Document 6w55d2YOyrE4w8R1on3Q0aVDg

IN D U STR! AcPrl YGIENE FOUNDATION O ERI C A, IN C Mellon Institute, 4-4-00 Fifth Avenue O! ' L^ .) Pittsburgh 13, Pa. June 17, 1954 Mr. O. H. Cilley, General Manager Raybestos- Manhattan, Inc. United States Asbestos Division Manheim, Pennsylvania Dear Mr. Cilleyy This letter will constitute a memorandum of the conference we held at your offices on Thursday, June 1C. In addition to summarizing the subject matter of our discussion, it includes, as you will note, a number of afterthoughts. At the outset we expressed the opinion that, with one or two exceptions, a primary nroblem in an intelligent attack directed toward further reduction of dustiness in the various departments of your plant is in establishing beyond any doubt the exact sources of_dust remaining at each machine and operation. Dust control measures that ha.-e been_instituted during the past fifteen years or more have succeeded in eliminating most of the obvious sources of dust and measures that need to be taken to reduce the dust still further requires certain knowledge of the particular elements of each machine that continue to contribute to air-borne dust. In order to meet tlis need we proposed a tool and a procedure which consists in providing a complete enclosure for the machine being studied or of some representative portion of it, supplying the enclosure with a stream of filtered air and measuring the dustiness in the air leaving the enclosure. The product of the dust concentration and the rate of air flow will permit a description of the dustiness of the enclosed machine elements in the units --particle s of dust per minute. Various at NOUS I Al. MTGtENE FOUNDATlS^-OF AMERICA.INC Mr. O. H. Cilley 2 June 17, 1954 experimental modifications can then be applied to the enclosed machine and the effect in reduction of dustiness measured quantitatively. By this technique all guess work will be eliminated as to the effect on dustiness of any particular adjunct applied to the machine. It was brought out in this conference that primary attention should doubtless be accorded to the twisters and if the experimental scheme previously outlined were to be applied to a study of this machine, a few spindles at one end would be enclosed and various schemes of whatever apparent merit would be applied to each of the enclosed spindles and the effects measured quantitatively. The question ol replacement of the twister by speeders, a matter which has evidently been discussed throughout the years, was again considered during this conference, but we did not have the benefit of dust count information during most of this discussion which Mr. .Luttenberger obtained from his files at the end of the day. Measurements made some time ago by the State Division of Industrial Hygiene appeared to establish beyond little doubt that the speeder produced very much less dust than the twister, whereas, prior to an examination of this data we had felt that there was no objective basis at all on which a sound decision could be reached for the replacement of twisters by speeders. In the light of this we should state as our first objective in the testing program, a qualitative determination of the extent to which dust will be reduced by substitution of speeders for twisters. This assumes that no ideas will be forthcoming for further reduction of dust from speeders. On a visit to the Preparation Department gross production of dust was noticed at the blending process. It appeared from our discussion that the major proportion of this dust could.be readily eliminated by the construction of an enclosure_above the batching bed with an exhaust at a rate of six to seven thousand cubic feet per minute. This idea had the advantage that no design problems intervene; that is, this corrective measure could be instituted without delay and would, furthermore, not interfere with incompletely formed plans described by Mr. Luttenberger tor some mechanical feeding. INDUSTRIAL HYGIENE EOUNOATI^Tj of AMERICA. INC r\ ' Mr. O. H. Cilley 3 June IT, 1 954 In our discussion of dust counting it was agreed that for the purposes of equipment study it would be feasible to train one of the men now on the labr ratory staff in the use of the impinger sampling equipment and in the use of the microscope for counting the dust content of that sample. It was suggested that this man be sent to the laboratories of the State Department of Health for a few days training to be followed, perhaps, by a day or two at our laboratories here. It is possible that the latter might be omitted without any loss. It is not the thought, however, that this amount of training would >e sufficient for this individual to conduct dust count studies in the various departments of the plant. It is possible that at some later date it may be deemed advisable to provide him with some supplementary training enabling him to be used in such a capacity. In this connection v e discussed the status of existing American dust counting techniques and expressed the opinion that with dust concentrations reduced, for the most part, to levels of two and three million, the results of such dust count measurements now' have but limited value bec ause of the lack of criteria for their interpretation. On the basis cf the information obtained by you in England concerning the levels of dustiness prevalent in the plant of Turner Brothers we could see the value in a dust count survey made for the purpose of comparing conditions in your plant with those in the English plant. This wo'iid necessitate adoption of the English procedures in toto, at least for the duration of that particular study'. In consideration of this idea you had planned to write immediately to your industrial friends in England for detailed information on the sampling and dust counting procedure. Confirming my conversation with youour charges for field work and consultation are based on a rate of $150 per diem and expenses except that the rate is $100 per diem for the younger members of the staff who perform dust counting where required. I shall now- await word from you as to when you will be readv for me to make a return visit. Sincerely yours, W CLH:br W. C. L. Hemeon Engineering Director