ECFIA – Representing the European High Temperature Wool Industry RCF / ASW (aluminosilicate wools)
ECFIA – Representing the European High Temperature Wool Industry
RCF / ASW
(aluminosilicate wools)
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 1
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 2
CONTENTS
PREFACE
BACKGROUND (Recognition)
1 What is HTIW?
2 ASW/RCFproducts, uses and applications
3 How to recognise ASW/RCF products
4 Workforce and tasks
5 ASW/RCF is not asbestos
ASSESSMENT OF EXPOSURES (Evaluation)
6 The European CARE programme
7 Workplace concentrations associated with production and use of
ASW/RCF
8 Principal sources of dust
CONTROL OF EXPOSURES (Control)
9 General guidelines
10 Specific guidelines for the reprocessing of products
(secondary production)
11 Specific guidelines for end use in furnaces (installation and removal)
12 Specific guidelines for other end uses
CONCLUSION APPENDICES
A Expanded list of functional categories with definitions and examples
B Operations monitored in the primary production group
C Operations monitored in the secondary production group
D Operations monitored in the furnace-related group
E Operations monitored in the other end-uses group
F Generic trade names of RCF products from Unifrax
G ECFIA generic Material Safety Data Sheet (MSDS) for RCF products
H Respirable Crystalline Silica (RCS) in after use HTIW
Recognition and Control of Exposure to Refractory Ceramic Fibres (RCF)
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 3
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 4
page 3
PREFACE
HTIW (High Temperature Insulation Wools) are man made mineral fibres usedpredominantly in industrial applications. They have a unique combination oflight weight, low thermal conductivity, low volumetric heat capacity (low heatstorage), resistance to thermal shock, and ease of installation, to provideenergy efficient, high-temperature insulation (up to 1800°C).
The earliest and most important of these wools are Alumino-silicate wools also called Refractory Ceramic Fibres (ASW/RCF), which have been in use for over 50 years. Based on some several animal experiments RCF/ASW wereclassified by the EU as a category 2 carcinogen (Directive 67/548EEC) andshould be treated as if they were a human carcinogen. This classificationimposes a number of obligations on producers and users of ASW/RCFincluding the development of alternatives and substitution where possible.Many applications now use Alkaline Earth Silicate (AES) wools fortemperatures up to 1250°C.
It is also mandatory to reduce exposures to category 2 carcinogens to thelowest levels practicable thus minimizing any possible health risks. Since itsinception in 1979, the ECFIA representing the HTIW Industry in Europe hasactively promoted the safe use of ASW/RCF products through its productstewardship programme. One important aspect of the product stewardshipprogramme is the CARE (Control and Reduce Exposure) programme whichhas been running in Europe since 1996. The objective of this programme is to provide customers with professional and carefully tailored industrial hygieneadvice on reducing exposures to all ECFIA members’ products. As a result of the CARE Programme, ECFIA has amassed an impressive amount ofinformation and insight on exposures and control methods across a widecross-section of industries. Our intent in producing this guide is to share thisinformation and our experience in assessing and controlling exposures toASW/RCF. The document contains three sections:
Recognition: describes ASW/RCF and the products made from them, the workforce exposed, the tasks where ASW/RCF are used and highlightsfundamental differences between ASW/RCF and asbestos.
Evaluation: briefly presents the CARE Programme, shows dust concentrationsfor several industry sectors and reviews the principal mechanisms governingdust release and dust concentrations.
Control: provides an in-depth review of sources and control methods for these Industry groups. The emphasis throughout the guide is on providing the reader, whether a health and safety officer, company manager or otherprofessional seeking advice on ASW/RCF, with practical guidance onexposures and their control.
Recognition and Control of Exposure to Refractory Ceramic Fibres (RCF)
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 5
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 6
BACKGROUND
1. What are High Temperature Insulation Wools(HTIW)?
2. ASW/RCF products, uses and applications
3. How to Identify ASW/RCF products
4. Workforce and tasks
5. ASW/RCF is not asbestos
page 5
Recognition and Control of Exposure to Refractory Ceramic Fibres (RCF)
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 7
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 8
1 What are High TemperatureInsulation Wools (HTIW)?
The term HTIW describes a family of man made synthetic vitreous fibres thathave a range of compositions and uses.
The Chemical Abstract Service (CAS) defined ASW/RCFs under the name“Refractories, fibres, aluminosilicate”. (number 142844-00-6) as:-
“Amorphous man-made fibres produced from melting, blowing or spinning ofcalcined kaolin clay or a combination of alumina (Al2O3) and silica (SiO2).Oxides such as zirconia, ferric oxide, magnesium oxide, calcium oxide andalkali may also be added. Approximate percentages by weight of compoundsfollow: - Alumina: 20-80% - Silica: 20-80% - Other oxides in lesser amount”
European ASW/RCFs are high purity alumino-silicates containing 46-58% silicaand 42-54% alumina. The production also includes zirconia ASW/RCFscontaining 14-18% zirconia and 28-36% alumina with a silica content similarto that in the high purity fibres.
The AES Wools are included in CAS numbers 329211-92-9, 308084-09-5 and436083-99-7 and were developed by reformulating glass wool compositionsto increase application temperatures.
A third type of material is also a member of HTIW. These are polycrystallinealumina or mullite fibres produced by the Solgel process. These are particularlyuseful for very high temperatures where capital equipment costs are not crucial.
The term “ceramic fibre” has been used to describe many materials with verydifferent physical properties and chemical compositions, including: crystals orwhiskers of silicon nitride, silicon carbide or potassium titanate fibres. Thesecrystalline fibres are not HTIW and are not the subject of this guide.
AW/RCFs and AES wools are manufactured by random spinning or blowingprocesses and contain fibres with diameters and lengths that vary both withinindividual products and between different product types. The polycrystallinewools are made by a variety of processes all of which result in a narrowerdistribution of diameters.
page 7
Continuous filaments
Mineral wools
Refractory Ceramic fibresRCF
Alkaline Earth Silicate fibresAES
Microfibres
Vitreous (amorphous) fibres
One crystal fibres(Whiskers)
Polycrystalline fibres
Crystalline fibres
Mineral synthetic fibres Organic synthetic fibres
Man-made fibres
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 9
Their maximum use temperatures are far higher than those for asbestos, rock and glass fibres (Fig.1).
Experimental ASW/RCFs were first produced in the early 1940s andcommercial production began in the 1950s. The energy crisis of the 1970sand early 1980s encouraged their use because they were recognised as acost effective and energy efficient substitute for denser brick and castablerefractories. Their use as high-temperature insulation can reduce energyconsumption by more than 50% compared with alternative products. Table 1.1 shows the properties of ASW/RCF.
Table 1.1:
Fig.1:
Temperature ranges for
the use of inorganic
synthetic wools
page 8
• Maximum use temperature up to1800°C
• Low thermal conductivity
• Very low thermal mass
• Excellent resistance to thermal shock
• Low density
• Resiliency and flexibility
Polycrystalline wool (PCW)
Aluminiumsilicate wool
(ASW)
AES wool
Mineralwool
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 10
the RCF market:
a small proportion of
the artificial mineral
vitreous silica market
Percentage share of
RCF production for the
year 2005 in Europe
(Source ECFIA)
page 9
Continuous filaments18%
RCF 0,9%AES-Wool1,1%
Polycristalline Wool0,04%
Mineralwool 80%
The AES wools were developed during the 1980s and 1990s as therequirement was for more soluble and hence less biopersistent materials.Industry was concerned about health implications when using ASW/RCF andmoved on to looking for alternative insulation materials.
The world production of synthetic vitreous fibres (glass, rock, slag) is around 8million tonnes per year. ASW/RCF represents 2%, i.e. 160,000 tonnes. In 2005annual production of ASW/RCF in Europe was 25,000 tonnes, AES 17,750tonnes and PCW 2,500 tonnes.
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 11
ASW/RCF production processes consist of either blowing an air stream on themolten material flowing from an orifice at the bottom of the melting furnace(blowing process) or by directing the molten material onto a series of spinningwheels (spinning process).
The fibrous mass produced, known as “bulk fibre”, can be further processed intoblanket, which is needled to improve handling strength. Bulk fibre can also beconverted into many different product forms. Using processes similar to those inthe paper industry, bulk can be processed into boards, shapes, felts and papers. It can also be used for manufacturing textile products and mixed into cements andmastics. Blankets are often used directly, (e.g. as a furnace insulation material), butare also converted into blocks known as “Modules” (also used for furnacelinings),gaskets and other products. These conversion activities are undertaken bythe three ASW/RCF producers in Europe but also by more numerous independentcompanies (convertors). ASW/RCF products are shown in Photo 2.1.
ASW/RCF are energy efficient, high-temperature insulation for products usedthroughout industry, (e.g. steel, ceramics, petrochemicals, foundry, non-ferrousmetals, power generation, glass, chemicals, fertilizers, heat treatment, cementsand forging industries). Table 2.2 presents the major applications in theseindustries. The largest single use of ASW/RCF is for furnace linings and relatedapplications; accounting for approximately 65% of consumption. ASW/RCF havedisplaced conventional insulating refractories, such as castables and fire bricks,because of their superior physical and chemical properties and lower life-cyclecost. The use of fibrous insulation can save up to 50% of energy consumption in industrial furnaces and kilns compared with some conventional refractories.This results in a substantial reduction of greenhouse gas emissions (CO2),estimated at 100 million tonnes per annum in Europe, with the resulting benefit for the environment.
2 ASW/RCF products, uses andapplications
Photo 2.1:
HTIW Products forms
page 10
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 12
ASW/RCF are also used for other applications including those in the automotiveindustry, (e.g. catalytic convertors, metal reinforcement, heat shields, and airbags), aerospace, (e.g. heat shields), defence industries, fire protection andgeneral industrial insulation. The manufacture and uses of ASW/RCF can bedivided into four segments: primary production, secondary production, furnace-related and other uses. Recommendations provided within this guide are basedon industrial hygiene studies carried out in each of these sectors.
Table 2.2
Example of applicationsfor ASW/RCF
Applications Steel Ceramics Petrochem Foundry Non- Power Automotive Glass Otherferrous generation
Furnace linings ✓ ✓ ✓ ✓ ✓ ✓
Back up insulation ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Ingot mould linings ✓ ✓ ✓
Ladle covers ✓ ✓ ✓
Molten metal transp. ✓ ✓& distribution
Expansion joints & seals ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Burner quarls ✓ ✓ ✓ ✓ ✓
Turbine insulation ✓
Heat curtains ✓ ✓ ✓ ✓
Weld stress relief ✓ ✓
Pipe insulation ✓
Fire protection ✓ ✓ ✓
High temp. filtration ✓
Catalytic convertors ✓
Slow cooling blankets ✓ ✓
Primary Production(Bulk and Blanket)
Secondary production(convertors)
Modules,shapes,boards,paper,textiles
Furnace related Other uses
page 11
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 13
In accordance with the EU Classification and Labelling Directive andRegulations all ECFIA members provide hazard warning labels for theirASW/RCF products. Please refer to the ECFIA web site for further details atwww.ecfia.eu.
Material Safety Data Sheets (MSDS) designed in accordance with Directive91/155/EC are available by referring to ECFIA website. By contacting yoursupplier’s purchasing department, it should be possible to find information on specific products. In order to help recognise those containing ASW/RCF,Appendix F lists trade names and types of products manufactured by thethree companies involved in the primary production of ASW/RCF in Europe:Unifrax, Rath, Thermal Ceramics. Note that other trade names could be usedby convertors or distributors. Contact them directly for information.
Recognising ASW/RCF products in-situ may be difficult. Bulk fibre resemblescotton wool. White needled blankets may be recognised by their characteristictexture of the surface, (see Photo 3.1). Rigid boards and moulded parts areusually a beige colour. However, a variety of other fibres might resembleASW/RCF, but the packaging of other products is usually different. It istherefore recommended to always keep products in their original packagingwhere trade names and any health and safety labels are visible. When in doubtas to the identity of a fibre, a bulk sample of the in-situ material should becollected and analysed by an expert laboratory.
How to Identify ASW/RCF products3
In addition MSDSs are
supplied for all
ASW/RCF products.
page 12
Photo 3.1
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 14
ASW/RCF are principally industrial products and are therefore handled byprofessional users and not the general public. These users should have accessto relevant product safety information, (e.g. material safety data sheets), expertadvice, (e.g. industrial hygiene personnel), specialised training, and personalprotection equipment. ECFIA estimates that the total workforce exposed toASW/RCF in Europe in 2005 was approximately 16,800.
Tasks performed can be classified into nine major job categories: primaryproduction, mixing/forming, finishing, assembly, module assembly, installation,removal, auxiliary operations, others (NEC). Refer to appendix A for detaileddescription.
Workforce and tasks4
page 13
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 15
Unfortunately ASW/RCF is quite often confused incorrectly with asbestos,which can be misleading. In fact the two fibre types have many fundamentaldifferences, (see Table 5.1).
1µm 1µmChrysotile - TEM RCF (ASW) - SEM
ASW/RCF is not asbestos5
page 14
Asbestos
Natural mineral - mined and processed
Wide variety of industrial and consumerproducts including asbestos-cementpipe, roofing tile, floor tile, wall covering,millboard, textiles, automotive brakeshoes, cements, building and pipeinsulation.
Crystalline
Principally longitudinal - fibres break apartinto an increased number of thinnerdiameter fibres. This increases theirairborne persistence, degree of difficultyin detecting fibres with PCOM, and mayresult in fibres of increased toxicity(Assuncao and Corn, 1975).
Relatively fine - depending upon the typeof asbestos, median fibre diametersrange from approximately 0.02 µm to0.45 µm (HEIAR, 1991).
Attribute
Origin
Applications
Form of fibre
Fibre fracture mechanism
Fibre diameter
Workplace concentrations(diameters)
ASW/RCF
Synthetic, made from alumina and silica
ASW/RCF is not an asbestos substitute.ASW/RCF is an industrial product usedfor such applications as high-temperature furnace and kiln insulationat temperatures >800° C.
Amorphous (vitreous)
Transverse - fibres break into shorterfibres with same diameter ultimatelybecoming dust (TIMA, 1993).
A function of production method, butgenerally thicker than asbestos (TIMA,1993). Mean diameter of aerosolreported as 1-1.5 µm (medianapproximately the same) in authoritativestudy (Mast et al., 2000).
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 16
ASW/RCF and asbestos have different physical, chemical and industrialproperties. Asbestos is not a refractory fibre and is used in a wide range ofconstruction materials, such as asbestos cement.
• ASW/RCFs are synthetic and produced as a glass wool with variablediameter tapering fibres and glass shot, this is formed into blankets andseveral other product forms
• ASW/RCFs are a relatively homogeneous group of materials made fromapproximately equal weight proportions of alumina and silica meltedtogether and fiberised by blowing or spinning. Some types have higherconcentrations of silica and in some a low concentrations of other oxidespredominately zirconia is added. These changes affect some aspects ofhigh temperature behaviour but have no significant effects on surfacechemistry or other putative health related properties.
• ASW/RCFs are confined to industrial applications and are not found in theenvironment
Attribute
Workplace concentrations(diameters)
Durability / Biopersistence
Exposure
Animal carcinogen?
Human carcinogen?
IARC classification
Regulatory status
Asbestos
Typically higher than ASW/RCF becauseof low diameters (Assuncao and Corn,1975).
In-vitro durability and in-vivobiopersistence of amphibole materialsubstantially greater than that forASW/RCF.
At one time, very large. Now eliminatedin many countries, but still very large incountries where usage permitted.
Several inhalation studies indicate thatasbestos (particularly amphiboleasbestos) is an animal carcinogen (IARC, 2002).
Numerous epidemiological studiessupport carcinogenicity of asbestos -there is some controversy over thecarcinogenic potency of chrysotileasbestos (Hodgson and Darnton, 2000).
Group 1 - the agent is carcinogenic tohumans (IARC, 2002).
Banned in many countries. EPAattempted to ban asbestos in the U.S.Bills now before Congress to banasbestos.
ASW/RCF
Typically lower than asbestos becausefibre diameters are greater.
More durable than many other SVFs,but less durable than amphiboleasbestos (Maxim, et al., 1999).
Approximately 25,000 in Europe and thesame in the United States.
RCC studies indicate that high doses ofASW/RCF have resulted in lung cancerand mesothelioma in rats and hamsters.Accurate interpretation is not possiblebecause of particulate contamination(Mast et al., 2000; Brown et al., 2005).
University of Cincinnati epidemiologystudy has not shown interstitial fibrosis,incremental lung cancer, or anymesothelioma (Walker et al., 2002;LeMasters et al, 2003; Lockey et al.,2002).
Group 2B-the agent is possiblycarcinogenic to humans (IARC, 2002).
Not banned in any country.Occupational exposure limits (OELs) arepublished in several countries.
Table 5.1: Comparison ASW/RCF with Asbestos
ASW/RCFs
page 15
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 17
• ASW/RCFs inherent characteristics mean that it is only applied to high-temperature, thermal insulation applications. As such, ASW/RCF is a niche-market product.
• The toxicity of ASW/RCF is suspected on the basis of confusing andconflicting experimental studies. ASW/RCF has no demonstrated humantoxicity. As a matter of precaution, and in accordance with the recentclassification of ASW/RCF, exposures must be controlled and kept as lowas possible. Control strategies and methods developed for asbestos shouldnot be automatically transposed to ASW/RCF without accounting for thefundamental differences between the two fibre types and the two markets.This guide outlines a series of precautions tailored to the use of ASW/RCFproducts. These are based on the more general requirements for theprotection of workers from carcinogens at work.
• ASW/RCF products contain some fibres in the respirable range, but overallASW/RCF fibres are much coarser than asbestos fibres, with diametersdistributed around 3 microns. Consequently, ASW/RCF products havelower potential for dust release, (see Table 5.2). Airborne ASW/RCF fibrestend to settle rapidly and have a lower probability of penetrating into thealveolar region of the lung
• Asbestos is virtually ubiquitous in human lung samples with concentrationsof up to about 106 fibre per gram of dry lung in non-occupationally exposedpersons being not uncommon.
• The toxicity of asbestos is proven by many human and experimental studies
• An important property determining dust release and control is the sizedistribution of fibres. Asbestos fibres are very fine. For example, thediameter of chrysotile fibrils is about 0.03 µm.
• Because of this small diameter, asbestos products can generate fibrousdust that remains airborne for long periods and, if inhaled, has a very highprobability of penetrating deep into the lungs. Almost all airborne asbestosfibres are in the respirable range (fibres with a diameter less than 3microns).. Length and diameter analysis by electron microscopy shows that the distributions of ASW/RCF and chrysotile airborne fibres are quitedistinct, with very little overlap. Phase-contrast optical microscopy candetect the vast majority of ASW/RCF airborne fibres, whereas transmissionelectron microscopy is needed for asbestos. For ASW/RCF dust, an opticalmicroscopy count will detect almost all fibres present; However, it mayreport only a few percent for asbestos.
Consideration of fibre size distribution is relevant for exposure controlstrategies. Owing to the low capacity for ASW/RCF dust to disperse into the general environment, it is more advantageous to concentrate efforts andresources on controlling the environment close to the worker. This can beachieved by a variety of measures; the best being complete or partialenclosure with dust extraction equipment. This should be properly adjusted to the aerodynamic behaviour of ASW/RCF dust.
ASBESTOS
page 16
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 18
ASSESSMENT OF EXPOSURES
6. The European CARE programme
7. Workplace concentrations associated withproduction and use of ASW/RCF
8. Principal sources of dust
page 17
Recognition and Control of Exposure to Refractory Ceramic Fibres (RCF)
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 19
6The European CARE programme
In 1996, ECFIA initiated an industrial hygiene assistance programme known as CARE:"Controlled and Reduced Exposure". (This programme does not yetinclude polycrystalline wools (PCW), however the care programme will start toinclude PCWs from the end of 2008.) The cornerstone of the programmeconsists of industrial hygiene surveys during which ECFIA hygienists evaluateworkplace control methods and monitor personal concentrations of fibrous dust.Workplace monitoring is carried out using the WHO-EURO method (Germanmethod ZH1/120.31). Personal samplers are used to measure concentrations in the workers' breathing zone. Fibre counting is done by an independantlaboratory using phase-contrast optical microscopy (PCOM) in accordance with WHO Euro counting rules. Average concentrations are recorded for themonitoring period (from 50 to 500 min.) and reported as Actual Time-WeightedAverages (ATWA). During the last nine years of the CARE programme, a total ofover 4,822 ATWA measurements were made. These measurements were theresult of regular monitoring at ECFIA primary production plants and of surveys at customers' premises. The customers included volunteers and customersselected at random with selection probability proportional to ASW/RCFpurchases in the preceding year. At the start of the programme customers were selected based on ASW/RCF products purchased.
Measurement from the ECFIA plants were taken on randomly selected workers.The secondary and end-user facilities were a mix of randomly chosencustomers and customers who had volunteered for the measurements.Analysis of concentrations showed no statistically significant difference betweenthose selected and those that volunteered. Workers were chosen within eachfacility to have a cross section of workers handling ASW/RCF. Samplingdurations at the secondary and end-users sites were sometimes less than thefull work shift. These ATWAs may overestimate the full-shift, time-weightedaverages. Further, the concentrations presented are those found in the workers'breathing zones. They do not account for respirator use, which correlated fairlywell with dust concentration. The workers actual exposures will have beenlower. The concentrations given here result from a mix of workplace conditions:from well-controlled to poorly controlled. Variations will occur from site to siteaccording to the process and control measures employed.
page 18
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 20
100
90
80
70
60
50
40
30
20
10
100
90
80
70
60
50
40
30
20
10
100
90
80
70
60 50 40
30
20
10
90
80
70
60
50 40
30
20
10
0
90
80
70
60
50
40
30
20
10
100
90
80
70
60
50 40
30 20
10
0
100
90
80 70 60 50 40
30
20
10
0
100
90
80
70
60
50
40
30
20
0
90
80
70
60
50
40
30
20
10
0.01
0.1
1
10
0.01
0.1
1
10
Functional Job CategoryData set: Fi rst - ninth-year CARE data (4,832 observations)
Assembly Auxi l iary InstallationFinishing MixingForming
Other RemovalFibreProduction
Modules
7Workplace concentrations associated with production and use of ASW/RCF
Figure 7.1 shows that priority must be given to secondary manufacture ofproducts (module assembly and finishing) and furnace-related applications(Installation and removals).
Mean concentrations were higher in “secondary production” and “furnace-related uses”. The ATWA values reported correspond to concentrationsaveraged over the monitoring period. Times profiles were not established.Instantaneous concentrations can obviously be higher or lower than the mean.
The ladder diagram shown in Figure 7.2 presents an example of thedistributions of ATWAs in selective group.
Fig. 7.1:
Mean fibre concentrations
across FJC
Fig. 7.2:
Ladder diagram:
Gives the percentage of
workplaces measured
below a given
concentration
page 19
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 21
In Europe, exposure limits for ASW/RCF are in the range of 0.10 f/ml to 1.0f/ml. Such limits can be used as reference points, even if strictly speaking anATWA figure cannot be compared to an 8-hour averaged exposure limit. Inmany operations, the use of HTIW during the work shift is far less than the full8 hours.
The objective is to reduce exposures to levels as low as technically possible.Industrial hygiene aims at reducing concentrations at the source.
The rest of the document emphasizes measures to reduce concentrations in these areas. Operations were classified in the eight job categories, (see Fig. 7.3). Concentrations (geometric means) associated with each category are reported in the bar chart. It can be seen that module assembly, finishingand removal operations carry the highest potential for exposure.
Geometric Mean (f/ml)
0.0 0.2 0.4 0.6 0.8 1.0
Removal
Finishing
Modules
Installation
Mixing/Forming
Assembly
Auxi liary
Other (NEC)
Fibre Production Nine Years' Data, Manufacturers and
Customers
Functional Job CategoryFig. 7.3:
Geometric Mean Fibre
Concentration by Functional
Category, Manufacturers
and Customers,
Nine Years' Data
page 20
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 22
8Principal sources of dust
All ASW/RCF materials can release dust: the amount depends on how the material is handled. High concentrations are usually found during removal of after-use ASW/RCF from furnaces and also during mechanical finishingactivities and in the assembly of modules. Where fibre products aremechanically abraded by sawing, sanding, routing or other machining theairborne fibre concentrations will be high if uncontrolled. Dust release is furthermodified by the intensity of energy applied to the product, the surface area to which the energy is applied, and the type, quantity and dimensions ofmaterials being handled or processed. Dispersion or dilution of dust produceddepends on the extent of confinement of the sources and the work area, as well as the presence and effectiveness of exhaust ventilation. Individualexposures depend on work methods, work organisation and the use andeffectiveness of protective equipment. The extent to which these materials are handled will also determine dust release and substantial effort should bedirected towards reducing it. In many cases, reorganization of work flow caneliminate handling steps and reduce exposures. Ideally, automation of part orall of a process should be considered, and will often yield gains in productivity.Airborne fibres generated by ASW/RCF materials are coarse and settle rapidly.As a consequence, ambient concentrations are often low (e.g., much less than0.1 f/ml). It is not unusual to find ambient measurements lower than personalmeasurements by a factor of ten.
page 21
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 23
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 24
CONTROL OF EXPOSURES
9. General guidelines
10. Specific guidelines for the reprocessing ofASW/RCF products (secondary production)
11. Specific guidelines for end use in furnaces
12. Specific guidelines for other end-uses
page 23
Recognition and Control of Exposure to Refractory Ceramic Fibres (RCF)
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 25
9General guidelines
ASW/RCFs are high temperature insulation products that should be used inapplications which require its unique combination of properties. These productsshould be limited to professional use only. Exposure to dust should bemaintained at low levels by correctly applying appropriate control measures.
Controls should always be applied in the following hierarchy:
• control or elimination at the source (e.g. using dust suppressed or pre-sized products);
• control between source and worker, (e.g. exclusion barriers, enclosure andexhaust ventilation
• control at the level of the worker, (e.g. information showing use of respiratoryprotective equipment).
Respiratory protective equipment (RPE) should be used only as a temporarycontrol measure, i.e. for short-term exposures that are otherwise difficult tocontrol and where concentrations are unknown. RPE should not be used as a long-term solution.
ASW/RCF products, in some cases, can be made virtually dust free by pre-cut, pre-shaped, encapsulated or coated with dust suppressants, to significantly reduce potential dust release. Use of dust-suppressed products should be encouraged.
Alternatively, wetting products with a fine clean mist of water prior to andduring handling can substantially reduce dust. If dust emissions cannot becompletely avoided or suppressed at their source, exposures should bereduced to the lowest achievable levels.
Enclose sources as much as possible to prevent unnecessary exposure.Segregation can be achieved by physical or airflow barriers.
Many instances of passive exposure are unnecessary and can be avoided by reorganizing the work area or work activities. All effort should be applied to avoiding unnecessary exposures. Work practices can usually be improvedto reduce the number of handling steps or their duration. Processes can beautomated to achieve the same end; this will often increase productivity.Automated stages of a process can be easier to enclose and extract the dustgenerated during the processing, e.g. Local Exhaust Ventilation (LEV) equipment.
Extraction systems must be designed to capture dust as close as possible to the sources. Design of the extraction hood to effect capture at source willminimize dust dispersion and reduce the volumes of air required. Extracted air
page 24
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 26
should undergo high-efficiency filtration and be treated according to localregulations. The air velocities required to control dust depends on the rate atwhich the dust is released from the product. As a general guideline, Table 9.1provides ranges of air velocities required to capture respirable ASW/RCF dust.For many manual handling operations, a well designed local exhaust ventilation(LEV) System will capture velocities between 0.5 and 1.0 m/s at dustgeneration points should ensure good control.
Photo 9.3:
Local exhaust extraction system for
assembly of RCF materials
Photo 9.4:
Mobile down-draught bench
Photo 9.1:
Down-draught table with integrated bin
for waste
Photo 9.2:
Down-draught system
Table 9.1:
Capture velocity value
depends on particle
velocity
Capture velocity required
at the point of dust
generation
0.5 to 1.0 m/s
1.0 to 5.0 m/s
5.0 to 25m/s
page 25
Example
Conveyor transfer, unrollingblanket, cutting blanketmost manual handling
Textile, spinning, weaving
Band sawing, machiningfinishing
Nature of source
Low velocity
Moderate velocityemissions
High velocity emissions
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 27
To ensure efficient control of dust sources and avoid errors, the design of the dust-control system should be carried out by an experienced ventilationengineer. Prior to implementation, the plans should be reviewed by theprocess operator and by an industrial hygienist.
After redesigning a workstation or implementing control measures, operatorsshould be trained in proper operating and handling procedures that will helpminimize dust, as outlined in the ECFIA “Code of Practice”. Waste and debriscan present a secondary source of exposure and should be controlled bygood housekeeping techniques. Dry sweeping and compressed air cleaningshould be prohibited. The work area and work surfaces should be regularlycleaned using a vacuum cleaner equipped with a high-efficiency filter.
Every employee who handles ASW/RCF should be familiar with the potentialhealth risks and with proper working procedures. Level P3 respiratoryprotection is recommended where excursions above the exposure limit areless than a factor of ten. Level P2 protection can be provided on a voluntarybasis for concentrations below the occupational exposure limit.
To prevent skin irritation (itching) and the contamination of employees' clothing,the use of disposable protective coveralls made from a material impervious tofibres is recommended.
The recommended control measures presented in this document take intoaccount the general principles imposed by European legislation and includepractices currently in use in certain industries. We have also indicated wherepossible the lowest levels documented during the CARE measurement programfor specific operations. For further information or assistance in controllingexposures to ASW/RCF dust, contact an ECFIA industrial hygienist.
page 26
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 28
10Specific guidelines for thereprocessing of ASW/RCF products(secondary production)
In secondary production, ASW/RCF in the form of bulk or blankets istransformed or processed to make product forms, such as vacuum-formedshapes, boards, felts and papers, cements, modules, die-cut parts andtextiles. As a general guide, Table 10.1 presents an overview of the main jobsand their associated concentrations.
To further guide the reader, the data are classified into four categories ofaverage concentration. Variations in work organization and tasks will result indifferent concentrations. Thus, information in Table 10.1 should serve only asgeneral indication of what to expect. The most important sources of dust arethe finishing (machining) operations in which fibrous products are subjected toconcentrated mechanical energy from powered equipment or machinery suchas sanders, saws, die-cutting presses, routers and others. The next mostimportant source is handling of fibre and fibre-based products. As can beseen in the Table, jobs in which these activities feature prominently tend tohave average concentrations in excess of 0.5 f/ml. Several activities will beexamined in further detail. They are: - vacuum forming - production ofmodules - production of die cut parts - machining. For each of these, a tableproviding a summary of emission sources, average dust concentrations andrecommended control methods is given.
Table 10.1:
Secondary Production,
main jobs and
dust concentrations
Jobs with arithmetic mean concentrations less than 0.2 f/ml
Means
Geom. Arith. Min Max N
0.088
0.110
0.123
0.127
0.147
0.175
0.022
0.010
0.024
0.640
0.378
0.760
14
28
24
Slitting and rolling of ASW/RCF
paper
Warehouse workers handling
wrapped/packaged ASW/RCF,
forklift drivers in the warehouse
Supervision of secondary
production tasks
Dry end paper
Warehouse/
forklift
Supervisor
page 27
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 29
Jobs with arithmetic mean concentrations between 0.2 and 0.5 f/ml
Means
Geom. Arith. Min Max N
0.160
0.139
0.231
0.187
0.157
0.134
0.214
0.214
0.233
0.314
0.279
0.222
0.231
0.263
0.266
0.277
0.288
0.292
0.310
0.390
0.408
0.436
0.020
0.010
0.040
0.010
0.010
0.020
0.010
0.010
0.020
0.161
0.015
0.960
1.016
0.633
1.345
1.823
1.393
1.140
1.468
3.127
1.404
1.208
39
56
24
231
44
20
76
58
182
9
47
QA/QC activities associated
with manufactured ASW/RCF
products
Other workers with passive
exposures (e.g., welders,
electricians, administrative
workers, production area forklift
drivers), and unspecified
auxiliary workers
Cutting ASW/RCF materials
with high-pressure water jet
Vacuum forming board,
shapes, and paper
Insertion, attachment,
application of ASW/RCF
materials to a commercial
product
Insertion, attachment,
application of ASW/RCF
materials to a commercial
product, with some finishing
Handling or packaging
ASW/RCF products
Making ASW/RCF textile
products such as rope or cloth
(e.g., operate loom, spinner,
carding machine)
Both wet mixing and forming
performed on a shift
Maintaining or cleaning of
secondary production area or
equipment
Laminating or encapsulating
ASW/RCF (e.g. with aluminum
foil)
Quality control
Auxiliary
Water jet cutting
Vacuum forming
Assembly with
ASW/RCF
Assembly with
ASW/RCF,
some finishing
Packaging
Textile
manufacture
Mixing and
forming
Maintenance /
Cleaning
Laminating /
Encapsulating
page 28
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 30
Jobs with arithmetic mean concentrations between 0.5 and 1.0 f/ml
Means
Geom. Arith. Min Max N
0.325
0.503
0.353
0.596
0.489
0.503
0.453
0.546
0.604
0.584
0.779
0.474
0.521
0.651
0.661
0.697
0.702
0.769
0.771
0.784
0.830
0.849
0.943
0.972
0.019
0.100
0.054
0.199
0.026
0.05
0.05
0.080
0.116
0.041
0.220
0.015
4.028
2.341
3.190
1.820
4.638
3.597
4.084
3.509
4.038
3.244
3.219
16.020
150
66
18
36
189
177
119
31
38
61
22
67
Wet mixing ASW/RCF for
vacuum forming boards,
shapes or paper
Handling or packaging
ASW/RCF products in close
proximity to to a finishing
operation
Dry mixing fo bulk ASW/RCF
with other ingredients (for
vacuum forming or cements)
Operate board sander
All jobs connected with
production of ASW/RCF
modules (folding, trimming,
attach hardware, etc.)
Operate die cutting machine
and take-off of product
Cut various materials on a
power saw (circular saw, table
saw)
Operate board saw
Power sanding of formed
ASW/RCF product
Finishing using hand tools
Operate both of these
machines
More than one finishing task
during the shift
Mixing
Packaging in
finishing area
Dry mixing
Board sanding
Module
production
Die cutting
Cutting, sawing
Board sawing
Sanding
Hand finishing
Board Sanding
& Board Sawing
Multiple finishing
tasks/
miscellaneous
Jobs with arithmetic mean concentrations between 1.0 and 4.0 f/ml
Means
Geom. Arith. Min Max N
0.824
0.798
1.777
3.822
1.212
1.360
2.358
3.822
0.123
0.1
0.188
3.822
6.060
5.600
5.708
3.822
58
58
16
1
Operate these power tools
(hand held or fixed installations)
Cut various materials on band
saws
Operate linisher
Operate ball mill to mill bulk
ASW/RCF
Drilling, grinding,
routing, lathe,
milling
Band sawing
Linishing
Ball milling
page 29
Unifrax Health & Safety 2008 NEW 12/10/09 15:28 Page 31
Vacuum-formed (VF) products are shapes produced from bulk fibre in a five-stage process, with operators involved at each stage: mixing, forming,drying, inspection and packaging (Table 10.2). At the mixing stage, theoperator introduces dry ingredients in to the mixing tank (typically starch andbulk ASW/RCF). Additional wet ingredients are added last (typically colloidalsilica). The forming stage is the "wet-end" of the process, where VF shapesare formed using a mould and suction, the shapes are removed and placed on a drying rack in a curing oven. At the packaging stage, dried VF shapes aremanually removed from the drying rack, inspected and packed into boxes.
Exposures are concentrated in the dry ends of the process when adding dryingredients to the mix and when handling the dried shapes (unloading, packingand inspection).Compression of empty bags into waste can also release dust.
1 Complete or partial cover on the mix tank. 2 Delivery chute at HTIW introduction point. 3 Spillage of materials around tank should be immediately cleaned.4 Water spray applied at the point where dry materials are added. 5 LEV hood at dry ingredients weigh station.6 LEV hood at HTIW introduction point.7 Wetting of used bags prior to disposal.8 Segregate wet process from the dry operations such as packing and
inspection.9 Use appropriate personal protective equipment (PPE) including respiratory
equipment.
Secondary exposure can occur where there is re-suspension of spilt materials,this can be addressed with good housekeeping. Vacuum cleaners fitted withHEPA filter should be used to clean up dry spillages. A wet scrubbingtechnique should be used where practical at the end of each shift.
Control methods for
vacuum forming and
other wet mixing
processes
Controls
page 30
Photo 10.1
Forming station
Photo 10.2
Packaging of RCF boards
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 32
Table 10.2: Control methods for vacuum-forming
0.325
0.187
0.233
0.214
0.503
0.521
0.266
0.390
0.292
0.651
0.019
0.010
0.020
0.010
0.100
4.028
1.345
3.127
1.140
2.341
150
231
182
76
66
Slitting of bags
Manual loosening and pushing of
fibre into tank
Compression of empty fibre bag
into waste container
Spillage of fibre around tank
Negligble sources due to mainly
wet process
If concentrations are elevated,
likely cause are other dusty
process or dried out material
being disturbed
As above
Dried shapes are friable
Handling of the VF shapes during
removal from drying racks,
inspection and packaging
Hand removal or surplus edges
Note that packing boxes are often
reused and unless pre-cleaned
using a vacuum, will accumulate
dust and debris in the bottom of
the box
As above
Mixing
Vacuum forming
Mixing and
forming
Packaging
Package in
finishing area
MeansGeom. Arith. Min Max N
Job Sources of exposure
ranked by importance
Recommended controlmeasure
page 31
Use of soluble bags for bulk
fibre
- Automatic opening of bag and
feed in to tank
- complete or partial cover on
tank
Delivery chute at fibre
introduction point
Water spray where fibre is
introduced into tank
LEV hood at dry ingredients
weigh station
LEV hood at fibre introduction
point
Wetting of used bags prior to
disposal
Use vacuum with HEPA filter to
clean up dry spillage
PPE/RPE
Segregate the forming
operations from other dusty
processes (e.g fininshing)
Wear impervious gloves to
prevent irritation and drying of
skin
PPE/RPE
As above
Change work methods to
minimise extent of handling
and movement of pieces
around the work area
Use fine water mist on parts to
suppress dust prior to packing
Use new or pre-vacuumed
boxes for packing
Conduct inspection and
packing in a ventilated booth.
Maintain good housekeeping
at all times using a wet
scrubber and or vacuum
containing HEPA filter.
Use correct PPE and RPE
As above
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 33
Modules and veneers are laminated blocks of blanket, which are eithermanually produced or produced by a semi automatic process. (Table 10.3).
ASW/RCF blanket is hand cut into sections using a template and a hand knife. Sections are stacked onto a pallet. Waste fibre is bagged or boxed. At completion, the sections are transferred to an assembly area. For theassembly, the pre-cut sections are inserted into a magazine for compressionto the desired thickness. Compression is maintained by application of straps,tape, metal clasps, or by insertion of the module into a plastic bag. Modulesare often pierced to allow insertion of metal fixtures. Modules may be trimmedusing a band saw or circular saw, either at this stage or prior to compressing.Band sawing of blanket can produce very high concentrations of fibrous dust.Consequently, particular attention should be paid to this step of the process.
The semi-automatic process is typically used to produce standard sizedmodules. One variant of this process uses sections of blanket that have beenprecut on a die-cutting press (see die-cutting). Stacks of precut sections ofblanket are manually positioned into a press that automatically compresses the block. Straps, tape or extrusion into a plastic bag are used to maintaincompression. Metal fixtures are added automatically or manually. Modules arepacked into cartons or on pallets.
The pleated blanket process uses rolls of blanket directly. Rolls of fibre areunwrapped and loaded into a folding machine. The standard size blanket is fed manually or automatically. After a certain number of folds a cross-cutsaw is activated. Pleated sections are manually transferred to a press andcompressed to the desired size. Compression is maintained as in the manual or pre-cut process. Metal fixtures are added and modules are packedinto cartons.
Veneer modules are thin modules usually produced by hand. Precut strips of blanket are manually placed on edge into a compression jig. Strips areattached either by plastic mesh or by strips of glue along the cut edges of the blanket. Assembled modules are then trimmed and packed into cartons.
Modules and
Veneers
Manual production:
Semi Automatic
Production:
page 32
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 34
Table 10.3: Control methods for production of modules and veneer modules
0.489 0.702 0.026 4.638 189MANUAL PRODUCTIONSegregate the module/veneerassembly area. Restrict accessonly to operators involved in theprocess.Minimise manual handling byreorganising the work; reducedistances between operationsUse an extraction booth withdowndraft table (with integratedwaste bin) for unwrapping,unrolling, cutting and stacking ofparts. The table should be largeenough to allow all dustproducing operations to becarried out on its surface, withinthe dust capture zones providedby the exhaust system.The table should be designed toprovide at least 0.5 m/s ofcapture velocity at the pointswhere dust is generated.Use fine water mist on productprior to and during compressionand folding.Bag waste material immediately,label and store in segregatedarea.
BANDSAWReplace the band saw blade with a “band knife” or finetoothed saw without tooth offset.Segregate the band saw fromother operations.Ensure adequate LEV at the 3main dust generation points:– at the height adjustable bladeguide above the work table- directly below the table wherethe blade exits the blanket- immediately after the 6 o’clockposition of the lower drive wheelinside the guard housing.Between 600 and 800 m3/h ofexhaust air is normally requiredfor each dust collection point.
COMPRESSION PRESSESEnclose press as much aspossible, install LEV to capturedust from press, from insertionof block into plastic bag,insertion of metal fixtures, andfrom packing.
OTHERConduct QC tests on downdrafttable.Clean work equipment andsurfaces regularly during shiftusing a HEPA equipped vacuumcleaner.Use disposable clothingimpervious to fibres.Use RPE appropriate toexpectedconcentrations(typically P2 or P3)
Unwrapping, unrolling of blanketHand cutting of blanketHand folding of blanketHand stacking of blanketBagging of waste fibreCompressing stacks of blanketInserting into plastic bagAdding metal fixturesConducting QC testingPacking
Manualproduction ofmodules
Means
Geom. Arith. Min Max N
Job Sources of exposure
ranked by importance
Recommended control
measure
page 33
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 35
Die-cut parts are produced from flat sections or rolls of fibrous product(blanket, paper or felt) in a manual or semi-automated die-cutting press. Inmanual die-cutting, the operator unrolls blanket, paper or felt onto a table,cuts rectangular sections with a hand knife and stacks the rectangles on apallet as feedstock for the press. Several layers of ASW/RCF are then placedon the press table, advanced under the press and die cut (Photo 10.4).
The operator then withdraws the table from the press, removes the die cutpieces for packing, and removes the waste trims to a bag or box. In semi-automated die-cutting, rolls of blanket, paper or felt are loaded onto the feedsection of the press and unrolled. The product is fed through the press, asection is die-cut, the product advanced and the die-cutting repeated. At thetakeoff end of the press, operators manually remove cut pieces and stack onto pallets or into boxes. Waste edge trims are also manually removed andcompressed into bales. The most important sources of dust are the die-cuttingplate, handling of the die-cut pieces and handling of the waste trims.
Concentrations during loading and alignment of the rolls can be elevated, but are brief. Concentrations can be substantially reduced by enclosing thepress and providing proper dust extraction at the sources. More moderncutting techniques can dramatically reduce concentrations. For example, high-pressure water-jet cutting produces essentially no dust and leaves dampedges that further reduce dust during handling of cut pieces. In another newprocess, blanket is unrolled onto a suction table, then covered by a plastic filmand maintained in place by suction applied beneath the blanket (photo 10.3).
A small, computerized knife-cutting head cuts pieces to the desired shape,with very little dust emission. During handling of the cut parts, however, dustconcentrations of about 0.5 to 1.0 f/ml are typical unless handling is doneunder local exhaust ventilation.
Die Cutting of
fibre products
page 34
Photo 10.3 (Automatic)
Blanket held under plastic film
on suction table.
Photo 10.4 (Manual)
No exhaust ventilation or other controls.
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 36
Table 10.4: Control methods for production of die-cut parts
0.503 0.769 0.002 3.597 177Segregate the die-cutting area.
Restrict access to the press -
Unwrapping, unrolling of
blanket only to be operators
involved in process
Hand picking of cut pieces -
Ensure adequate LEV around
all sides of die cutting
equipment
- Hand stacking of pieces on
pallets cutting tools - Packing
into boxes - Enclose press as
much as possible - Handling,
compression and bagging of
fibre pieces
- Enclose take-off area and
extractdust, design so that
airflow is downward (e.g. Slot
hoods level with take off table)
Install automated waste trim
take off with LEV
Ensure LEV at pallet packing
and box packing stations use
adjustable table to allow
packing at correct height
Conduct QC tests on down
draught table
Clean work equipment and
area regularly during shift using
a HEPA vacuum cleaner
Use disposable clothing
impervious to fibres.
Use RPE appropriate to
expected concentrations
(typically P3)
- Die cutting plate, jig
- Unwrapping, unrolling of blanket
- Hand picking of cut pieces
- Hand stacking of pieces
on pallet
- Packing into boxes
- Handling, compression and
bagging of waste fibre
- Conducting QC testing
Die-cutting
press operator
MeansGeom. Arith. Min Max N
Job Sources of exposureranked by importance
Recommended controlmeasure
LEV – Local exhaust ventilationPPE- Personal protective equipmentHEPA – High efficiency particulate arrester.
page 35
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 37
Table 10.5: Control methods for machining
0.596
0.546
0.604
0.798
0.453
0.824
0.697
0.784
0.830
1.360
0.771
1.212
0.199
0.080
0.116
0.033
0.008
0.123
1.820
3.509
4.038
5.600
4.084
6.060
36
31
38
68
119
58
Segregate the machining area,
restrict access only to
operators involved in the
process.
Ensure adequate LEV around
sources of emissions, at points
where machining head or tool
is in contact with HTIW.
Ensure adequate LEV at
machine entry and exit.
Ensure adequate LEV around
manual handling and stacking
(packing) operations.
Enclose machines as much as
possible and extract dust
close to the dust generation
points.
Clean work equipment and
surfaces regularly during shift
using HEPA –equipped
vacuum cleaner.
Use disposal clothing
impervious to fibres
Use RPE appropriate to
expected concentration
(typically P2 or P3 filters)
Application of concentrated
mechanical energy to abrade,
cut or machine HTIW product
Handling, packing and
stacking machined HTIW
product into boxes or onto
pallets
Handling of HTIW prior to
machining
Removal of packaging from
HTIW product
Sanding,
Sawing,
Routing,
Milling
Board
sanding
Board
sawing
Sanding
Band
sawing
Cutting,
sawing
Drilling,
grinding,
routering,
milling
MeansGeom. Arith. Min Max N
Job Sources of exposureranked by importance
Recommended controlmeasure
page 36
Photo 10.5
Belt Sander equipped with local
exhaust ventilation, air-jet stripper,
enclosure of entry and exit points,
and waste capture bins.
Photo 10.6
Local exhaust ventilation hood on horizontal band saw.
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 38
page 37
11 Specific guidelines for end use in furnaces
HTIW are commonly used as a high-temperature insulating lining insidefurnaces and kilns in the metallurgical, steel, petrochemical, chemical andceramic industries.
The life-cycle of ASW/RCF in furnaces has three stages: installation, use andmaintenance of the furnace, and removal. The installation and removal ofASW/RCF are dust producing jobs that require preventive measures. Once in place, ASW/RCF insulation will not produce dust during use of the furnaceunless there is abrasion of the lining. The service life of ASW/RCF insulation ina furnace is typically several years, depending on the application. Furnacedismantling and rebuilding operations can produce high concentrations of dustif certain preventative measures are not taken. Such operations include theremoval of furnace lining insulation at the end of its service life. There are fourreasons for the potentially high concentrations: 1/ after-use ASW/RCF materialis extremely friable - 2/ a large volume of material is removed - 3/ removaltakes place in a confined space, often with inadequate dust extraction - 4/ there is pressure to remove material quickly.
Photo 11.1
Refractory Industry:
RCF insulation inside a furnace.
Photo 11.2
Glass Industry: installation of RCF
blanket into expansion joint of a
new furnace.
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 39
This work should be carried out by trained teams of specialized contractorsequipped with air-supplied respirators and disposable clothing. Thedismantling and rebuilding of a furnace can result in exposures to otherhazardous materials such as crystalline silica, heavy metals and rock-woolfibres, depending on the application. Health hazards must be correctlyidentified and controlled, in addition to the preventive measures takenspecifically for ASW/RCF. Note that after extended periods above 900°C,ASW/RCF can partially convert to various phases of crystalline silica (refer toappendix H). This silica fomation is within the matrix of the fibre itself. Technical measures to prevent exposure to ASW/RCF and other dusts arebest anticipated at the planning stage. These measures should be designed to reduce dust emissions and limit personal exposures to the lowest levelpracticable. They should be listed in the project specification and integratedinto the prevention programme: clearly specifying organization andimplementation. As a general guide to the dust concentrations that can beexpected for furnace-related jobs, Table 11.1 presents an overview of the mainjobs and the associated dust concentrations. Actual concentrations in a givenapplication will vary according to the dimensions of the furnace, the nature andquantity of ASW/RCF insulation employed and the work methods andpreventive measures used. Overall, average dust concentrations for furnace-related applications were 1.7 f/ml. Dust concentrations for wet removal and5f/ml for dry removals were highest during dry removal of ASW/RCF (average5.03f/ml, average sampling duration 2 hours). Note that by properly wettingASW/RCF, after it has cooled down to typically 50°C, can reduceconcentrations, on average, by a factor of three (1.75 f/ml, average samplingduration 2 hours).
The installation of ASW/RCF materials generates lower average concentrations( 0.886 f/ml ). Dust concentrations for workers in the vicinity of a furnace whilstASW/RCF materials were being installed or removed were indirectly exposedto generally low dust concentrations (0.122 f/ml). This demonstrates thatASW/RCF fibres tend to settle rapidly
page 38
Removal
Photo 11.3
Steel Industry: wetting of
after-use RCF prior to removal.
Photo 11.4
Steel Industry: removal of after-use
RCF from a furnace.
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 40
page 39
0.38
7
0.68
3
0.74
9
0.83
1
0.08
1
Wet
rem
oval
Dry
rem
oval
0.88
6
0.84
4
1.75
1
5.03
4
0.12
2
0.01
5
0.18
0
0.08
0
0.05
0.05
6.16
6
2.16
6
5.45
6
53.6
16
0.39
2
84 30 9 52 21
270
309
110
176
321
Use
pre
cut,
pre-
size
d pi
eces
whe
re p
ossi
ble
If po
ssib
le, p
erfo
rm a
ll cu
ttin
g in
a s
egre
gate
d ar
ea, r
estr
ict
acce
ss o
nly
to o
pera
tors
invo
lved
in t
he p
roce
ssP
erfo
rm a
ll cu
ttin
g on
a d
own
drau
ght
tabl
e
Wet
sur
face
prio
r ta
mpi
ngC
lean
up
wor
k ar
ea r
egul
arly
dur
ing
the
shift
usi
ng a
HE
PAeq
uipp
ed v
acuu
m c
lean
erP
rohi
bit
use
of d
ry b
rush
ing
and
com
pres
sed
air
clea
ning
Bag
and
sea
l was
te im
med
iate
lyU
se d
ispo
sabl
e cl
othi
ng im
perv
ious
to
fibre
sU
se R
PE
app
ropr
iate
to
expe
cted
con
cent
ratio
n (ty
pica
lly P
2or
P3
filte
rs)
Enc
lose
and
seg
rega
te r
emov
al u
sing
pla
stic
she
etin
g or
poly
then
eIf
poss
ible
pre
wet
ting
of A
SW
/RC
F sh
ould
be
appl
ied
Use
wat
er la
nce
for
rem
oval
or
Use
vac
uum
-tru
ck fo
r re
mov
alP
rovi
de m
ultip
le v
acuu
m h
oses
(filt
ered
and
ven
ted
outs
ide
encl
osur
e)fo
r co
nven
ient
cle
anup
of s
pilla
ge o
r us
e po
rtab
leH
EPA
vac
uum
sE
nsur
e th
orou
gh p
enet
ratio
n of
wet
ting
agen
t th
roug
hout
AS
W/R
CF
laye
r (u
se d
ilute
det
erge
nt)
Bag
was
te a
s so
on a
s po
ssib
le a
nd d
ispo
se o
f AS
W/R
CF
into
cov
ered
con
tain
er /
skip
.C
lean
wor
k ar
ea r
egul
arly
dur
ing
shift
usi
ng H
EPA
vac
uum
sP
rohi
bit
use
of d
ry b
rush
ing
and
or c
ompr
esse
d ai
r cl
eani
ng.
Use
dis
posa
ble
clot
hing
impe
rvio
us t
o fib
res.
Use
indu
stria
l glo
ves
and
RP
E a
ppro
pria
te t
o th
e ex
pect
edco
ncen
trat
ions
(typ
ical
ly T
HP
3)R
estr
ict
area
to
wre
ckin
g or
inst
alla
tion
area
to
wor
kers
dire
ctly
invo
lved
in p
roce
ss
Han
d cu
ttin
g H
TIW
Han
dlin
g m
ater
ials
dur
ing
inst
alla
tion
Tam
ping
sur
face
s of
HTI
W m
ater
ials
Han
dlin
g w
aste
mat
eria
lsC
lean
up o
f wor
k ar
eaH
and
cutt
ing
HTI
WH
andl
ing
HTI
W m
ater
ials
dur
ing
inst
alla
tion
Tam
ping
sur
face
s of
HTI
W m
ater
ials
Han
dlin
g w
aste
mat
eria
lsC
lean
up o
f wor
k ar
ea
Bre
akin
g of
afte
r -
use
HTI
W m
ater
ials
Han
dlin
g of
afte
r -
use
HTI
W m
ater
ials
Scr
apin
g re
sidu
al H
TIW
from
furn
ace
surfa
ces
Cle
anup
of w
aste
fibr
e on
floo
rs a
ndsu
rface
s
Pre
senc
e in
wre
ckin
g or
inst
alla
tion
area
Inst
alla
tion
of H
TIW
Inst
alla
tion
of H
TIW
with
som
efin
ishi
ng o
rta
mpi
ng
Rem
oval
Aux
iliary
Mea
nsG
eom
.A
rith
.M
inM
axN
Job
Ave
rag
eD
urat
ion
So
urce
s o
f ex
po
sure
ran
ked
b
y im
po
rtan
ceR
eco
mm
end
ed c
ont
rol m
easu
re
Ta
ble
11
.1:
Co
ntr
ol
me
tho
ds
fo
r fu
rna
ce-r
ela
ted
en
d u
se
Inst
alla
tion
Inst
alla
tion
& ta
mpi
ng
Aux
illary
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 41
12 Specific guidelines for the use in furnaces
The versatility of ASW/RCFs means that they are employed in a wide variety ofindustrial applications. For convenience, applications in "Other end-uses" aregrouped by industry sector.
• Removal of ASW/RCF from kiln cars and moulds, Installation of ASW/RCF • Careful handling practices • Provide adequate PPE
• Removal of ASW/RCF blanket from casting moulds , Unrolling, cutting andinstallation of ASW/RCF blanket onto moulds
• Use automated water-lance system to remove ASW/RCF instead of dryabrasive blasting or manual removal
• Unroll, cut and install ASW/RCF blanket on down-draught tables
• Removal of ASW/RCF blanket from moulds, Unrolling, cutting andinstallation of ASW/RCFblanket onto moulds
• Carry out removal under local exhaust ventilation • Unroll, cut and install ASW/RCF blanket on down-draught/back-draught
table
• Die-cutting or sawing ASW/RCF (uncommon), Handling of ASW/RCF parts,Cleaning of work area
• Purchase pre-cut or preshaped pieces, preferably coated with dustsuppressant
• If cut on site, use cutting techniques that minimize dust and provideadequate extraction ventilation at dust generation points (especially bandsaws)
• Assemble ASW/RCF materials on down-draught tables (can achieve lessthan 0.1f/ml)
• Manual handling during assembly with ASW/RCF • Purchase pre-cut or pre-shaped pieces, preferably coated with dust
suppressant • Assemble RCF materials under LEV (can achieve <0.1 f/ml)
• Maintenance of kiln cars (remove after-service ASW/RCF, reline),load/unload bricks
• Careful handling practices • Provide adequate PPE
Abrasives
Aerospace
Aluminium
Boiler
Bricks
Automotive
(exhaust systems)
page 40
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 42
page 41
• Manual handling during assembly with RCF materials, Quality control testing • Use pre-cut or pre-shaped pieces, preferably coated with dust suppressant • Assemble ASW/RCF materials under LEV (can achieve less than 0.1 f/ml)
• Manual handling during assembly with RCF materials, Quality control testing• Use pre cut or pre shaped pieces, preferably coated with dust suppressant• Assemble RCF materials under LEV (can achieve <0.1 f/ml)
• Removal of after-use ASW/RCF from casting, Removal of RCF from kilncars, Cutting and installation of RCF material into moulds, Indirect exposureto foundry operators working in adjacent areas
• Prohibit compressed air cleaning of moulds, replace by brushingaccompanied by local exhaust ventilation
• Prohibit sweeping of kiln car, instead, use a vacuum cleaner with a HEPAfilter
• Provide local exhaust ventilation for cutting and installation operations • Provide adequate RPE for mould cleaning operations (e.g. THP 3) • Provide adequate RPE to indirectly exposed operators (e.g. FFP2)• Restrict access to work area to authorised and trained personnel.• Apply careful handling practices• Pre-wet used RCF prior to removal where possible• Bag and contain fibre waste immediately to prevent secondary exposure
• Wrap moulds with ASW/RCF, remove ASW/RCF from moulds, end-use ofmoulds in glass making
• Carry out removal under local exhaust ventilation (LEV)• Unroll, cut wrap RCF on down-draught or back draught table
• Maintenance of kiln cars (remove after-service ASW/RCF, reline),maintenance of furnace lining (install/remove), end use kiln cars andfurnace in ceramics manufacture
• Prohibit compressed air cleaning of moulds, replace by brushingaccompanied by local exhaust ventilation
• Prohibit sweeping of kiln car, instead, use a vacuum cleaner with a HEPAfilter
• Provide local exhaust ventilation for cutting and installation operations• Provide adequate RPE for mould cleaning operations (e.g. THP 3)• Provide adequate RPE to indirectly exposed operators (e.g. FFP2)• Restrict access to work area to authorised and trained personnel.• Apply careful handling practices• Pre-wet used RCF prior to removal where possible• Bag and contain fibre waste immediately to prevent secondary exposure
• Manual handling during assembly with RCF• Purchase pre cut or pre shaped pieces, preferably coated with dust
suppressant• Assemble RCF materials under LEV (can achieve less than 0.1f/ml)• Provide adequate RPE to indirectly exposed operators (e.g FFP2)
Domestic appliances
Fire protection
Foundry
Glass
Industrial Ceramics
Industrial Equipment
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 43
• Removal of RCF blanket from casting moulds, Removal of RCF from kilncars, Unrolling, cutting and installation of RCF, Indirect exposure ofoperators working in adjacent areas
• Prohibit compressed air cleaning of moulds, replace by brushingaccompanied by local exhaust ventilation
• Prohibit sweeping of kiln car, instead, use a vacuum cleaner with a HEPAfilter
• Provide local exhaust ventilation for cutting and installation operations• Provide adequate RPE for mould cleaning operations ( e.g. THP 3)• Provide adequate RPE to indirectly exposed operators (e.g. FFP2)• Restrict access to work area to authorised and trained personnel.• Apply careful handling practices• Pre-wet used RCF prior to removal where possible• Bag and contain fibre waste immediately to prevent secondary exposure
• Handling finished ASW/RCF products (generally wrapped and/orpalletized), move with forklifts, load trucks for shipping
• Careful handling practices should be applied
Overall, the concentrations are low ,the highest potential for exposure can befound during the removal of after-use ASW/RCF materials from kiln car, ladlesor moulds in foundries and the steel industry.
The average concentrations produced by these activities were 0.6 f/ml;substantially lower than those found during removal of ASW/RCF fromfurnaces. This is because "other end-use" removal work is usually carried outin open areas and involves small quantities of ASW/RCF. The most commonlyencountered operation is assembly work. Here, ASW/RCF materials areinserted into, attached to or applied to other materials to form an intermediateproduct or a finished, commercial product. When no finishing operations areinvolved, (e.g. cutting, trimming, sanding), average concentrations of dust forassembly operations were 0.25 f/ml (n=111). With finishing, concentrations ofdust were higher by a factor of four (0.82 f/ml, n=21). Dust concentrations forworkers indirectly exposed, (e.g. supervisors and fork lift drivers) were low, onaverage 0.18 f/ml (n=39).
The variety of applications covered in "other end-uses" prevents a thoroughexamination of concentrations by application. Instead, examples are providedto show how the CARE programme has improved the workplace. The firstexample given is a detailed procedure for working safely with ASW/RCF,developed by a major European steel producer. The second example showshow a car exhaust system manufacturer reduced already low dustconcentrations further, by careful attention to dust sources, information andtraining of workers.
Steel
Warehouse
Control methods for
other end uses
page 42
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 44
page 43
Photo 12.1
Installation of die-cut RCF blanket
into catalytic converter shell, on
downdraft table.
Photo 12.2
Installations of RCF blanket onto casting
mould, inside backdraft exhaust booth.
This procedure specifies the precautions required when working with materialscontaining ASW/RCF. Applications of these measures will provide adequateprotection of workers directly handling these materials and workers in thevicinity of these operations.
This procedure is applicable to all ASW/RCF materials, notably boards and textilesas used in high temperature insulation. The procedure applies to the construction,maintenance and dismantling of thermal installations containing ASW/RCF.
Where conditions allow, alternative thermal insulation products exempt fromany carcinogenic classification should be considered.
Authorisation to work with ASW/RCF is granted by the employers’s medicalofficer, who guarantees that the employee is:
• medically fit for work• informed of health risks• Trained in safe working procedures, including the proper use of Personal
Protective Equipment (PPE).
Dust levels associated with various operations involving ASW/RCF depend onhow the material is used. It is useful to distinguish four categories ofoperations that are likely to present different exposure potentials:
a) Assembly of high temperature insulation components b) Installation of assembled components, or episodic intervention on the
insulation, (e.g. maintenance)c) Removal of componentsd) Work conducted outdoors
Example 1:
Safe working
procedure for
ASW/RCF materials in
the steel industry
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 45
page 44
Assembly operations essentially consist of cutting ASW/RCF materials with a knife or a saw, then inserting or applying the ASW/RCF insulation to othercomponents. Such operations can produce substantial quantities of dust, butonly over short periods. Cutting with hand tools is preferred to using power tools.If power tools must be used, those with low rotational speeds are preferable
Cutting should be carried out on a downdraught table or, if not possible, inside an enclosure. The enclosure limits dust dispersion and clearly identifiesthe cutting area. Access to the enclosure should be formally restricted toauthorised operators equipped with appropriate PPE and RPE. Smoking,eating or drinking should not be allowed inside the enclosure.
The quantities of ASW/RCF unpacked on the work site should be limited tothe amount required for the job at hand. Prepared insulation should betransferred to the point of use in plastic bags or boxes. New materials shouldbe stocked in a manner that preserves packaging integrity. Unused materialsshould be repacked. The work site should be kept clear of all waste fibre.Waste ASW/RCF materials should be placed immediately into tear resistantplastic bags, sealed and labeled “Refractory Ceramic Fibre”. Floors and worksurfaces should be regularly cleaned during the work shift by vacuum cleaning(HEPA filtration) or wet cleaning. Dry sweeping and use of compressed airshould be prohibited.
The number of operators allowed on the work site must be limited. The operators must wear the following PPE: • Full-face respirator with powered filtration (level P3)• Disposable protective clothing impervious to fibres, closed at wrist and neck• Gloves to prevent skin irritation
After completion of cutting and assembling operations, the enclosure shouldbe vacuumed clean. Protective clothing should also be vacuumed clean, thenremoved and disposed of in a plastic bag.
A work zone is determined in which air-borne fibres can be generated. Thiszone is clearly marked-off by tape or rope, accompanied by signs and apictogram prohibiting access to persons not equipped with a type P3respiratory protective device.
Operators within the zone should wear:• Type P3 respirator• Gloves • Safety glasses• Disposable protective clothing impervious to fibres, closed at wrist and
neck and fire-retardant if necessary.
Whenever possible, the work zone should be maintained wetted or treatedwith a coating or rigidiser. Smoking, eating or drinking should not be allowedwithin the zone. A list of authorised personnel should be posted.
Installation of
assembled
components, or
episodic intervention
on the insulation,
(e.g. maintenance)
Assembly of
high temperature
insulation components
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 46
page 45
Removal of ASW/RCF insulation can generate substantial quantities of dustbecause aged insulation is brittle and extensive manual operations may berequired for complete removal, (e.g. brushing, scraping, grinding). If theremoval work zone cannot be enclosed or sealed off, the boundaries of thezone must be determined by experience or by measurements. The zoneshould be clearly marked-off by tape or rope, accompanied by signs and apictogram prohibiting access to persons not equipped with a type P3respiratory protective device.
Operators within the zone should wear:• Full-face respirator with powered filtration (level P3)• Disposable protective clothing impervious to fibres, closed at wrist and
neck and fire-retardant if necessary• Gloves to prevent skin irritation and appropriate for the task.
In cases where removal work generates high short-term concentrations,access to the work zone should be restricted to the removal operatorscarrying out the brushing, scraping or grinding operations. Whenever possible,the removal area should be removed or maintained wetted or treated with acoating or rigidiser. Smoking, eating or drinking should not be allowed withinthe zone. A list of authorised personnel should be posted. Waste ASW/RCFmaterials should be placed immediately into tear-resistant plastic bags, sealedand labelled “Refractory Ceramic Fibres”. These should be stored in adesignated area.
Preparation: same as for assembly, installation and removal of materials:intervention by authorised personnel equipped with P3 masks, safety glassesand appropriate gloves.
The zone should be clearly marked-off by tape or rope, accompanied by signsand a pictogram prohibiting access to persons not equipped with a type P3respiratory protective device.
ASW/RCF materials are used in the manufacture of exhaust systems.
Removal of
components
Work conducted
outdoors
Example 2
Reduction of
dust concentrations
during assembly
of an automotive
exhaust system
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 47
page 46
ASW/RCF felt provides high-temperature insulation of the catalytic convertercore. Pieces of ASW/RCF blanket, bought in pre-cut, are assembled on theceramic core.
The company described had already initiated some exposure reductionmeasures by installing down-draught tables at each of the five assemblyworkstations, but wished to reduce exposure levels further. An ECFIA hygienistmeasured personal exposures to fibrous dust on five operators over a workshift and assessed the efficacy of the control measures in use. Dustconcentrations were low overall (0.03 to 0.15 f/ ml, average 0.07).
During the measurement, several deficiencies were noted in the implementedcontrols. The recommendations were: • Improve capture velocity above one down-draught table (0.2 m/s during
the measurements) • Ensure equal distribution of air velocities above all down-draught tables to
ensure capture of dust from all sources handled • Use vacuum cleaners equipped with high-efficiency filters to clean floors
and surface instead of dry brushes • Unpack ASW/RCF pieces from boxes on the down-draught tables • Remove waste fibre from empty boxes by vacuum cleaning prior to
handling and discarding boxes • Inform workers of the risks of working with ASW/RCF and train them in
safe working procedures.
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 48
The company implemented essentially all of the ECFIA recommendations and conducted repeat measurements of personal exposures to fibrous dust 4 months later.
Dust concentrations were substantially lower than those measured initially(0.001 to 0.04 f/ml; average 0.003). In addition, the company prepared apamphlet to inform workers about ASW/RCF, state of knowledge on healtheffects, European classification, reductions of dust concentrations, along withrecommendations for limiting exposures.
Installation of
assembled
components, or
episodic intervention
on the insulation,
(e.g. maintenance)
Removal of
components
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 49
The CARE programme data presented here show that average concentrationsin fibre production, mixing-forming, and most assembly and installationoperations are below 0.5 f/ml. Average figures do not, of course, tell thewhole story. Individual applications can produce elevated exposures,especially if the appropriate control measures are not used. This guideidentifies applications where concentrations are likely to be higher than manyexposure limits and provides practical advice for limiting exposures throughtechnical or organizational means. Operations known to generate excessivedust concentrations and for which technical control measures are difficult,(e.g. furnace wrecking; certain finishing operations) will require appropriaterespiratory protective equipment. This comprehensive review, based oninternationally recognised data, allows workplace concentrations to beestimated for many situations, and technical and organisational measures tobe devised. Proper application of these measures will not only satisfy stringentEU requirements, but more importantly, protect worker health.
CONCLUSION
page 48
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 50
APPENDICES
A Expanded list of functional categories withdefinitions and examples
B Operations monitored in the primaryproduction group
C Operations monitored in the secondaryproduction group
D Operations monitored in the furnace relatedgroup
E Operations monitored in other uses group
F Trade names of RCF products for Unifrax,Rath and Thermal Ceramics
G ECFIA generic Material Safety Data Sheet(MSDS) for RCF products, refer to ECFIAwebsite
H Respirable Crystalline Silica (RCS) in after use HTIW
page 49
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 51
APPENDICES
Appendix A - Expanded List of Functional Categories with Definitions and Examples
Definition
The production or manufacture of
ASW/RCF bulk or blanket, except
in a supervisory capacity. Includes
all job functions on the production
line, from mixing the raw
ingredients to packaging the
finished product (bulk or blanket) at
the end of the line.
Cutting or machining ASW/RCF
materials after fibre manufacture.
Hand or power tools may be used
in finishing operations.
General
Examples
• Raw materials, furnace man,
furnace operator, or assistant
furnace operator.
• Production worker or relief.
• Blanket line.
• Working leader.
• Needler.
• Slit/cut/pack.
• Line utility.
• Utility operator.
• Chopper operator.
• End of line, bagging of bulk
ASW/RCF.
• End of line trimming, rolling, and
packaging of ASW/RCF blanket.
• Operating diestamp on
ASW/RCF blanket or paper
except for automotive
applications.
• Sawing, slotting, trimming, or
filing casting tips or riser
sleeves.
• Cutting blanket for ductwrap.
• Cutting or trimming ASW/RCF
board or other vacuum-formed
ASW/RCF material.
• Sanding ASW/RCF board or
other vacuum-formed ASW/RCF
material.
• Loading sander.
• Off-line cutting and tandem
rerolling and/or repackaging of
ASW/RCF blanket.
• Cutting or trimming ASW/RCF
modules for use in appliances.
• Milling or routing ASW/RCF
board or other vacuum-formed
ASW/RCF material.
• Off-site cutting of batten strips
from ASW/RCF blanket.
Functional
Category
Fibre
Manufacturing
Finishing
Additional
and Guidance
None to date.
• Working in an area
where finishing
operations are taking
place, although not
personally working with
ASW/RCF materials,
unless in a supervisory
or other “Auxiliary
Operations” capacity.
EXAMPLE: Unloading dryforms from the dryingoven and taken them tothe finishing area for finalshaping or packagingshapes immediately afterfinishing would beconsidered finishing whileunloading dry forms froman oven and taking themto be packaged, as wellas packaging shapes thatcome directly from thedrying oven would beconsidered “AuxiliaryOperations.”
page 50
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 52
page 51
Definition
Building or manufacturing industrial
furnaces or boilers, refinery or
petrochemical plant equipment,
kilns, foundries, electric power
generators, and industrial
incinerators at end-user locations,
and building large furnaces and
furnace parts at remote factories in
cases where use of engineering
controls is impractical (examples:
(1) work is performed in an
enclosed area [i.e., inside the
furnace]; (2) large size or
orientation of furnace parts
precludes application of
engineering controls.) Includes
furnace maintenance. Does not
include factory manufacture of
small industrial furnace
components when work is
performed in an open area outside
the furnace where engineering
controls would be used.
Removal of after-service ASW/RCF
material from an industrial furnace,
etc., that has completed its
economic life. Includes the removal
of ASW/RCF material in furnace
maintenance.
Combining or assembling
ASW/RCF material with other
material (ASW/RCF or other),
except automotive applications.
This includes factory assembly of
industrial furnace components
when work is performed in an
open area outside the furnace
where engineering controls are
practical.
General
Examples
• Unwrapping and knocking out
moulds.
• Furnace disassembly.
• Furnace maintenance.
• Cleanup and disposal of
removed material.
• Laminating.
• Encapsulating ASW/RCF
blanket.
• Assembling appliances.
• Off site assembly of industrial
furnace components when work
is performed in an open area
outside the furnace where
engineering controls are
practical.• Changing ASW/RCF gaskets,
etc. in appliances.• Cutting and assembling material
for sound proofing exhaustducts.
• Sewing ASW/RCF material.• Stapling ASW/RCF material.• Ball milling or grinding
ASW/RCF material.• Lamination of ASW/RCF paper.
Functional
Category
Installation
Removal
Assembly
Operations
Additional
and Guidance
Employees working inside
furnace during the removal
of ASW/RCF materials,
even though not working
directly with that material
(e.g., a plumber or
electrician working inside a
furnace during a removal).
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 53
Definition
Wet-end production of vacuum-
cast shapes, board and felt and
paper. Includes mixing ASW/RCF
mastics, compounds, or castables.
Jobs in which employees are
“passively” exposed to ASW/RCF
while performing their normal
duties and whose exposures are
not likely to parallel those of
employees working directly with
ASW/RCF materials. Includes
certain jobs in which ASW/RCF
may be handled, but with small
probability of significant exposures
(e.g., warehouse worker or person
unloading completed parts for
packaging.)
All duties performed in the
production of ASW/RCF paper,
textiles, and automotive
components or other industry
sectors not covered in any of the
foregoing categories. Also,
exposures that cannot reasonably
be included in the categories listed
above (i.e., not elsewhere
classified). IH personnel should
explain tasks and industry sectors
as fully as possible for observations
in this category.
General
Examples
• Forming ASW/RCF board or
shapes.
• Weighing, batching, or mixing
materials to be formed.
• Placing wet parts on conveyor.
• Operating mixing machine.
• Felting.
• Wet-end papermaking.
• Mixing ASW/RCF mastics,
compounds and castables.
• Driving forklift.
• Making cartons to package
ASW/RCF at end of line.
• Quality control inspection.
• Packaging dry parts.
• Maintaining or repairing
equipment except furnaces.
• Cleaning furnaces or plant areas
where ASW/RCF is used.
• Removing vacuum-formed parts
from oven and/or packaging
them (no finishing).
• Moving ASW/RCF-wrapped
moulds into and out of furnace.
• Warehouse duties, including:
Dockwork, loading trucks,
moving materials.
• Supervising.
• Diecutting parts for automotive
airbag filters, gaskets, mufflers
or catalytic converters.
• Wrapping substrate for catalytic
converter.
• Operating former to make
roving.
• Operating tape loom.
• Operating carding machine.
• End-use applications.
• Dry-end papermaking,
supervision of papermaking.
Functional
Category
Mixing/Forming
Auxiliary
Operations
Other (NEC)
Additional
and Guidance
Premixing dry materialsbefore adding to mix tank.
page 52
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 54
page 53
Appendix B - Operations monitored in the primary production group
Furnace Includes operating the fibre production furnace and mixing raw materialsNeedler Operating the needler for blanket productionBagging Packing bulk RCF
Reel End Slitting, cutting and packaging/boxing blanket, sometimes termed ‘reel end’Chopping Chopping blanket scrap
Fibre line general operation/Miscellaneous Fibre line helpers, spare men, miscellaneous fibre line workersMaintenance/cleaning Maintenance and cleaning activities associated with the fibre production lines
and equipmentSupervision Supervisors associated directly with the fibre lines and other supervisors not
directly associated with secondary productionQuality control QA/QC activities associated with bulk and blanket
Warehouse/forklift Warehouse workers handling wrapped/packaged RCF and forklift drivers in thewarehouse
Auxiliary Other workers with passive exposure, (e.g. electricians, administrative workers,production area forklift drivers) and unspecified Auxiliary workers.
Appendix C - Operations monitored in the secondary production group
Manufacturing modules All jobs connected with making modules from blanket (folding, trimming,hardware installation)
Mixing Wet mixing RCF for vacuum forming boards, shapes or paperForming Vacuum forming board, shapes and paper
Mixing and Forming Both wet mixing and forming performed on a shiftDry mixing Dry mixing bulk RCF with other ingredients (for vacuum forming or cements)
Ball Mill Ball mill bulk in preparation for mixing operationDry end paper Slitting, rolling of paper
Board saw Operate board saw (at ECFIA member plants only)Board sander Operate board sander (at ECFIA member plants only)
Board sander and board saw Operate both machines (at ECFIA member plants only)Band saw Cut various materials on a band sawCut, saw Cut various materials on a power saw (circular saw, table saw)
Die cut Operate die cutting machine, take cut productHand finishing Fishing using hand tools
Linishing Operate linisherSanding Sanding various materials with power tools
Drill, grind, router, lathe, mill Operate these power toolsWater-jet cutting Cutting with a high-pressure stream of water
Package in finishing area Package parts in close proximity to a finishing operationMultiple finishing task/misc. More than one finishing task listed, and miscellaneous samples
Laminate/Encapsulate Laminate or encapsulate RCF, (e.g. with aluminium of aluminium foil)Textiles Making RCF extile products such as rope or cloth
Assembly with RCF Primary a task that is categorised in the ‘Use’ groupsAssembly with RCF, some finishing Same as above but includes some amount of finishing work
Packaging Handling or packaging RCF productsQuality control QA/QC activities associated with manufactured RCF products
Supervision Supervision of secondary product tasksMaintenance/Cleaning Maintaining or cleaning of secondary production area or equipment
Warehouse/forklift Warehouse workers handling wrapped/packaged RCF and forklift drivers in thewarehouse for manufactured RCF products
Auxiliary Other workers with passive exposure, (e.g. welders, administrative workers,production area forklift drivers) and unspecified Auxiliary workers
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 55
Appendix D - Operations monitored in the furnace-related group
Install Install blanket, board or modules in the furnaceInstall + some finishing, Tamping Same as above but including some cutting or tamping of the RCF product
Install + other jobs Other jobs inside a furnace during installation of RCFRemove Remove after service RCF from furnace
Remove-wet Same as above, but the RCF lining is wetted before removal to suppressairborne fibre and dust
Cleanup, disposal Cleanup and disposal of removed RCF wasteCut, saw Cutting RCF blanket for installers (on-site within furnace installation)Auxiliary Passive exposure to installation or removal, supervision
Appendix E - Operations monitored in the other end-uses group
Industry Sector ActivitiesAbrasives Production of abrasive shapes and wheels
Aerospace Manufacture of components used in aerospace applicationsAluminium Primary aluminium and aluminium casting
Automotive Manufacture of automotive parts Boiler Manufacture of boilers
Domestic appliances Manufacture of domestic water heaters, ovens, and fireplace unitsFire protection Manufacture of expansion joints
Foundry Casting of metal partsGlass Manufacture of glass and glass products
Industrial ceramics Manufacture of industrial ceramics parts and refractory blocksIndustrial equipment Manufacture of various equipment such as rolling steel doors, welding shields,
sampling probes, ventilation ducting and ovens for industrial useSteel Manufacture of steels
See also Table 13.3: Other end uses
Jobs monitored in the ‘other end-uses’ group
Assemble with RCF Assembly of parts, appliances or equipment including (generally prefabricated)Assemble + some finishing As above, but including some cutting, sanding or other finishing activities
Change seal Change RCF seal periodicallyEnd use Use equipment or furnace with RCF parts, but no manipulation of RCF
Line kiln cars, moulds, ladles Install RCF on kiln cars, molds, ladles, etcKiln car, ladle removal, mould knock out Remove after-service RCF from kiln cars, molds, ladles, etc
Furnace repair ‘Spot’ repair of furnace liningMaintenance/Cleaning Maintenance and custodial activities
Packaging Packaging completed parts or equipmentQuality control QA, QC activities
Supervision Supervisors, foremen, etcWarehouse/Forklift Shipping, warehouse, and forklift operation inside the warehouse
Auxiliary Other passive exposure including forklift operation on the production floor
page 54
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 56
Appendix F
Unifrax Fiberfrax, Fiberfrax ZThermal ceramics Cerafibre, Kaowool
Rath Alsitra
Appendix G
MSDS for ASW/RCF products - refer to web site
Appendix H
Respirable Crystalline Silica (RCS) in after use HTIW
page 55
Health aspects of Crystalline Silica in devitrified HTIW, more specifically RCF and AES, have been extensivelytested.
After-service RCF have been tested in animals in long term high dose testing by intratracheal injection (IP) andby inhalation and have shown no carcinogenic effect. Heat treated AES (up to 900°C) have been tested and have shown no decrease of their biosolubility comparedto products as sold.
After-service AES have been tested in vitro on rat lung macrophage and have shown no additional toxicitywhen compared to the as sold material and have a non significant level of toxicity compared to quartz DQ 12.
Fibrosis and cancer occurrence in humans has only been observed in freshly cleaved free crystalline silica inrespirable dust.
In devitrified fibres, the crystalline silica is trapped in grain boundaries between a matrix predominantlyconsisting of other crystal formations, (mixed minerals) or glass. Furthermore devitrified fibres are more easilyremoved from the lungs due to faster breakage and clearance.
What about exposure?
Regulation does not differentiate between biologically available (free freshly cleaved) and embedded crystallinesilica. Regulation applies therefore as long as respirable crystalline silica is present in the dust.
In order to address this question the CARE programme occupational hygienists took samples in after-serviceoperations in order to evaluate crystalline silica concentrations in addition to fibre concentrations. The tablebelow (Table 12) summarises these findings of about 190 samples analysed for quartz, cristobalite andtridymite, 3 polymorph forms of crystalline silica.
• 3 measurements gave concentrations above the limit value• Source of quartz may not be coming from fibres • Excluding quartz samples over-passing the limit value one measurement remains above the limit value out of
190 samples.
Total number Number of Average Most stringent Number of % of TWA
of samples samples over the concentration limit value mg/m3 samples over the
detection limit of samples over above the limit limit value
the detection
limit mg/m3
Quartz 191 26 0.023 0.10 2 1.05
Cristobalite 187 6 0.041 0.05 1 0.53
Tridymite 163 2 0.03 0.05 0 0.00
Table 12
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 57
page 56
80%
85%
90%
95%
100%
Quartz
% o
f sam
ples
Cristobalite Tridymite
Number of samples above occupational exposure limit
Number of samples over the analytical detection limit
Number of samples below the analytical detection limit
Conclusion
IARC evaluation indicates clearly that not all occupational exposure situations or forms of CS are carcinogenic.
Animal data indicate clearly that after-service RCF do not show additional toxicity due to CS. Similarly after-service AES wools have been tested in vitro and do no show any toxicity linked with the presence of CS.Biosolubility of after-service AES is not reduced compared to as sold products and CARE data show clearlythat crystalline silica is rarely present in respirable dust from removal operations.
Crystalline silica is rarely present in dusts. It is therefore unlikely that CS levels reach levels where specificprecautions measures need to be taken. If the fibre limit value is complied to then no further measures inconnection with CS exposure are required.
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 58
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 59
3 rue du Colonel Moll, 75017 Paris, France.
Tel: +33 (0) 631 487426Email: [email protected]
Unifrax Health & Safety 2008 NEW 12/10/09 15:29 Page 60