Document Eqz2QEwkMwZGd2D944eR9bnqN

FILE NAME: Asbestos Sacks and Bags (ASB) DATE: 1931 DOC#: ASB019 DOCUMENT DESCRIPTION: Govt Report on Conferences between Employers & Inspectors Concerning Methods for Suppressing Dust Asbestos Textile Factories H O M E OFFICE. iov 0 4 1980 REGD [Crown Copyright Reserved.] Report on Conferences between Employers and Inspectors concerning Methods for Suppressing Dust in Asbestos Textile Factories LO N D O N : P R IN T ED AND P U B L ISH ED BY H IS M A JE ST Y 'S ST A T IO N ER Y O FFIC E. To be purchased directly from II.M . S T A T I O N E R Y O F F IC E nt the following addresses: Adastral House, K ingsw ay, London, W .C .a; 120, George Street, Edinburgh; York Street, Manchester; i, St. Andrew's Crescent, Cardiff; i$, Donegall Square West, Belfast; or through any Bookseller 3 5 - 2 4 1931Price Is. 0<1. nefe. T N lz o '^ 7 S' A? 3/ ? * r ; . .. f . .* t PaWfiSSSn # ^ c ., 1 flf* a3 * 7, Home Office, % 10th April, 1981. To the Right Hon. J. R. Clynbs, M .P., His Majesty's Principal Secretary of State for the Home Department. Sir, In the Report by Dr. E. R. A. Merewether and Mr. C. W. Price published in March, 1930,* it was made clear that the prin cipal safeguard against the ill effects of asbestos dust on the lungs of the workers is to be found in improved ventilation and dust suppression. At the same time it was indicated that new7problems in ventilation were involved and that much experimental work would be necessary--more particularly in the textile branch of the industry--before a decision could be reached as to the best methods to be applied to the various machines used in the processes. Following on the publication of the Report, the asbestos textile manufacturers were invited to a Conference at the Home Office to discuss these problems. At this Conference there was complete agreement that everything possible must be done to suppress dust and the manufacturers undertook to render every possible assist ance. As an initial step, it was decided to set up a Committee con sisting of three representatives of the industry and two of the Engineering Inspectors of Factories. This Committee was consti tuted as follows:-- Mr. Leonard Ward, H.M. Senior Engineering Inspector of Factories (Chairman). Mr. J. Gow, The Cape Asbestos Co., Ltd. Mr. W . C. Fenton, British Belting Asbestos, Ltd. Mr. P. G. Kenyon, Turner Bros. Asbestos Co., Ltd. Mr. C. W. Price, H.M. Engineering Inspector of Factories. I now have the honour to submit the Report of this Committee. Complete agreement was reached, and a most helpful series of recommendations (pages 9 to 35) adopted by the Committee has been subsequently confirmed by a second Conference of Manu facturers held on 17th March, 1931. This Report has also been communicated to the General Council of the Trades Union Congress, who have made certain suggestions which will be taken into account in drafting a Code of Regulations under the Factory and Workshop Act, 1901, to give statutory effect to the Agreements arrived at by the Conferences. There is one matter referred to in the Committee's Report which calls perhaps for some comment. * Effects of Asbestos D ust on the Lungs and D ust Suppression in the Asbestos In d u stry . H .M . S ta tio n ery Office (34-20(3, P rice Is. 5d. w ith postage). A 2 The Couuriitt.ee have pointed out (page 6) that in some textile orocesses, the amount of dust normally evolved appears to be too mail in the light of present knowledge to warrant special recom mendations being made for its suppression, and that they have therefore embodied in the Agreements their opinion in respect of each of these processes whether or not the amount of dust calls for the application of remedial measures at the present time. This opinion is necessarily based on one important assumption,'^' namely;* the existence of a critical limit of dust concentration below which workers may be employed without injury to health. As the Committee rightly observe, the ofily working basis that can be adopted at present is a finding in the previous Report which suggests that the conditions in flyer spinning earned on without exhaust may be regarded as the " dust datum it is however desirable to emphasise that this limit is clearly provisional and is subject to alteration in the light of further medical experience. ^ In conclusion, I wish to record my high appreciation of the public spirit shown by the leading manufacturers in this industry, through their ready consent to pool for the benefit of their industry their experiences in regard to the difficult problems to be solved, and also of the valuable results which have only been achieved by the expenditure of much time and labour on the part of the Committee. I am. Sir, Your obedient Servant, G erald B ellho cse. Chief Inspector of Factories. t V . f - REPORT ON CONFERENCES BETWEEN EMPLOYERS AND INSPECTORS CONCERNING METHODS FOR SUPPRESSING DUST IN ASBESTOS TEXTILE FACTORIES. The Report issued in March last on " Effects of Asbestos Dust on the Lungs and Dust Suppression in the Asbestos Industry " * showed that, while exhaust ventilation had been applied with suc cess at many points in both the textile and non-textile branches of the industry, practical difficulties hindered its application to a number of processes, more particularly in the textile factories, in which dust is produced in harmful amount. An informal Confer ence of asbestos textile manufacturers and Home Office representa tives was therefore arranged to consider these difficulties and the best methods which could be adopted generally for suppressing dust in manufacturing and other processes. Tire Conference, which was fully representative of the Trade, took place at the Home Office on the 8th July, 1930, under the Chairmanship of Mr. D. E . Wilson, C.B.E., H.M. Deputy Chief Inspector of Factories. The Conference agreed unanimously that everything practically possible should be done to suppress dust and the manufacturers promised their full assistance to secure this result. It was then decided to set up a Committee consisting of three Trade represen tatives and two technical members of the Factory Department to consider the problem in detail and to collect all information avail able concerning dust suppressing methods. As the appointed Trade representatives are connected with the larger works they have direct knowledge of the conditions under which the great majority of asbestos textile workers are employed. The Committee have reviewed the conditions in each textile process and have given special attention to those processes in which the provision of adequate remedial measures has hitherto presented many difficulties, e.g., mixing arid blending (in preparatory work), card cleaning, spinning and weaving, and also to the special diffi culties appertaining to mattress making, strictly a non-textile pro cess but carried on to an important extent by several textile manu facturers. It was therefore felt that this Report would be incom plete unless this process were dealt with. The Committee have sought assistance from all asbestos textile manufacturers including those not represented at the July Confer ence. * R eferred to thro u g h o u t th is rep o rt as " The Asbestos R e p o rt." 373 A 3 6 During the period covered by the Committee's deliberations, opportunity has been taken by the Trade Members of the Com mittee to experiment, in their factories, with new or improved dust removal apparatus applied to the various processes in which the special difficulties already referred to are met with. The exiperiments include (1) the use, in place of hand strickles, of a traversing brush, fitted with an exhaust connection to a portable vacuum plant, for cleaning the cylinder and doffers of carding machines; (2) the application of exhaust to mixing and blending (in opening processes) and to ring spinning; and (3) new methods of applying exhaust to wearing. These experiments, which are de scribed later in this Report. have resulted in a gratifying measure of success. A. series of Agreements covering all the processes reviewed has been reached, in most cases embodying specific recommendations for securing the suppression of dust by exhaust ventilation. In addition, the Agreements deal with such matters as ventilation, heating, and the settling of dust extracted from the workrooms. In some textile processes, the amount of dust normally evolved appeared to the Committee to be insufficient, in the light of present knowledge, to warrant special recommendations being made for its suppression. The Committee have therefore embodied in the Agreements their opinion whether or not the amount of dust so evolved calls for tlie application of remedial measures at the present time, with the reservation that revision may be necessary if there is variation from the working methods generally adopted, or in the materials now used. The Committee have found valuable guidance from Dr. Merewether's view, stated at page 12 of the Asbestos Report, " that in order to prevent the full development of the disease (asbestosis) amongst asbestos workers within the space of an average working lifetime, it is necessary to reduce the concentration of dust in the air of the workrooms to a figure below that pertaining to spinning at the time over which these cases (i.e., those dealt with in the Asbestos Report) were exposed." For practical purposes, the conditions arising from flyer spinning carried on without exhaust under good general conditions may, it seems to the Committee, be taken as the " dust datum " . Flyer spinning is less dusty than ring spinning to which process exhaust ventilation has now bjien successfully applied. If, therefore, a particular process apperirs to give rise to dust in excess of that asso ciated with such flyer'.spinning, the Committee regard the lreed for preventive measure^ as established. This criterion is simple to apply to processes such as mixing, blending, carding and dry weaving which are obviously more dusty than flyer spinning. But difficulties were found to arise as regards other processes, partly because the Committee felt that they lacked 7 necessary information of the nature and amount of the fibre or dust in the atmosphere, produced by these processes. The assistance of Dr. Merewether, and of Mr. McNair, Engineering Inspector of Factories, who has made important investigations on dusty atmo spheres, was therefore sought concerning these difficulties, which were as follows :-- (1) In certain processes on opened material from which dust has been efficiently removed, a considerable amount of floating fibre may be given off into the air by attrition of the material. iThe collection by hand, at carding machines, of uncondensed carded fibre, the recovery of side waste from the condensers of finisher cards, and the handling of opened material in disintegrator cham bers are cases in point. The Committee were not satisfied at first that in such cases, where there may be much visible long fibre, there is of necessity also finer dust in excess of that produced in flyer spinning, which may be readily inhaled into the lung. From the examination of samples, Dr. Merewether has come to the conclusion that such visible floating fibre is always associated with finer particles invisible to the naked eye, and these are being continually augmented by fracture of the larger fibres. The Com mittee accept this view and have based some of their recommenda tions upon it. (2) In some cases, precise determinations in individual factories may be necessary to ascertain whether the dust evolved in a par ticular process is in excess of the criterion suggested above. Similarly, such determinations may also be required to show the extent of the improvement effected by the introduction of any par ticular method of dust suppression. A gravimetric method of de termining the dust content in the air is briefly described in the Appendix, page 36. The Committee recognise that such investi gations may have to be undertaken in the future, but felt that the position was such that this report ought not to be delayed on this account. Notes on each Agreement will be found in the text together with descriptions and, where necessary, drawings of the dust-suppress ing plants recommended. The Asbestos Keport contained a number of Eeeommehdations, many of which the Committee have adopted. They have concen trated on Eecommendation 1 (application of efficient localised ex haust ventilation at dust-producing points) as being the prime essential. They feel confident that at any rate the majority of the difficulties attendant on carrying out this Eecommendation can be overcome, in which case other precautionary measures re commended in the Eeport become unnecessary. The Agreements as a whole are aimed at interfering as little as possible with existing working methods or lay-out of premises, e.g., substitution of mechanical methods for handwork, separation of 3373 A 4 8 processes and wider spacing of plant are not specifically urged nd, apart from the process of hand strickling (cleaning) of card cylinders and doffers, prohibition of any existing working methods is not suggested. The Committed recognise that improved con ditions for the workers might be obtained in some cases bv such changes, and indicate later in the report the advantages resulting from the adoption of mechanical methods, but are convinced that the effect of applying exhaust ventilation on the more extended lines which they recommend will result in such a degree of dust control as to leave only minor operations in which the conditions as regards dust are in excess of the " datum " suggested. The Trade representatives on the Committee are unanimous in supporting the Agreements arrived at, as presenting a practicable solution of many of the problems confronting the industry, but desire to emphasise that they do so in their capacity as individual members and that they cannot commit the Trade as a whole. The Committee realise that provision of means for carrying out some of the recommendations must take a considerable time, and the Trade representatives expect that a sufficient period will be allowed before requirements based upon them are enforced. They have also in mind that the British factories may be subject to unfair competition if restrictive requirements enforceable in this country are not adopted in foreign countries. They hope, there fore, that some appropriate action may be possible which will lead to uniform international requirements. r 8th January, 1931. W. C. F eston. ' ^ J ames Gow. P. G. Kenyon. Charles W . P rice. L. W ard, Chairman. y AGREEMENTS. 1. Crushing,--including preliminary Sack Emptying, Rough Mixing on Floor near Crushers, Feeding and Discharging. All processes give rise to dust and exhaust draught should be applied. Crushers of both types, i.e., fixed pan and revolving pan, and those of small size, e.g., bowl crushers, should be en closed except for the necessary working openings. Feed and delivery lattices to be enclosed and/or exhaust applied. The crusher (Fig. 1), enclosed and exhausted as recommended in the A greem ent, is fed mechanically from, th e enclosed elevator w hich is supplied from the hand-fed lattice. E xhaust connections are provided a t th e feed ing point of the lattice and a t the elevator enclosure. W here a rough mixing of different grades or asbestos is made on the floor beside the crusher, th e exhaust d rau g h t applied to th e crusher may be utilized, as shown in P la te 1,* to control th e dust evolved. The crusher (m ortar m ill type) is completely enclosed, except for th e working opening, in a wooden structure. The enclosure is extended in fro n t of th is opening to form a mixing chamber, which is open in front to th e ex ten t shown in Fig. 2. The exhaust d ra u g h t applied to th e top of th e crusher enclosure extracts the dust produced in the mixing chamber. W ork in the chamber is reduced to a m inim um . The sacks are ta k en in to th e cham ber to be hooked on th e hoisting rope passing thro u g h th e to p , b u t a re hoisted, tu rn ed over and em ptied upon th e floor from outside. M ixing is also accomplished from outside by long-handled tools. The men enter the chamber to feed the pan after the dust produced in m ixing has been extracted. As an additional precaution, respirators are worn. The crushed m aterial is shovelled from th e pan through an opening in th e side of the enclosure, a cover, kept closed during the crushing, being provided in the woodwork. The m aterial falls into the fully enclosed hopper feed of a sieving m achine (see A greem ent 6). 2. Mixing and Blending of Crushed Asbestos. The process is dusty and exhaust draught should be applied. Exhaust ventilation has recently been applied, in one large factory, P late 2. An exhaust pipe, 12 ft. long is symmetrically placed about 3 ft. 6 ins. above th e m ixing a re a which may m easure some 15 ft. x 10 ft. E xtractio n takes place a t a series of slots, 6 ins. X 1 ins., on both side of the pipe near th e bottom. The average d u ct velocity provided for is 3.000 ft. p er minute corresponding to a discharge of about 4,000 cubic ft. of air per m inute from the mixing area. This is the first application of exhaust to this hand process but, although much d u st is removed, i t is n ot yet clear th a t th is arran g em en t .will fully m eet th e case. The Com m ittee think, however, th a t it should be accepted a t th e present tim e hut it may be th a t enclosed mechanical m ixing machines will be developed in the future. 3. Sack Emptying and Filling, Floorwork and preliminary Hand ling Processes involving contact icith Asbestos Fibre. These operations are dusty and exhaust draught should be applied. The Agreement is intended to apply to all m anipulation of asbestos in opening processes .whereby d u st is produced. The filling an d em ptying of * The P lates follow page 36. -.u. 9373 A a ( F io . 2.-- M ix in o and Cui) suing C iiamiieks. 12 ;eks an d skips, shovelling, raking and weighing are included. The method f ap p lying the exhaust will depend upon circum stances. P late 1 shows ne method. F or such m anipulation as is involved in mixing or blending Agreement 2), th e exhaust arrangem ent shown in P late 2 can be adopted. For m an ip u latio n work in chambers, see A greem ent 10. The delivery on th e floor of m a terial from machines, entailing subsequent -e-collection, should be dispensed w ith to th e greatest possible extent. Bagging lattices, see A greem ent 7, can b e adopted in m any cases, th e reversible type (Fig. 3) being of special u tility where .work is continuous and rapid. 4. Filling of Lattice and Other Hoppers. 'These operations are dusty and exhaust draught should be applied, or the hoppers so enclosed as to prevent escape of dust. Lattice and other hoppers covered by the Agreem ent include those a t crushing plants, sieving machines, disintegrators, Crighton openers and cards. Examples of exhaust applied a t lattice hoppers are shown for opening p la n ts in P lates 3 and 4--th e p la n t in P la te 4 being fed by shoot from an u p p e r floor--and for a hand-fed d isin te g ra to r (F ig. 5). Safeguards adopted in one factory for the feeding of card hopper lattices are described under Agreement 11. 5. Separating, to remove Iron. The process should be so enclosed as to prevent escape of dust. Electrom agnets can always be enclosed so th a t dust cannot escape. The A greem ent is directed against th e use of open a p p a ra tu s which m ay giverise to dust. 6. Sieving. (a) Jig Type.--The process is dusty. The machine should be effectively covered over on the top and enclosed at the sides, and exhaust applied. (b) Rotary Type.--Dust is produced at the feeding point to which exhaust should be applied. The machine should be enclosed and/or under exhaust. The Agreem ent applies to the sieving of both crude and crushed asbestos. H itherto, jig sieves have not been enclosed to the ex ten t possible. The sieve shown, in P lates o and 6 (a) is alm ost completely enclosed, w ith exhaust d ra u g h t applied to th e top of th e enclosure; escape of d u st isgreatly reduced. The m aterial can. be collected a t short inclined bagging lattices, th u s avoiding the dust associated w ith hand collection and floor shovelling. W here a rotary sieve is fed mechanically as from an elevator, and th e feeding p o in t is enclosed by the elevator connection (see Plate 4), the exhaust is applied to the casing. 7. Crighton Openers. Dust is produced at the feeding point and at the delivery (e.g., lattice) and both should be under exhaust. 'The exhaust applied A. F io. 3.-- R eversible B agging L attice. to the delivery cage by the machine fan may not deal with dust produced on the outside of the cage or lattice and an independent :haust connection is then required. The Agreem ent applies to openers of both types, i.e. horizontal and orticai. Exhaust draught should be applied both to hand feeding, and to open echanical feeding, as from an exposed lattice. Exhaust applied to the eding points of vertical Crighton openers is shown in Plates 6 (a) and (&). Although the am ount of du st produced a t delivery lattices or other delivery apparatus connected with Crighton openers varies considerably, the am ount in all cases is sufficient to render application of exhaust draught necessary. D elivery lattices and bagging lattices may be enclosed a t th e sides and above, and exhaust applied as in P late 6 (6). In th is case, much of th e d u st produced w ithin th e machine is withdrawn by a selfcontained fan through exhaust passages in the fram ing, connected to the perforated cage from which th e opened m aterial passes to the delivery lattice. The d rau g h t thus applied is usually incapable of controlling th dust produced a t the delivery lattice. 8. Opening by Willeys, Teasing and similar Machines. Dust is produced at feeding and delivery lattices and both should be under exhaust. The exhaust applied to the delivery cages or otherwise by the machine fan (if any) may not deal with dust which may arise from feed rollers, etc., due to overfeeding or other cause and independent exhaust is then necessary. Opening m achines of th e willey or teaser types also give rise to d u st at feeding and delivery lattices, and the Agreement aims a t securing appli cation of exhaust, as already illu strated for C righton openers (see Agree ment 7). T he am ount of d u st em itted a t feed rollers may be increased by overfeeding or by an unsuitable speed, m atters which should be kept under observation. Self-contained fans for removal of dust generated within the machines ire usually incapable of dealing w ith the dust a t delivery lattices. 9. Disintegrating. Dust is produced at the feed, and exhaust should be applied f the suction draught produced by tfie machine does not prevent he escape of dust. The Agreem ent is intended to apply to all disintegrators. The suction iraught produced a t the feed point may not be sufficient to carry away .11 th e d u st produced in feeding, in which case exhaust is necessary. M echanical feeding is adopted in many cases, b u t hand feeding is still etained w here different grades a re tre a te d . T he d u st so produced is reloved, in one factory, by the arrangem ent shown in Fig. 4. Exhaust is ppl'ed to th e cham ber into which th e fiberized m aterial is delivered, th u s reducing a much stronger draught through th e feed opening of the disltegrator. ! i &WJiV!9U F io . 4.-- E xhaust at D ibinteouatob Cham bers. D isintegrators (not shown) uro sbovo tiio chambers. 10 0. Chambers in connection with Disintegrators, and Willeys, Teasing and similar Machines, and Bins jor Opened Material. aambers are not necessary for delivery from willeys, teasers similar opening machines for textile material, and automatic action can be adopted. This is also true for disintegrators king on certain classes of material and it is hoped that it will atually prove to be the case for all. In certain non-textile k, e.g., mattress making, a reserve of opened bulk material st be stored and chambers are regarded as essential. Whether se are entered or not, exhaust should be applied to handling its. and in addition possibly other safety measures, e.g., respira5 , limitation of hours worked by individuals, etc. Bins to be bated as chambers. Handling includes shovelling, weighing and nilar manipulation. The chambers d ealt w ith in this Agreement are those in which opened iterial is deposited--either by the direct action of th e opening machinery by being blown forw ard by a fan connected to the discharge of the ening m achinery--and which are entered by th e workers. Bins are open sto rag e places to which m aterial is ta k e n and from which it re-collected when required. [n view of th e serious risk of inhalation of d u st resulting from .work in imbers and a t bins, the Committee have carefully considered whether it s possible to recommend th e ir prohibition but reg ret th a t it is not so a t i present tim e. y tern ativ e arrangem ents can be used for much chamber work. F ig 5 ws a system now applied extensively to deal w ith opened m aterial from integrators. An exhaust fan connected w ith the delivery from th e disegrator blows th e m aterial into a large hopper container, from which it ollected, u n d e r p ractically dust-free conditions; a trav ellin g band a t th e e of the container conveys it to a reversible bagging lattice. The veiling band is enclosed and " sealed " a t th e delivery point by a ssure roller. The a ir, freed of its charge of asbestos, is retu rn ed from th e tainer, being re-circulated through the system to th e fan inlet. Excess entering the system is released at a filtering " balloon " connected to a nch duct on th e retu rn air line. f chambers are discarded, it is im portant th a t apparatus which is sonably free from risk should be substituted, e.g., bagging lattices fitted h exhaust as previously described. Storage chambers for m attress m aking be arranged so th a t i t is not necessary to en ter them for th e filling of &, etc. T he filling is done from th e fro n t u nder th e influence of an aust draught. 11 chambers which are en tered should be under an exhaust d ra u g h t b u t does n o t a p p e ar to be possible to prevent th e inhalation of d u st ciently by this means. Pending th e elimination of chambers, other lautions should be adopted as indicated in the Agreement. 11. Carding. xhaust to be applied to all cards at feed apron, licker-in, of cylinder and each doffer comb and brush. Collection of aed fibre is dusty and exhaust should be applied. lie A greem ent is intended to apply to all types of carding machines. 17 The different methods of applying exhaust adopted up to the present tin -. ) are n o t equally successful. The Com m ittee have come to th e con ch1 ion th a t th e m ost successful method yet devised of applying exhaust v tilation to carding machines is th a t in use a t Messrs. T urner Bros, i jestos Co.. L td ., Rochdale. This firm have adopted a stan d ard arranger at which is fitted to each new carding machine installed (Fig. 6). The f owing description has been prepared in the m ain from notes supplied by firm :--1 ?ive m achines as a m axim um are exhausted by one m ain, th e fan dischargj to its independent settling plant. A fter installation, extensions and orations are not perm itted. Not more than one card on each set is pertted to be cleaned a t one tim e. D uring cleaning a large auxiliary branch '.nection, which a t other tim es is sh u t off by a slide dam per, is brought to use a t th e head of th e cylinder to increase *the air removal, from th a t A pplied a t : (a) Cylinder head. (b) Feed Apron. (c) F ly Combs. (d) L icker-in. nachine by a definite am ount provided for in the design, as described below, io slide dam pers are provided except those on the branch connection and the listribution of th e d rau g h t cannot be interfered w ith. No filtering uaterial is used in the settling system (described later); the resistance and he air volume rem ain constant. Exhaust is applied a t th e following p o in ts:--head of cylinder, feed apron, y Combs, an d licker-in, a t all of .which cover hoods are fitted. Branch ducts re connected to both sides of th e cover hoods, except a t the hood for the ,cker-in to which a single d u ct only is connected a t one end, directed o control th e d u st across th e e n tire w idth of card (Fig. 7). Pyram idal oeds with central branch duct connections have been entirely discarded. he cover hood for the cylinder head which is specially designed is pi .m etrically supported 4 ins. above an opening in th e to p of th e cylinder 3' 5r, a gap of th is depth, as seen from th e feeding o r licker-in side of th e icehine, being left for inflow of air from the room (Plate 7). The openig in th e cylinder cover is 40J ins. long (for a card 50 ins. wide) and 13 ins. HE C lose fit t in g C over H ood for L ickek-in and E x h au st C on n ectio n . N o te: A ltern ativ e to (d). The back and sides of the cover hood are sealed off d u rin g card in g ,, swivel wooden flap " valve " shown. The effect of this arrangem ent ,t d u st risin g from the cylinder head is cau g h t by th e air en terin g th e i from the room through the front gap, and carried away w ith the it. W here hoods are fixed directly to an opening in th e cylinder this satisfactory resu lt cannot be obtained. The wooden flap, when i back, perm its the cylinder cover to be raised when preparing for Jg. average d u ct velocity throughout the system should be 3,000 feet per ,e. An effective are a of 152 square inches is provided in th e m ain d u c t ich card, 48 ins. to 60 ins. wide, accounted for as follow s:-- (a) For Carding. , Sq. Jns. .Cylinder h e a d : two 4-inch c o n n e c tio n s........................................25 Feed apron and L ick er-in : one 41-inch c o n n e c tio n ............... 16 Fly com bs: tw o 21-inch connections ... ............................10 (approx.) ... 51 (b) For Card Cleaning and Grinding. n additional 100 square inches, for the special 11 in . auxiliary branch nection (cross section 95 sq. ins.), brought into use as required, as preisly explained. flowing for one grin d in g connection being in use, effective m ain duct neters fo r the set of 5 cards are 14, 151, 17, IS}, and 20 inches, he uniform ity of distribution throughout the system is fu rth er ensured by sful designing, e.g. :-- Reductions of diam eter in th e main d u ct are made on the top, ensuring a horizontal base line, and so avoiding an y settlem ent of d u st in the m ain duct. Branches enter th e m ain at an angle of not more than 30' to the lino of flaw. Junctions are smoothly finished internally. T inned iro n is used, to minimize friction. Sliding and cleaning doors are not necessary b u t end caps are pro vided for exam ination purposes. Muff couplings are provided for the connections which have to be broken and re-made for cleaning purposes. P ipe ends term inating in muff couplings are wired internally and finished sm ooth; muff couplings are wired externally. 'arded F ib re.--As previously referred to, the collection by h and of carded e results in a ttritio n of the m aterial which may subject the workers to :. Suitable precautions are necessary including the application of efficient aust draught, which the Committee recognize may be difficult. This can avoided by adopting autom atic collection a t th e machine, as found in tain factories, an inclined lattice (Fig. 8) being provided in fro n t of th e Per, to tvhich exhaust is applied as in F ig . 6. 1Scotch " feed and o th e r lattices, for feeding between break er and sher cards, may give rise to some amount of floating fibre. The move nt is slow an d th e m aterial, in th e form of a fleece, is b u t little dis hed. The Comm ;tee regard th e am ount of floating fibre as likely to o small, provide ! the lattices are m aintained in efficient order, as to r special precautions unnecessary. e C om m ittee's recommendations to deal w ith d u st in th e filling of :e hoppers (see J.greem ent 4) are intended to apply to hopper feed es a t ca rd in g m achines. In one large works, th e opened m aterial ought in bags of rubber-proofed fabric; the mouth is somewhat larger 22 th an th e bottom . These bags give rise to much less d u st th an th e ordinary sack, as shaking o u t is not required to loosen clinging m aterial. They are being brought into use for all tran sp o rt of asbestos w ithin the factory. At this factory, all the lattices are fitted w ith m etal covers kept closed during the process except when feeding is necessary. F or th is operation, th e bag is inserted in the feed opening provided in the cover. Some feed hoppers are provided w ith cloth covers, b u t these cannot' be recommended. 12. Card Stripping (Cleaning). Hand strickling, or other hand cleaning process before grinding, gives rise to very dusty conditions and should be prohibited. The Asbestos R eport drew special attention to the extremely dusty opera tion of card and doffer cleaning w ith hand strickles, and to the inadequate standard of dust suppression reached. The R eport also referred to the possibility th a t a m echanically-operated brush m ight be devised which, .with exhaust applied, would be effective in reducing th e d u st. The Com mittee find th a t a brush of this description (P la te 8) designed by Messrs. B ritish Belting & Asbestos L td., Cleckheaton, has been on tr ia l for some tim e and has given much satisfaction both for cleaning and for dust suppression; the Committee are glad to rep o rt th a t th e firm have no objection to other asbestos firms adopting this appliance. The following particulars have been prepared from notes supplied by th e firm. A revolving cylindrical brush, faced w ith card clothing, is almost com pletely enclosed w ithin a cover, connected by flexible armoured hose to a portable vacuum p la n t. T he exposed portion of th e brush effects th e clean ing, the dust created being removed by the draught. The brush is mounted on a " Dronsfield " traverse wheel g rin d er mechanism (Xo. 120) by which it is moved slowly to and fro across th e cylinder or doffer as required. The mechanism is set up in the grinding brackets and is driven in the m anner adopted in many textile works for cross traverse card grinding. When the card has run clear and all rollers, clearers, fancies, etc. have been re moved, the two doffers are draw n back in. from th e cylinder, suitable distance pieces, e.g. washers, being inserted between th e doffer carriage and tho m ain fram e. A " Dronsfield " slow m otion drive is fitted to th e bottom doffer shaft (Fig. 9), this giving the necessary motion, from the opposite side of th e machine, to the upper doffer and the cylinder (Fig. 10). The Diameters BA.-GCryoloinvdeedrRSeox'Pj/fey 24% F ig. 9. amener5 .K<a7r-afanLc-y1P2u* He, 2 3 F i g . 10. *23 diam eters of various pulleys required are as m arked; th a t of th e card cylinder shown is 50 ins. The pulley B (Fig. 9), which is normally a fast pulley, m ust be convertible in to a loose pulley. F o r th is purpose, a lock bolt has been provided as used in lathes. Tho overall diam eter of the brush, i.e. over the stripping wire, should be th e same as th a t of the grinding roller. The brush used has an outside d iam eter of 7 ins. an d a speed of 400 revolutions p er m inute. A surface speed of the card clothing of about 20 ft. per m inute has proved satisfactory. The speed of the traverse is so arranged th a t for one complete revolution of th e cylinder or doffer, th e brush, 3 ins. wide, moves slightly less th a n tho w idth of the w ire th e re o n ; in th e p resen t instance th e movement is 2} ins The pitch of th e traverse screw is ins. and a fu rth e r means of adjust m ent is provided by the tw in pulley drive shown in P late 8. The pulley A on th e tube drives the double jockey swinging pulley B by means of a belt. A second belt drives pulley C, which is fixed on the traverse screw and m ade so th a t it can be slightly expanded, allowing th e rate of traverse to be adjusted as required. A S turtevant No. 4 turbine vacuum cleaner is used for collecting the dust. The Committee feel th a t, in view of the success achieved w ith th is mechanical cleaning brush, the T rade should a t once take steps to adopt it and th a t the hand process should be prohibited. 13. Card Grinding. Card grinding may be productive of asbestos dust and efficient exhaust should then be applied. The A greem ent applies to the grinding of cylinder and doffers ; very little m etallic dust is produced and if prelim inary cleaning is efficiently done, as w ith th e m echanical brush described under A greem ent 12, th e am o u n t of asbestos dust should also be small and the ordinary exhaust arrangem ents provided a t the machine capable of effecting its removal. 14. Grinding of small Card Rollers at Grinding Machine. This process is dusty and efficient exhaust should be applied. Efficient exhaust is readily applicable (P late 9) to th e g rin d in g fra m e o r m achine normally used. The enclosure of the machine should be a s com plete as practicable. The present method of collecting the heavy debris which falls w ithin the machine, by raking th e m aterial to th e shop floor, gives rise to much d u st which would be obviated if shallow containers, e.g. tra y s , w ere provided, to receive the m aterial as produced. 15. Card Waste End Machines. The delivery of the fibre by blowing it upon open perforated cages produces dusty conditions and efficient exhaust should be applied. W aste ends should be collected only under " suction " conditions (F ig . 11). W here a m achine of th e ty p e shown in F ig. 12 is adopted, th e fib re being blown upon perforated cylinders to which exhaust is not ap p lied , dusty conditions are inevitable. The Agreem ent, in effect, would p ro h ib it th e use of such a machine. F ig . 11.-- Card W aste E nd M achine. F ig . 12.--Card W aste E nd M achine. (Unsuitable type for collecting Asbestos W aste End.) o F ig . 13.-- E xhaust at H ing Sp in n in g F iu m e , 26 16. Derby Doubler Machines. The " dust " conditions do not appear to call for special action at present. Derby doublers are but little used and only giye rise to a small am ount of dust. 17. Spinning, including Doubling, Plaiting, and Braiding. Ring spinning is dusty and efficient exhaust should be applied. The amount of dust produced in flyer spinning, doubling, plaiting and braiding is apparently not such as to necessitate provision of exhaust arrangements. Ring spinning is obviously more dusty th an flyer spinning. At th e Cape Asbestos Co., L td ., B arking, exhaust ventilation has recently been success fully applied to rin g spinning, as shown in F ig . 13. an d th e conditions in consequence greatly improved, dust not being visible a t breathing level. A series of hoods, connected to horizontal exhaust ducts above the tin rollers, are fitted behind th e spindles on each side of th e fram e, each hood dealing w ith th e d u st from 4, 5 o r 6 spindles. The lower p arts of th e fram es and th e endshave been dosed in w ith wood panelling, to concentrate th e flow of a i r to th e exhaust hoods more completely a t th e spindle line. The to ta l volume of a ir removed from each spinning fram e is estim ated a t 3,400 cubic feet per m inute. The arrangem ents do not obstruct the process. The Committee have explained a t an earlier stage of this Report th a t flyer spinning carried on w ithout exhaust draught may be productive of so little dust th a t exhaust ventilation for its suppression does not, in the light of present knowledge, appear to be necessary. They have therefore not suggested precautionary measures for flyer spinning, b u t it may be th a t some sp in n ing of th is kind is carried on u nder less satisfactory conditions th a n those in d icated an d in th a t case precautions will be necessary. As exhaust ventilation has now been successfully applied to ring spinning, it appears th a t it could also be adopted for flyer spinning if necessary. 18. Warping and Winding. The " dust " conditions at these machines do not appear to call for action at present. The Committee have formed the opinion th a t the conditions in these irocesses are, in general, probably not less satisfactory th a n those in flyer pinning which the Committee have taken as the " dust datum ." t may be, however, th a t dust determ inations will show th a t d certain circumstances more dusty conditions prevail, in which aso rem edial measures should be adopted, e.g. by applying localized exhaust. 19. Weaving. Dry weaving is necessary for certain classes of yarn and apparntly cannot be discontinued. Dry weaving (except fine yarn istings) and much so-called wet weaving is dusty and exhaust 27 F ig . 14.-- E xhaust V entilation at C loth L oom.-- Applied u n d e r W arp. should be applied at least (a) between the fell of the cloth and the healds and (b) between the healds and the back rest. The method of applying the draught cannot be standardised at present owing to the varying types of looms in use. Since the issue of the Asbestos Report, the possibility of applying localized exhaust ventilation more effectively a t looms has been investigated a t the works w ith which th e Trade representatives are connected. The results obtained show th a t it is possible by exhaust ventilation to render conditions in the process as satisfactory as in flyer spinning, but the cost is considerable. Tile less dusty conditions have been obtained by applying the d raught under th e warp. Inverted collecting hoods are placed both in front of and behind th e healds and as close to them as can conveniently be arran g e d (Fig. 14). The mouth of each hood should be as close as possible to the tvarp th read s. F or .wide looms, two hoods in line should be used in stead of 1 single hood, to ensure a more uniform draught over the entire w idth of ;he loom. The hoods m ust be arran g ed so as to afford access to th e bottom acks or tappets. The under warp exhaust may be supplemented by an idditional exhaust hood, of tapered form, fitted above the breast, conlected a t its larger end w ith a branch d u ct a t th e side of th e loom. E xmples are shown in Fig. 15. T his provision is m ade to remove d u s t proueed in beating up. The forw ard movement of th e sley may prevent some f the dust from being drawn to the hood under the warp, in which ease t is desirable th a t the breast hood should be fitted. The exhaust hoods nd duets are much larger th a n those h itherto adopted and the volume of lr removed is considerably greater. F ig . 15.-- E xhaust V en tila tio n at B rake B and L in in g L oom. Applied a t Breast. 29 P la te 10 shows a recent application of exhaust in which hoods are fitted above the warp threads behind the health, and a t the beating-up point. This m ethod follows th e older practice, b u t the hoods are of large dim ensions and th e volume of air removed per m inute is much g reater th a n previously. The considerable cost involved in providing exhaust ventilation on these liberal lines will inevitably lead th e Trade to adopt w et methods wherever possible. Such methods hitherto have not, in many eases, reduced the d u st to th e low concentration required. D am ping has been done in a m ore or less haphazard m anner, e.g. by w et brushing of th e w arp or by d ip p in g the shuttle cop in w ater. The Committee do not think any w et m ethod should he accepted unless it can be shown, by actual test, th a t the necessary reduction of dust has been achieved. F ig . 16.-- Arrangem ent op W ater T ray and I dle R oller fo r W et W eaving. A new method has recently been adopted which is apparently m ore effective than those referred to. An idle roller, partly immersed in a shallow tra y of w ater, is provided under the .warp. (Fig. 16). All th e w arp th re a d s in t u r n make contact with this wet roller. The Committee feel th a t th is m ethod, and others which suppress dust, m ay be found to be satisfacto ry . The fine listings referred to in th e Agreement are very narrow " ta n e s " which give rise to little or no dust. 20. Processes subsequent to Weaving, i.e., Cloth Examining, Pressing, Calendering, etc. The conditions as to dust do not appear to call for special action at present. The final processes on woven fabrics are n o t entirely free from dust, but i t appears th a t th e concentration is less th a n in flyer spinning. 21. Mattress Making. Mattress making gives rise to much dust. Fibre-filled mat tresses should be effectively damped and, if this is not sufficient to suppress the dust, exhaust should be applied. Such exhaust may be by cross ventilation of the room. Benches and floors should be water sprayed. Efficient respirators should be worn during filling, beating or levelling. Localized exhaust v entilation has n o t yet, so fa r as th e Com m ittee are aware, been applied to m attress m aking. The problem presents exceptional difficulty, especially as regards large m attresses. The Committee believe, however, th a t precautions can be taken which should reduce the d u st in the air to a low concentration (except d u rin g th e intervals required for filling and for beating or levelling out) b ut little different from th a t found in flyer spinning. The precautions recommended are: -- (a) D irectional cross ventilation applied in each workroom as in F ig. 17. The v entilation effected is equivalent to about 15 changes of a ir per hour. The fresh a ir supply, suitably w arm ed in. cold w eather, is ad m itted on one side of the room a t about 4 ft. above th e floor, a t a series of openings on the inclined upper face of th e air tru n k , so being directed slightly upwards. Other openings, e.g. windows, are k ep t closed. The dust-laden air is ex tracted a t the other side of th e room through an opening in a large duet, which is exhausted by a propeller fan, discharging to the atmosphere. The benches are placed parallel to th e line of a ir flow. (b) D ivision of workroom by parallel p a rtitio n s into two, th ree o r more similar com partm ents, as shown. D uring filling, which is done by one or two workers, the other workers are w ithdraw n to adjoining compartments to work on filled m attresses. A continuous passage-way is left along th e sxtraction side of the compartments, doors being provided in the partitions >n this side. (e) W ide spacing of benches. O ver-crowding of m attress m aking workooms w ith benches, m aterials, etc. is p a rtic u la rly undesirable. (d) D am ping of floors, .workbenches and m attress covers. The Committee ittach special importance to this precaution which, when done efficiently, uppresses th e d u st appreciably. Effective m eans for spraying floors and enches should be provided. Floors and benches should be k ep t damp d u rin g working hours. The covers for fibre-filled m attresses should be thoroughly prayed previous to filling, and the same precaution adopted as fa r as ossible for m attress covers generally. -Most of th e m attresses made in textile factories are filled with asbestos bre, " magnesia " or other compositions which contain a proportion of shestos not being used. The Agreem ent has been draw n up w ith special igard to th e conditions under which fibre-filled m attresses (the m aking of hich is doubtless attended with the greater risk) are m anufactured. The ommittee feel, however, th a t their recommendations, with certain exiptions, can and should be applied to th e m aking of all insulation attresses productive of asbestos dust. i)X F ig . 17.-- Cross V en tilation and S ub- d iv is io n of M attress M aking R oom. T lM B fn ilB H P tH B I 32 F io. 18. 22. Separation of Dust Collecting Apparatus from Workrooms. Dust collecting and separating plants, including balloons, should be effectively separated from workrooms and the air dis charged from such plants should not be allowed to escape into any workroom. The Agreement is directed ag ain st th e practice of installing dust collect ing plants, and particularly those provided with filtering fabrics to arrest fine dust, in the workrooms. 23. Dust Filtering Apparatus. Dust filtering apparatus provided in connection with a system of exhaust ventilation should be so designed and maintained as not to affect the efficiency of the exhaust side of the system. The Committee recognize t h a t th e T rad e generally m ust be p re p a re d t-o in stal plant of th e highest efficiency and so to m a in ta in it. Some of the particulars given in various Agreements are intended to suggest minimal requirements for various details of such plants, and these and other particulars will afford, th e Com m ittee hope, useful guidance to designers. The usual practice in the T rade is to use filtering fabric for d u st settling, but the overall area of such m aterial is often insufficient. Lack of room m ay be the reason for this. F ig. 18 shows an ex tern al d u st filtering -structure used in one large works. The m aterial, a coarse fabric, permit some dust to pass into the atmosphere, but the stru ctu re is in th e open air and well separated from all th e facto ry buildings. The deep eaves an d th e inclined shields under them prevent the fabric becoming wet in rainy weather. The deep rectangular cavities made in all th e sides afford a much larger filtering area than would otherwise he possible on an equivalent space. As filtering fabrics become d irty , th e d u st removal cannot be constantly m aintained a t th e highest efficiency. A utom atic cleaning ap p a ra tu s m ight, to a large extent, remedy th is b u t it has n o t yet been adopted. One firm has abandoned filtering fabric in favour of a dust settler which consists of a large chamber into which th e fan discharges and where th e heavier dust collects, and a cyclone for settlin g finer dust, connected d irectly to th e chamber (Fig. 19). This se ttlin g p la n t takes up a la rg e cu b ic space. Its effect on the dust removal p lan t does not vary--an im portant advantage. Cleaning is only necessary once every few months, th e men concerned then wearing respirators. A cyclone used in this way appears to be a more efficient apparatus for settling fine d u st than when used for receiving dust laden air direct from the fan. 24. Factory Ventilation and Heating. Each workroom should be ventilated so as to ensure the efficient operation at all times of all dust removal plants therein. The air admitted for ventilation should be sufficiently warmed, when necessary. The dust removal plants in asbestos textile works are on such a large scale th a t inadequate ventilation of the factories need not be an ticip ated . B ut the arrangem ents for the supply of fresh air may be inadequate in some cases to ensure the necessary air movement to the extraction points. Should th is occur, the efficiency of th e d u st rem oval will fall. The A g re em en t is intended to obviate this. In many factories, plenum v en tilatio n , w ith arrangem ents for h eating the a ir supply in cold w eath er, a re in sta lle d , an d th is should be th e general practice. ELM P ig . 19.-- D ust Settling Arrangements for Carding M achine E xhaust System. 25. Precautionary Leaflet for Workers. Precautionary leaflet for the guidance of workers in the industry should be prepared by the Home Office. The Committee think much good would result and apprehension be allayed by distributing to all workers in the industry and to new workers entering, it, a leaflet giving them inform ation in simple term s of th e risk attendant upon inhalation of asbestos dust, and how best th is risk can be avoided. They understand th at the leaflets issued in other industries for such pur poses have been productive of much good. Note on Factory Cleaning.--The Trade members have made careful trials of various systems of vacuum cleaning and the Committee are disappointed with the results. The Committee think that when the improvements recommended above in this Report are effective, the danger attendant on dry cleaning will not be so great as was anticipated. 36 A P P E N D IX . Gravimetric D etermination of D ust. The d u st is arrested in a small q u an tity of sugar placed in a Gooch rucible, the sugar being afterw ards dissolved in water and filtered through iared filter paper which is afterw ards dried an d re-weighed. (If preferred, n u n tared filter paper m ay lie used and afterw ards b u rn t to ash and eighed.) The arrangem ent of th e ap p a ratu s is shown in the draw ing below. The -ooch crucible (1) is fitted in th e usual fashion in to th e neck of a filter tile (2), which is connected by rubber tu b in g th ro u g h a " T " bend (3) to n exhaust hand pump (4). The " T " bend dips into w ater in an otherwise osed bottle (o). A t each stroke of the pum p th e w ater is draw n up th e irtical tu b e and m aintained thro u g h o u t a t th e m ark (6) so th a t each stroke exhausted under the same pressure conditions. The pump must be dibrated: this may be done by attaching it when set up, as if for use, to w ater m eter placed beyond the Gooch crucible. A large glass vessel should * interposed between the m eter and the inlet to the Gooch crucible to event undue fluctuation of pressure. The volume equivalent of each stroke thus ascertained. M7.`1 K Vl.ATK l ' l-ATK 3 . P i ai k 4. P late 5. P late (5 (a). I P late 6 (b). * i -6 P l . AT K 9 . [ P late ! 10. <9373-4) \Vt. 27030 9003/2283 750 7/31 P . St. 0 . 3