42 CFR § 84.146 - Method of measuring the power and torque required to operate blowers.

---
identifier: "/us/cfr/t42/s84.146"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "42 CFR § 84.146 - Method of measuring the power and torque required to operate blowers."
title_number: 42
title_name: "Public Health"
section_number: "84.146"
section_name: "Method of measuring the power and torque required to operate blowers."
chapter_name: "PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "G"
subchapter_name: "OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES"
part_number: "84"
part_name: "APPROVAL OF RESPIRATORY PROTECTIVE DEVICES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "29 U.S.C. 651  30 U.S.C. 3, 5, 7, 811, 842(h), 844."
regulatory_source: "60 FR 30355, June 8, 1995, unless otherwise noted."
cfr_part: "84"
---


# 84.146 Method of measuring the power and torque required to operate blowers.

As shown in Figure 1 of this section, the blower crank is replaced by a wooden drum, a (13 cm. (5 inches) in diameter is convenient). This drum is wound with about 12 m. (40 feet) of No. 2 picture cord, b. A weight, c, of sufficient mass to rotate the blower at the desired speed is suspended from this wire cord. A mark is made on the cord about 3 to 4.5 m. (10 to 15 feet) from the weight, c. Another mark is placed at a measured distance (6-9 m./20-30 feet is convenient) from the first. These are used to facilitate timing. To determine the torque or horsepower required to operate the blower, the drum is started in rotation manually at or slightly above the speed at which the power measurement is to be made. The blower is then permitted to assume constant speed, and then as the first mark on the wire leaves the drum, a stopwatch is started. The watch is stopped when the second mark leaves the drum. From these data the foot-pounds per minute and the torque may be calculated.