A special inquiry was undertaken by one of the Engineering Staff with the object of collecting information as to appliances which can be adopted to avoid resort to the dangerous practice of mounting belts at ordinary speeds by direct handling at the driving pulley. Information of a like character has also been obtained from foreign sources and it is proposed in the near future to issue a comprehensive pamphlet on the subject for the guidance of employers and others. The precautionary measures to be adopted may be summarised as follows: 1. Stopping the machine or running it dead slow under suitable conditions. 2. Sectionalising the machinery. 3. Mounting at ordinary speed by means of a belt pole or, where this is impracticable, by a mechanical or other special type of belt mounter. 4. Maintaining belts in satisfactory working order by efficient and systematic attention and inspection. Enforcing safe practices by workers. 5. All these safeguards are used in British industrial organizations to some extent but it has been found that there is a wide field in which none are adopted. Until this position has been rectified as far as possible, distressing though avoidable accidents must continue to occur. Apart from the specific danger of belt mounting, there is the extreme risk of approaching revolving shafting in motion for miscellaneous reasons such as have been referred to, namely, lubricating, whitewashing walls and ceilings and such like. This is a quite unnecessary risk and there is no valid reason why any worker should be exposed to such danger. If such work must be done in the vicinity of unfenced millgearing, the gearing should be stopped until the work is completed. Already, as the result of the High Court decisions, a stimulus has been given to the evolution of appliances for the safe mounting of belts and means of lubricating which render it unnecessary for the worker to come in close proximity to the gearing at all. The department is encouraging every effort in this direction but the chief difficulty to be overcome is ignorance of the illegality of the practice of approaching unfenced millgearing running at normal speed for any purpose whatever and ignorance of the grave danger incurred. This ignorance is widespread and, to combat it satisfactorily, not only employers and managers but foremen and employees must be educated. The education of the actual operative is important, as it is he who is usually the victim of shafting accidents, and it is not uncommon for him to be told by a fellow workman, quite unauthorized, to do some work involving great risk in the vicinity of shafting. In an endeavour to secure this education, the Staff at their various visits of inspection have devoted a great deal of time and continue to do so. Cranes. Mr. Ward, Senior Engineering Inspector, contributes the following report on this subject : Fifty-nine cases of crane failure were reported, an increase of 25 per cent. on last year's figures. These 59 cases caused 13 fatal and 40 non-fatal accidents, while in 12 cases no persons were injured. In one failure 1 person was killed and 3 others injured, in another 1 man was killed and 1 injured, and in another 2 persons were killed. The main causes of failures for the year may be summarised as follows:- Breakage of holding bolts on guys, masts, etc. Overturning 10 6 Periodical examination of cranes and their accessories by a competent person is most essential, but in 23 cases no examination appears to have been made. In 19 cases examinations, of a kind, were made by crane drivers, foremen, greasers and fitters, while only in the remaining 17 cases does any comprehensive examination appear to have been made. Insurance Companies are now being called in to a greater extent than formerly to make examinations of cranes coming under the Docks Regulations, but for general safety proper periodical examination of all cranes is very much needed. Wire Rope.-Careful record has been kept of all reported wire rope failures. Seventy-six cases were reported during the year, an increase of 24 per cent. on the previous year's total. These failures caused fatal injuries to 7 and non-fatal injuries to 37 persons; in 34 cases no one was injured. A general review of these failures shews the main causes to be as follows:-Corrosion 15, Overloading 12, Overwinding 12 (in 6 cases overwinding devices were fitted but did not act), Cut on sharp edges 11, Excessive wear 9, Rough usage 5, Miscellaneous, etc., 13. Calculations have been possible in 60 cases and are set out in the table herewith. Rope Failures. (b) Ratio of Pulley to Wire Diameter. under 101-| 200| 300-1400-500-600-700- | 800- These results shew a great divergence of practice amongst manufacturers of lifting appliances, and in some cases the ratios are so low as to make the life of these ropes very short through subjecting them to severe bending stresses. A ratio below 15 is totally inadequate for any class of rope, and a ratio below 20 is undesirable for other than special flexible ropes. In only nine cases did the value exceed 30. The ratio of pulleys to wire diameter gives somewhat similar results. A ratio below 200 is very bad; a ratio above 500 is recommended by some authorities. In no case did the value exceed 1,000. Power Presses.-Following the practice of previous years, a detailed analysis has been made of last year's power press accidents. The total number (480) shows a decrease of over 20 per cent., on the previous year's figures, but this must be put down largely to stagnation of industry from of industry from May onwards. If any reliable deduction can be based on a comparison of the 1925 and 1926 figures, it would appear to be that the accidents occurring in the operations of raising, bending, and piercing show a reduction which is considerably greater than the reduction in the total accidents. From this one might conclude that the automatic guards which are required for the more elaborate operations are being improved and are being better maintained. A similar improvement in the position in respect of fixed guards is, however, not evident, as the accidents arising in the operations of cutting out and blanking have not been reduced to a really satisfactory extent. Dough Machinery.-Mr. Brown (Scotland Division) reports favourably on this subject and indicates the satisfactory completion of negotiations with the Scottish Employers : Further progress has been made with regard to the fencing of dough brakes and mixers. Last year I reported that up to the end of 1925 no guard suitable for existing lip-tilting mixers was available. During 1926 three engineering firms have devised guards suitable for this type of mixer, and these are now on the market. It was not considered necessary to call a special conference with the Scottish Association of Master Bakers to complete the Agreement regarding the fencing of machinery by including half-tilting and lip-tilting mixers. The report of the Executive Committee to the Annual Conference of the Association held in June, 1926, contained the following paragraph:-" The Factory Department of the Home Office lately have shown considerable activity in the enforcement of the Factory and Workshop Act, 1901, with regard to the fencing of dangerous machinery. Prosecutions have taken place in several instances in which accidents have occurred in connection with brakes and mixers which were unfenced. In moving approval of this paragraph one member said "where fencing was done it was practically impossible to have an accident in a bakery. He thought if they made a representation to the Insurance Companies they would get their premiums reduced. It was unguarded brakes in bakeries which made their premiums so high." The Secretary said that "the whole of the machines now working in Scottish bakeries might be fitted with guards. The last machine brought in was the lip-tilter." In October the Association issued to their members a resumé of the different Agreements, the last of which was reached in July, 1924, regarding fencing of machinery, with the following additions :-"On 8th January, 1925, it had been reported that a guard had been applied to a half-tilting mixer and was working satisfactorily. On 28th May, 1926, a similar report was received with regard to the lip-tilting mixer." The reports referred to were from myself. So far as Scotland is concerned, this brings to a close the negotiations which were begun twelve years ago. The problem of devising guards for existing machines was very difficult and at times appeared to be insurmountable, but fortunately, with perseverance and ingenuity on the part of engineers and bakers, not unaided by suggestions from Inspectors, these difficulties have been surmounted. The Scottish Association of Master Bakers deserves great credit for the active interest they have taken in the devising of suitable guards and in encouraging the adoption of these guards, at a considerable outlay, by their members. During the year there have been 4 prosecutions, one under Section 136, for unfenced brakes, and 4 (three under Section 136), for unfenced mixers. Penalties ranging from £2 to £20 were inflicted. Breaking up old Castings.-A recent fatal accident again directs attention to the danger which attends the work of breaking up old castings unless adequate precautions are taken to prevent any person (whether actually employed at the process or otherwise) from being struck by pieces of flying metal. The usual method adopted is to drop a heavy weight or "monkey" from a considerable height on to the casting to be broken. The energy stored up in the moving mass is dissipated at the moment of impact, and the casting is usually shattered under the blow, the pieces being projected with great force in all directions. In the case above referred to the falling weight weighed 41⁄2 tons and the height of fall was about 70 feet. A protection shelter was provided about 60 feet from the centre of the fall but the evidence indicated that the men seldom used it and obtained protection by crouching behind pieces of scrap metal which lie about the site. When work of this kind is carried out a complete and deep shelter of steel plates or railway sleepers should be erected around the breaking position, and the ball should not be released until the person in charge of the control rope is certain that no person is within the enclosed danger zone. Explosion of Sealed Metal Vessels.-An accident at a scrap metal works involving serious injuries to two men emphasises the danger of heating closed vessels unless the precaution has been taken of first drilling a relief hole in the vessel to allow the escape of steam or gas from the interior of the vessel. In the case under review the men were heating and breaking up under hammer blows large and heavy pieces of non-ferrous metal scrap. Amongst the metal was, what appeared to be, a solid bar of gunmetal nearly 4 inches diameter and about 3 feet long. This was heated to redness and placed on end, when one of the men dealt it an axial blow with a sledge hammer for the purpose of breaking it into pieces. On receipt of the blow the metal burst, the fragments flying in all directions, and two of the men engaged at this work were injured. One of the pieces of metal was afterwards found about 200 yards away. After the occurrence it was found that the metal was hollow, the walls being inch thick. One end was inch thick and fitted with a screwed plug which had been brazed after it had been fitted to the shell. It is probable that the cylinder was an old pump plunger and that some water had gradually found its way into the hollow cavity. This water would be converted into steam at high pressure under the conditions stated, and the hammer blow, added to this internal pressure, caused the explosion of the vessel. It was said to be the practice at this works to drill a relief hole in any hollow piece of metal before heating, but in this case the men evidently took it to be a solid bar, which is the more remarkable since the solid bar would have weighed about 280 lb., whereas the piece in question weighed about half that. A somewhat similar case occurred at a motor repair garage where a bent (and apparently solid) shaft from a motor car was heated in a smith's hearth, prior to its being straightened. In this instance also the shaft was hollow, but with closed ends, and it burst under the heat applied. It is almost impossible for water or other liquid to remain in the bore of the shaft before the ends are plugged during manufacture, but water may find its way into the bore in course of time during the use of the car. The presence of water would be of little moment except for the risk of the shaft being heated, at some subsequent date, for repair purposes. It is found that some motor car manufacturers realise the danger and drill a small axial relief hole in shafts of this kind. Dust Explosions.-Mr. McNair, Engineering Inspector, has paid special attention to dust explosions and reports :— Several dust explosions have occurred during 1926, but fortunately none of them caused fatal injuries. In the first case, which I investigated with Mr. Jenkins (Bristol), an explosion started in a disintegrator which was being used for grinding cattle food. No precautions had been taken to prevent such an explosion from passing to other parts of the mill, with the result that the explosive wave travelled up an elevator, through a disused dressing machine, down to the ground floor and, by way of a conveyor, to the next building, where it passed up an elevator and travelled along a chain conveyor casing and blew out of the manhole at the top of a storage bin, where it severely burnt a boy who was standing close by. Steps have since been taken to provide for an intercepting device and also for a relief vent pipe, so that any explosion which occurs in the disintegrator will be prevented from travelling to other parts of the plant. Similar precautions were also asked for at a Liverpool mill at which an explosion occurred, and also in the case of two plants, one used for sugar and one for grinding dye stuff, in which explosions occurred. It is rather surprising to find, that although many firms are interested in preventing such explosions, and provide many safeguards with this object, they do not as a rule take into consideration what is probably the most important safety measure, i.e. preventing the explosion in its initial stages from passing to neighbouring elevators or screens, and thus causing more serious results. Another explosion, which might have been very serious, is reported by Mr. Franklin (Manchester East). This occurred in the cyclone of a mill used for grinding sulphur. The ignition was attributed to an electro-static spark. It is important that such plants should be provided with proper relief vents exhausting to a safe place, and Mr. Franklin is of opinion that better earthing was also required. A very serious coal dust explosion reported on by Mr. Hodgson (Middlesbrough) which injured two men, was due to one of them using a match in order to see the amount of coal in a large bunker. The electric lamp provided was out of order and was actually being replaced by one of the injured men. Acetylene. Six fatal accidents, due to explosions of acetylene, were referred to the Engineering Branch. |