Proof of the greater danger from orange chrome is found in the fact that Dupré was able to wash 1 pound of dust (0·29 per cent.) from 345 pounds of heavy orange yarn, and only 1 pound (0·03 per cent.) could be washed from 3,300 pounds of light yellow or green yarn.
In none of the factories were the workers engaged solely on the dangerous yellow and orange chrome-dyed yarn. In some the work may last an hour or two every day, in others for an hour or two every day in alternate weeks, or for one week in every three or four weeks, and perhaps in a dozen factories the work may not be done more frequently than half a day a month, or even one in three months.
Particular attention was paid to the nature of the exhaust ventilation at the “heading” posts, as this is the most important point in the protection of the workers. It was provided in eight out of the nine principal yarn-dyeing factories. The exception was one where the work was said to be solely for the home market. In one a 2 foot 6 inch Blackman fan was placed in the wall without connection of the “heading” posts with it by means of ducts and hoods. In four, hoods and ducts of wood, square in section, with right-angle bends, had been locally applied to the posts. In other four, hoods and ducts were of metal, circular in section. The velocities in feet per minute (obtained with a Davis self-timing anemometer) were taken at the opening into the branch duct behind or under the post. The value of anemometric tests in detecting blockages or interference in the ducts is evident from the table on [p. 300].
| (1) | (2) | (3) | (5) | (6) | (7) | (8) | (10) | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fan. | Fan. | Fan. | Fan. | Fan. | Fan. | Fan. | Fan. | Fan. | Fan. | Fan. | Fan. |
| 240 | 820 | 330 | Nil | 1,200 | 420 | 450 | 210 | 780 | 570 | 700 | 850 |
| 450 | 450 | 20 | 420 | 510 | 210 | 570 | 700 | ||||
| 480 | 270 | 450 | 270 | 780 | 360 | 420 | 390 | 660 | 540 | 490 | 850 |
| 480 | (750) | 420 | 270 | 360 | 420 | 430 | 540 | 570 | 570 | ||
| 480 | 330 | Nil | 250 | 270 | 120 | 420 | 510 | 540 | 530 | ||
| 450 | (440) | Nil | 300 | 300 | 120 | 490 | 540 | 540 | |||
| 324 | 320 | 300 | 180 | 350 | 480 | 450 | 300 | 300 | 450 | ||
| 280 | (420) | 250 | 150 | 290 | 480 | 420 | 300 | 450 | |||
| 25 | 130 | 350 | 430 | 390 | 510 | 420 | |||||
| 25 | 220 | 180 | 420 | 360 | 460 | 400 | |||||
| 360 | 300 | 240 | 420 | ||||||||
| 240 | 280 | 450 | 480 | ||||||||
| Nil | 210 | 390 | |||||||||
| Nil | 210 | 390 | |||||||||
| Nil | |||||||||||
| Nil | |||||||||||
(1) The draught here was obtained from the main chimney-shaft. The small velocities at the end post, it was subsequently found, arose from the fact that the double heading post was connected by means of a very small duct to the end of the large duct which served the other posts.
(2) Wooden duct connected up with fan. The area of the openings into the duct could be enlarged or diminished by means of a shutter. The figures in brackets were those obtained when the shutter was fully opened.
(3) In this factory originally a 2 foot 6 inch fan was simply placed in the wall. Subsequently they were boxed in and ducts of wood brought within a foot of the noddling bar. Four of the branch ducts were found to be blocked.
(5) Wooden ducts and hoods behind bar both close to the fan.
(6) Circular metal ducts with curved angles, and placed about 8 to 10 inches behind post; all connected up with a 4 foot 6 inch fan. The small velocities (120 feet) at two posts was due to loose connection of the branch ducts allowing air to be drawn in at the foot.
(7) Metal duct distant about 2¹⁄₂ feet from the post, and situated immediately below and not behind the bar. Dust was prevented from rising above the post by a glass screen, the projection of which also prevented the worker from coming too near to, or getting his head over, the post.