ARPAT

(Agenzia regionale per la protezione ambientale della Toscana)

Toscana Regional Environmental Protection Agency

CEDIF (Technical Sector)

RISK PROFILES INJURIES AND REMEDIES

RISKS, INJURIES AND REMEDIES

in

SAND CAST FOUNDRIES

in the

FLORENCE AREA.

1. GENERAL BACKGROUND INFORMATION

This document deals with sand cast iron foundries in the Florence province.

In the province, this manufacturing sector includes 6 firms totalling approximately 245 employees. The firms break down as follows:

· 3 firms, totalling 79 employees, are located in industrial/trade estates in the Barberino Val d’Elsa area;

· 1 firm, 80 employees, is located in an industrial/trade estate at Calenzano;

· 1 firm, 11 employees, is located in the outer suburban area of Florence, though not directly adjacent to any residential areas.

The quasi-totality (approximately 95%) of the employees is engaged in production-related activities, the remainder are administrative staff. The latter group also includes technical staff which has dealings with the workshop floor and consequently faces identical albeit reduced-entity risks to those faced by production staff. The number of purely administrative staff is relatively small.

· the sixth firm, though also located on the outskirts of the Florence suburban area, differs from the previous ones in that it is a large multinational manufacturing plant where the foundry is only a department with 65 employees (50 production line and 15 administrative). The number of employees working in the foundry shop is only a small percentage of the firm’s total employees. The firm produces only large, high-precision and high quality castings. The firm resorts to outsourcing for less important pieces and production cycles involving greater hazard to worker health. Casting operations are performed daily but all pieces are one-offs, thus no series production is carried out. Production output includes both iron and steel castings.

Our research activity centred on the first five foundries due to the particular characteristics and specificity of the sixth firm’s production, where the risks involved are more closely related to those encountered in steel mills.

Non-recent data indicates this sector includes 400 firms and 25,000 employees. Data shall be subjected to a reassessment as CEDIF-ARPAT and Health Units of the Toscana Region are currently pursuing a concerted accident-prevention program.

Accident data was drawn from non-official sources as the competent agencies have not been to date in a position to furnish sector-specific figures. The following data sequences relate to the 1989-1993 period.

Based on available data the accident frequency index (defined as the number of accidents times 10⁶ /number of working hours) varies between 195 and 215 over the five-year period: the injury severity index varies between 4 and 5. This is considerably higher than average for the metallurgical industry, both in the province and the rest of the Toscana region.

Accidents involving recovery periods in excess of three months were due to burns caused by molten iron splashes.

Data relating to occupational illnesses are reported on a working schedule phase-by-phase basis.

2. GENERAL WORKING CYCLE DESCRIPTION

2.1 GENERAL DATA AND FOUNDRY CLASSIFICATION

Metal, in the form of ingots, comes to the foundry from smelting plants. The ingots are melted again and cast in moulds in order to obtain the casting, that is the desired end item. Mould materials vary depending on the casting type.

Foundries may be classified in the following three main categories:

· sand casting foundries

· shell foundries

· pressure die-casting foundries

The differences between the above foundry types substantially relate to the following:

· raw material utilised (aluminium, mazak, bronze and brass may be utilised by all three, while cast iron may only be utilised by the sand casting foundries.

· operating temperatures (cast iron melts at approximately 1200 C° while the other metals’ melting point is around 700 C°).

· casting size (iron castings tend to be larger while die-castings tend to be smaller).

· mould materials (metal dies for shell and pressure casting foundries, while sand casting foundries utilise generally silica sand-based moulds.

Our research activity has dealt solely with sand casting iron foundries.

Diverse types of iron are utilised so as to produce in castings possessing the required mechanical properties. Ingots from the blast furnace, foundry scrap and salvaged iron resulting from the demolition of mechanical components are melted together.

2.2 WORKING CYCLE DESCRIPTION

The following table shows a block diagram of a sand casting iron foundry. A summary description of the complete working schedule is furnished. Part III of the present document, including a more detailed description of each phase, analyses the risks and measures.

The pattern reproduces the item to be cast. Light metal alloy patterns are utilised in large production runs, while wooden ones are utilised in standard practise. The pattern is used in the mould making process, that is the making of the refractory material-lined concave shape of the casting. The molten metal is poured or tapped into the shape.

Belt conveyors carry the casting sand to the hoppers which feed the moulding machines. The pattern is placed inside iron/cast iron moulding boxes or flasks and sand is tightly packed around it. For any given casting, two half-moulds closed by latches form the shell within which the molten metal is poured.

If the desired casting is hollow, the pattern shall also include a core. The core exactly reproduces the parts of the finished casting that are to remain hollow and is contained within the core box. The box is made during the initial part of the production cycle (core making). The core box is a wooden pattern whose empty spaces correspond to the desired core shape.

After having packed the sand in the moulding box, the pattern is removed and the resulting shape is finished off by inserting the core, during the mould completion phase, if the casting to be realised is hollow.

Crucibles, cupolas or electric furnaces are employed to smelt the casting metal. The molten metal is poured or tapped into the moulds using refractory material-lined metal containers called laddles.

The mould is allowed to cool and is then delivered to the knockout station, where it is placed on vibrating grills. The moulding box or flask is then split open and most of the sand is collected in the underlying hopper. The spent casting sand is cycled back to the sand conditioning station.

The casting is then sent onto the “flogging” station where all the sand residues on the casting surface and cavities is removed.

The casting now moves to the final cycle phases: shot blasting, trimming of unwanted metal such as flashings and risers, grinding and painting.

During shot blasting, a jet of abrasive or steel shot is directed onto the casting, leaving it perfectly free of all residues.

The trimming of excess or unwanted metal, traditionally referred to as fettling and dressing, involves the use of hand-held grinding tools or band saws, to remove the flashings along the mould joints and the risers, the part of the casting extending from the item to the pouring gate.

The casting surface is then finished off by grinding.

The finished piece is sent to the packing station prior to being delivered to the client.

SAND CASTING IRON FOUNDRIES

WORKING SCHEDULE FLOW CHART

RECUPERO TERRE SPENT SAND

SABBIA NUOVA FRESH SAND

STOCCAGGIO TERRE SAND MILL

ADDITIVI ADDITIVES

ADDITIVI ADDITIVES

PREP. TERRE PER FORMATURA MOULDING SAND CONDITIONING

PREPARAZIONE MODELLI PATTERN SHOP

PREP. TERRE PER ANIMISTERIA CORE MAKING SAND CONDITIONING

FORME MOULDS

RESINA RESIN

STAFFE FLASKS

FORMATURA MOULD MAKING

ANIMISTERIA (FORMATURA ANIME) CORE MAKING SHOP

FERRO LEGHE IRON ALLOYS

A VERDE GREEN SAND MOULDING

A RESINA RESIN MOULDING

ROTTAME SCRAP

VERNICIATURA FORME MOULD PAINTING

VERNICIATURA ANIME CORE PANTING

CARICAMENTO LOADING

FORME MOULDS

ANIME CORES

RAMOLAGGIO FORME/MONTAGGIO STAFFE

MOULD COMPLETION AND FLASK ASSEMBLY

FUSIONE E AFFINAZIONE SMELTING AND REFINING

COLATA TAPPING

DISTAFFATURA SHAKEOUT

STAFFE FLASKS

TERRE SAND

GETTI CASTINGS

DISTERRATURA FLOGGING

RECUPERO TERRE SAND REGENERATION

GRANIGLIATURA SHOT BLASTING

SBAVATURA FETTLING AND DRESSING

SMATEROZZATURA RISER REMOVAL

FINITURA / SCRICCATURA / COLLAUDO

POLISHING/SCARFING/INSPECTION

GETTI FINITI FINISHED CASTINGS

VERNICIATURA PAINTING

SPEDIZIONI DISPATCH

IMBALLAGGIO PACKAGING

3. RISK ANALISYS AND MEASURES

3.1 “PATTERN PREPARATION” PHASE - RISK ANALISYS AND MEASURES

The risk factors present in a carpentry shop are also present in a foundry pattern shop and, as such, are not dealt with by this document. Refer to specific literature dealing with that manufacturing sector. Many foundries perform contract work and the client furnishes the pattern of the commissioned item.

Glass fibre may also be utilised as a pattern material and hence the specific technologies and inherent risks of those production processes apply.

Specific provisions: Technical Rule UNI 473 (Foundry patterns and related auxiliary equipment).

3.3 “SAND STORAGE AND CONDITIONING” PHASE - RISK ANALISYS AND MEASURES

3.3.1 “SAND STORAGE AND CONDITIONING” - WORKING CYCLE DESCRIPTION

Casting sand must under all circumstances display the following features:

· malleability so as to best copy the pattern’s surface,

· cohesion so as to best retain pattern shape after appropriate packing,

· refractoriness so as to withstand the heat of the molten metal,

· permeability so as to allow gasses to escape during casting.

Casting sand is a mixture of silica and binders: they may be inorganic (generally clay but at times chalk, etc.) or organic (natural and synthetic resins, fish and vegetable oil-based driers, molasses, etc.). The silica-based casting sand is mixed with various additives depending on the mould making process.

Silica is 90-99% SiO₂ (quartz), the remainder is Al ₂O₃ , FeO, CaO+MgO and alkalis. Dried sand is supplied in paper bags and appears as different sized and shaped granules. Various types of sands are available, the difference being solely the particle size: 90% of dried sand particles are in the 0.1 to 0.8mm. size range. Generally the sand is washed and practically dust-free: dust content is approximately 1%, particle size is <75 micron and the inhaleable component is <5 or 10 micron.

Fish oil-based driers are employed as organic binders. They contain fatty acids and unsaturated higher fatty acid esters, have a pungent odour and a dark, oily appearance. Generally they are delivered in steel drums.

Vegetable oil-based driers are employed as organic binders. They contain mixtures of various types of vegetable oils, have an oily appearance with a vast range of colours, depending on their origin. They are delivered in steel or plastic drums.

Gypsum is employed as an inorganic binder in mould and core making sand. It contains calcium sulphate, a white or bone coloured powder (CaSO₄?2H₂ O) and is delivered in plastic or paper bags.

Ferrous oxides are employed as sand additives for mould and core making and to avoid or reduce casting surface defects such as pinholes, scabs, etc..

They are delivered either bagged in plastic or paper, or in drums. These oxides appear as reddish to dark brown powders and their chemical composition is generally Fe₂O₃, FeO and Fe₃O₄ (ranging from 65 to 92% content) while the remainder is SiO₂, Al₂O₃, CaO and MgO.

Green sand mould making involves the following additives: clay (montmorillonite-based) employed as an inorganic binder; seacoal (bituminous fossil coal powder, various hydrocarbons, water, sulphur and ash). Pregelled starches are sometimes employed as organic binders. At times ready-made mixes are used containing at least 60% bentonite (calcium and sodium silicates/aluminates and water) and seacoal making up the balance. High Carbon/Hydrogen ratio synthetic and/or natural resins are sometimes used as additives. Bentonite consists chiefly of crystalline clay minerals, belonging to the smectite group, whose main component is montmorillonite.

Montmorillonite is an hydrous aluminium silicate in which some Al and Si atoms have been replaced by Mg and Fe ones. The substitution is responsible for a residual negative surface charge. The mineral’s exchangeable ions and water are contained within its layered, stacked structure. The nature of the ions may be alkaline or alkaline earth ions but is prevailingly sodium and/or calcium. Bentonite is listed in ECOIN (European Core Inventory) as CAS 1302-78-9 (Chemical Abstract Service). Bentonite used in the preparation of ready-made mixtures generally possesses a low crystalline silica content containing approximately 1% of the inhaleable fraction. The inhaleable free crystalline silica particle size is <5-10 micron.

Prior to use sand is subjected to the following operations:

· mullers are employed to render the mixture homogeneous and to ensure that the quartz particles are covered by the clay. This operation last approximately three minutes and the operator monitors the equipment and the quality of the mixture.

· screens are employed to ensure a uniform particle size.

· disintegrators are employed to ventilate the mixture and remove dusts.

Resin mould making involves the following additives: synthetic resins (phenols or furanes) and catalysts (sulphuric acid) to speed up the chemical reaction of the components. Sand for resin mould making is conditioned and utilised immediately as the mixture tends to lose its malleability as the time-dependent chemical reaction progresses. For this reason the risk factors inherent to the resin mixture preparation are analysed in the section dealing with mould making operations.

Belt conveyors collect shakeout (see under) and excess moulding sand. It is delivered to a deferrization station, then to revolving screens and finally to storage silos or hoppers in order to be again fed to the mullers, where the cycle begins anew.

3.3.2 “SAND STORAGE AND CONDITIONING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.3.2.1 Sand is crushed and moistened by the muller. The muller appears as a large iron tub in which two broad and heavy, hardened steel drums rotate. The two drums are placed at different distances from the rotation axis so as to sweep the whole interior surface of the tub.

3.3.2.2 Sand is predominantly conveyed to and from sand handling equipment by rubber belt conveyors.

3.3.2.3 The deferrization station removes tramp metal from the sand. The station includes two counter-rotating iron studded cylinders which crush the sand, an oscillating sand feeding device and an electro magnet-studded drum which attracts and dumps tramp metal particles present in the sand.

3.3.2.4 Rotary screens separate the various particle sizes after grinding and deferrization. The machine appears as two inclined and overlapping vibrating screens.

3.3.3 “SAND STORAGE AND CONDITIONING” PHASE - RISK FACTORS

The main risk factors in this phase are:

3.3.3.1 Noise hazards, essentially produced by mullers..

Noise levels generated by mullers do not generally constitute a priority issue.

3.3.3.2 Mechanical hazards due to proximity to muller rotating parts. Muller rotating speed is adjusted by sliding the belt drive on the pulley.

3.3.3.3 Dust hazard due to exposure to free crystalline silica particles, (quartz, cristobalite, tridymite) present in the sand. Operator exposure occurs upon bag opening and emptying, storage and pressurised component loading operations. Free crystalline silica (quartz) is listed in ECOIN (European Core Inventory) as CAS 14808-60-7. EC Risk and Safety Marking Code: R20 (Dangerous to health if inhaled), S22 (Do not inhale dust). Dust dispersion occurs during storage, pick up and mixing. During this operation dispersion is generally limited as the sand has been moistened. Dispersion in this phase is due to the belt conveyors which carry the completely dry, spent sand from the flask opening station for regeneration.

3.3.3.4 Exposure to graphite dusts employed as a moulding sand additive. Graphite powder is amorphous or crystalline graphite whose carbon content varies from 40 to 90%, colour ranging from matt to silvery black, generally supplied in paper bags. Dusts develop during storage, pick-up and mixing operations.

3.3.3.5 Exposure to clay dusts employed as an inorganic moulding sand binder. Delivered in plastic or paper bags, the pale yellow clay powder contains complex hydrous Al, Fe, Mg silicates and alkali. Dusts develop during storage, pick-up and mixing operations.

3.3.3.6 Exposure to pregelled starch dusts employed as organic moulding sand binders. Supplied in plastic or paper bags, the starch powder and flakes (C₆H₁₀O₅)_n vary from bone to pale yellow in colour. Dusts develop during storage, pick-up and mixing operations.

3.3.3.7 Exposure to FeO dusts employed as moulding sand additive. Dusts develop during storage, pick-up and mixing operations.

3.3.3.8 Exposure to gypsum dusts employed as an inorganic moulding sand binder. Dusts develop during storage, pick-up and mixing operations.

3.3.3.9 Handling of fish and/or vegetable oils employed as organic moulding sand binders. These oils give off a particularly pungent odour.

3.3.4 “SAND STORAGE AND CONDITIONING” PHASE - EXPECTED AND RECORDED INJURIES

3.3.4.1 The noise levels directly generated by mullers rarely cause hearing injuries as operator exposure is limited due to the generally automated nature of the operation which dispenses with constant operator monitoring.

3.3.4.2 Risk of injuries inherent to mullers are bruises, trapping, entanglement, crushing and drawing in.

3.3.4.3 If inhaled, free crystalline silica dusts may cause silicosis but only rare cases have been registered in foundry environments. Pneumoconiosis cases are more frequent and are functionally characterised by a prevailing obstructive component, with a greater incidence in smokers. In the majority of cases however respiratory functionality tests reveal no alterations. The radiological picture is top ranked by I.L.O. (1/0p).

[see Coscia G.C. et al, “X-ray-clinical study of operators exposed to foundry risks” (Indagine Clinico Radiologica di esposti al rischio di fonderia); Farina G.A. “Respiratory pathologies in a group of ex-casters in a population of the upper Val d’Elsa valley” (Patologie respiratorie in un gruppo di ex fonditori in un gruppo dell’Alta Val d’Elsa) - proceedings Sand Cast Foundry Conference - Poggibonsi 1986].

The above pathologies are typical of exposure to relatively low-content silica dusts associated to the action deployed by other respiratory pathogenic agents such as fumes, non silicosis-producing dusts, chemical agents, up to envisaging a mixed dust pneumoconiosis characterised by slow evolution and relative clinical benignity at least in those patients where it is not associated to a chronic bronchial obstructive syndrome. This syndrome may be negatively affected also by non occupational factors such as cigarette smoke.

3.3.4.4 Graphite dusts, together with the presence of other types of dust, may contribute to the development of mixed dust pneumoconiosis.

3.3.4.5 Clay dusts, together with the presence of other types of dust, may contribute to the development of mixed dust pneumoconiosis.

3.3.4.6 Pregelled starch dusts, together with the presence of other types of dust, may contribute to the development of mixed dust pneumoconiosis.

3.3.4.7 FeO dusts, together with the presence of other types of dust, may contribute to the development of mixed dust pneumoconiosis.

3.3.4.8 Gypsum dusts, together with the presence of other types of dust, may contribute to the development of mixed dust pneumoconiosis.

3.3.4.9 Vegetable or fish oils are not a major risk factor as they merely cause inconvenience due to their pungent odour.

3.3.5 “SAND STORAGE AND CONDITIONING” PHASE - ACCIDENT PREVENTION MEASURES

3.3.5.1 Exposure to muller noise may be cut down by segregating the machine in a sound-dampening enclosure. This measure will also reduce dust dispersion.

3.3.5.2 The muller shall be fitted with an emergency cut-out switch as well as a device which inhibits automatic machine start-up after a power failure; the tub must be guarded; the drive belt must be protected by a guard fitted with an automatic cut-out in case of guard removal.

3.3.5.3 In order to reduce exposure to dusts, powdered additives and mixtures should be handled in a sludge form. A looped circuit system shall be implemented; access to dusty environments shall be limited as far as feasible; loading stations shall be fitted with LEVs; a general workplace extraction/ventilation system shall be installed; appropriate maintenance shall be carried out on the machines. The whole facility and more specifically the hoppers, mullers and belt conveyor load stations shall be enclosed and fitted with an exhaust system. Handling of additives and mixtures not in the sludge form shall require the use of IPDs-Individual Protection Devices (grade P2 dust-proof face mask, protective gloves and apron).

3.3.5.4 Handling of oils requires IPDs (face mask, protective gloves and apron). Appropriate ventilation shall be implemented in order to reduce operator exposure to the pungent odours.

3.3.6 “SAND STORAGE AND PROCESSING” PHASE - OUTSOURCING

Outsourcing is generally not practised.

3.3.7 “SAND STORAGE AND PROCESSING” PHASE - PERTINENT REGULATIONS

In addition to the general accident prevention regulations, attention is drawn to the following:

3.3.7.1 Dusts: ref. Art. 21 D.P.R. 303 dated 1956.

According to ACGIH recommendations, MEL (Maximum Exposure Limit) for inhaleable free crystalline silica is 0,4 mg/m³ during an average 8-hour work shift (TWA). As no limit has been set for shorter exposure times, mean exposure during a 10 minute period should not exceed three times the 8-hour TWA limits.

Inhaleable free crystalline silica (quartz) TVL is 0,1 mg/m³ for an 8-hour exposure period.

Carbon TVL is 2 mg/m³ of workplace ambient air.

3.3.7.2 Noise: ref. D.Lgs. 277 dated 1991.

3.3.7.3 Protection of moving parts: ref. D.P.R. 547 dated 1955 and the Machine Directive.

3.3.7.4 Mullers: ref. Technical Rule UNI 5883 (Testing of mullers for foundry moulding sand preparation).

3.3.7.5 Atmospheric emissions: ref. DPR 203/88

3.3.8 ENVIRONMENTAL IMPACT.

This phase’s environmental impact is principally due to the dusts coming from the ventilated automatic sand storage and conditioning plant. The remedial measure is the adoption of a scrubbing plant fitted with electrostatic precipitators, fabric filters or multi-cell mechanical filters.

3.4 RISK ANALYSIS AND MEASURES IN THE “GREEN SAND MOULDING” PHASE

3.4.1 “GREEN SAND MOULDING” PHASE - WORKING CYCLE DESCRIPTION

The composition of green sand for mould making has been described above in the sand conditioning paragraph. Sand is either conditioned by automatic mills for series production or manually (see paragraph “Sand Conditioning”).

Sand is packed around the pattern in the moulding box or flask. Box or flask filling is achieved partly by gravity feed, from the overhead hopper (height: approx. 2 meters) and partly by hand.

Green sand moulding is also referred to as “automatic moulding” as it is performed by individual “jolt-squeeze” moulding machines which shake and consolidate the sand around the pattern. The operators place the boxes or flasks on the work surface, monitor sand metering from the hopper into the box and manually spread it evenly. After the machine cycle, operators verify sand packing. The box or flask is then automatically overturned and shaken so as to remove the pattern.

3.4.2 “GREEN SAND MOULDING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.4.2.1 The jolt-squeeze machine uses pneumatic power to generate successive shocks so as to pack the sand around the pattern in the moulding box. High pressure is exerted almost simultaneously on the sand above the pattern. The pattern is subsequently removed from the box.

3.4.2.2 The moulding boxes or flasks are metal (cast/iron/steel) containers in which the sand is tightly packed around the pattern. Two “half-moulds” are needed for each casting. Once the two halves are clamped together they form the shell in which the molten metal is cast.

3.4.3 “GREEN SAND MOULDING” PHASE - RISK FACTORS

The principal risk factors are:

3.4.3.1 Noise exposure, due to the moulding machines, is generated principally by vibrations. Noise levels are higher when a number of machines are operating simultaneously.

3.4.3.2 Dust exposure, principally the free crystalline silica component of the dry, fine moulding sand particles and graphite, occurs during box/flask filling.

3.4.3.3 Mechanical hazards due to proximity to jolt-squeeze machine moving parts.

3.4.4 “GREEN SAND MOULDING” PHASE - EXPECTED AND RECORDED INJURIES

3.4.4.1 Noise exposure entails a high probability of severe hearing injuries due both to the levels achieved and to the throbbing nature of moulding machine-generated noise.

3.4.4.2 Dust exposure (see above) may cause mixed dust pneumoconiosis.

3.4.5 “GREEN SAND MOULDING” PHASE - ACCIDENT PREVENTION MEASURES

3.4.5.1 A number of ways to reduce noise exposure, some of which may be implemented jointly, are listed below.

3.4.5.1.1 Substitution of old jolt-squeeze machines with newer automatic hydraulic or pneumatic ones. This latter type of machine entails a significant reduction of operator noise exposure levels. Silencers shall be fitted to the compressed air vent valves of the various pneumatic feed systems. Constant monitoring and adjustment of the system is essential, especially the shakeout vibration intensity and the velocity of the compressed air jets used to clean the moulds.

3.4.5.1.2 Passive type measures aimed at segregating individual moulding machines and isolating them from surrounding work areas so as to avoid the additive effects of noise overlap from parallel production lines. These measures also reduce direct noise exposure to operators engaged in other near-by production operations. Segregation may be achieved by means of sound deadening enclosures and surface finishes to dampen machine-generated noise. Appropriate ventilation, especially during the warmer months, and suitable layout, so as not to generate a cramped operator workstation, are some of the design parameters. Enclosure design shall be such as not to require its removal during machine loading-unloading operations. Where implemented, this type of measure has proved to be effective in achieving set goals and has been favourably accepted by foundry management. The following data was acquired subsequent to a site inspection carried out in one of the foundries in the research area: Leq was reduced from 96,6 dB(A) to 93,8 dB(A) for moulding machine operators and from 94,0 dB(A) to 88,1 dB(A) for indirectly exposed operators of other adjacent work cycles. (Measure: RISOL N° 92). Use of IPDs is mandatory for directly-exposed operators (ref. D.Lgs. 277/’91) and recommended for those exposed indirectly.

3.4.5.1.3 Use IPDs..

3.4.5.2 Dust exposure reduction requires the installation of a ventilation system and of a sealed sand transportation system: IPDs shall be used when manual sand handling is performed.

3.4.5.3 Accident prevention measures for large box-flask jolt-squeeze machines include guarding of tipping systems and use of interlocking access systems to moulding press control panels.

3.4.6 “GREEN SAND MOULDING” PHASE - OUTSOURCING

Outsourcing is generally not practised.

3.4.7 “GREEN SAND MOULDING” PHASE - PERTINENT REGULATIONS

· DPR 456/96 (Machine Directive)

· D.Lgs. 626/94

· D.Lgs. 277/91

· DPR 303/56

· DPR 547/55

· DPR 203/88

· DPCM dated 01.03.91 (external noise)

· Technical Rule UNI 6764 (Foundry tools. Moulding box-flask size, type and identification).

· Technical Rule UNI 6765 (Foundry tools. Moulding box-flask linear positioning markings).

· Technical Rule UNI 6766 (Foundry tools. Moulding box-flask triangular positioning markings).

· Technical Rule UNI 6767 (Foundry tools. Moulding box-flask positioning bushes)

· Technical Rule UNI 6768 (Foundry tools. Moulding box-flask wedges and clamp fasteners).

· Technical Rule UNI 6769 (Foundry tools. Moulding box-flask positioning pins).

· Technical Rule UNI 6770 (Foundry tools. Metal pattern plate with linear markings).

· Technical Rule UNI 6770 (Foundry tools. Metal pattern plate with triangular markings).

· Technical Rule UNI 6771 (Foundry tools. Metal pattern plate with positioning dowels).

3.4.8 “GREEN SAND MOULDING” PHASE ENVIRONMENTAL IMPACT

The environmental impact of this phase is principally due to the dusts coming from the ventilated automatic mould making plant. The remedial measure is the adoption of a scrubbing plant fitted with electrostatic precipitators, fabric filters or multi-cell mechanical filters.

3.5 “RESIN MOULDING” PHASE RISK ANALYSIS AND MEASURES

3.5.1 “RESIN MOULDING” PHASE - WORKING CYCLE DESCRIPTION

Resin moulding is also referred to as “manual moulding” as, unlike green sand moulding where moulding machines are used, only manual operations are involved in this mould making process. Operators position the pattern in the box or flask, fill it with sand fed by the hopper, manually spread it and employ pneumatic rammers to pack sand around the pattern.

In addition to using different sand mixture components, resin moulding differs from green sand moulding in the binders used (resins and catalysts) which are added immediately before the mould-making stage.

Phenolic resins are phenol and formaldehyde condensation products. Their chemical composition is determined by: phenol-formaldehyde polycondensates, free phenol, free formaldehyde and various types of additives depending on utilisation.

Urea furane resin, also referred to as furfuryl alcohol, formaldehyde and urea condensation resin, is often employed.

Resins may be supplied either in the solid form (flakes or powder), or as a liquid (alcoholic, hydroalcoholic solution or watery emulsion).

Solid resins are supplied in bags (plastic or paper) or in cartons (cardboard or plastic). Liquid resins are supplied in steel drums or in tanks requiring transfer pumps. In all cases phenolic resin containers bear the mandatory toxic/noxious labelling.

The catalyst is a low-viscosity sulphonic and sulphuric acid solution constituted by paratoluensulphonic acid and sulphuric acid.

3.5.2 “RESIN MOULDING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.5.2.1 The pneumatic rammers are small, hand-held reciprocating-action jackhammers fitted with a steel ramming tool.

3.5.3 “RESIN MOULDING” PHASE- RISK FACTORS

The principal risk factors in this phase are:

3.5.3.1 Exposure to organic vapours (free phenol, formaldehyde and furfuryl alcohol). The vapours originate both from the reaction products, generated by synthetic resin reticulation, and the resin’s own monomers. In addition to the mould-making stage, vapours may also be given off during resin storage, pickup and metering operations.

Furfuryl alcohol is listed as CAS 98-00-0; EEC n° 603-018-00-2  and labelled Xn (noxious), R20 (noxious if inhaled), R21 (noxious upon skin contact), R22 (noxious if swallowed).

Formaldehyde is listed as CAS 50-00-0; EEC n° 605-001-00-5 and labelled T (toxic), R23/24/25 (toxic if inhaled/swallowed/upon skin contact), R40 (possible irreversible effects), R43 (may cause skin sensitisation).

3.5.3.2 Handling of dangerous products and substances due to the handling of resins. Resin danger levels are proportionate to their composition. According to EEC Directive n° 73/173 dated 14.07.73, products whose free phenol content is < 1% are not listed; the product is labelled Xn (noxious) if content is included between 1% and 5% ; the product is labelled toxic (T) if content is > 5%. paratoluensulphonic acid is listed as CAS 104-15-4 and labelled C (corrosive); R34 (causes burns). Sulphuric acid is listed as CAS 7664-93-9 ; EEC n° 016-020-00-8  and labelled C (corrosive), R35 (causes severe burns).

Labelling of low-viscosity sulphonic and sulphuric acid solutions is marked S14 (store away from resins), S26 (in case of contact with eyes immediately rinse with abundant water and seek medical advice), S37/39 (use suitable protective gloves, mask and goggles).

3.5.3.3 Exposure to dusts due to the dry, fine sand particles. Compared to green sand moulding, resin moulding carries a somewhat higher risk factor as sand has not been subjected to moistening.

3.5.3.4 Exposure to HAVS (Hand-Arm Vibration Syndrome) due to the use of hand-held pneumatic rammers.

3.5.3.5 Exposure to noise generated by the pneumatic rammers.

3.5.3.6 High work pace. The use of resins and catalysts cause fast mould and core hardening. This entails the need for speedy operations and consequent higher physical exertion during this phase of the working schedule.

3.5.3.7 Incorrect job postures. Operators adopt uncomfortable working positions during manual moulding with a consequent greater physical exertion.

3.5.4 “RESIN MOULDING” PHASE - EXPECTED AND REPORTED INJURIES

3.5.4.1 Exposure to organic vapours (phenol and formaldehyde) may cause eye and throat irritation. IARC has listed formaldehyde as a group 2A carcinogen, a probable carcinogenic agent for humans.

3.5.4.2 Contact with furfuryl alcohol may cause skin sensitisation, eczema and delipidization. May cause irritation in case of contact with eyes.

3.5.4.3 Contact with formaldehyde may cause skin sensitisation, eczema. May cause irritation and keratitis in case of contact with eyes.

3.5.4.4 Contact with sulphuric acid may cause skin sensitisation, eczema and necrosis. May cause irritation and keratitis in case of contact with eyes.

3.5.4.5 Contact with paratoluensulphonic acid may cause skin sensitisation. May cause irritation and keratitis in case of contact with eyes.

3.5.4.6 Furfuryl alcohol inhalation may cause pulmonary sensitisation, vomiting, diarrhoea, narcosis, depression.

3.5.4.7 Formaldehyde inhalation may cause pulmonary sensitisation, pulmonary oedema, vomiting, abdominal colics, diarrhoea. Formaldehyde is a suspected carcinogenic agent (C3)

3.5.4.8 Sulphuric acid inhalation may cause pulmonary sensitisation, oedema, fibrosis, emphysema. In addition it may also cause mucosae sensitisation and vomiting.

3.5.4.9 Paratoluensulphonic acid inhalation may cause pulmonary sensitisation and oedema. In addition it may also cause mucosae sensitisation, vomiting and abdominal colics.

3.5.4.10 Exposure to dusts may cause mixed dust pneumoconiosis. During this cycle phase there is a medium-to-high onset probability as a function of exposure type.

3.5.4.11 Exposure to HAVS causes upper limb circulatory, nervous and joint damage (Raynaud’s syndrome). Smoking and excessive cold further compound vibration-induced circulatory damage. Pathology onset is proportional to exposure time. Exposure time during this phase is not prolonged.

3.5.4.12 Exposure to rammer-generated noise may cause hearing injuries.

3.5.4.13 Injuries resulting from contact with phenol resins varies as a function of the concentration levels of the individual substance present in the resins and ranges from sensitisation and allergic dermatitises to burns.

3.5.4.14 The high work pace may cause stress and hence increase accident probability.

3.5.3.1 Incorrect job postures may cause skeletal-muscular disorders.

3.5.5 “RESIN MOULDING” PHASE - ACCIDENT PREVENTION MEASURES

Vapour and dusts exposure reduction measures include installation of natural ventilation systems, exhaust systems and use of IPDs. Suitable design parameters should be adopted so as to correctly proportion duct size to exhaust air velocity so as to avoid the possibility of flammable product condensation build-up in the ventilation ducts. 

3.5.5.1 HAVS reduction measures include the adoption of low-vibration or reduced vibration-impact rammers, vibration dampening grips, workplace ambient heating during the colder months, cutting exposure times by operator rostering. It is advisable to warn operators of the negative effects of cigarette smoking on HAVS.

3.5.5.2 Resin contact reduction measures include: use of appropriate IPDs (gloves, aprons, etc.), appropriate LEV and general ventilation systems. Use of NBR gloves, goggles, face guards, splash-proof aprons and protective non-absorbing clothing is recommended when handling furanes.

3.5.6 “RESIN MOULDING” PHASE - OUTSOURCING

Outsourcing is generally not practised.

3.5.7 “RESIN MOULDING” PHASE - PERTINENT REGULATIONS

· Sulphuric acid TVL-TWA is 1 mg/m³ , TLV-STEL is 3 mg/m³ .

· DPR 456/96 (Machine Directive)

· D.Lgs. 626/94

· D.Lgs. 277/91

· DPR 303/56

· DPR 547/55

· DPR 203/88

· Law n° 319/76 (process water discharge) and Municipal public sewers regulations.

· Technical Rule UNI 6764 (Foundry tools. Moulding box-flask size, type and identification).

· Technical Rule UNI 6765 (Foundry tools. Moulding box-flask linear positioning markings).

· Technical Rule UNI 6766 (Foundry tools. Moulding box-flask triangular positioning markings).

· Technical Rule UNI 6767 (Foundry tools. Moulding box-flask positioning bushes)

· Technical Rule UNI 6768 (Foundry tools. Moulding box-flask wedges and clamp fasteners).

· Technical Rule UNI 6769 (Foundry tools. Moulding box-flask positioning pins).

· Technical Rule UNI 6770 (Foundry tools. Metal pattern plate with linear markings).

· Technical Rule UNI 6770 (Foundry tools. Metal pattern plate with triangular markings).

· Technical Rule UNI 6771 (Foundry tools. Metal pattern plate with positioning dowels).

3.5.8 “RESIN MOULDING” PHASE - ENVIRONMENTAL IMPACT

The environmental impact of this phase is principally due to the emission of organic vapours and dusts coming from the green sand mould making plant LEV and general ventilation systems. The remedial measure is the adoption of a scrubbing plant fitted with Venturi-type or centrifugal wet dust removers. Scrubbing plant sludge is pumped to the settling tanks prior to disposal.

3.6 “CORE MAKING” PHASE - RISK ANALYSIS AND MEASURES

3.6.1 “CORE MAKING” PHASE - WORKING CYCLE DESCRIPTION

The core is a mould which exactly reproduces the hollow parts of the casting. Sand is packed in the core box. The box’s empty spaces will result in the casting’s hollow parts. Sometimes cores are painted prior to being used employing the same paint as for the moulds (see para. “Painting”).

There are four distinct core making processes:

3.6.1.1 Ashland core making: cores are cold moulded using automatic machines called “core-blowers”. Compressed air is used to blow the sand into the core box.

The resin-conditioned casting sand undergoes a chemical reaction when an appropriate gaseous catalyst is blown through it.

A binary-component resin is used. Generally one of the components is a phenol resin dissolved in a suitable solvent while the other component includes polyisocyanates, also dissolved in a solvent. The flash point of these binders is approximately 45-50 C°.

Aliphatic amines are used as catalysts. These substances are inflammable and may produce explosive mixtures. CO₂ is employed to dilute the amines.

3.6.1.2 Shell-moulding core making: cores are hot-moulded using “core-blower” machines. Catalysed heat-setting resins are used to condition the moulding sand. The mixture is blown or shot in the core box at temperatures around 250°C.

The mixture includes: silica, chromite, zircon, olivine, etc. previously conditioned using organic binders; the heat setting resin (novolacche-type) is obtained by allowing phenol to react with formaldehyde; the catalyst is hexamethylen-tetramine; the lubricating medium is zinc or calcium stearate. The mixture appears as different sized granules and is supplied in paper/plastic bags or containers, metal or otherwise.

Silicones are employed as core box-core parting agents. Silicones are supplied as a liquid (in drums), emulsion or dough (in metal or plastic containers).

3.6.1.3 CO₂ core making: cores are made by blowing CO₂ through the sand in the core box. A highly alkaline sodium silicate solution is used as a binder to condition the sand.

Sodium silicate and other sodium silicate-based mixtures employed as binders are supplied in steel drums bearing appropriate mandatory labelling as they are classified as corrosive agents. Chemical composition varies from Na₂O·SiO₂ to Na₂O·4SiO₂ ,in aqueous solution, at times with organic additives (generally carbohydrates).

Carbon dioxide, a colourless odourless gas, is supplied in liquid form in suitably labelled steel cylinders (capacity 10 to 30 kg.).

3.6.1.4 Resin core making: cores are manually bench-made following similar processes to those employed in resin moulding (see para. “Resin Moulding).

3.6.2 “CORE MAKING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.6.2.1 Core box: the metal core box is closed by pneumatic rams. The top of the box is connected to a hopper which holds the sand. High pressure compressed air is blown into the hopper, thus driving the sand into the box. In shell moulding an electrical heating coil is used to heat the boxes.

3.6.3 “CORE MAKING” PHASE - RISK FACTORS

3.6.3.1 Ashland core making risk factors.

The principal risk factors are:

3.6.3.1.1 Exposure to dusts generated by the substances listed above.

3.6.3.1.2 Exposure to carbon monoxide gas (CO).

3.6.3.1.3 Exposure to carbon dioxide gas (CO₂).

3.6.3.1.4 Exposure to aliphatic and aromatic hydrocarbon vapours.

3.6.3.1.5 Exposure to free phenol vapours (C₆H₅OH). Work cycle operating temperatures liberate the non-reacting part of the phenol present in the resins.

3.6.3.1.6 Exposure to free formaldehyde vapours (HCHO). Work cycle operating temperatures liberate the non-reacting part of the formaldehyde present in the resins.

3.6.3.1.7 Exposure to ammonia vapours developed as a result of catalyst decomposition.

3.6.3.1.8 Exposure to hydrocyanic vapours.

3.6.3.1.9 Exposure to steam.

3.6.3.1.10 Use of inflammable substances apt to produce explosive mixtures.

3.6.3.1.11 Use of pressurised CO₂ gas cylinders.

3.6.3.2 Shell-moulding core making risk factors.

The principal risk factors are:

3.6.3.2.1 Exposure to dusts generated by the substances listed above.

3.6.3.2.2 Exposure to carbon monoxide gas (CO).

3.6.3.2.3 Exposure to carbon dioxide gas (CO₂).

3.6.3.2.4 Exposure to aliphatic and light aromatic hydrocarbon vapours.

3.6.3.2.5 Exposure to phenol vapours (C₆H₅OH). Work cycle operating temperatures liberate the non-reacting part of the phenol present in the resins.

3.6.3.2.6 Exposure to formaldehyde vapours (HCHO). Work cycle operating temperatures liberate the non-reacting part of the formaldehyde present in the resins.

3.6.3.2.7 Exposure to ammonia vapours developed as a result of catalyst decomposition.

3.6.3.2.8 Exposure to hydrocyanic vapours.

3.6.3.2.9 Exposure to furfuryl alcohol vapours (traces).

3.6.3.2.10 Exposure to steam.

3.6.3.2.11 Exposure to radiant heat during core extraction from the machines.

3.6.3.3 CO₂ core making risk factors.

The principal risk factors are:

3.6.3.3.1 Handling of corrosive substances, due to the use of sodium silicate and sodium silicate-based binders. These chemicals are listed as corrosive agents due to free NaOH content (>5%). The presence of silicic acid in the system reduces the risk of burns upon contact.

3.6.3.3.2 Exposure to carbon dioxide gas (CO₂).

3.6.3.3.3 Use of pressurised CO₂ gas cylinders.

3.6.3.4 resin core making risk factors

Resin core making risk factors are the same as those encountered during resin mould making (see para. “Resin mould making”).

3.6.4 “CORE MAKING” PHASE - EXPECTED AND REPORTED INJURIES

3.6.4.1 Severe burns are produced by contact with sodium silicate and other sodium silicate-based binders.

3.6.4.2 Carbon dioxide inhalation (5% concentration) for 30 minutes causes dyspnoea, vomiting, vertigo. A 10% concentration gives rise to the same symptoms within a few minutes. In addition to the above symptoms, prolonged inhalation will give rise to sweating, convulsions, respiratory difficulties, coma and death.

3.6.5 “CORE MAKING” PHASE - ACCIDENT PREVENTION MEASURES

3.6.5.1 IPDs (gloves, aprons, goggles) must be used in order to reduce risks when handling corrosive agents. Operators shall be specially trained and adequately informed as to the risks and the most appropriate procedures to be implemented in case of contamination. In case of contact with corrosive agents, especially the eyes, immediately rinse with abundant water and remove all contaminated articles of clothing. Operator shower facilities must include eye wash stations. Facilities shall always be ready for use and shall not be used for storage purposes. Operators shall immediately seek medical assistance after having rinsed away the corrosive agent.

3.6.5.2 Pressurised CO₂ gas cylinders shall be stored away from heat sources.

3.6.5.3 LEV and general ventilation systems shall be installed due to the presence of dusts and vapours.

3.6.5.4 Following the initial manifestation of carbon dioxide intoxication symptoms, the operator shall be immediately led away from the workplace and medical assistance shall be sought. Operators shall be specially trained and adequately informed as to the risks and the most appropriate procedures to be implemented in case of contamination.

3.6.6 “CORE MAKING” PHASE - OUTSOURCING

At times certain foundries resort to outsourcing for core making. This is especially true when the foundry has been contracted to supply small-sized series-produced castings whereas cores for non-series production runs are prevailingly made in-house.

3.6.7 “CORE MAKING” PHASE - PERTINENT REGULATIONS

· DPR 456/96 (Machine Directive)

· D.Lgs. 626/94

· D.Lgs. 277/91

· DPR 303/56

· DPR 547/55

· DPR 203/88

· Law n° 319/76 and Municipal Public Sewers Regulations

· DPR 915/82, “Ronchi” decree dated 1997 and subsequent implementation decrees (Wastes).

3.6.8 “CORE MAKING” PHASE - ENVIRONMENTAL IMPACT

The environmental impact of this phase is principally due to the emission of vapours and dusts coming from the core making plant LEV and general ventilation systems. The remedial measure is the adoption of a scrubbing plant fitted with Venturi-type or centrifugal wet dust removers. Scrubbing plant sludge is pumped to the settling tanks prior to disposal.

3.7 “PAINTING” PHASE - RISK ANALYSIS AND MEASURES

3.7.1 “PAINTING” PHASE - WORKING CYCLE DESCRIPTION

As shown in the block diagram, painting operations may be performed during a number of working schedule phases. Finished castings may be painted, if so requested by the client, however it is generally a functional operation of the working schedule. In green sand or automatic moulding, moulds and cores are painted and then flame hardened, in order to avoid casting-to-mould bonding.

Various types of paints are employed for mould and core painting, however they all belong to the heat-resistant type. In general their composition includes: a mineral component (e.g. graphite, olivine, chromite, mica, sodium and zircon silicate, etc.); a suspension medium (often carboxymethylcellulose, alginic sodium salts and various types of resins); solvents (methyl alcohol, isopropyl alcohol, isobutyl alcohol, acetone, trichloroethylene, etc.) and antifermentative agents (sodium benzoate, etc.). In view of the vast variety of products, please refer to manufacturers’ product data sheets for other characteristics and labelling. Paints may be supplied in various forms: powder, slurry, water or organic solvent-based liquids.

Paint preparation may sometimes be performed on-site in the foundry, using ground mica and isobutyl alcohol. Alternatively an alcohol-based, heat resistant slurry, containing dangerous substances such as isobutyl alcohol, isopropyl alcohol or acetone, is employed.

Mica is supplied in paper bags. Mica, a yellowish coloured fine powder, is a non-combustible product containing aluminium and potassium silicate crystals.

Isobutyl alcohol is an easily flammable, noxious product if inhaled. It is supplied in plastic or steel drums, glass containers or in bulk (tanks). In all cases it bears the specific mandatory labelling for noxious products (Xn).

Painting operations are performed in painting booths employing either brushes or compressed air spray guns.

3.7.2 “PAINTING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.7.2.1 Spray painting booth of the type used also in other manufacturing plants.

3.7.2.2 Compressed air spray gun of the normally available commercial type.

3.7.3 “PAINTING” PHASE - RISK FACTORS

There is a huge range of different paint component formulae. Consequently, risk factors are equally wide ranging. In order to establish the specific risks incurred, paint components must be ascertained on a case-by-case basis, depending on the paints employed by each individual firm.

That being stated, the principal risk factors are:

3.7.3.1 Exposure to organic solvent vapours (alcohol, aromatic and aliphatic hydrocarbons, acetates, etc.) contained in paint solvents.

Isobutyl alcohol is labelled: Xn (noxious), R20 (noxious if inhaled); CAS 78-83-1; EEC 603-004-00-6.

Isopropyl alcohol is labelled: F (easily flammable), CAS 67-63-0, EEC 603-003-00-0.

Acetone is labelled: F (easily flammable), CAS 67-64-1, EEC 606-001-00-8.

3.7.3.2 Handling of noxious and easily flammable products contained in the solvents (e.g. isobutyl alcohol) employed during on-site paint preparation.

3.7.3.3 Exposure to dusts coming from the “dry residue” of the paints. Residues generally contain inorganic pigments (lead salts, chrome salts and salts of other metals), binders (synthetic resins) and fillers (calcium carbonate).

Dusts are also generated by the handling of powdered paint components during storage, pick-up and metering operations.

3.7.4 “PAINTING” PHASE - EXPECTED AND RECORDED INJURIES

3.7.4.1 Isopropyl alcohol coming into contact with the skin may cause irritation, sensitisation, eczema, delipidization. Contact with eyes may cause irritation and keratitis.

3.7.4.2 Isopropyl alcohol inhalation may cause pulmonary irritation. Other symptoms include hypotension,, narcosis, depression, behavioural modifications, diarrhoea.

3.7.4.3 Isobutyl alcohol coming into contact with the skin may cause irritation, eczema, delipidization. Contact with eyes may cause irritation and keratitis.

3.7.4.4 Isobutyl alcohol inhalation may cause pulmonary irritation. Other symptoms include depression..

3.7.4.5 Acetone coming into contact with the skin may cause irritation, delipidization. Contact with eyes may cause irritation and keratitis.

3.7.4.6 Acetone inhalation may cause pulmonary irritation. Other symptoms include narcosis, depression, behavioural modifications.

3.7.1 “PAINTING” PHASE - ACCIDENT PREVENTION MEASURES

3.7.5.1 Organic solvent vapours exposure reduction measures involve the use of IPDs and the adoption of appropriately ventilated painting booths. Paint preparation shall be performed under an extractor cowling.

3.7.5.2 Accident risk reduction measures when handling and using easily flammable and noxious substances involve: smoking ban, storing the substances away from heat sources, using IPDs (mouth-nose mask, gloves, aprons) and employing qualified and specially trained operators.

3.7.5.3 Dust exposure reduction measures involve: use of IPDs (mouth-nose mask, gloves, aprons) when handling paint components in powdered form. Special care shall be dedicated to cleaning operations. Such operations shall be performed frequently, using IPDs and industrial-type cleaning equipment.

3.7.6 “PAINTING” PHASE - OUTSOURCING

Painting may be outsourced when dealing with finished castings. Mould and core painting is generally performed in-house unless also core making is outsourced.

3.7.7 “PAINTING” PHASE - PERTINENT REGULATIONS

Isobutyl alcohol TVL-TWA is 150 mg/m³ .

Isopropyl alcohol TVL-TWA is 985 mg/m³, TLV-STEL is 1230 mg/m³ .

Acetone TVL-TWA is 1780 mg/m³, TLV-STEL is 2375 mg/m³ .

· DPR 456/96 (Machine Directive)

· D.Lgs. 626/94

· D.Lgs. 277/91

· DPR 303/56

· DPR 547/55

· DPR 203/88

· DPR 915/82, “Ronchi” decree dated 1997 and subsequent implementation decrees (Wastes).

· Law n° 319/76 and Municipal Public Sewers Regulations

· Technical Rule UNI 9941 (Spray painting booths. Design and construction: Safety requirements).

3.7.8 “PAINTING” PHASE - ENVIRONMENTAL IMPACT

The environmental impact of this phase is principally due to the emission of vapours and dusts coming from the spray panting booth LEVs. The remedial measure is the adoption of a scrubbing plant fitted with Venturi-type or centrifugal wet dust removers. Scrubbing plant sludge is pumped to the settling tanks prior to disposal.

3.8 “MOULD COMPLETION” PHASE - RISK ANALYSIS AND MEASURES

3.8.1 “MOULD COMPLETION” PHASE - WORKING CYCLE DESCRIPTION

Mould completion is a manual operation common to all types of mould making. Mould completion involves finishing off the moulds, cleaning them with a jet of compressed air, positioning the core when called for, drilling the casting and gas exhaust passages and the application of parting agents. The agents may be paints, brushed on and subsequently flame hardened, or powders (super areated talc, natural lycopodium or silver graphite)

After this process has been completed the two semi-flasks are brought together, thus forming the “shell” within which the molten metal is cast.

3.8.2 “MOULD COMPLETION” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.8.2.1 Conventional overhead travelling cranes are employed to transport the two half-flasks to the assembly station.

3.8.2.2 Compressed air gun..

3.8.2.3 Automatic equipment rotates one semi-flask, positions the core (if any) and proceeds to the positioning of the other semi-flask.

3.8.3 “MOULD COMPLETION” PHASE - RISK FACTORS

The principal risk factors are:

3.8.3.1 Exposure to free crystalline silica dusts dispersed during the mould cleaning operations involving compressed air.

3.8.3.2 Exposure to organic solvent vapours (methyl alcohol, hexane, etc.) due to the presence of solvents in the parting agents.

3.8.3.3 Exposure to super areated talc dusts during manual brushing. The talc, an extremely fine white-coloured powder, chemical composition: Mg₃(OH)₂Si₄O₁₀, CaO, Al₂O₃, is generally supplied in plastic or paper bags.

3.8.3.4 Exposure to natural lycopodium dusts during manual brushing. Natural lycopodium appears as an impalpable pale-yellow coloured powder.

3.8.3.5 Exposure to silver graphite dusts during manual brushing.. The almost pure allotropic state carbon appears as grey lamellae with a quasi-metallic sheen.

3.8.3.6 Manual handling of loads due to the frequent lifting and shifting of the flasks during this cycle phase.

3.8.4 “MOULD COMPLETION” PHASE - EXPECTED AND RECORDED INJURIES

3.8.4.3 Prolonged inhaling of talc dusts may lead to the onset of talcosis, a talc-generated type of pneumoconiosis.

3.8.4.6 Manual handling of loads may lead to injuries of the rhachis.

3.8.5 “MOULD COMPLETION” PHASE - ACCIDENT PREVENTION MEASURES

3.8.5.1 Appropriate load handling equipment (hoists, overhead travelling cranes, trolleys) shall be employed depending on the weight of the piece to be handled or, alternatively, two operators shall be called to perform the handling. Particular care shall be placed in training and informing operators as to the appropriate procedures and postures to be adopted when handling loads. IPDs (steel-capped safety boots) shall be used during these operations.

3.8.5.2 The appropriate dust exposure reduction measures (i.e. ventilation systems and IPDs) have been described above.

3.8.6 “MOULD COMPLETION” PHASE - OUTSOURCING

Outsourcing is generally not practised.

3.8.7 “MOULD COMPLETION” PHASE - PERTINENT REGULATIONS

D.Lgs. 626/94.

DPR 303/56.

DPR 203/88

Law n° 319/76 and Municipal Public Sewers Regulations.

3.8.8 “MOULD COMPLETION” PHASE - ENVIRONMENTAL IMPACT

Analogously to the descriptions furnished above, dusts and vapours drawn in by the ventilation system are ducted to the wet scrubbing plant.

3.9 “SMELTING” PHASE - RISK ANALYSIS AND MEASURES

3.9.1 “SMELTING” PHASE - WORKING CYCLE DESCRIPTION

The casting metal (or alloy) is heated until it achieves its molten state. The temperature is raised beyond the melting point until the casting or tapping temperature is reached. At the tapping temperature, the metal will maintain its liquid form for the duration of mould casting operations.

The various types of smelting furnaces are described below.

The following additives are added periodically to the molten metal, both in the furnace and in the laddles:

n Inoculants and corrective agents (Fe and Si alloys with other metals such as tin, nickel, magnesium, aluminium, copper). These metals are employed to give the casting the desired properties.

n scorifying agents like: mineral silicates, sodium fluoride, sodium chloride, flux (CaCO3), calcium and magnesium carbonate; these substances are employed to remove impurities contained in the molten metal.

Compounds in the powder form, containing cryolite (Na₃AlF₆) as principal component and calcium fluoride and sodium fluoride as secondary components) are employed as flux for Al-containing bronze and manganese/silicon-containing brass.

Small furnace loading operations are performed manually, while crucible movement and tapping operations are performed both manually and by using a hoist.

Loading of larger furnaces is performed automatically from above.

Metal is fed to the furnaces in the form of ingots, bars, mechanical component scrap and with rejected production items.

Furnace loading systems include belt conveyors which carry the metal to be smelted, smelting additives and foundry coke for the cupolas.

3.9.2 “SMELTING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

There are two principal types of smelting furnaces:

n Electric furnaces. In this type, various systems are employed to convert electricity into heat (coil, arc, induction).

n Fuel-fired furnaces. These furnaces may be further broken down into: crucible, cupola and reverberatory furnaces. In crucible furnaces, generally gas or oil-fired, the molten metal is kept separate from the fuel and combustion products. In the other two types, generally fired with foundry coke, the metal is in contact with the fuel and/or the products of combustion.

The different furnace types are employed depending on the type of alloy to be smelted, the type of production envisaged (small/large, continuous/intermittent, constant/variable), the required casting quality and on the availability of the heat source.

3.9.3 “SMELTING” PHASE - RISK FACTORS

There are numerous risk factors involved in the smelting phase, the principal ones being:

3.9.3.1 Exposure to metal vapours given off by the molten metal. The nature of the vapours depend upon the metals being smelted, the additives employed (iron, nickel, copper, tin, manganese, magnesium, lead, chromium, zinc, etc.) and the respective oxides produced.

3.9.3.2 Exposure to carbon oxide gases (CO, CO₂) given off by the furnaces depending on the fuel used.

3.9.3.3 Exposure to hydrofluoric acid gas due to the scorification process.

3.9.3.4 Exposure to nitrous and sulphur dioxide gases.

3.9.3.5 Handling of irritant dusts originating from the handling of chemicals/mixtures (sodium chloride, sodium fluoride, calcium fluoride, cryolite), used as smelting additives.

3.9.3.6 Exposure to high temperatures when working in proximity to the outside panels of the smelting furnaces.

3.9.3.7 Exposure to an unfavourable microclimate: high ambient temperatures in the furnace department. Operators moving from these areas to adjacent non-heated areas (store rooms, finishing shop, outside storage areas) are subjected to sudden temperature changes, especially during the colder months.

The high ambient temperatures are due to the radiant heat generated by the furnaces, especially in the vicinity of the stokehole. High ambient temperatures prevent the use of IPDs such as ear protection, goggles, etc.

3.9.3.8 Exposure to infrared radiation emitted by the molten metal.

3.9.3.9 Exposure to noise generated by furnace burners and by cupola air blowers.

3.9.4 “SMELTING” PHASE - EXPECTED AND RECORDED INJURIES

The high physical effort that smelting operators are subjected to further compounds the effects of exposure to high temperatures.

In the above mentioned study performed by the National Health Service local unit (ex-USL 10/G), two cases of pneumoconiosis (silicosis) and four cases of noise-induced threshold shift were found among a population of 5 smelting operators.

3.9.5 “SMELTING” PHASE - ACCIDENT PREVENTION MEASURES

Smelting furnaces must be fitted with appropriate and efficient local exhaust ventilation systems.

The furnace’s automatic loading area must be guarded against the risk of falling objects.

3.9.6 “SMELTING” PHASE - OUTSOURCING

Outsourcing is not practised as this is the principal phase of the whole production cycle.

3.9.7 “SMELTING” PHASE - PERTINENT REGULATIONS

· DPR 303/56 (Health Checks).

· DPR 336/94 (Occupational Illnesses)

· T.U. 1265/34 and Ministry of Health Decree n° 05/09/94 (Unhealthy industries).

· DPR 203/88 (Atmospheric emissions)

· DPR 915/82, “Ronchi” Decree dated 1997 and subsequent implementation decrees (Wastes).

· Law n° 319/76 (Waste process waters) and Municipal Public Sewers Regulations.

· D.L. 626/94 (Worker safety and health)

· Ministry of the Interior Decree n° 16/02/82 (Fire prevention)

· Rule ISO 7243 dated 1982 (Heat stress)

· Technical Rule UNI 7415 (Industrial furnaces. Types, Terminology, Definitions).

· Technical Rule UNI 7416 (Industrial furnaces. Order, inspection and acceptance testing rules).

· Technical Rule UNI 7728 (Industrial furnaces. Safety Directives. Gas, liquid, solid and mixed fuel-fired industrial furnaces).

· Technical Rule UNI 8129/1 (Heat resistant materials for industrial furnaces. Classes, size and testing procedures).

· Technical Rule UNI 8129/1 (Heat resistant materials for industrial furnaces. Classes, size and testing procedures).

· Technical Rule UNI 8129/2 (Heat resistant materials for industrial furnaces. Tender, order, inspection and acceptance testing data).

· Rule UNI 9022 (Fuel-fired furnaces. Energy performance measurement).

3.9.8 “SMELTING” PHASE - ENVIRONMENTAL IMPACT

Dust, gas and vapours produced by the cupola furnaces and drawn in by the ventilation system shall be subjected to wet scrubbing. Scrubbers shall be capable of resisting corrosion produced by sulphuric acid (presence of sulphur dioxide). Electrostatic precipitators or fabric filters shall also be employed. Scrubbing plant process waters shall be neutralised and treated.

Cupola cooling waters discharged to the sewer network may cause a negative environmental impact due to their high residual temperatures (heat pollution of waters). Furnace combustion-air blowers may have a considerable noise impact on the environment.

Dust, gas and vapours produced by electrical arc furnaces and drawn in by the ventilation system are generally subjected to dry scrubbing.

3.10 “TAPPING” PHASE - RISK ANALYSIS AND MEASURES

3.10.1 “TAPPING” PHASE - WORKING CYCLE DESCRIPTION

After smelting, the molten metal is subjected to “scorification” or slag removal process prior to performing actual tapping. Any slag is removed by allowing it to drop into a pit just in front of the furnace.

After slag removal, the metal is poured into laddles and transported to the tapping line, where the flasks from the mould making shop are ready for casting.

The metal-filled laddles are transported using mechanical lifting devices such as hoists, overhead travelling cranes or lift trucks. In certain cases laddles are handled manually.

Generally two operators manually tilt the laddle to pour the molten metal into the flasks.

In semi-automatic tapping lines, laddle tilting is performed by an electric powered hoist.

Operators performing tapping operations on large sized castings must work above floor level which entails the use of appropriate equipment such as scaffolding, etc.

3.10.2 “TAPPING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.10.2.1 Load lifting devices: overhead travelling cranes, hoists.

3.10.2.2 Laddles: various sized metal containers lined with heat-resistant materials.

3.10.2.3 Tapping truck.

3.10.3 “TAPPING” PHASE - RISK FACTORS

The principal risk factors are:

3.10.3.1 Handling of high temperature materials due to the presence of molten metal. Operators may be splashed by molten metal during tapping and laddle handling operations.

3.10.3.2 Staff passage through a dangerous area due to foundry staff movements while tapping and laddle handling operations are being performed.

3.10.3.3 Exposure to fumes and vapours of diverse nature and origin produced by:

n casting sand, depending on mixture components. The following may be produced: carbon black (carbon), carbon monoxide (CO), carbon dioxide (CO₂), polycyclic aromatic hydrocarbons (PAH), phthalates, ammonia, aromatic acids, formaldehyde, sulphur dioxide, acrolein. These pollutants are contained in the sand mixture and are produced by the molten metal coming into contact with mould and core sand. The heat breaks down the molecular bonds of the synthetic resin lattice and the atomic bonds, especially the carbon-carbon ones. Polycyclic aromatic hydrocarbons are generated in the work place environment by the combination of powdered coal with other high-carbon content natural and synthetic additives. The use of self-drying oils as organic binders in mould and core making sand mixtures generates CO, CO₂ and acrolein.

Subjected to high heat, furanes used in resin moulding may give off dangerous by-products such as carbon monoxide, replaced phenols, formaldehyde, aliphatic and aromatic hydrocarbons, NO_x (various nitrogen oxides), ammonia and traces of HCN (hydrocyanic acid).

n CO and CO₂ are also given off when the molten metal comes into contact with the parting agents (lycopodium or silicon) previously applied to moulds and cores.

n metal smelting operations also result in the production of fumes and vapours.

3.10.3.4 Exposure to an unfavourable microclimate: high ambient temperatures in the furnace department. Operators moving from these areas to adjacent non-heated areas (store rooms, finishing shop, outside storage areas) are subjected to sudden temperature changes, especially during the colder months. The high ambient temperatures are due to the radiant heat generated by the laddles and the flasks holding molten metal. High ambient temperatures prevent the use of IPDs such as ear protection, goggles, etc..

3.10.3.5 Exposure to infrared radiation generated by the molten metal.

3.10.3.6 Load handling using mechanical lifting devices: laddles are transported using hoists, overhead travelling cranes, lift trucks. Obviously greater risk levels are involved when laddles are filled with molten metal.

3.10.3.7 Falling from scaffolding, tapping truck.

3.10.4 “TAPPING” PHASE - EXPECTED AND RECORDED INJURIES

3.10.4.1 Furfuryl alcohol inhalation may cause pulmonary sensitisation, vomiting, diarrhoea, narcosis, depression.

3.10.4.2 Formaldehyde inhalation may cause pulmonary sensitisation, pulmonary oedema, vomiting, abdominal colics, diarrhoea. Formaldehyde is a suspected carcinogenic agent (C3).

3.10.4.3 Sulphuric acid inhalation may cause pulmonary sensitisation, oedema, fibrosis and emphysema. Inhalation may also cause vomiting and mucosae sensitisation.

In the above mentioned study performed by the National Health Service local unit (ex-USL 10/G) one case of noise-induced threshold shift was found among a population of 4 tapping operators.

Attention is drawn to the fact that, due to the high temperature stresses generated in this work phase, tapping operators are often drawn from the youngest worker group. As time progresses, these operators are then transferred to other working schedule phases prior to the manifestation of the injury.

3.10.5 “TAPPING” PHASE - ACCIDENT PREVENTION MEASURES

3.10.5.1 Molten metal spillage and splash protection measures envisage appropriate floor covering so as to avoid metal dispersion apt to attain operators’ feet. Numerous small foundries adopt the practice of covering the floor with casting sand. This practice entails that operators are subjected to dust exposure. Though this is a lesser evil than being splashed with molten metal, the practice is not deemed acceptable. The appropriate measure lies in implementing a grill floor. Grill sections shall be easily removable for cleaning operations. Steps shall be avoided and differences in floor levels shall be overcome using inclined planes whose slope does not exceed 15°.

3.10.5.2 Molten metal spillage and splash protection measures also envisage safer and easier laddle handling. Laddles shall be fitted with handling assist devices, such as step-down geared hand wheels.

3.10.5.3 Molten metal spillage and splash protection measures further envisage that the tapping area be clearly marked and guarded. A suitably broad belt around the tapping area (e.g. 5 meters) shall be marked and a “no-access” ban be applied to all staff not associated to tapping operations. The tapping area shall be kept free of obstacles and stock-piled materials to facilitate evacuation in case of accidental spillage. For emergency evacuation purposes, a safety corridor at least 80 cm. wide shall be implemented between parallel tapping lines or when lines are located adjacent to walls or other obstacles.

3.10.5.4 Molten metal spillage from flask sides upon filling envisages the installation of protective, floor-mounted metal shields all along the tapping line. Shield height shall be greater than flask joint line.

3.10.5.5 Protective measures against molten metal splash and heat deriving from contact or irradiation envisage the use of Individual Protective Devices such as the following:

n Safety helmet fitted with a fireproof, heat reflecting visor.

n steel-capped, heat-resistant, ankle-high, slip-on safety boots with reinforced heel guard.

n Leather leggings.

n Leather or kevlar gauntlets.

n Leather or other heat-resistant material aprons.

3.10.5.6 In view of the unfavourable workplace microclimate and use of IPDs, careful task sharing is required, in order to limit the effects of the high work pace and physical exertion on operators.

3.10.5.7 Pursuant to the preceding point, manual handling of monorail-hung laddles shall be limited to those cases in which laddle handling requires the application of a force <10 kg.

3.10.5.8 Fume and vapour inhalation protection measures envisage the installation of a local exhaust ventilation system encompassing the whole tapping line. The LEV shall be designed so as to completely trap all polluting agents. Fumes generated during tapping operations rise at a speed of approximately 2 m/s.

3.10.5.9 Unfavourable microclimate protection measures envisage appropriate job tasking such as to reduce as far as feasible operator presence close to radiant heat sources. Appropriate tasking shall furthermore include rest periods away from heat sources and the availability of cool, mineral salt-enriched beverages for body fluid re-integration. Furnace stokehole lids shall be used.

3.10.5.10 Infrared radiation protection measures envisage the use of lids and IPDs.

3.10.5.11 Accident prevention measures when using mechanical lifting aids envisage the employment of appropriate load handling equipment (hoists, overhead travelling cranes, trolleys), depending on the weight of the piece to be handled or, alternatively, two operators shall be called to perform the handling. Particular care shall be placed in training and informing operators as to the appropriate procedures and postures to be adopted when handling loads. IPDs (steel-capped safety boots) shall be used during these operations.

Lifting devices hoisting in excess of 200 kg shall be inspected by ISPESL upon initial installation. Subsequently they shall be inspected annually by the local NHS unit (Azienda Sanitaria Locale).

3.10.6 “TAPPING” PHASE - OUTSOURCING

Outsourcing is not practised as this is the principal phase of the whole production cycle.

3.10.7 “TAPPING” PHASE - PERTINENT REGULATIONS

According to ACGIH recommendations PAHs present in workplace ambient air shall not exceed 0,2 mg/m³ (TLV ). Furfuryl alcohol TLV-TWA is 40 mg/m³, TLV-STEL is 60 mg/m³. Formaldehyde TLV-C = 0,37 mg/m³ .

· DPR 303/56 (Health Checks).

· DPR 336/94 (Occupational Illnesses)

· T.U. 1265/34 and Ministry of Health Decree n° 05/09/94 (Unhealthy industries).

· DPR 203/88 (Atmospheric emissions)

· DPR 915/82, “Ronchi” Decree dated 1997 and subsequent implementation decrees (Wastes).

· Law n° 319/76 (Waste process waters) and Municipal Public Sewers Regulations.

· D.L. 626/94 (Worker safety and health)

· Ministry of the Interior Decree n° 16/02/82 (Fire prevention).

· Technical Rule UNI 8491 (Heat resistant products for foundries. Slag tapping filters)

3.10.8 “TAPPING” PHASE - ENVIRONMENTAL IMPACT

Vapours, fumes, gas and dusts originating from tapping laddles shall be treated in a wet scrubbing plant. Non-condensable gases and residual dusts may be discharged to the environment. Scrubber water must be pumped to the treatment plant.

3.11 “FURNACE AND LADDLE MAINTENANCE “ PHASE - RISK ANALYSIS AND MEASURES

3.11.1 “FURNACE AND LADDLE MAINTENANCE “ PHASE - WORKING CYCLE DESCRIPTION

The most important maintenance activity of a sand cast foundry relates to the maintenance of furnaces and laddles.

Furnaces require periodic renewal of the refractory lining and this entails the demolition of the old lining using jackhammers.

At the end of each working day, partial lining maintenance is performed by introducing into the warm furnace a mixture including “French earth”, fireclay and flux. The mixture is allowed to melt and then cool down again, changing the area where this occurs every day. This procedure allows the ongoing cyclical regeneration of the whole furnace lining.

Periodically the furnace lining must be completely removed and renewed.

Moistened fireclay (also called “packing”) is applied to the inner surface of the furnace using templates and then packed by an operator, working inside the furnace, using a compressed air powered tool. The same procedure is employed to periodically renew the stokehole ring, which is particularly subject to wear.

Materials employed for furnace lining renewal include the following:

n Ready-mixed fire resistant mortar, generally tabular alumina based, chemically bonded to aluminium monophosphate and containing other components such as clay (silica is present in the combined form) and trivalent chromium oxide (Cr₂O₃). The mortar is often supplied in small plastic drums.

n Aluminium silicate is a neutral fire-resistant material, chemical composition 3Al₂O₃·2SiO₂ (mullite) and Fe₂O₃, TiO₂, CaO, MgO (impurities). It is normally supplied as granules, bagged or in metal drums, or as manufactured items (bricks).

n Aluminium oxide (alumina or corundum). It is a neutral, fire-resistant material, chemical formula Al₂O₃ (85-99%) obtained by bauxite ore induction melting. It is normally supplied in bags or metal drums, or as manufactured items (bricks).

n Magnesium oxide and calcined magnesite. A basic fire-resistant material, chemical formula MgO, it appears as a white coloured, very fine grained amorphous powder. It is supplied in bags or metal drums, often mixed with other fire-resistant materials.

n Natural chromium oxide (cromite). It is a neutral, fire-resistant material normally supplied in bags or metal drums, or as manufactured items (bricks).

3.11.2 “FURNACE AND LADDLE MAINTENANCE“ PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.11.2.1 Jackhammers fitted with differently-shaped tools are used to remove the brick lining and slag.

3.11.3 “FURNACE AND LADDLE MAINTENANCE“ PHASE - RISK FACTORS

3.11.3.1 Exposure to silicosis-producing dusts including graphite, chamotte, aluminium silicate, aluminium oxide, magnesium oxide, calcined magnesite, chromite, etc. liberated during storage and handling of production-related substances and products. Dust is also liberated during lining repair, demolition and renewal operations.

3.11.3.2 Exposure to noise generated by the jackhammers used during lining removal operations.

3.11.3.3 Exposure to HAVS caused by the use of jackhammers.

3.11.3.4 Handling of dangerous substances and products.

3.11.3.5 Manual load handling of the spent materials after demolition and of the fresh materials used for lining renewal.

3.11.3.6 Risk of injuries during operations involving the use of jackhammers.

3.11.4 “FURNACE AND LADDLE MAINTENANCE“ PHASE - EXPECTED AND RECORDED INJURIES

3.11.4.3 Exposure to HAVS causes upper limb circulatory, nervous and joint damage (Raynaud’s syndrome). Smoking and excessive cold further compound vibration-induced circulatory damage. Depending on the weight of the piece to be handled, appropriate load handling equipment (hoists, overhead travelling cranes, trolleys), shall be employed or, alternatively, two operators shall be called to perform the handling. Particular care shall be placed in training and informing operators as to the appropriate procedures and postures to be adopted when handling loads. IPDs (steel-capped safety boots) shall be used during these operations.

3.11.5 “FURNACE AND LADDLE MAINTENANCE“ PHASE - ACCIDENT PREVENTION MEASURES

3.11.5.1 Prevention measures affecting dusts generated during furnace and laddle maintenance operations involve the use of IPDs (face masks, gloves, goggles, aprons).

3.11.5.2 In case of contact with eyes subsequent to the handling of substances and products used during lining renewal, implement manufacturer’s recommendations and abundantly rinse with water and seek medical advice. For example, when using ready-mixed mortar, due to the acidic nature of the binder, the manufacturer recommends immediate initial rinsing with abundant water and subsequently, using a 3% borax solution. The product data safety sheets of all substance and products used in the working schedule shall be kept on site. Workers shall be duly trained and informed as to the proper utilisation of the substances and products and as to the appropriate emergency procedures to be implemented in case of contamination.

3.11.6 “FURNACE AND LADDLE MAINTENANCE“ PHASE - OUTSOURCING

Outsourcing may be practised.

3.11.7 “FURNACE AND LADDLE MAINTENANCE“ PHASE - PERTINENT REGULATIONS

DPR 303/56 (Health checks).

DPR 336/94 (Occupational Illnesses)

T.U. 1265/34 and Ministry of Health Decree n° 05/09/94 (Unhealthy industries).

DPR 915/82 “Ronchi” Decree dated 1997 and subsequent implementation decrees (Wastes).

DPR 203/88 (Atmospheric emissions)

D.L. 626/94 (Worker safety and health)

3.11.8 “FURNACE AND LADDLE MAINTENANCE“ PHASE - ENVIRONMENTAL IMPACT

Dust drawn in by mobile LEV hoses and by the workplace general ventilation system are ducted to the dry scrubbing plant.

3.11 “SHAKEOUT” PHASE - RISK ANALYSIS AND MEASURES

3.11.1 “SHAKEOUT” PHASE - WORKING CYCLE DESCRIPTION

After the tapping operations, the flasks are allowed to cool (200-300 C°), generally on rails adjacent to the shakeout station.

Shakeout operations initially involve removing the mould from the flask and, subsequently, the removal of the casting from the mould. Moulds are removed from the flasks using percussion tools or mallets. The moulds are then placed on vibrating grills. The sand shaken loose drops through the grill , is collected and conveyed to the sand conditioning plant. The castings are sent onto the next station (flogging) while the flasks are transported back to the mould making station.

3.11.2 “SHAKEOUT” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.11.2.1 Compressed air driven percussion tools.

3.11.2.2 Vibrating grills.

3.11.3 “SHAKEOUT” PHASE - RISK FACTORS

The principal risk factors are:

3.11.3.1 Exposure to fumes and vapours generated by the molten metal as it cools in the flasks. The substances involved, the same as those generated during tapping operations, are present in greater quantities as the chemical breakdown of the synthetic resins affects all the material contained in the flasks, including both the moulds and the cores. The temperature in this working schedule phase is lower than the tapping temperature and this entails that the free carbon atoms, coming from the breakdown of the carbon-carbon bonds, may reform rings thus resulting in the formation of aromatic hydrocarbon nuclei and carbon oxide reduction, large quantities of which are present in the tapping fumes.

3.11.3.2 Exposure to silicosis-generating dusts coming from the now dried moulding sand. Dust dispersion is augmented by the sand dropping to the floor near the vibrating grills, especially when the grills are undersized with respect to the flasks.

3.11.3.3 Exposure to noise originating from two sources: grill vibration-generated noise and noise generated by the impact of the flasks and castings falling onto the grills. Another source is generated by the impact of the castings thrown into the bins after shakeout.

3.11.3.4 Manual load handling especially flasks and castings.

3.11.4 “SHAKEOUT” PHASE - EXPECTED AND RECORDED INJURIES

Expected injuries are similar to the ones described above in those phases where the same risk factors are present.

3.11.5 “SHAKEOUT” PHASE - ACCIDENT PREVENTION MEASURES

3.11.5.1 Fumes and gas exposure reduction measures involve the installation of LEV above the flask cooling station prior to shakeout. In addition, also note the following measures.

3.11.5.2 Certain foundries, especially those with medium-to-large production runs, have adopted the following global approach to fumes, gas, dusts, noise and manual load handling risk exposure reduction.

The vibrating grill shakeout plant has been completely enclosed within a sound-proof tunnel. Sound-deadening and sound-proof materials were employed. The tunnel is subjected to a negative pressure by the dusts, gas and fumes extraction system. The tunnel also includes an automatic casting transfer system using a mobile lifting magnet to transfer castings from the shakeout grills to the bins (Measure RISOL.N°110). The measure has a dual benefit:

· Elimination of pollutant dispersion in the workplace environment by enclosing and ventilating the shakeout plant during flask-casting separation operations.

· Elimination of the casting extraction task from the process and, hence the attendant operator, thanks to the automatic casting transfer system.

Where implemented, the measure has been met with favourable management and worker acceptance. The measure however does not seem to have been implemented by many small foundries.

Certain small foundries have partially implemented the measure, limiting the enclosure and ventilation only to the shakeout plant. Casting transfer from the grills to the bins is still performed manually. Under this measure, the operator is still exposed to the risk factors relating the manual load handling operations and to the presence of fumes, gases and dusts during casting extraction, albeit to a much reduced degree by virtue of the ventilation system.

For oversize mould shakeout, segregation is achieved by means of two, self-propelled half-booths moving on rails which come together around the machine prior to mould shakeout. The piece is suspended by means of chains and an overhead travelling crane. Booth sealing is achieved by means of sashes flexibly mounted on the doors and rubber sealing hoods on the chains. An appropriate ventilation system generates a negative pressure inside the booth. The implementation of this measure has produced a noise Leq reduction from 100 dB(A) to 80 dB(A) (Measure RISOL N° 36).

3.11.5.3 Another noise exposure reduction measure involves lining the casting collection bins with shock dampening materials. Rubber or plastic may not be employed as the temperature of the castings is still sufficiently high. A drawn sheet steel mesh grill is positioned inside the bin, leaving a suitably wide gap between it and the bin wall. The mesh grill will deform under casting impact and shall be replaced when pierced. Where implemented, this measure has met with favourable management and worker acceptance. In one case the measure produced a noise Leq reduction from 94,2 dB(A) to 90,3 dB(A) (Measure RISOL N° 93). IPDs shall however be employed during these operations.

3.11.5.4 Depending on the weight of the piece to be handled, appropriate load handling equipment (hoists, overhead travelling cranes, trolleys), shall be employed or, alternatively, two operators shall be called to perform the handling. Particular care shall be placed in training and informing operators as to the appropriate procedures and postures to be adopted when handling loads. IPDs (steel-capped safety boots) shall be used during these operations.

3.11.5.5 In order to reduce spillage of shakeout sand on the floor and the resultant dust dispersion, the size of the vibrating grills shall be appropriate to the size of the flasks being used.

3.11.6 “SHAKEOUT” PHASE - OUTSOURCING

Normally outsourcing is not practised.

3.11.7 “SHAKEOUT” PHASE - PERTINENT REGULATIONS

DPR 303/56 (Health checks).

DPR 547/55 (Guarding of moving mechanical components)

D.Lgs. 277/91 (Noise)

DPR 336/94 (Occupational illnesses)

T.U. 1265/34 and Ministry of Health Decree 05/09/94 (Unhealthy industries).

DPR 203/88 (Atmospheric emissions)

D.Lgs. 626/94 (Worker safety and health)

DPR 915/82 (Wastes)

3.11.8 “SHAKEOUT” PHASE - ENVIRONMENTAL IMPACT

Dusts generated by the shakeout equipment, especially fine grain, silicosis-producing dusts, and drawn in by the ventilation system, shall be ducted to the dry scrubbing plant fitted with electrostatic precipitators or fabric filters.

3.12 “FLOGGING” PHASE - RISK ANALYSIS AND MEASURES

3.12.1 “FLOGGING” PHASE - WORKING CYCLE DESCRIPTION

Flogging involves the complete elimination of all residual moulding and core sand from the casting’s surface. A small, compressed air powered percussion tool is employed to clear the casting’s hollow parts.

3.12.2 “FLOGGING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.12.2.1 Pneumatic percussion hammer: a small, compressed air powered percussion tool.

3.12.3 “FLOGGING” PHASE - RISK FACTORS

The principal risk factors inherent to this operation are:

3.12.3.1 Exposure to silicosis-producing dusts generated during manual casting cleaning.

3.12.3.2 Exposure to noise generated by the pneumatic percussion tool.

3.12.3.3 Exposure to HAVS due to pneumatic percussion tool use.

3.12.4 “FLOGGING” PHASE - EXPECTED AND RECORDED INJURIES

Exposure to HAVS causes upper limb circulatory, nervous and joint damage (Raynaud’s syndrome). Smoking and excessive cold further compound vibration-induced circulatory damage.

3.12.5 “FLOGGING” PHASE - ACCIDENT PREVENTION MEASURES

3.12.5.1 Exposure to silicosis-producing dusts can be reduced through the installation of ventilation/extraction systems and the use of IPDs.

3.12.5.2 Exposure to noise can be reduced through the use of IPDs. Sound-deadening panels used to segregate the workstations are a further measure.

3.12.6 “FLOGGING” PHASE - OUTSOURCING

Outsourcing in this phase may be resorted to, especially if the ensuing two phases, the riser and other unwanted metal removal, are also outsourced.

3.12.7 “FLOGGING” PHASE - PERTINENT REGULATIONS

DPR 303/56 (Health checks).

D.Lgs. 277/91 (Noise)

DPR 336/94 (Occupational illnesses)

T.U. 1265/34 and Ministry of Health Decree dated 05/09/94 (Unhealthy industries).

DPR 203/88 (Atmospheric emissions)

D.Lgs. 626/94 (Worker safety and health)

DPR 915/82, “Ronchi” decree, 1997 and subsequent implementation decrees (Wastes)

3.12.8 “FLOGGING” PHASE - ENVIRONMENTAL IMPACT

Dusts produced during this phase and drawn in by the ventilation system shall be ducted to the dry scrubbing plant equipped with electrostatic precipitators or fabric filters.

3.13 “SHOTBLASTING” PHASE - RISK ANALYSIS AND MEASURES

3.13.1 “SHOTBLASTING” PHASE - WORKING CYCLE DESCRIPTION

Shotblasting, also referred to as sand blasting, is a cleaning operation which involves directing a jet of abrasive or steel shot against the castings. This operation is performed either by machines called shot/sand blasters or manually. Manual shotblasting is performed within a cabinet: the operator blasts the castings using compressed air as the shot-carrying medium. Cabinet shotblasting is solely used for large sized castings. This type of casting production is not performed by the foundries affected by this study.

Shot may be spherical, chip or cylindrical shaped, comes in different particle sizes and is supplied in jute or plastic bags.

3.13.2 “SHOTBLASTING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

A wide range of shotblast machinery may be found within the foundry industry, depending on the size of the castings:

n table blast machines: these machines are employed for cleaning small sized castings. Castings are subjected to steel shot blasts inside a booth while being constantly mixed by a rolling conveyor.

n cabinet blast machines: these machines are employed for cleaning medium sized castings. Castings, suspended from an overhead conveyor, are transferred inside a tunnel-like cabinet and pass in front of shotblast wheels.

3.13.3 “SHOTBLASTING” PHASE - RISK FACTORS

The principal risk factors are:

3.13.3.1 Exposure to noise coming from the shot hitting the castings, the shot wheels in the cabinet machines, casting-to-casting impact in the table machines.

3.13.3.2 Exposure to silicosis-producing dusts coming from the residual sand on the castings after flogging. Dusts are dispersed especially during transport and loading operations. Older type shotblasting machines, requiring the presence of the operator inside the enclosed area, entail a greater risk factor.

3.13.3.3 Exposure to FeO_x dusts present in the shot and dispersed in the air upon shotblast-to-casting contact.

3.13.4 “SHOTBLASTING” PHASE - EXPECTED AND RECORCED INJURIES

3.13.5 Noise-induced threshold shift.

3.13.6 Pneumoconiosis, silicosis.

3.13.7 “SHOTBLASTING” PHASE - ACCIDENT PREVENTION MEASURES

3.13.5.1 Noise exposure reduction entails implementing a series of measures to sound-proof the shotblasting machines.

For example, a three prong approach was implemented for a shotblasting machine for small sized castings (10kg maximum):

n shock-absorbing lining (rubber-coated fabric) on the inner surface of the casting collection bins.

n fitting a double sided sound-deadening panel between the operator and the machine.

n sound-deadening panels fitted to the wall adjacent to the control panel.

Rubber-coated fabric and polyurethane foam were the sound deadening materials employed.

The measure implemented proved successful as noise produced during casting collection bin loading dropped from an Leq of 104-108 dB(A) to 86-89 dB(A); this measure implies regular replacement of the rubber-coated fabric when bin lining is deteriorated. The measure was favourably accepted by both management and operators (Measure: RISOL N° 105).

3.13.5.1 Dust exposure reduction involves the complete enclosure and ventilation of the shotblasting machines. The ventilation/dust removal system shall generate a negative pressure inside the enclosures. Particular care shall be dedicated to maintaining the efficiency of the machines’ shot recovery system. When the operator is called upon to perform his task in a walk-in cabinet, he shall employ IPDs such as gloves, face mask and external air supply or respirator. The operator shall also employ leather protection clothing against the risk of fugitive shot.

3.13.6 “SHOTBLASTING” PHASE - OUTSOURCING

Outsourcing may be practised.

3.13.7 “SHOTBLASTING” PHASE - PERTINENT REGULATIONS

DPR 303/56 (Health checks).

D.Lgs. 277/91 (Noise)

DPR 336/94 (Occupational illnesses)

T.U. 1265/34 and Ministry of Health Decree 05/09/94 (Unhealthy industries).

DPR 203/88 (Atmospheric emissions)

Law N° 319/76 (Process waters disposal)

D.Lgs. 626/94 (Worker safety and health)

DPR 915/82 “Ronchi” Decree 1997 and subsequent implementation decrees (Wastes).

3.13.8. “SHOTBLASTING” PHASE - ENVIRONMENTAL IMPACT

Dusts drawn in by the ventilation system during shotblasting operations contain free crystalline silica. They shall initially be ducted to a centrifugal separator and subsequently to a wet scrubbing plant. Scrubber water shall be pumped to the treatment plant for processing and sludge disposal.

3.14 “FETTLING AND DRESSING” PHASE - RISK ANALYSIS AND MEASURES

3.14.1 “FETTLING AND DRESSING” PHASE - WORKING CYCLE DESCRIPTION

The riser or feedhead is the part of the casting extending from the desired finished item (in the mould) and the pouring or tapping gate. During fettling and dressing, casting risers are removed employing a variety of tools and machines, described in the following paragraph.

Fettling involves the trimming of all excess metal such as flashes, risers, snags, etc. During this phase the castings are lapped and polished, generally employing band grinders and hand-held grinders. After completion of the fettling and dressing operations, small sized castings are collected in metal bins.

3.14.2 “FETTLING AND DRESSING” PHASE - DESCRIPTION OF EQUIPMENT AND MACHINERY

3.14.2.1 Band saws

3.14.2.2 Disc saws

3.14.2.3 Pedestal grinders

3.14.2.4 Hand-held grinders

3.14.2.5 Oxyacetylene torches

3.14.2.6 Compressed air hammers.

The abrasive surfaces of grinding tools contain the following compounds:

n abrasives: silicon carbide (carborundum), chemical formula SiC; corundum (natural and synthetic), chemical formula Al₂O₃ (70-85% content in the natural substance, 90-99% in the synthetic one), the balance is TiO₂, SiO₂, FeO.

n binders: shellac, rubber, heat-setting synthetic resins. Shellac generally includes the following: waxy-resinous secretions produced by various insects (65-80%); non-alcohol soluble waxy substances (4-8%); other aluminous substances, colouring agents, sugars, etc.. Rubber is caoutchouc or synthetic rubber. Heat-setting synthetic resins are phenolic resins and other phenol-based plastics.

3.14.3 “FETTLING AND DRESSING” PHASE - RISK FACTORS

The principal risk factors are:

3.14.3.1 Exposure to noise generated by the tools and machines described above and produced by the tool impacting the casting. Noise is also generated by the operators throwing the castings in the collection bins after fettling and dressing.

3.14.3.2 Exposure to metal dusts produced during the removal of excess metal from the casting.

3.14.3.3 Exposure to shellac, rubber, synthetic resins, silicon carbide, corundum (natural and synthetic). These dusts are contained in the abrasive compounds of the grinding wheels and are dispersed during grinding operations as the wheel’s surface is worn away.

3.14.3.4 Exposure to injury caused by work tasks involving proximity with moving parts: band saws, band polishers, circular saw, hand-held grinding tools, etc.

3.14.3.5 Exposure to HAVS during use of hand-held grinders and sanders.

3.14.3.6 Manual load handling during transport of the castings for fettling..

3.14.3.7 Work tasks performed adopting incorrect postures when operators employ hand-held tools at the work bench.

3.14.3.8 Exposure to unfavourable microclimate: often the areas where fettling and dressing operations are performed have low ambient temperatures as they are not heated during the colder months. Operators moving from these areas to the smelting and tapping areas are subjected to noticeable temperature differences.

3.14.4 “FETTLING AND DRESSING” PHASE - EXPECTED AND RECORDED INJURIES

Exposure to HAVS causes upper limb circulatory, nervous and joint damage (Raynaud’s syndrome). Smoking and excessive cold further compound vibration-induced circulatory damage.

3.14.5 “FETTLING AND DRESSING” PHASE - ACCIDENT PREVENTION MEASURES

3.14.5.1 Individual noise reduction measures for fettling and dressing operators involve the use of appropriate IPDs. Reducing the noise exposure of other foundry operators involves locating the fettling and dressing stations in separate rooms and the use of sound deadening panels to erect semi-enclosed work stations.

As a noise and vibration reduction measure, hydraulic-powered wedge-headed riser removal tools were adopted (Measure: RISOL N° 96). The adoption of this relatively straight forward measure has led to a noise Leq reduction, from the previous 97 dB(A) to less than 70 dB(A) and has been favourably accepted by both foundry management and operators. The adoption of the measure has substantially modified the working task. Previously the risers were cut off the casting whereas the adoption of the wedge-headed tools allows the riser to be chipped off. Moulds have been partially modified in order to facilitate the task.

The casting collection bins have been lined with rubber or perforated sheet so as to avoid casting-to-bin contact which gives rise to the typical tolling bell effect (Measure: RISOL N° 93).

3.14.5.2 Dusts exposure reduction measures entail the installation of a general work place ventilation system as well as local exhaust ventilation on tool workstations and benches.

3.14.5.3 HAVS reduction has been brought about through the adoption of wedge-headed riser removal tools (ref. Measure: RISOL N° 96 - see above noise reduction measure).

3.14.5.4 A guard shall be fitted to the band of band polishing machines.

3.14.5.5 Depending on the weight of the piece to be handled, appropriate load handling equipment shall be employed or, alternatively, two operators shall be called to perform the handling. Particular care shall be placed in training and informing operators as to the appropriate procedures and postures to be adopted when handling loads. IPDs (steel-capped safety boots) shall be used during these operations.

3.14.5.6 Workstations shall be suitably laid out in order to favour the adoption of ergonomically correct postures (appropriate workbench height, etc.).

3.14.6 “FETTLING AND DRESSING” PHASE - OUTSOURCING

Outsourcing may be practised.

3.14.7 “FETTLING AND DRESSING” PHASE - PERTINENT REGULATIONS

DPR 303/56 (Health checks).

D.Lgs. 277/91 (Noise)

DPR 336/94 (Occupational illnesses)

T.U. 1265/34 and Ministry of Health Decree 05/09/94 (Unhealthy industries).

DPR 203/88 (Atmospheric emissions)

Law N° 319/76 (Process waters disposal)

D.Lgs. 626/94 (Worker safety and health)

DPR 915/82 “Ronchi” Decree 1997 and subsequent implementation decrees (Wastes).

Technical Rules UNI 4012, UNI 4013, UNI 4014 (Circular saws for metals).

Technical Rules UNI 7749, UNI 5758 : ISO 666 (Disc grinding wheels).

3.14.8 “FETTLING AND DRESSING” PHASE - ENVIRONMENTAL IMPACT

Dusts drawn in by the ventilation system shall be ducted to the dry scrubbing plant equipped with electrostatic precipitators or fabric filters.