Materials Handling in Industries: Equipment and Types

In this article we will discuss about:- 1. Meaning of Material Handling 2. Equipment for Material Handling 3. Types.

Meaning of Material Handling:

Material handling is the preparation, placing and positioning of materials to facilitate their movement or storage. In most industries, the handling of materials, articles and equipment is one of the main sources of injuries. Before discussing the safety aspects in material handling, it may be of interest to look at a few statistics about material handling.

The Anglo-American Productivity Report gives the following figures:

(i) Material handling does not add to the value of the product but adds to the cost of the product.

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(ii) Materials handling accounts for 36% of production costs.

(iii) Nearly 50—100 tons of materials are handled and re-handled for every one ton of finished product.

(iv) About 20—80% of total labour costs go to labour used in handling.

(v) About 2/3rd of manufacturing cycle time is spent on handling.

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(vi) About 40% of industrial accidents are in handling.

Every type of material and article handled in a factory must be studied in detail and consideration given to factors such as the weights handled, character of material or article, size, weight, rate of handling, distance moved, the purpose of moving or handling, etc. and suitable methods of handling decided upon.

Probably, no phase of modern production has undergone more radical changes than has material handling. In fact, mass production would be impossible without the highly mechanised material handling equipment now in use.

Equipment for Material Handling:

Equipment for handling materials commonly used in industrial establishments are:

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(i) Hand lift trucks

(ii) Dragging or sliding on skids or rollers

(iii) Wheel barrows

(iv) Hand-trucks, power trucks and tractors

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(v) Hoisting apparatus

(vi) Overhead travelling cranes

(vii) Conveyors

(viii) Mechanical shoves

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(ix) Elevators and Escalators

(x) Chutes (gravity or under pressure), and

(xi) Pipe lines or pumps for liquids.

The basic fact that the unsafe acts of individuals are a causative factor in the majority of accidents justifies of itself the substitution of mechanical for manual operations wherever practicable. This statement implies, of course, that the mechanical means used must be of safe design and construction suited to their purpose, thoroughly guarded, properly maintained and that the personnel selected to operate them be properly qualified and adequately supervised.

Typical hazards of the use of such equipment are overloading, poor management of material, operating at excessive speed, lack of adequate space for operation, lack of skill and improper attitude on the part of the operator.

Types of Material Handling:

1. Manual Handling:

i. Unsafe Working Habits:

In material handling, the common unsafe working habits are:

(a) Lifting improperly,

(b) Carrying too heavy a load,

(d) Failure to wear personal protective equipment.

Accidents can be avoided by good training, effective supervision, pre-employment examination and periodic re-examination to check physical weaknesses.

ii. Proper Method of Lifting:

(a) The feet should be placed close to the load and properly spaced for body balance,

(b) Back straight and as nearly vertical as possible,

(d) Grasp the load firmly with the hand, then lift should be completed by straightening the knees, keeping the load close to the body,

(e) Tuck your chin in,

(f) keep body weight directly over feet.

While putting down a load, the above procedure should be followed in the reverse order.

iii. Team Work:

In lifting a load, the worker should first make a preliminary lift to be sure that the load is within his lifting capacity, if not secure help.

If two or more men are required they should be similar in size and physique. One of them should act as leader. The leader gives orders for ‘lift carry’ and ‘put down’. The leader must ensure that each man is correctly positioned before giving orders for lift. When two men carry long sections on shoulders, the section should be supported on same shoulder and walking should be done in step.

iv. Lifting of Specific Types of Articles:

(a) Boxes and Cartons:

Grasp them at opposite top and bottom corners-draw a corner between legs.

(b) Barrels and Drums:

Up ending—Two men stand on opposite side-grasp both chimes near the high point up end while pressing down the bottom and straighten up with the drum.

Handling on Incline:

Use of ropes and tackle-to control motion, pass a rope around a drum-one end of the rope fastened to the platform at higher-worker keeps a firm grip on the free end and then gradually lower or raise the drum.

(c) Sheet Metal:

Handle with leather gloves, hand leathers, or gloves with metal insert because of sharpened edges and corners.

(d) Glass Sheet:

Handle with gloves or hand leather, cover wrists and fore-arms with long leather sleeves. Leathers, or canvas apron and guards for feet and ankles should also be worn. Carry the glass sheet with the bottom edge resting in palm turned outward and with the other hand holding the top edge to steady it or balance it. Never carry glass sheet under the arm because a fall might severe on artery.

(e) Long Objects:

Long pipes, barestock, limber should be carried over the shoulders with the front and held as high as possible to prevent striking other employees specially at corners.

(f) Metal Scrap:

Wear goggles or hand leathers, safety shoes and skin guards. Workers should be cautioned against tripping or slipping on objects which may roll or slide under feet. Mechanical handling of this commodity (say magnetic lift crane) is preferable.

v. Accessories for Manual Handling:

Each tool or other device should be kept in good repair and used for the job for which it is designed.

(a) Hooks:

Danger of glancing off hard objects. When carried in a belt, the point should be covered. Sharp point necessary for handling logs, crates, boxes etc.

(b) Crow Bar:

Main hazard is slipping. Point or edge should have a good bite. Proper position of hand and body to minimise chances of hand pinching or worker falling if the bar slips. Never work astride a crow bar. When not in use, keep on a rack.

(c) Rollers:

Heavy or bulky objects often moved on the rollers. Main hazard is fingers or toes getting pinched or crushed between the roller and the floor or the roller and the object, when the direction of the roller is changed. To move a roller under load, use a sledge or a bar; never hand or foot.

vi. Hand Trucks, Wheel Barrows:

(a) Knuckle guards should be provided to protect jamming of hands against door frames or other obstruction.

(b) Wheel should be under the truck if possible to save injuries to toes and feet. Wheel guards are preferable.

(d) Inspect daily and keep in good repair.

(e) No one truck is right for handling all types of material.

(f) Loader should keep their foot clear of wheels. Load should be so placed that it will not tip, shift, fall off or block clear view ahead.

(g) On two wheelers centre of gravity of load should be placed well forward.

(h) Four wheelers should be pushed and not pulled.

(i) Avoid collisions especially at blind corners.

(j) Do not park trucks in aisle-ways, so as to obstruct traffic or causing stumbling hazards.

Storage of Specific Materials:

(i) Bagged Materials:

Cross tied with mouths inside. When pile is 1.5 metre high step back by row for each additional one metre. Do not remove a bag from a lower row first.

(ii) Pipe Bar Stock:

Consider strength of floor. Pipe in layers with strips of wood or iron between layers. Strips should have block at one end or one end turned up. Bar steel stock should be stored in racks inclining towards the back.

(iii) Barrels and Kegs:

Pyramid shape is safer. Bottom row should be blocked. If piled on ends, planks should be laid between rows.

(iv) Liquid Chemicals:

Portable containers such as drums, barrels and carboys are used. Store room should have impervious walls and floors and provision for safe disposal of spillage. Before handling check corrosion of nails or weakening of packing by the chemical. For transporting carboys, use a carboy truck.

Safe way to empty a carboy is to move liquid by suction from vacuum drop or start the siphon by means of rubber. Bulb, carboy inclinators, properly designed are also satisfactory. Before piling, empty carboys should be thoroughly drained and stoppers replaced.

(v) Gas Cylinders:

(a) Cylinders may be rolled on the bottom edge but never dragged,

(b) Carry cylinder in a cradle or in a suitable type of carrying device,

(d) While returning empty cylinders or when not in use, close the valve and replace valve protection cap.

(e) Always consider cylinders as full and handle them with care. Do not store gas cylinders in the sun.

2. Mechanical Handling:

(i) Cranes, Hoists and Lifting Tackles:

The Factories Act deals with the safety requirements in respect of hoists, lifts, lifting machines, chains, ropes and lifting tackles and requires that these should be of good construction, sound materials and of adequate strength. These are to be properly maintained and thoroughly examined by a competent person atleast once in every period of six months, in the case of hoists and lifts and 12 months in the case of the others.

(a) Hoists and Lifts:

Every hoist or lift shall have the safe working load plainly marked on it and no load far greater that such load should be carried on it. The cage of every hoist or lift used for carrying persons should be fitted with a gate on each side from which access is afforded to a landing and such gates should be fitted with inter-locking or other efficient devices to ensure that they cannot be opened except when the cage is at the landing and the cage cannot be moved unless all the gates are closed.

The following further legal requirements are laid down in the Factories Act relating to hoists and lifts used for carrying persons, which have been installed after 1st April, 1969.

Wherever the cage is supported by rope or chain there shall be atleast two ropes or chains separately connected with the cage and balance weight and each rope or chain with its attachment should be capable of carrying the whole weight of the cage together with the maximum load.

Further, efficient devices should be provided and maintained capable of supporting the cage together with its maximum load in the event of breakage of the ropes, chains or attachments. There should be an efficient automatic device to prevent the cage from over-running.

(b) Overhead Travelling Cranes:

In the use of overhead cranes, great care be given to the provision of safe and adequate means of access. It is necessary, that all ladders and stops should be provided with secure hand-holds and foot-holds. Stairways are preferable to ladders. Proper landing or stages should be provided at the point of transfer from ladder to the driver’s cabin.

While any person is employed or is working on or near the wheel-track of a travelling crane in any place where he would be liable to be struck of the crane, effective measures shall be taken to ensure that the crane does not approach within 6 metres of that place.

In many factories even today no action is taken to eliminate the possibility of injury to any person on or near this wheel track of an overhead crane and in some factories steps taken are totally inadequate. Effective means should be arranged to prevent a crane from travelling into the dangerous zone, should the driver suffer from a lapse of memory.

(c) Jib Cranes:

A Jib crane means a stationary or mobile crane in which suspension rope is supported by a projecting, horizontal or inclined member known as a jib. It is important that capacity marking for jib cranes clearly showing the maximum safe working load for the various inclinations of the jibs or various positions of the trolley on a horizontal jib should be marked on the sides of the jib or on the mast or on the pillars.

A number of accidents have occurred due to overloading of jib cranes particularly with the mobile type resulting into overturning of the cranes. It is recommended that the jib cranes should be fitting with automatic indicators which will give efficient sound signal whenever the load being moved is in excess of the safe working load.

(d) Lifting Tackles:

According to the Factories Act Rules, no lifting machines, chains, ropes and lifting tackles should be taken into use unless it has been tested and all parts have been thoroughly examined by a competent person and a certificate of such test and examination specifying the safe working load or loads is kept.

Also no lifting machine, chain, rope of lifting tackle should be, except for the purpose of testing, loaded beyond the safe working load. The safe working load shall be plainly marked on each such gear together with an identification mark and corresponding entries made in a register. Wherever these cannot be marked, a table showing the safe working loads of every kind and size of lifting machine, chain rope or lifting tackle in use should be displayed in prominent positions.

Many accidents have occurred in the factories through failure of lifting tackles and some of these accidents could have been avoided if the users had possessed more intimate knowledge of the strength of the lifting tackles and the proper method of using them. By lifting tackles, we mean, fibre rope slings, wire rope slings, chain slings, hooks, rings, shackles.

Generally, manila and sisal ropes are used in handling or hoisting and lowering operations. There are various grades of ropes and therefore while purchasing, their guaranteed breaking strengths should be obtained from the manufacturers in order to assess the safe working loads of the ropes.

Fibre ropes are very susceptible to mechanical damage and they should therefore be frequently inspected for their strength. Particular care is necessary when it is suspected that the rope may have been contaminated by chemical action.

Periodical inspection of the whole length of rope is necessary to detect broken wires, amount of wear, corrosion, rust, etc. Broken wires in a rope must always be regarded as warning sign. Wire ropes must not be knotted. They should be joined by proper splicing. For the same working load, the chain is 5 to 6 times as heavy as wire rope but it has a longer life, stands up better rough use and is almost 100% flexible.

Today chain is obtainable in many grades:

(i) Wrought iron,

(ii) Mild steel,

(iii) High stensile steel and

(iv) Alloy steel.

Wrought iron chains require to be periodically heat treated to remove brittleness. The standard hook is either of a circular section or trapezoidal. The former is meant for light loads upto 5 tons.

Shackles according to the difference in shapes are known respectively as D and Bow shackles. The pins are usually of circular section. The methods of securing shackle pins in position vary according to the nature of the use of the shackles. When there is a risk of the pin working out, pins are secured by means of a nut and cotter pin. A cotter pin affords more rigidity than a plain pin.

(ii) Power Trucks:

Power trucks usually operate on storage batteries or internal combustion engines and are extensively used in factories for handling of materials to and from stockpiles, to and from machines and on through to ware-house or loading platforms.

These trucks are of many types, such as fixed platform, elevating type of platform is inserted under the skid elevated to lift it from the floor and the truck carries it to some other point. The forklift truck makes the lift by means of a two prong form instead of a platform and lifts the load up from the floor permitted in high piling to conserve space. They could also be fitted with special attachments for handling barrels, paper reels etc.

Safety precautions to be observed in operation of work lift trucks are:

(a) The capacity of every lift truck should be marked on the truck and they should not be overloaded.

(b) Loaded or empty forks should be carried as low as possible but high enough not to strike a ramp.

(d) Personnel must not be allowed to ride on the forks.

(e) Forks should be driven well under the load, preferably full length or at least 2/3rd of the length.

(f) When there is a danger of falling objects over the operator, canopy guard should be provided.

(g) Aisles, floor, etc. should be maintained in good condition including proper lighting.

(iii) Conveyors:

Various types of conveyors and monorail systems are used in many industries to eliminate manual labour to expedite the movement of materials and also to facilitate the processing or assembling. Belt conveyors are widely used and they are of flat or troughed type and can be horizontal or inclined. They are used for handling almost all the materials of modern industry including coal, coke, grain and building materials such as sand and gravel.

Some of the important safety measures to be taken are:

(a) Conveyors shall be so constructed and installed as to avoid hazardous points between moving and stationary parts or objects.

(b) Where workers have to cross over conveyors, regular crossing facilities affording safe passage and adequate lighting shall be provided.

(c) Conveyors shall be provided at loading and unloading stations and at other convenient places with devices for stopping the conveyor in an emergency.

(d) When two or more conveyors are operated together, the controlling device shall be so designed that no conveyor can feed on to a stopped conveyor.

(e) Where conveyors extend to points not visible from the control station, they should be equipped with gongs, or signal lights to be used by the operators before starting the machinery so as to warn workers who might be in position of danger.

(f) Conveyors shall be provided with automatic and continuous lubrication system or with lubricating facilities so arranged that oiling and greasing can be performed without the oiler coming into dangerous proximity of the moving parts.

(g) Workers should not ride on conveyers.

Handling of Dangerous Substances:

(i) Dangerous substances should be handled and stored under the supervision of a competent person who is familiar with the risks and the precautions to be taken.

(ii) In case of doubt as to the nature of the risk or the precautions to be taken, the necessary instructions should be obtained from the competent authority.

(iii) When dangerous substances are to be handled or stored, the workers concerned should be given adequate information concerning their nature and the special precautions to be observed in handling them.

(iv) Special precautions such as the provision of mats, sling nets, boxes and high-sided pallets, should be taken to prevent breakage of or damage to containers of dangerous substances.

(v) If containers of dangerous substances are broken or damaged to a dangerous extent, work should be stopped and the workers concerned removed to a safe place until the danger has been eliminated.

(vi) When highly flammable material is being handled, special measures should be taken to ensure that an incipient fire can be controlled immediately.

(vii) Where necessary, non-sparking tools should be provided and used in explosive atmosphere.

(viii) Where corrosive substances are handled or stored, special precautions should be taken to prevent damage to the containers and to render any spillage harmless.

(ix) Workers handling harmful substances should thoroughly wash the hand and face with soap before taking any food or drink.

Other Factors:

Safety in material handling involves more than the purchase and correct use of good material handling devices. There are less obvious factors which must be considered thoroughly.

Some of these factors are considered below:

1. Floors:

Depending upon the type of operations, the conditions of the floor such as:

(a) Cleaning of Floors:

Clean floors are a necessity to any safety programme. If debris is left lying on floors, it may cause falls and unhygienic conditions. The use of mechanical sweeping devices would be more efficient than the conventional manual methods.

(b) Floor Repairs:

The tendency is to permit cracks and pot-holes in the floors to remain unrepaired until a wide area becomes bad enough to warrant complete resurfacing. Now-a-days there are several excellent patching materials available which can be applied to a floor and run over almost immediately afterwards, with little interruption to normal traffic. However, patching should not be misunderstood as permanent repairing. It should be considered also only a temporary measure.

(c) Floor Marking:

Lines marked on floors inside and outside the plant can be more good, than almost another precautionary measure to organise production activities in a plant so that they are efficient and safe. Lines ensure safety by specifying areas for aisles, storage, raw material areas, parking, etc. Line marking devices are now-a-days available which can cut short the time spent in marking the aisle ways in a big plant. Self-adhering plastic tapes can also be quickly and easily applied.

(d) Aisles should be clearly marked. Corners should preferably be cut off on a diagonal. For vehicular traffic, the width of the aisle should be at least twice the width of the circle with load plus 1 metre if the aisle is to be used by the pedestrians also.

The following colours are commonly used for marking:

i. Purple:

The basic colour for designating radiation hazards.

ii. Black and White:

Combinations of black and white or the two colours used individually are for the designation of traffic and housekeeping markings. These colours will help to identify dead ends or aisels or passageways, location and width of aisleways, stairways, and re-directional signs.

iii. Yellow and Black:

Combination of yellow and black strips are used to indicate dangers from obstructions, sudden change of levels, etc.

2. Lighting:

Poor lighting may not be the primary cause of an accident every time. But one can find that inadequate light was a factor behind many slips and falls and other injuries which occurred in the industries. There are various types of light fittings available and these should be selected and used for specific work or areas. The required levels of illumination for different operations are given in the Indian Standard I.S. 3646.

(iii) Ramps:

Ramps gradient should not exceed 1 in 10.

(iv) Obstructions:

Pipes, granduits, drain valves, fire apparatus, etc. are necessary parts of any structure yet they often cause hazards. In planning the plant such parts should be so placed that they will cause a minimum of interference with persons or materials.

(v) Ladders:

Do not climb on stockpiles, use ladders. If possible, fixed ladders are preferable. If the height exceeds 2 metres provide railing and handholds for the ladders.

(vi) Bridge Plates:

Bridge plates should be of adequate strength and they should always be properly anchored.

Materials Handling in Industries: Equipment and Types | Engineering

Meaning of Material Handling:

Equipment for Material Handling:

Types of Material Handling: