Humidifying Air with Steam - SI units

The table below can be used to estimate the amount of vapor in 100 m³ air volume.

Vapor in Air (kg per 100 m3airflow)
Dry Temperature (oC)	Relative Humidity (%)
	100	85	80	75	70	65	60	55	50	45	40	35	30
32	3.39	2.89	2.72	2.55	2.38	2.19	2.04	1.93	1.7	1.53	1.36	1.19	1.02
31	3.22	2.73	2.57	2.41	2.25	2.1	1.93	1.77	1.61	1.45	1.29	1.13	0.97
30	3.05	2.59	2.44	2.29	2.13	1.97	1.83	1.67	1.52	1.37	1.22	1.07	0.91
29	2.89	2.45	2.31	2.17	2.02	1.88	1.73	1.59	1.45	1.3	1.16	1.01	0.87
28	2.73	2.32	2.19	2.05	1.91	1.78	1.64	1.5	1.37	1.23	1.1	0.96	0.82
27	2.59	2.2	2.07	1.94	1.81	1.68	1.55	1.42	1.29	1.16	1.03	0.91	0.78
26	2.45	2.08	1.96	1.83	1.71	1.59	1.47	1.34	1.22	1.1	0.97	0.86	0.73
25	2.31	1.97	1.85	1.73	1.62	1.5	1.39	1.27	1.16	1.04	0.93	0.81	0.69
24	2.19	1.86	1.75	1.64	1.53	1.42	1.31	1.2	1.09	0.98	0.87	0.77	0.66
23	2.06	1.76	1.63	1.55	1.45	1.34	1.24	1.14	1.03	0.93	0.83	0.72	0.62
22	1.95	1.66	1.56	1.46	1.36	1.27	1.17	1.07	0.98	0.88	0.78	0.68	0.59
21	1.84	1.56	1.47	1.38	1.29	1.2	1.1	1.02	0.92	0.83	0.74	0.67	0.55
20	1.74	1.48	1.39	1.3	1.22	1.13	1.04	0.98	0.87	0.78	0.69	0.61	0.52
19	1.63	1.39	1.31	1.23	1.15	1.06	0.98	0.9	0.82	0.74	0.65	0.57	0.49
18	1.54	1.31	1.24	1.16	1.08	1	0.93	0.85	0.77	0.69	0.62	0.54	0.46
17	1.45	1.24	1.16	1.09	1.02	0.94	0.87	0.8	0.73	0.65	0.59	0.51	0.44
15	1.29	1.1	1.03	0.97	0.9	0.84	0.77	0.71	0.66	0.58	0.52	0.45	0.39
10	0.94	0.8	0.76	0.71	0.66	0.61	0.57	0.52	0.47	0.43	0.38	0.33	0.28
0	0.49	0.41	0.39	0.37	0.34	0.32	0.29	0.27	0.24	0.22	0.2	0.17	0.15
-5	0.33	0.28	0.26	0.25	0.23	0.21	0.2	0.18	0.16	0.15	0.13	0.11	0.1
-10	0.22	0.18	0.17	0.16	0.15	0.14	0.13	0.12	0.11	0.1	0.09	0.08	0.06

Note! In psychrometric charts and Mollier diagram the amount of vapor is given in kg/kg dry air. The values from the table above can be transformed dividing by the air density at the actual temperature.

Example - Humidifying Air with Steam

Air at 20^oC and 30% relative humidity are humidified to 20^oC and 80% relative humidity.

From the table above it can be estimated that air at 20^oC and 30% relative humidity contains 0.52 kg water vapor per 100 m³ air flow. Air at 20^oC and 80% relative humidity contains 1.39 kg per 100 m³ air flow.

The amount of water vapor can be calculated like

Amount of Water Vapor = 1.39 (kg) - 0.52 (kg)

= 0.87 kg

is the amount of water vapor necessary for an air volume of 100 m³.