§ 84.172 - Airflow resistance test.

§ 84.172 Breathing tubes; minimum requirements.

Flexible breathing tubes used in conjunction with respirators shall be designed and constructed to prevent:

(a) Restriction of free head movement;

(b) Disturbance of the fit of facepieces, mouthpieces, hoods, or helmets;

(c) Interference with the wearer's activities; and

(d) Shutoff of airflow due to kinking, or from chin or arm pressure.

Airflow resistance test.

(a) Resistance to airflow will be measured in the tight-fitting respiratory inlet covering of a complete particulate respirator mounted on a test fixture with air flowing at continuous rate of 85 ±2 liters per minute, before each test conducted in accordance with § 84.173.

(b) Resistance of a complete tight-fitting powered air-purifying particulate respirator system will be measured with the blower off if the manufacturer indicates that the respirator should not be doffed in the event of a blower failure.

(c) The maximum allowable resistance requirements for air-purifying particulate respirators are as follows:

Maximum Resistance

[mm water-column height]

Respirator type	Inhalation		Exhalation
	Initial	Final
Non-Powered (N, R, and P)	35	N/A	25
Powered (tight fitting) (HE class and PAPR100 class)	50	70	20