British Manufacturer Of Custom Built Air Handling Units

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AHU Sizing Guide

Unit Size	External Width	External Height	Standard Base Height	High Volume (3m/s)	Mid Volume (2.5m/s)	Optimum Volume (2m/s)
1	750	590	74	0.51	0.43	0.34
2	750	830	74	0.84	0.70	0.56
3	1050	830	74	1.38	1.15	0.92
4	1250	950	74	1.85	1.72	1.38
5	1350	950	74	2.28	1.9	1.52
6	1350	1110	74	2.66	2.32	1.86
7	1350	1190	74	3.02	2.52	2.02
8	1350	1350	74	3.40	2.94	2.35
9	1450	1350	90	3.89	3.22	2.58
10	1550	1350	90	4.16	3.50	2.80
11	1650	1350	90	4.62	3.78	3.02
12	1750	1350	90	4.75	4.06	3.25
13	1950	1350	90	5.35	4.62	3.70
14	1950	1430	90	5.94	4.95	3.96
15	1950	1670	90	7.06	5.89	4.71
16	2550	1430	140	8.05	6.71	5.36
17	2550	1670	140	9.59	7.99	6.39
18	2550	2030	140	11.99	9.99	7.99
19	3200	2030	140	15.36	12.80	10.24
20	3200	2390	140	18.44	15.36	12.29
21	3200	2630	140	20.48	17.07	13.66
22	3800	2630	140	22.97	19.14	15.31
23	4400	2630	140	27.29	22.74	18.19
24	5000	2630	140	31.61	26.34	21.07
25	5600	2630	140	35.93	29.94	23.95
26	6200	2630	140	40.25	33.54	26.83
27	6200	2800	140	40.25	33.54	26.83

Approximate Component Section LengthsApproximate Component Section Weights

Notes:

• Dimensional restrictions may dictate a higher velocity of around 3m/s. This, however, is likely to mean that the air handling unit specific fan power will exceed Building Regulations requirements.
• Subject to external static pressure and internal components, Building Regulations requirements may be met at an air handling unit velocity of 2m/s.

Instructions:

• Choose velocity required (3m/s = red, 2.5m/s = orange, 2m/s = green)
• Select volume required from table (or next highest value)
• Read off Unit Size, External Width and External Height from left hand columns
• Add base height to external unit height and 50mm for pitched roof if the unit will be sited in an external location