A Study Of Dust Control Methods In An Asbestos Fabricating Plant

Our plain-English summary of A Study Of Dust Control Methods In An Asbestos Fabricating Plant, by R.T. Page, J.J. Bloomfield (1937).

The study

• Authors: R.T. Page, J.J. Bloomfield
• Published: Public Health Reports 52(48):1713-1727, November 26 (1937)
• Type of article: Government report
• Our copy: from Johns-Manville's own medical library, J-M no. 002925.

In plain English

This 1937 report by U.S. Public Health Service engineers, supplementing a larger Service study of asbestos workers' health, described dust control methods in one asbestos textile plant. The plant employed about 300 people, 180 in departments with a potential asbestos dust hazard. The authors took 82 dust samples at workers' breathing level: 69 under normal working conditions and 13 with exhaust ventilation turned off. They also calculated air drawn through the exhaust systems, mostly from velocity measurements in the ducts. Results were in M.P.P.C.F., the article's dust-count unit. With exhaust running, dry looms averaged 0.7 and carding averaged 1.7. With exhaust fans off for 1 hour in preparation, while pneumatic conveyors kept running, dust rose to about 50. The authors called this only a partial measure of uncontrolled conditions. In a special carding run with exhaust off and windows closed, dust reached 62.4 after 1 hour. Twisting, mostly without exhaust, averaged 11.0. Noting the program was only partly complete, the authors concluded that, while threshold limits for asbestosis had not been established, conditions reached by practical dust control could serve as temporary industry standards.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Industrial hygiene and engineering survey of dust control methods in a single asbestos textile plant, supplementing a larger U.S. Public Health Service medical and engineering study of asbestos workers. Dust was sampled with an impinger at breathing level. Exhaust air volumes were calculated from pitot tube measurements in the pipe lines. Hood volumes were calculated from main-line velocities where individual measurements were impractical.
• Who was studied: One asbestos textile (fabricating) plant, not named and with no location given, reported in 1937. It had about 300 employees, of whom 180 worked in the departments studied: preparation; carding; spinning, twisting and winding; and weaving.
• Exposure: Airborne asbestos dust from textile processes: crushing, opening, mixing, picking, carding, spinning, twisting, winding, weaving and inspection. Raw material was practically all crude Canadian or South African asbestos, mixed with cotton. Exposure was measured as dust counts in M.P.P.C.F., with and without exhaust ventilation.
• Main results:
  • Of the 82 dust samples, 69 represented present working conditions and 13 represented conditions with the exhaust apparatus turned off for 1 hour.
  • In the preparation department, the exhaust fans were shut off for 1 hour while pneumatic conveyors remained in operation. Dust concentrations rose steadily to about 50 M.P.P.C.F. The authors described this as only a partial measure of uncontrolled conditions.
  • In the carding department, dust concentrations during carding averaged 1.7 M.P.P.C.F. under normal operating conditions.
  • In a special run of a group of carding machines with all exhaust ventilation turned off and windows closed, the dust concentration was 62.4 M.P.P.C.F. at the end of 1 hour.
  • Inside an active carding-room stock bin, dust reached as high as 40.4 M.P.P.C.F. Just outside the door of the same bin, it was 4.6 M.P.P.C.F.
  • Weavers on dry looms with exhaust had an average exposure of 0.7 M.P.P.C.F. Wet weaving without exhaust averaged 2.6 M.P.P.C.F.
  • Samples beside a dry loom without exhaust showed 9.6 M.P.P.C.F.
  • Twisting, where all but one trial machine had no exhaust, averaged 11.0 M.P.P.C.F. A maximum of 18.8 M.P.P.C.F. was recorded beside a twisting frame.
  • At the Foster winders (spoolers), dust averaged 2.9 M.P.P.C.F. It rose to 9.6 M.P.P.C.F. within 30 minutes after the ventilation was shut off.
  • During picker charging in the preparation department, dust ranged from 4.0 to 9.5 M.P.P.C.F. and averaged about 6.7 M.P.P.C.F. Picker operators wore respirators during charging.
  • During cloth inspection with exhausted brushes, dust averaged 0.5 M.P.P.C.F.
• The authors' conclusion: The authors stated that published data were not yet adequate to set threshold limits of dustiness for asbestosis. They held that any appreciable decrease in asbestos dust would decrease the incidence and severity of asbestosis. They concluded that conditions achieved by practical dust control could be used as temporary standards by an industry.
• Limitations the authors state:
  • The plant had only partly completed its dust control program, so the authors said the results should not be read as the maximum possible efficiency of asbestos dust control.
  • Each dust-controlled process tended to lower dust in later processes. The authors said this must be considered when comparing this plant's results with other plants.
  • The samples taken with the preparation-department exhaust fans off were only a partial measure of uncontrolled conditions, because the hoods and enclosures still had some control value.
  • No accurate measurements could be obtained of the efficiency of the trial exhaust system on the single exhausted twister.

Topics

Medical terms in this study, explained in our Lexicon: Dust Control, Carding.

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