42 C.F.R. § 84.103 – Man tests; performance requirements.

(a) The apparatus shall satisfy the respiratory requirements of the wearer for the classified service time.
(b) Fogging of the eyepiece shall not obscure the wearer's vision, and the wearer shall not experience undue discomfort because of fit or other characteristics of the apparatus.

(c) When the ambient temperature during testing is 24 ±6 °C. (75 ±10 °F.), the maximum temperature of inspired air recorded during man tests shall not exceed the following, after correction for deviation from 24 °C. (75 °F.):

Where service life of apparatus is—	Where percent relative humidity of inspired air is—	Maximum permissible temperature of inspired air shall not exceed—
°F.	°C.
1⁄4 hour or less	0-100	135	57
1⁄4 hour to 3⁄4 hour	0-5050-100	1251 110	521 43
1 to 2 hours	0-5050-100	1151 105	461 41
3 hours	0-5050-100	1101 100	431 38
4 hours	0-5050-100	1051 95	411 35
1 Where percent relative humidity is 50-100 and apparatus is designed for escape only, these maximum permissible temperatures will be increased by 5 °C (10 °F).