Document NeBz0MEpZva6EMRrQnROvQkvD

For Inter-Organization Letters of FRIGIDAIRE DIVISION GENERAL MOTORS CORPORATION Jane 3, 1944 DEPUTMENT KAPSIY Hr. Hay lialtOD, Supervisor Department #711 re: Employe grievence #10714, by Basil Pearson, 711B-032 reIntire to dust conditions in blade grinding. Plant #2. Piled June 2, 1944. On May 25 Mr. J. S. Brown, Mfg. Process, Plant #2 called my attention to general complaints in regards to dust plugging the screens placed over the exhaust rents on a good many of the blade benches in Department #711. These screens are one inch mesh and are Installed in a fixed position over the entrance to the exhaust slot in such a manner that it Is very difficult to remove coarse aluminum grindings from behind them and in front of the rents. The screens were installed in answer to a request of the fire insur ance underwriters to prevent oily rags, paper and pieces of steel from entering the exhaust system and causing fire damage. Sereral dust determinations were made prior to the filling of grievance #10714 and are Included in the data below. Ttoo counts were made on the Job of Pearson, 711B-032, to show the effect of stoppage of exhaust ventil ation. Dust counts were also made on polishing operations in this area*. Operators remarked that their hoods did not plug like thegrinding hoods, but that paraffin wax did collect on the hoods at the rents and should be cleaned frequently. One count was made on the Job of A. Schuh, 711B-215, when the Dracco system was down for repairs. This high count showr that dust protection should bo provided when it is necessary to snut down the duat collectors. Scabbing operation with #16 emery grit on camber aide of il. S. blade. Air samples taken in breathing zone. Employe Bench Post Blade Vent condition Disc Dust particles per cubic foot of air. B. Pearson 118 K-as Z Plugged except #1 711B-022 for 20 inches from shank end m r ft Cleaned n J. Cook 711B-163 66 1-87 r 5/8 the plugged n If It VI Cleaned m 3,000,000 1,530,000 5,no,ooo 1,024,000 ft0 -2- June 3, 1944 Employe Bench Post Blace Vent condition Disc Dust particles per cubic foot of air Roy Etas11 64 711B-028 J-05 S 5/8tha plugged #16 3,240,000 w It "4 " Cleaned ft 3,010,000 Note: In the case of Small there was a steady strong currant of air blowing across his work position from the rear. The following, polish operations were also checked. These benc ho a were not plugged because of the finer dust. X. Richerds 119 K-84 Opened 711B-220 #80 3,920,000 n It ft It #120 2,200,000 A. Schuh 711B-215 202 J-78 F Blower shut <down #120 old 34,700,000 It 60 1-63 " Opened m It It It ft m ft m It #50 #80 #120 3,600,000 2,350,000 4,100,000 Aluminum dust is considered non-toxic to the human lungs. Authorization for this statement is based upon findings of J. L. Blaisdell, U.D. and others working on the prevention of silicosis in London, Ontario in Canada. Their work has proven aluminum dust harmless to the lungs and a definite benifit in prevention of silicosis, a lung disease caused only be free silica dust (SiOg). Further fact regarding the harmless nature of aluminum is shown by the use of aluminum oxide and other alum inum salts in a great many stomach medicines. Frigidaira Dust Policy has Included limits of 5,000,000 particles c dust per cubic foot of air. This limit is considered safe by the Industrial Hygiene Engineer of the Ohio Industrial Conalsalon. Sev.-ral operators have coop la load to me, while taking dust counts, that the "trench" or exhaust slot in the reer of the bench is too narrow to allow large masses of aluminum to pass. These exhaust slots are designed to give an -iven distribution of exhaust air flow ov-.ir the full length of the slot and at a definite rate of speed. They can not be wldenod without sacrificing the air speed and thus the amount of dust particles that wia.1 be drawn down from the grinding operation. These v-mts were not designed to trap ell of the grinding dust, but were set up to keep a steady flow of air across the operator's breathing zone and tnus clear the fine dust from the air. Many previous air analyses have shown the Frlgidairo dust limit of 5 million particles per cubic foot of air to be satisfactory for Department 711, blade grinding. -3- June 3, 1944 I found it true that screens placed over the exhaust vents make it vary difficult to clean the benches. As much as 15 or 20 minutes time was required to clean some Of the badly plugged scresns. The men used files and hammers to loosen the "balled" aluminum. I 8Iso noted that men were hammering on the backs of the hoods. Ibis will in time bend the slots out of shape. An investigation into the reasoning behind the placing of screens over the exhaust vents on these blade benches has revealed that this was recommended by the Western Factory Fire Insurance Company, underwriters for Frigldalrs Division. Inasmuch as the Fire Insurance Company has demanded that we install screens on these benches, v ry little can be done toward removing them without the insurance coopany's permission. Saturday noon a meeting with Uossers Trottman, Brown, Pantz, G. Fischer, Daeter end myself, was held and the matter of either removing the screens or putting hinges on them was discussed. It was decided that tha Insurance company be contacted at onoe regarding the problem of bench cleaning and dust removal for their decision in these matters. Meanwhile, the Process Department is obtaining estimates on the cost of putting hinges on the screens. In summary the above dust counts on benches when scabbing operations are performed, do not show health hazards, but rather that the problem of removing dust from benches and screens presents a time loss, as well as dissatisfaction among operators. These exhaust systems likewise provide air changes in the operator's working position and thus enable the oper ator to remain reasonably coofortable. In this manner air flow through the exhaust vents cuts down the number of cases of heat raah. c.c. Messers M. H. Shafer, M.D. B. T. Trottman H.?2.Hoges T. L. Pantz G. !!. Fischer C. H. Deeter H. D. Pine R. I. Douglas J. S. Brown R. F. Zimmerman H. S. Kline Industrial Hygiene Lab. I)F PigTMFi T SAFETY May 22, 1944 Dr. M. Li. Shafer ra: Dust counts on Blade buffing and polishing operations, Dapt. 711, Plant #2. According to Vr. Rhodes, Ufg. Prooess Department, baffles hare bean re moved from Buffit* and polishing hoods in Department #711, Plant #2. Ha stated that a complaint had been received as a result of this action and suggestod that dust oounts be made to determine whether or not the baffle should be replaced* On hJay 16, four dust counts were made in this department. Tho operator on Banoh #172, wae checked on both the polishing and buffing operations. This bench is located near Post J-% The dust count showed 5,300,000 particles per cubic foot of air in the breathing zone while the operator polished for four minutes, and 8,260,000 particles while he buffed for l minutes. A second operator on bench #184 near Post L-95 was also checked. The dust counts in his breathing zone showed 2,300,000 part icles per cubic foot of air on the polish operation which required two minutes and 3,540,000 particles for a 1-1/3 minute buffing operation. Inasmuch as one set of reaulte is above Frigidaire's dust limits we plan to make further study of this department in the near future before any action is taken on a decision regarding the hood baffle. c.c. Messers B. Trottman R. Ziasnerman R. Walton J. Brown H. 3. Kline Ind. Hygiene lab. Fora 76HTU printed In u.S.A. For Inter-Organization Letters of FRIGIDAIRE DIVISION GENERAL MOTORS CORPORATION DEFAttTWCST SATfilY March 23, 1944 Ur. B. T. Trottmnn Ufg. Process Plant #2 re: Dust counts in Dept. #711, Blade Grinding with and without hood baffle. At the request of Ur. Rhodes, dust counts were taken in the breathing zones of several blade grinding operators with the baffles both in and out of the hoods. In addition to the experimental tests several other counts were made with baffles in, bo that we could obtain a general idea of dust conditions. All determina tions were made in the Camber Grinding Section. Date Post Bench Baffle Disc Dust per cubic fd 3-18 3-20 K-80 K-80 J-00 J-82 K-82 K-83 HP-12734 12754 1839 6119 6144 6146 In Out In In In In 120 120 SO fc 120 120 16 16 22,900,000 5,360,000 1,381,000 975,000 350,000 1,222,000 3-21 J-80 J-80 K-80 K-80 2770 2770 12754 12754 In Out In Out 16 16 120 120 5,400,000 4,620,000 8,880,000 3,930,000 The above results shew that apparently the baffle in these hoods is not necessary, at least with the new one inch screen placed across the rent. We noticed that with the combination of screen and baffle that there was a tendency toward plugging of the vents. We will be glad to assist in making further checks of dust conditions if you desire them. c.c. DR. M. M. Shafer R. Walton C. Harris R. Zimmerman H. S. Kline, Ch. E. Ind. Hygiene lab. B WffK