) 0.12 (31) 0.27 (68) 0.18 (47)
1400 (661) 0.06 (15) 0.09 (23) 0.10 (24) 0.15 (38) - - 0.23 (58)
1600 (755) 0.06 (16) 0.12 (31) 0.11 (29) 0.18 (45) - - 0.28 (69)
1800 (850) 0.07 (18) 0.14 (35) 0.13 (34) 0.21 (53) - - - -
2000 (944) 0.08 (19) 0.16 (41) 0.16 (39) 0.24 (61) - - - -
2200 (1038) 0.08 (21) 0.19 (49) 0.18 (45) 0.28 (70) - - - -
If the filter size that you are looking for is not contained in Table 5, refer to Table 6 for a comparison of Pressure Drop (initial/clean resistance
to airflow) versus Face Velocity for a variety of filter media types.
The following equations relate Face Velocity (FPM), Filter Area and Airflow (CFM):
Filter Face Velocity = Airflow / Filter Area
Minimum Filter Area = Rated System Airflow / Maximum Filter Face Velocity
Table 6 – Filter Media Pressure Drop (Clean) Versus Face Velocity-- In. W.C. (Pa)
Face Velocity
Factory-Accessory
Washable
Representative After-Ma rket Filter Media*
Fiberglass* Pleated*
FPM (m/s) (1-in. / 2.5 cm) (1-in. / 2.5 cm) (2-in. / 5 cm) (1-in. / 2.5 cm) (2-in. / 5 cm)
200 (1) 0.04 (10) 0.05 (13) 0.08 (20) 0.18 (47) 0.12 (31)
300 (1.5) 0.05 (14) 0.09 (22) 0.13 (34) 0.30 (75) 0.21 (52)
400 (2) 0.07 (17) 0.13 (32) 0.20 (50) - - 0.31 (78)
500 (2.5) 0.08 (21) 0.18 (44) 0.27 (69) - - - -
600 (3) 0.09 (23) 0.23 - - - - - - -
700 (3.6) 0.10 (26) 0.29 - - - - - - -
Ta ble 7 – Air Filter Selection and Duct Sizing -- In. (mm)
FILTER CABINET HEIGHT --- IN (MM) F I LT E R S I Z E --- I N ( M M ) FILTER TY PE
14--- 3/16{ (360) 14 x 25 x 3/4 (356 x 635 x 19) Washable or Media*
16 (406)
(1) 16 x 25 x 3/4* (406 x 635 x 19) or
(1) 16 x 25 x 4---5/16 (406 x 635 x 110)
Washable or Media*
20 (508)
(1) 20 x 25 x 3/4* (508 x 635 x 19) or
(1) 20 x 25 x 4---5/16 (508 x 635 x 110)
Washable or Media*
24 (610)
(1) 24 x 25 x 3/4*or (610 x 635 x 19) or
(1) 24 x 25 x 4---5/16 (610 x 635 x 110)
Washable or Media*
* Recommended to maintain air filter face velocity. See Product Data for part number.
{ Not all families have these models.