---
kind: "section"
citation: "42 C.F.R. § 84.179"
title: "42"
number: "84.179"
heading: "Silica dust loading test—PAPR series HE filtration."
url: "https://uscodex.org/cfr/42/84.179"
---

# §84.179. Silica dust loading test—PAPR series HE filtration.

- (a) Three powered air-purifying particulate respirators will be tested for a period of 4 hours each at a flowrate not less than 115 liters per minute for tight-fitting facepieces, and not less than 170 liters per minute for loose-fitting hoods and helmets.
- (b) The relative humidity in the test chamber will be 20-80 percent, and the room temperature approximately 25 °C.
- (c) The test suspension in the chamber will not be less than 50 nor more than 60 mg of flint (99 + percent free silica) per m 3 of air.
- (d) The flint in suspension will be 99 + percent through a 270-mesh sieve.
- (e) The particle-size distribution of the test suspension will have a geometric mean of 0.4 to 0.6 µm and the standard geometric deviation will not exceed 2.
- (f) The total amount of unretained test suspension in samples taken during testing must not exceed 14.4 mg for a powered air-purifying particulate respirator with tight-fitting facepiece, and 21.3 mg for a powered air-purifying particulate respirator with loose-fitting hood or helmet.

## Notes

### Source

Source: 85 FR 20608, Apr. 14, 2002, unless otherwise noted.

### Authority

Authority: 29 U.S.C. 651 et seq.; 30 U.S.C. 3, 5, 7, 811, 842(h), 844.

### Source

Source: 60 FR 30355, June 8, 1995, unless otherwise noted.