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Pagina IUNI EN 12779:2005

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UNIEnte Nazionale Italianodi Unificazione

Via Battistotti Sassi, 11B20133 Milano, Italia

UNI EN 12779

LUGLIO 2005

Sicurezza delle macchine per la lavorazione del legno

Sistemi fissi d’estrazione di trucioli e di polveri

Prestazioni correlate alla sicurezza e requisiti di sicurezza

Safety of woodworking machines

Chip and dust extraction systems with fixed installation

Safety related performances and safety requirements

La norma specifica i requisiti delle prestazioni correlate alla sicu-rezza e specifica i metodi per l’eliminazione dei pericoli o le misureche devono essere adottate per limitare i pericoli dei sistemi fissi diestrazione di trucioli e polveri, connessi alle macchine per la lavo-razione del legno, progettate per tagliare legno massiccio, pannellidi particelle, pannelli di fibra o legno compensato ed anche questi

materiali ricoperti con laminati plastici o bordi.

TTT EEE SSS TTT OOO III NNN GGG LLL EEE SSS EEE

La presente norma è la versione ufficiale in lingua inglese della

norma europea EN 12779 (edizione dicembre 2004).

ICS 79.120.10

Documento con tenuto ne l p rodo t to UNI 626 ed iz ione 2006 .

E ' v ie ta to l ' uso in re te de l s ingo lo documento e la sua r ip roduz ione . E ' au to r i zza ta la s tampa per uso in te rno .

© UNI Pagina IIUNI EN 12779:2005

Le norme UNI sono elaborate cercando di tenere conto dei punti di vista di tutte le partiinteressate e di conciliare ogni aspetto conflittuale, per rappresentare il reale statodell’arte della materia ed il necessario grado di consenso.Chiunque ritenesse, a seguito dell’applicazione di questa norma, di poter fornire sug-gerimenti per un suo miglioramento o per un suo adeguamento ad uno stato dell’artein evoluzione è pregato di inviare i propri contributi all’UNI, Ente Nazionale Italiano diUnificazione, che li terrà in considerazione per l’eventuale revisione della norma stessa.

Le norme UNI sono revisionate, quando necessario, con la pubblicazione di nuove edizioni odi aggiornamenti. È importante pertanto che gli utilizzatori delle stesse si accertino di essere in possessodell’ultima edizione e degli eventuali aggiornamenti. Si invitano inoltre gli utilizzatori a verificare l’esistenza di norme UNI corrispondenti allenorme EN o ISO ove citate nei riferimenti normativi.

PREMESSA NAZIONALE

La presente norma costituisce il recepimento, in lingua inglese, del-la norma europea EN 12779 (edizione dicembre 2004), che assumecosì lo status di norma nazionale italiana.

La presente norma è stata elaborata sotto la competenza dellaCommissione Tecnica UNI

Sicurezza

La presente norma è stata ratificata dal Presidente dell’UNI, condelibera del 9 maggio 2005.



EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 12779

December 2004

ICS 79.120.10

English version

Safety of woodworking machines - Chip and dust extractionsystems with fixed installation - Safety related performances and

safety requirements

Machines pour le travail du bois - Installations fixesd'extraction de copeaux et de poussières - Performances

relatives à la sécurité et prescriptions de sécurité

Sicherheit von Holzbearbeitungsmaschinen - OrtsfesteAbsauganlagen für Holzstaub und Späne -

Sicherheitstechniche Anforderungen und Leistungen

This European Standard was approved by CEN on 20 October 2004.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.

CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATIONC O M I T É E U R O P É E N D E N O R M A LI S A T I O NEUR OP ÄIS C HES KOM ITEE FÜR NOR M UNG

Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2004 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.

Ref. No. EN 12779:2004: E



EN 12779:2004 (E)

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Contents

page

Foreword..............................................................................................................................................................4 Introduction .........................................................................................................................................................5 1 Scope ......................................................................................................................................................6 2 Normative references ............................................................................................................................7 3 Terms, definitions, terminology and symbols ....................................................................................9 3.1 Terms and definitions ...........................................................................................................................9 3.2 Terminology .........................................................................................................................................12 3.3 Symbols and units ...............................................................................................................................12 4 List of significant hazards ..................................................................................................................13 5 Safety requirements and/or measures ..............................................................................................14 5.1 General..................................................................................................................................................14 5.2 Controls ................................................................................................................................................14 5.2.1 General..................................................................................................................................................14 5.2.2 Safety and reliability of control systems...........................................................................................15 5.2.3 Position of and other requirements to controls ...............................................................................16 5.2.4 Mode selection .....................................................................................................................................17 5.2.5 Speed changing ...................................................................................................................................17 5.2.6 Failure of the power supply ................................................................................................................18 5.2.7 Failure of control circuits....................................................................................................................18 5.3 Protection against mechanical hazards ............................................................................................18 5.3.1 Stability of supports ............................................................................................................................18 5.3.2 Risk of break up during operation .....................................................................................................18 5.3.3 Tool holder and tool design................................................................................................................18 5.3.4 Braking systems ..................................................................................................................................18 5.3.5 Ejection .................................................................................................................................................18 5.3.6 Work-piece support and guides .........................................................................................................19 5.3.7 Prevention of access to moving parts...............................................................................................19 5.3.8 Automation and mechanisation .........................................................................................................19 5.3.9 Clamping devices ................................................................................................................................19 5.3.10 Multi-station machines........................................................................................................................19 5.3.11 Safety appliances.................................................................................................................................19 5.4 Protection against non-mechanical hazards ....................................................................................19 5.4.1 Fire and explosion ...............................................................................................................................19 5.4.2 Noise .....................................................................................................................................................33 5.4.3 Emission of chips, dust and gases....................................................................................................36 5.5 Electricity..............................................................................................................................................42 5.6 Ergonomics and handling...................................................................................................................42 5.6.1 Electrical controls................................................................................................................................42 5.6.2 Mechanical controls ............................................................................................................................42 5.7 Lighting.................................................................................................................................................42 5.8 Pneumatics...........................................................................................................................................42 5.9 Hydraulics.............................................................................................................................................42 5.10 Vibration ...............................................................................................................................................43 5.11 Laser .....................................................................................................................................................43 5.12 Static electricity ...................................................................................................................................43 5.13 Errors of fitting.....................................................................................................................................43 5.14 Isolation ................................................................................................................................................43



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5.15 Maintenance.........................................................................................................................................44 6 Information for use..............................................................................................................................44 6.1 General .................................................................................................................................................44 6.2 Warning ................................................................................................................................................44 6.2.1 Warning devices ..................................................................................................................................44 6.2.2 Warning signs......................................................................................................................................44 6.3 Marking.................................................................................................................................................45 6.4 Instruction handbook..........................................................................................................................45 6.4.1 General .................................................................................................................................................45 6.4.2 Performance.........................................................................................................................................46 6.4.3 Explosion protection and safety systems ........................................................................................46 6.4.4 Information for use..............................................................................................................................47 6.4.5 Maintenance practice ..........................................................................................................................47 6.4.6 Noise declaration.................................................................................................................................48 Annex A (informative) Table with corresponding terms in English, French and German......................49 Annex B (informative) Relationship between airflow, vacuum, air velocity and power

consumption ........................................................................................................................................53 Annex C (informative) Verification of performance measurement.............................................................56 Annex D (normative) Noise reduction at the design stage ........................................................................58 Annex E (informative) Air velocity and extraction hood design................................................................60 Annex ZA (informative) Clauses of this document addressing essential requirements or other

provisions of EU Directives................................................................................................................62 Bibliography......................................................................................................................................................63



EN 12779:2004 (E)

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Foreword

This document (EN 12779:2004) has been prepared by Technical Committee CEN/TC 142 “Woodworking machines - Safety”, the secretariat of which is held by BSI.

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 2005 and conflicting national standards shall be withdrawn at the latest by June 2005.

This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s).

For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this document.

The European Standards produced by CEN/TC 142 are particular to woodworking machines and compliment the relevant “A” and “B” standards on the subject of general safety (see introduction of EN ISO 12100-1:2003 for a description of A, B and C standards).

This standard for Chip and dust extraction systems with fixed installation will be followed by a separate standard for Semi-stationary chip and dust extraction machines.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.



EN 12779:2004 (E)

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Introduction

This standard has been prepared to be a harmonized standard to provide one means of conforming to the Essential Health and Safety Requirements of the Machinery Directive and associated EFTA Regulations. This document is a type “C” standard as defined in EN ISO 12100-1:2003.

The machinery concerned and the extent to which hazards, hazardous situations and events covered are indicated in the scope of this document.

When provisions of this type C standard are different from those, which are stated in type A or B standards, the provisions of this type C standard take precedence over the provisions of other standards, for machines that have been designed and built in accordance with the provisions of this type C standard.

The requirements of this document are directed to manufacturers and their authorised representatives of chip and dust extraction systems. It is also useful for designers.

This document also includes information, which can be provided by the manufacturer to the user.



EN 12779:2004 (E)

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1 Scope

This document sets out the safety related performance requirements and specifies the methods for elimination of hazards or the measures that shall be taken to minimise hazards, which cannot be eliminated, on chip and dust extraction systems with fixed installation as defined in 3.1.1 and 3.1.2, for the purpose of this standard, hereinafter referred to as extraction system, connected to woodworking machines, designed to process solid wood, chipboard, fibreboard, plywood and also these materials where these are covered with plastic laminate or edgings. The extraction and conveying system operates pneumatically by vacuum and/or pressure between ± 0,3 bar.

This standard does not:

a) apply to fixed installations with an air flow capacity below 6 000 m3h-1 installed indoors;

b) apply to moveable units with an air flow capacity below 6 000 m3h-1;

c) apply to extraction equipment (e.g. extraction hoods, ducts) within a woodworking machine i.e. up to and including the outlet to which the extraction system is coupled;

d) apply to extraction systems connected to machines processing non-wood materials, such as plastic, plastic laminates, metals, glass or stone;

e) deal with the hazards from contact with or inhalation of dusts from wood coated with lacquer, plastic, aluminium and material with high additive contents or similar;

f) deal with shop fresh air supply;

g) apply to chip and dust extraction systems designed for Kst values above 200 bar ms-1;

h) apply to the silo discharge system;

i) cover the hazards related to Electromagnetic Compatibility (EMC) as required by the EMC Directive 89/336/EEC dated 3-5-89.

This document deals with the interaction with the silo discharge system if any.

This document covers the hazards relevant to these machines as stated in Clause 4. document

Directive 94/9/EC concerning equipment and protective systems intended for use in potentially explosive atmospheres can be applicable to the type of machine or equipment covered by this document.

The present standard is not intended to provide means of complying with the Essential Health and Safety Requirements (EHSR) of Directive 94/9/EC.



EN 12779:2004 (E)

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2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

EN 294:1992, Safety of machinery - Safety distances to prevent danger zones being reached by the upper limbs

EN 418:1992, Safety of machinery - Emergency stop equipment, functional aspects - Principles for design

EN 953:1997, Safety of machinery - Guards - General requirements for the design and construction of fixed and movable guards

EN 954-1:1996, Safety of machinery - Safety related parts of control systems - Part 1: General principles for design

EN 982:1996, Safety of machinery - Safety requirements for fluid power systems and their components –Hydraulics

EN 983:1996, Safety of machinery - Safety requirements for fluid power systems and their components – Pneumatics

EN 1127-1:1997, Explosive atmospheres - Explosion prevention and protection - Part 1: Basic concepts and methodology

EN 1366-1:1999, Fire resistance tests on service installations - Part 1: Ducts

EN 1366-2:1999, Fire resistance tests for service installations - Part 2: Fire dampers

EN 13284-1:2001, Stationary source emissions - Determination of low range mass concentration of dust - Part 1: Manual gravimetric method

EN 60204-1:1997, Safety of machinery - Electrical equipment of machines - Part 1: General requirements (IEC 60204-1:1997)

EN 60529:1991, Degrees of protection provided by enclosures (IP Code) (IEC 60529:1989)

EN 60947-4-1:2001, Low-voltage switchgear and controlgear - Part 4-1: Contactors and motor-starters - Electromechanical contactors and motor-starters (IEC 60947-4-1:2000).

EN 60947-5-1:2004, Low-voltage switchgear and controlgear - Part 5-1: Control circuit devices and switching elements - Electromechanical control circuit devices (IEC 60947-5-1:2003).

EN ISO 11202:1995, Acoustics - Noise emitted by machinery and equipment - Measurement of emission sound pressure levels at a work station and at other specified positions - Survey method in situ (ISO 11202:1995)

EN ISO 11688-1:1998, Acoustics - Recommended practice for the design of low-noise machinery and equipment - Part 1: Planning (ISO/TR 11688-1:1995)

EN ISO 12100-1:2003, Safety of machinery - Basic concepts, general principles for design - Part 1: Basic terminology and methodology (ISO 12100-1:2003)

EN ISO 12100-2:2003, Safety of machinery - Basic concepts, general principles for design - Part 2: Technical principles and specifications (ISO 12100-2:2003)

EN ISO 14122-2:2001, Safety of machinery - Safety means of permanent access to machinery - Part 2: Working platforms and gangways (ISO 14122-2:2001)

EN ISO 14122-3:2001, Safety of machinery - Permanent means of access to machinery - Part 3: Stairs, stepladders and guard rails (ISO 14122-3:2001)



EN 12779:2004 (E)

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EN ISO 14122-4:2004, Safety of machinery - Permanent means of access to machinery - Part 4: Fixed ladders (ISO 14122-4:2004)

ISO 7000:2004, Graphical symbols for use on equipment - Index and synopsis

ISO 10816-1:1995, Mechanical vibration - Evaluation of machine vibration by measurements on non-rotating parts - Part 1: General guidelines

HD 22.1 S4:2002, Cables of rated voltages up to and including 450/750 V and having cross-linked insulation - Part 1: General requirements.



EN 12779:2004 (E)

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3 Terms, definitions, terminology and symbols

3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in EN ISO 12100-1:2003 and the following apply.

3.1.1 chip and dust extraction system wood waste handling system including ducting, fans, filters, cyclones and storage facilities, including silo except its discharge system. The system is intended for conveyance, separation and storage of chips and dust from woodworking machines.

A typical example of an extraction system with fixed installation is illustrated as the shaded part of Figure 1

Figure 1 — Chip and dust extraction system



EN 12779:2004 (E)

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3.1.2 fixed installation extraction system which is permanently located and installed, or a moveable extraction system with air flow capacity greater than 6 000 m3h-1

3.1.3 chips particles of wood emanating from processing at woodworking machines. The particle size for chips is set to equal or greater than 0,5 mm

3.1.4 dust particles of wood emanating from processing at woodworking machines. The particle size for dust is set to less than 0,5 mm

3.1.5 ducting pipe-work, connecting woodworking machines to the fans and separators

3.1.6 main duct duct to which branch ducts from a group of machines are connected

3.1.7 fan component which produces the airflow for conveying chips and dust within the system

3.1.8 separator device for separation of chips and dust from the conveying air

NOTE Filters and cyclones are examples of separators.

3.1.9 silo fixed installed equipment for storage of chips and dust

3.1.10 bin movable equipment with a volume up to 0,5 m3 for storage of chips and dust

3.1.11 container movable equipment with a volume over 0,5 m3 for storage of chips and dust

3.1.12 silo discharge system system which continually or intermittently empties chips and dust from silo/container

3.1.13 emptying system system which continually or intermittently removes chips and dust from the separator

3.1.14 transport system system to convey chips and dust from one or more separator or silo to other parts of the extraction system



EN 12779:2004 (E)

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3.1.15 extraction vacuum static vacuum in a duct connecting point of a pneumatic extraction system

3.1.16 air velocity average velocity of the air inside a duct, calculated over the whole cross section and which allows the determination of the air flow rate (see Figure 2)

3.1.17 capture velocity minimum air velocity that will draw the chips and dust towards the extraction hood (see Figure 2)

1 2

Key 1 Air velocity 2 Capture velocity

Figure 2 — Air velocities

3.1.18 concurrency factor ratio in percent between the actual planned maximum air flow and the total air flow demand of all machines connected to the extraction system

3.1.19 Kst value explosive characteristic of combustible dust in air

NOTE Kst values are detailed in EN 26184-1.

3.1.20 dust loaded part dust loaded interior of the extraction system including ducting, silo, container, bin, separator etc. from the duct inlet connected to the wood working machine to the filter medium surface, where the air filtration is performed

3.1.21 clean air part interior of the extraction system from the filter medium surface, where the air filtration is performed, to the air outlet

3.1.22 return air filtered air reintroduced into the working area



EN 12779:2004 (E)

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3.1.23 servicing level level on which persons stand when operating or maintaining the equipment

3.2 Terminology

List of corresponding terms in English, French and German is included in Annex A.

3.3 Symbols and units

Following symbols and units are used in this document:

Parameter Symbol Unit Diameter D mm Length L m Area S m2 Volume V m3 Air velocity v ms-1 Air flow Qa m3h-1 Pressure p Pa Pressure differential Δp Pa Temperature t 0C Power P kW Material flow Qm kgh-1

Kst value Kst bar ms-1 Fan efficiency η %



EN 12779:2004 (E)

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4 List of significant hazards

This standard deals with all the significant hazards relevant to the extraction system defined in the scope:

⎯ for significant hazards, by defining safety requirements and/or measures or by reference to relevant B standards;

⎯ for general, minor or secondary aspects, by reference to relevant A standards, especially EN ISO 12100-1.

These hazards are listed below in accordance with Annex A of EN 1050:1996 which is based on EN ISO 12100-1:2003 and EN ISO 12100-2:2003 with one additional item (7.4).

Table 1 — List of significant hazards Number Hazard Relevant sub-clauses of this

document 1 Mechanical hazards caused for example by:

- shape; - relative location; - mass and stability (potential energy of elements); - mass and velocity (kinetic energy of elements); - inadequacy of the mechanical strength. Accumulation of potential energy by: - elastic elements (springs); or - liquids or gases under pressure; or - vacuum. of the machine parts or workpieces.

1.1 Crushing hazard 5.4.1.7; 5.3.7 1.2 Shearing hazard 5.4.1.7; 5.3.7 1.3 Cutting or severing hazard 5.4.1.7; 5.3.7 1.4 Entanglement hazard 5.4.1.7; 5.3.7 1.10 Ejection of parts (of machinery and processed

materials/workpieces) 5.3.2

1.11 Loss of stability of machinery and machine parts 5.3.1; 5.10 1.12 Slip, trip and fall hazards in relationship with machinery

(because of their mechanical nature) 5.4.1.7; 5.6.2

2 Electrical hazards caused for example by: 2.1 Electrical contact (direct or indirect) 5.2.2; 5.5 2.2 Electrostatic phenomena 5.4.1.4; 5.12 3 Thermal hazards resulting in: 3.1 Burns and scalds, by a possible contact of persons, by

flames or explosion and also by the radiation of heat sources

5.4.1

4 Hazards generated by noise resulting in: 4.1 Hearing losses (deafness), or other physiological

disorders (e.g. loss of balance, loss of awareness) 5.4.2; 6.4.6



EN 12779:2004 (E)

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Table 1 — List of significant hazards (continued)

Number Hazard Relevant sub-clauses of this document

7

Hazards generated by materials and substances processed, used or exhausted by machinery for example:

7.1 Hazards resulting from contact with or inhalation of harmful fluids, gases, mists, fumes and dust

5.4.3

7.2 Fire or explosion hazard 5.4.1 7.4 Suffocation and drowning 5.4.1.7 8 Hazards generated by neglecting ergonomic principles in

machine design (mismatch of machinery with human characteristics and abilities) caused for example by :

8.3 Neglect of use of personal protection equipment 6.4.5 8.6 Human error 5.15; 6.4 10 Hazards caused by failure of energy supply breaking

down of machinery parts and other functional disorders, for example:

10.1 Failure of energy supply (of energy and/or control circuits) 5.2.5; 5.8 10.2 Unexpected ejection of machine parts or fluids 5.3.2 10.3 Failure, malfunction of control systems (unexpected start

up, unexpected overrun) 5.2.2

10.4 Errors of fitting 5.4.3.2.1 10.5 Overturn, unexpected loss of machine stability 5.3.1; 5.10 11 Hazards caused by (temporary) missing and/or incorrectly

positioned safety related measures/means for example:

11.1 All kinds of guard 5.3.7; 5.4.1.7 11.2 All kinds of safety related (protection) devices 5.2.2 11.3 Starting and stopping devices 5.2.3; 5.6.2 11.4 Safety signs and signals 5.4.3.1.2; 6.2; 6.3 11.5 All kinds of information and warning devices 6.2 11.6 Energy supply disconnection devices 5.2.2; 5.2.3; 5.14 11.7 Emergency devices 5.2.2; 5.2.3.4 11.9 Essential equipment and accessories for safe adjusting

and/or maintaining 5.15; 6.4.5

5 Safety requirements and/or measures

5.1 General

The machine shall comply with the safety requirements and/or protective measures of this clause. In addition, the machine shall be designed in accordance with the principles of EN ISO 12100-1:2003 for hazards relevant but not significant, which are not dealt with by this document (e.g. sharp edges).

For guidance in connection with risk reduction by design, see Clause 4 of EN ISO 12100-2:2003 and for safeguarding measures see Clause 5 of EN ISO 12100-2:2003.

5.2 Controls

5.2.1 General

For the purpose of this standard all electrical equipment shall comply with the requirements of EN 60204-1:1997, and in addition:



EN 12779:2004 (E)

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5.2.2 Safety and reliability of control systems

For the purpose of this standard a safety related control system means the system controlling the extraction system from and including automatic blast gate(s) with detector(s) in the feeding system to the connected woodworking machine(s) if any are present, to the silo filling system including the final level switch in the silo.

The safety related control systems of this machine are those for:

⎯ emergency stopping (see 5.2.3.4); ⎯ interlocking (see 5.3.7 and 5.4.1.7); ⎯ fire detection (see 5.4.1.5); ⎯ starting (see 5.2.3.2); ⎯ normal stopping (see 5.2.3.3); ⎯ sequence interlocking (see 5.2.3.2, 5.2.3.3 and 5.2.3.4); ⎯ indication of extraction vacuum (see 5.4.3.1.2); ⎯ return air monitoring (see 5.4.3.2.2); ⎯ detection of pressure difference in separators (5.4.3.1.2); ⎯ detection of the emptying system function; ⎯ detection of silo/container filling.

The control systems for emergency stopping and for interlocking shall as minimum be Category 1 in accordance with the requirements of EN 954-1:1996 and shall be “hardwired”.

The other control systems can be equipped with an electronic system.

Well-tried components and principles for the purpose of this standard are:

a) electrical components if they comply with relevant standards including the following as:

1) EN 60947-5-1:2004 (Section 3) for control switches with positive opening operation used as mechanically actuated position detectors for interlocking of guards and for relays used in auxiliary circuits;

2) EN 60947-4-1:2001 for electromechanical contactors and motor starters used in main circuits;

3) HD 22.1 S4:2002 for rubber insulated cables;

4) HD 21.1 S4:2002 for polyvinyl chloride cable if these cables are additionally protected against mechanical damage by positioning (e.g. inside frames).

b) electrical principles if they comply with measures listed from first to fourth paragraph in 9.4.2.1of EN 60204-1:1997. The circuits shall be "hardwired“. Electronic components alone do not satisfy the “well-tried" requirements;

c) mechanical components if, for example, they operate in the positive mode in accordance with the description given in 4.5 of EN ISO 12100-2:2003;

d) mechanically actuated position detectors for guards if they are actuated in positive mode and their arrangement/fastening and the cam design/mounting comply with the requirements of 5.2 and 5.3 of EN 1088:1995;

e) interlocking devices with guard locking if they satisfy the requirements described in 5.3.7;

f) pneumatic and hydraulic components and systems if they comply with the requirements of EN 983:1996 and EN 982:1996 respectively;

g) detectors and indicators if they comply with the requirements of Category B of EN 954-1:1996;

h) time delay relays if they comply with the requirements of Category B of EN 954-1:1996 and are designed for 1 million operations.

The control systems including detectors, indicators and time delay relays (5.2.2 g) and 5.2.2 h)) shall as a minimum be of Category B in accordance with the requirements of EN 954-1:1996.

For the purpose of this standard Programmable Logic Controllers (PLC) are considered as Category B.



EN 12779:2004 (E)

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Verification : By visual inspection of the extraction system and by checking the relevant drawings and/or circuit diagrams. For any components by requiring confirmation from the manufacturer of the component which conforms to the relevant standards.

5.2.3 Position of and other requirements to controls

5.2.3.1 General

All electrical controls shall be placed at a minimum height of 600 mm and a maximum height of 1 800 mm from the servicing level.

(For the position of emergency stop controls see 5.2.3.4).

Verification: By visual inspection and measurement on the extraction system.

5.2.3.2 Starting

The starting conditions shall comply with the requirements in 9.2.5.2 of EN 60204-1:1997 (also see 6.4.4).

For extraction systems with an automatic emptying system, the starting sequence shall ensure that the emptying system is running prior to starting the extraction system.

NOTE For example the transport system between a filter and silo shall run normally before the extraction system connected to the woodworking machine is started.

After the emergency stop has been activated and reset, the extraction system shall perform a sequence that brings it to a point where a normal start up can be performed.

Verification: By visual inspection, checking the relevant diagrams and functional testing on the extraction system.

5.2.3.3 Normal stopping

The extraction system shall be fitted with a system stop control which, when actuated, shall provide a shut-down of all components in a predetermined sequence as defined by the manufacturer (see 6.4.4).

NOTE An example of a predetermined sequence is when the filter regeneration system has stopped, the filter emptying system shall continue until it has cleaned itself.

Any individual component stop control shall at least stop all components of the extraction system prior to the individual component in the correct sequence of operation.


5.2.3.4 Emergency stop

The emergency stop function shall be of Category 1 in accordance with the requirements of EN 60204-1:1997.

Emergency stop devices shall meet the requirements of EN 418:1992 and 9.2.5.4 and 10.7 of EN 60204-1:1997 and shall be provided as follows:

a) on the control panel where the normal electrical controls are situated;

b) a maximum of 50 m from all electrically connected parts of the extraction system;

c) a minimum of one emergency stop in each room with electrical parts or mechanical driven parts connected to the extraction system;

d) be directly accessible from any frequently used moveable interlocked guard (see 5.3.7) and if necessary any other point of access.

Examples of emergency stop location are shown in Figure 3.



EN 12779:2004 (E)

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A recommendation that the extraction system is re-started, as soon as the emergency situation has been cleared, shall be included in the instruction handbook (see 6.4.4 and 5.2.3.2).


50m

1

2

Key 1 Electrical 2 Control panel

Figure 3 — Examples of emergency stop control location

5.2.4 Mode selection

If a mode selection switch is provided (e.g. for selecting between normal mode of operation and setting mode of operation for silo’s equipped with an automatic silo discharge system (see 5.4.1.7 m)) it shall be of the lockable type.

5.2.5 Speed changing

Not relevant.



EN 12779:2004 (E)

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5.2.6 Failure of the power supply

Automatic re-starting of the extraction system shall be prevented (see 7.5 paragraphs 1 and 3 of EN 60204-1:1997).

When actuating the start control after failure of the power supply, the extraction system shall, before entering the normal starting sequence, perform a sequence in accordance with the requirements of 5.2.3.2 that brings the system into a position where a normal start up can be performed.


5.2.7 Failure of control circuits

See 5.2.2.

5.3 Protection against mechanical hazards

5.3.1 Stability of supports

All parts of the extraction system support structure shall be designed so that they can carry, at the same time, the weight of the component itself (e.g. duct, fan, separator or rotary valve) and any foreseeable additional load (e.g. the weight of unintended wood waste filled component interior (150 kgm-3), maintenance persons (100 kg per person), scaffoldings, reactions from internal movements, wind load, snow etc.)

Support structures for components with explosion relief shall also be able to withstand reaction forces resulting from the explosion blast wave.

NOTE 1 CEN/TC 305/WG 3 standards can provide helpful information (see Bibliography).

Fan supports shall be able to withstand the unbalance requirements shown in 5.10.

NOTE 2 For more information see 5.2.6 of EN ISO 12100-2:2003.

Verification: By requiring confirmation from the manufacturer of the relevant components and by calculation based on measurements and/or technical specifications.

5.3.2 Risk of break up during operation

Fans and components (e.g. ducts, separators and rotary valves) adjacent to the fan outlet shall be designed taking into account the stresses they are subject to (see 4.3 of EN ISO 12100-2:2003).

Verification: By requiring confirmation from the manufacturer of the relevant components and by calculation based on measurements and/or technical specifications.

5.3.3 Tool holder and tool design

Not relevant.

5.3.4 Braking systems

Not relevant.

5.3.5 Ejection

Not relevant.



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5.3.6 Work-piece support and guides

Not relevant.

5.3.7 Prevention of access to moving parts

Powered moving elements (e.g. fan wheels, chain conveyors, rotary valves, screw conveyors and automatic blast gates) of the extraction system shall be guarded with a fixed guard.

Where an opening is provided for frequent access (e.g. for setting, adjustment or cleaning) such openings shall be via a moveable guard interlocked with the dangerous movement of the extraction system. For the purpose of this standard frequent is more than once per week.

Any moving component (e.g. fans and rotary valves) with a run down time greater than 10 s and guarded by an interlocking guard shall also have guard locking.

Guards shall comply with the requirements of EN 953:1997 and the safety distances in EN 294:1992.

Verification: By visual inspection of the extraction system, measurement and checking the relevant drawings.

5.3.8 Automation and mechanisation

Not relevant.

5.3.9 Clamping devices

Not relevant.

5.3.10 Multi-station machines

Not relevant

5.3.11 Safety appliances

Not relevant.

5.4 Protection against non-mechanical hazards

5.4.1 Fire and explosion

5.4.1.1 General

Extraction systems shall be located and be constructed such that sources of ignition, fire and explosion are removed and risks caused by fire and explosion are minimised.

Extraction systems connected to woodworking machines processing only wood shall be designed with a Kst value of 200 bar ms-1.

If the extraction system is connected to woodworking machines processing wood combined with non-wood material (e.g. lacquer, laminate and aluminium) it is recommended to evaluate whether the Kst value is above 200 bar ms-1. If this is the case additional safety measures may be required (e.g. fire extinguishing devices, additional explosion relief, safety valves, added strength construction).

Verification: By checking the relevant drawings and visual inspection of the extraction system.

5.4.1.2 Location of separator, fan and silo

The separator, fan and wood waste accumulation system shall be located outdoors (outside the working areas) or in specially designed rooms/buildings.

The separator, fan and silo shall be located in a safe or non-hazardous area.



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Verification: By visual inspection of the extraction system.

5.4.1.3 Wood waste accumulation in ducts and separators

The conveying air velocity in all parts of the ducting shall be sufficient to avoid accumulation of wood waste in the ducts. The minimum conveying air velocity for dry wood waste shall be 20 m s-1 as an average on an hourly basis.

Inspection and cleaning of the ducting shall be made possible by means of inspection doors or easily detachable assemblies.

Examples of access methods for the inspection and cleaning of ducts are shown in Figure 4.

Figure 4 — Examples of duct access for inspection and cleaning

Ducts, branch ducts, inspection doors, dampers, blast-gates, fire-gates etc. in ducting conveying chips and dust shall be designed in such a way that all the chips always pass through without the risk of hanging.

If a mesh or a grate that can cause hanging is necessary in the extraction system, its function shall be controlled and a means for monitoring shall be provided (e.g. a pressure loss indicator window for visual inspection).

Separators shall be designed such that the material build-up within the filter housing is less than 200 l per 1 000 m3h-1 of air-flow-capacity.

NOTE 1 The 200 l/1 000 m3h-1 value is made up from 2 main elements:

a) surface build-up of waste on the filter sleeves;

b) build-up of waste in the filter hopper prior to release into the transport system.

NOTE 2 The cleaning cycle normally takes place before the build up on the filter surface is greater than 15 l/m2. This corresponds to an average thickness of 15 mm of material on the filter surface.



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Example of dust build-up is shown in Figure 5.

Verification: By visual inspection, calculations, measurements and functional testing on the extraction system.

1

15

Key 1 Dust build-up

Figure 5 — Example of chip and dust build-up in a reverse air cleaned filter



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5.4.1.4 Ignition sources

Components of the extraction system shall be designed in such a way that ignition sources are not generated by normal use and wear.

NOTE 1 Ignition sources cannot be eliminated due to the nature of the machines connected to the extraction systems. The risk of ignition sources will depend on the type of machine.

NOTE 2 For extraction systems including sanding machines, multi-blade saws etc. ignition detection and extinguishing devices are recommended (see Figure 6).

2

1

Key 1 Ignition detector 2 Extinguishing device

Figure 6 — Ignition extinguishing system

Hot surfaces shall be prevented (see 6.4.2 of EN 1127-1:1997).

NOTE 3 For wood, dust is defined in this standard as:

a) dust cloud minimum ignition temperature : 400 ºC;

b) dust layer minimum ignition temperature : 300 ºC.

Where, due to their function, parts made of steel, due to their function, operate under conditions where there is a risk of spark generation (e.g. through contact, sliding, meshing or rubbing), one of the parts shall be covered with copper or similar material in order to minimize the risk of sparks (e.g. fans positioned in the dust loaded part of the extraction system with less than a 20 mm gap between the inlet ducting and fan wheel (see Figure 7)).



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11

A

A

D+0 -

x

D1

+0 - x

20

2020

Key 1 Copper protection ring between two steel parts

Figure 7 — Fan spark protection

Extraction systems shall be earthed.

Support cages and support rings for filtering elements shall be earthed in order to lead any charge to ground potential.

Extraction system ductingshall be made of conductive material. In order to control discharge of static electricity the complete system shall have no potential difference between its individual parts.

Flexible hoses shall be able to lead charge to ground potential (see Figure 8).

Hose lengths greater than 0,5 m are only permitted when movement of the woodworking machine, to which the extraction system is connected makes it necessary.



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0,5

Figure 8 — Earthling of flexible hoses

Electrical components placed inside the system, in either the dust loaded or clean air sections, shall comply with the requirements for dust environments and explosion risk (see EN 1127-1:1997).

NOTE 4

a) Zone 20 : Dust loaded part of separator, transport system between separator and silo, and the silo;

b) Zone 21 : Duct system between the woodworking machine and separator;

c) Zone 22 : Clean air part.

Verification: By visual inspection, checking the relevant drawings, requiring confirmation from the manufacturer of the relevant components, and by measurement on the extraction system.

5.4.1.5 Damage control in the event of explosion/fire

Explosion protection of separators, silos and containers shall be in accordance with the requirements of 6.5.1.3 of EN 1127-1:1997.

The blast wave expelled from explosion relief elements shall vent to a safe place (e.g. outdoor atmosphere and away from work areas and gangways with open access).

The spread of any explosion through connecting ducts shall be obstructed.

NOTE 1 Examples of obstructing components are back pressure flaps, rotary valves and de-coupling devices.



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Also see 6.5.5.3 of EN 1127-1:1997.

Examples of components for damage control are shown in Figure 9.

2

15

43

1

2

Key 1 Explosion relief element 2 Explosion de-coupling element 3 Fire gate 4 Return air 5 Exhaust air

Figure 9 — Prevention of explosion transmission damage

The spread of fire through return air ducts shall be obstructed (e.g. by installing a fire gate with a temperature sensor which activates and stops the extraction system at temperatures exceeding 70 ºC).

The ducting from one fire zone shall either:

a) not pass through another; or

b) be equipped with fire gates of an appropriate class, suitable for material transporting ducts; or

c) be insulated in accordance with the requirements of EN 1366-1:1999 and EN 1366-2:1999, level in relation to the fire protecting wall in the subsequent fire zones.

The fire gate shall be of an appropriate class in relation to the fire protecting wall.



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An example of a section of ducting in a fire zone is shown in Figure 10.

21 4

3

1

3

Key 1 Fire gate 2 Fire protecting wall 3 Explosion de-coupling element 4 Insulation

Figure 10 — Section of ducting within a fire zone

NOTE 2 The position of the separator and the silo in relation to the buildings has a great impact on the risk of a fire spreading. The greater the separation distance the less the risk.

The type of building surface (e.g. burnable/non burnable, openings/no openings) also has a great impact on the risk of a fire spreading. Non burnable walls and roofs, without openings, are safest.

Verification: By visual inspection, checking the relevant drawings and requiring confirmation from the manufacturer of the relevant components.



EN 12779:2004 (E)

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5.4.1.6 Fire fighting

All filters and silos shall, as a minimum, have a dry sprinkler system installed with an attachment for coupling it to a water supply at level of 0,4 m to 0,8 m above ground and a minimum of 5 m away.

The sprinkler system(s) specification shall be defined by agreement between the extraction system manufacturer and the user.

The extraction system manufacturer shall specify the sprinkler system water consumption and water pressure (see 6.4).

Examples of dry sprinkler systems are shown in Figures 11 and 12.

Dimensions in metres

3

2

1

5m

0.4-0.8m

Key 1 Coupling for water supply 2 Nozzles 3 Hand valve

Figure 11 — Dry sprinkler system for a filter



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Dimensions in metres

2

1

5m

0.4-0.8m

Key 1 Water pipe 2 Nozzles

Figure 12 — Silo dry sprinkler system

Verification: By visual inspection of the extraction system and checking the relevant drawings.



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5.4.1.7 Silos

Safety requirements and/or measures are as follows:

a) the silo shall be free standing and positioned outdoors;

b) the bottom of the silo, on which the chips and dust are stored, shall be above ground level;

c) the cross-section of the silo shall either remain constant or decrease with height. The interior walls of silo shall be smooth and free from ledges, corners and projecting parts onto which the deposition of chips and dust could occur;

NOTE 1 Concrete surfaces and round screw-heads are acceptable.

d) the silo filling system and the opening for feeding the silo shall be designed in such a way that the chips an dust are distributed evenly in the silo;

e) the silo shall have openings for the manual discharge of chips and dust. The minimum size of such openings shall be 1,2 m wide and 2,0 m high. The openings shall be on the same level as the bottom of the silo (i.e. threshold maximum 100 mm and with sloping-bottom) see Figures 13 and 14;

5m

5m7m

50̊

6m

8m

4m

7m

Figure 13 — Position of silo openings (horizontal cross section)



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f) the number of openings required in the silo is as shown in Table 1. The required openings are to be placed in the front face of the silo and shall lead directly outdoors. If the dimensions of the silo measured in the direction of the discharge opening is greater than 6 meters, the same number of openings are required in the opposite face of the silo;

Examples for the arrangement of openings are shown in Figure 13.

Table 2 — Silo size and number of openings

Silo cross section Inside width/inside diameter Openings required

Square/rectangular up to 4,0 m 1 above 4,0 m up to 6,5 m 2 above 6,5 m up to 8,5 m 3 above 8,5 m 4 Round up to 5,0 m 1 above 5,0 m up to 7,5 m 2 above 7,5 m 4

g) where the filling height exceeds 6 m, apertures are required in the silo through which long poles for probing can be introduced in the same direction as the discharge openings. The apertures shall be placed directly above the discharge openings (see Figure 14) and at least 1 m above the standing surface. Where the filling height exceeds 9 m, additional apertures are required. The vertical distance between such apertures shall be a maximum of 6 m;

h) the size of the aperture required is related to the silo wall thickness. An aperture of 0,8 m × 0,8 m is recommended for concrete silos. A steel silo can have a smaller opening;



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1m

100

mm

2

3

54

1

Key 1 Opening for probing in the silo ceiling 2 Opening for probing in the silo wall 3 Discharge door 4 Maximum filling height 5 0,5 × D (minimum 3,5 m/maximum 6,0 m)

Figure 14 — Silo apertures

i) the discharge openings and probing apertures shall be equipped with lockable doors (e.g. by padlock), which open outwards (in the direction of discharge);

j) probing apertures shall be designed so that it is impossible for the operator to enter the silo through them (e.g. by its size or by installing bars) (also see EN 294:1992);

k) to reduce the material pressure on the doors and protect personnel when emptying the silo by hand, blinds shall be installed in the door openings. The blinds shall cover the full door opening and shall



EN 12779:2004 (E)

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consist of elements arranged in accordance with the requirements of Figure 15. A warning sign, clearly visible from the operators position, shall indicate the hazards related to emptying the silo by hand (see 6.2.2);

l) in front of the probing apertures and discharge doors which are located higher than 1 m above ground, working platforms shall be provided (see Figures 14 and 15). The platforms shall meet the requirements of EN ISO 14122-2:2001 and EN ISO 14122-3:2001;

m) platforms shall be easily accessible by means of stairs or stepladders in accordance with the requirements of EN ISO 14122-3:2001 with a warning at the entrance (see 6.2.2);

n) fixed ladders shall meet the requirements of EN ISO 14122-4.

Key 1 Door handle with padlock

Figure 15 — Silo opening details

o) where the silo is equipped with an automatic discharge system (e.g. a rotating screw conveyor) the access door(s) shall be interlocked with the automatic discharge system and the run-down time shall be less than 10 s;

p) for maintenance purposes it shall be possible to run the automatic discharge system with the door(s) in the open position. Therefore the automatic discharge system shall have a mode selection switch, situated on the control panel, for selecting either normal mode or setting mode. In setting mode any dangerous movement of the silo discharge system shall only be possible when the following requirements are met:

1) the movements shall be controlled by hold to run controls. An emergency stop shall be provided which can be actuated from the silo point of access;



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2) hold to run controls shall be located outside the silo, but the operator shall have an unrestricted view over the movements being initiated.

NOTE 2 Silo surface materials, distances etc. may be subject to national regulations.

Verification: By visual inspection, checking the relevant drawings and by measurement on the extraction system.

5.4.2 Noise

5.4.2.1 Noise reduction at the design stage

When designing chip and dust extraction systems the information and technical measures to control noise at source given in EN ISO 11688-1:1998 shall be taken into account.

NOTE The main noise sources and measures to reduce noise of chip and dust extraction systems are given in normative Annex D.

Verification: By visual inspection of the extraction system and checking the relevant drawings.

5.4.2.2 Noise emission measurement

5.4.2.2.1 General

Noise measurements shall be performed at the extraction system user’s premises for the following reasons:

a) extraction systems are large machines;

b) noise sources are distributed along the machine with long ducting arrangements often located at a high level;

c) noise sources are located in different places;

d) accurate noise measurement at the manufacturer’s premises is impossible as the site at which the extraction system is installed greatly influences the noise levels measured.

It shall be noted that noise levels measured in accordance with the following method are influenced by the configuration of the site at which the chip and dust extraction system is installed, by the type of chip and dust collection hood(s) used and the type of machine(s) attached to the extraction system.

5.4.2.2.2 Operating conditions

During the noise test the extraction system shall be operating with the air velocity and the static pressure/vacuum described in the extraction system specification. If more than one combination of the extraction system operating conditions are specified, a noise test shall be performed for the designed combinations with maximum airflow.

The noise measurements shall be performed on an extraction system installation with woodworking machines coupled to the extraction system at the appropriate places.

All woodworking machines shall be turned off during the noise measurements, i.e. the extraction system will be operating without chips and dust.

NOTE For the purpose of this standard only operation without chips and dust is prescribed. According to the guidelines for preparation of noise test codes operation with chips and dust should also have been included: however no suitable specification of the chips and dust content is available for this purpose.



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5.4.2.2.3 Background noise

Background noise is the noise emitted by all other noise sources other than the systemunder test. Woodworking machines and extraction hoods do not constitute part of the extraction system.

NOTE 1 Background noise may include various components (e.g. airborne, structure borne and instrumentation electrical noise).

The background noise level shall be measured at the positions defined in 5.4.2.2.5.

NOTE 2 As noise from extraction hoods will only be generated when the extraction system is operating, measurements of background noise will not include noise from extraction hoods.

In order to avoid background noise influencing the system measurement results, the A weighted background noise level shall preferably be at least 10 dB below the actual measurement results obtained when the extraction system is in operation.

If the difference between the A weighted sound pressure level measured when the extraction system is in operation and the background A weighted sound pressure level is less then 6 dB the measurement result is invalid. In this case the background noise shall be reduced in order that the specified measurements method can be applied.

In cases where the difference is between 6 dB and 10 dB the A weighted sound pressure level measured shall be corrected in accordance with the requirements of Clause 8 of EN ISO 11202:1995 in order to take account of background noise influence.

5.4.2.2.4 Influence from the acoustic environment

The noise emission level may be influenced by the acoustic properties of the environment in which the extraction system is installed. Information describing the actual environment (e.g. reverberation time, absorbing surfaces, screens) shall always be given.

NOTE For premises with acoustic correction in form of a sound absorbing ceiling, the noise emission level will be subject to an increase of approximately 3 dB to 5 dB compared to open field measurement. When the premises are not fitted with acoustic correction an increase of 5 dB to10 dB compared to free field conditions is to be expected.

5.4.2.2.5 Method

Measurements shall be performed for each of the following groups of components:

a) duct system;

b) blast gates/slide gates;

c) fans;

d) separators.

For each group of components, the maximum A weighted sound pressure level with S weighting shall be measured (see Figure 16).



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1.6

m

1.6

m

1.6

m

1m

1m

1m

1m2m

Figure 16 — Microphone position locations

The microphone positions shall be:

a) for components meeting the requirements of 5.4.2.2.5 a) and 5.4.2.2.5 b) at 1,6 m from ground under the axis of each duct line and minimum of 1 m from the component; and

b) for components meeting the requirements of 5.4.2.2.5 c) and 5.4.2.2.5 d) at 1,6 m from ground and at 1m from the reference surface enclosing the components.

The extraction hood does not constitute part of the extraction system and its influence on the measured sound pressure level shall be minimised by performing measurements at least 2 m away from the connected machine(s) (also see 5.4.2.2.3).

The instrumentation used shall be of Class 1 and shall further conform to the requirements given in Clause 5 of EN ISO 11202:1995.

In cases with fluctuating noise or periodic impulse noise, the time-averaged A-weighted sound pressure sound pressure level, LpAeq, shall be measured instead of the maximum A-weighted sound pressure level with S-weighting. In the latter case, the measurement shall be made over a period of at least 5 min, including at least one cycle (e.g. cleaning cycle). The number of cycles shall be declared. In addition, for cases with periodic impulse noise, the peak C-weighted sound pressure level, LpCpeak, shall be measured.

The measurement method consists of the following:

c) measure the maximum A-weighted sound pressure levels, LpAS, (or, if appropriate, the peak C-weighted sound pressure levels, LpCpeak, and the time-averaged A-weighted sound pressure levels, LpAeq) for each of the four groups of components shown in 5.4.2.2.5 when the extraction system is in operation under conditions given in 5.4.2.2.2;

d) measure the background noise level (A-weighted or C-weighted, as appropriate) when the extraction system is stopped, at the same measurement points;

e) correct the measured sound pressure level(s) when the extraction system is in operation for background noise, in accordance with the requirements of 5.4.2.2.3;

f) record and describe the acoustic environment at the test site;

g) report the corrected sound pressure levels in accordance with steps a) to d).



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5.4.2.2.6 Test report

Test report shall contain the following:

a) identification of the extraction system under test;

b) reference to this standard;

c) extraction system operating conditions used during the test;

d) measured noise values for each part of the system together with the location of the measurement positions;

e) correction values;

f) description of the acoustic environment.

Verification: By checking the test report.

5.4.3 Emission of chips, dust and gases

Emission of chips and dust resulting from wood processing is generated by the woodworking machine(s).

The extraction system controls the emission of chips and dust from the woodworking machines, extraction hoods etc. connected to it..

This standard covers the performance requirements of the extraction system based on specifications for the woodworking machines connected to it.

Emission of chips and dust from the extraction system is caused by leakage and incomplete filtration of return air.

NOTE 1 Emission caused by incomplete capturing of chips and dust by the woodworking machines, extraction hoods etc. is covered by the relevant machine standard.

Recommendations for the design of extraction hoods are given in Annex E.

NOTE 2 If gases are created in the working area they will be partially removed from the working area by the chips- and dust extraction system. However, these gases will not be filtered by the chip and dust separation process

NOTE 3 The ratio between the fresh air supply and return air may have to comply with local regulations on air exchange air quality.

5.4.3.1 Performance requirements

5.4.3.1.1 Plant design

The extraction system shall be designed taking account of:

a) the number and type of machines to be connected to it, their concurrency in use and the layout of the workshop or factory (information to be supplied by the user);

b) the machine manufacturer’s information or an experienced body’s information on required the required air flow and extraction vacuum for each extraction connection for each machine.

Examples of extraction system design calculation are given in Table 3.



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Table 3 — Example of extraction system design calculation

Air flow Combination A Combination B Machine type m3h-1 On/Off m3h-1 On/Off m3h-1

Moulder 10 000 On 10 000 Off 0 Saw 2 500 On 2 500 On 2 500

Band saw 3 200 Off 0 On 3 200 Planer 6 000 Off 0 On 6 000 Total 21 700 12 500 11 700

In the example shown in Table 3, the four machines can operate either in combination A or combination B. As 12 500 m3h-1 is larger than 11 700 m3h-1, the design air flow for the extraction system is then 12 500 m3h-1.

The plant design shall ensure that all machines operating under the specified working conditions will have as a minimum the indicated airflow and extraction vacuum. The specified performance shall be achieved after a running-in period and stabilization of the pressure difference at filter units etc. and must be verified through measurement in accordance with the requirements of 5.4.3.1.3.

An example of the relationship between airflow, extraction vacuum, air velocity and power consumption is shown in Annex B.

Verification: By checking the relevant drawings and by calculation based on measurements and/or technical specifications.

5.4.3.1.2 Performance indication

An indicator shall be provided at each main duct to demonstrate that the specified extraction requirement (e.g. vacuum) is achieved. It may be combined with a visual alarm activated when the actual performance is outside the preset area.

An example of the location of a performance indicator is shown in Figure 17.




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21

Key 1 Indicator 2 Alarm panel

Figure 17 — Performance indicator

5.4.3.1.3 Airflow measurement

Ducting shall be designed at each machine in such a way that airflow can be measured by a flow instrument (e.g. Pitot gauge)

NOTE An example of compliance with requirement is a duct, diameter D, with its linear part having a minimum length of 8 x D. A linear length of 5 x D is required before the measuring point and a linear length of 3 x D is required after the measuring point.

Example of ducting design with a measuring point is shown in Figure 18.



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5 x d

d

3 x d

Figure 18 — Example of duct measuring point location

Airflow and extraction vacuum shall be measured and reported in the documentation after the running-in period and stabilization of pressure difference at the filter units etc. (see 6.4.2.1).

An example of a test report is given in Annex C.

Airflow and extraction vacuum measurements shall be made at each connected machine outlet and for the planned combination of machines to be used concurrently.

Documentation of the measurements required in this clause shall be provided by the extraction system manufacturer.

Verification: By visual inspection of the extraction system and checking the test report.

5.4.3.2 Emission of dust

5.4.3.2.1 Leakage

Ducting placed inside the working area shall operate at pressures below atmospheric.

NOTE Leakage can be caused by defects in the components of the extraction system, inadequate mounting and/or assembly during installation, pressure and/or mechanical overload on components and/or assemblies, wear and/or corrosion defects, back-flow in the ducting during or after cleaning, inadequate maintenance (e.g. inaccurate detection and repair of wear and/or corrosion defects).

An example of a duct system with under pressure is shown in Figure 19.

Verification: By visual inspection, checking the relevant drawings and by measurement on the extraction system.



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1

2 3

Key 1 Duct with under pressure 2 Indoors 3 Outdoors

Figure 19 — Duct with under pressure inside the working area



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5.4.3.2.2 Residual dust in separator outlet/return air

When return air is used (depending on national regulations) the requirements of this clause shall be fulfilled.

The residual dust content in the return air shall be lower than 0,2 mgm-3 as a weighted average and all individual outlets shall have a dust content lower than 0,3 mgm-3.

NOTE 1 The requirement on dust concentration in return air is a system design figure. It is not to be seen as a limit value for the working place.

NOTE 2 Residual dust content in the outlet air from the separator in the extraction system (e.g. a filter) can arise from e.g. incomplete filtration of the air going through the filtration element, leakage in the filter housing and the fixation of the filter material.

Often the sources of residual dust cannot be separated.

From the extraction system commissioning date, the residual dust content concentration in the return air shall have achieved the values shown in this clause within 4 weeks.

NOTE 3 This is to allow the filter cake to develop to a stable level.

When the cleaned air is returned to the working area, the dust content in extraction systems with an air flow capacity larger than 10 000 m3h-1 shall be monitored continuously (e.g. by electrical dust alarm, air filter with pressure sensor, etc.).

When the residual dust content exceeds 0,3 mgm-3 the return air shall be diverted to the outdoor atmosphere and an alarm shall be given or the extraction system shall stop.

NOTE 4 The primary cause of dust content in the working area is the inability of the extraction hood to capture all the generated dust and the re-entrainment of dust from dust covered surfaces (e.g. floor, products, machine cleaning). One of the worst examples of dust re-entrainment is when cleaning is achieved by blowing with pressurised air (a vacuum cleaner should be used). The residual dust content in return air will only have a minor influence on the dust concentration in the working area.

The measurement of the residual dust content shall be made in accordance with the requirements of EN 13284-1:2001 and shall be carried out within 4 weeks of the commissioning date.

Operating conditions during the measurement shall be such that:

a) the air flow rate shall be at its maximum design level;

b) the dust load shall correspond to the production parameters for which the extraction system is designed;

c) the extraction system shall be operating with all features functioning as designed (e.g. cleaning system, emptying system).

The residual dust content in the extraction system outlets to the outdoor atmosphere is not covered by this standard.




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5.5 Electricity

The requirements in Clause 6 of EN 60204-1:1997 regarding the prevention of electric shock and Clause 7 of EN 60204-1:1997 for protection against short circuits and for protection against overloading shall apply.

The degree of protection of components situated in Zone 20, 21 or 22 (see 5.4.1.5) shall comply with the requirements of EN 1127-1:1997.

All other electrical components shall be of a minimum IP54 in accordance with the requirements of EN 60529:1991.

Verification: By checking the relevant diagrams and requiring confirmation from the manufacturer of the relevant components.

5.6 Ergonomics and handling

5.6.1 Electrical controls

See 5.2.3 and 5.2.3.2 to 5.2.3.4.

5.6.2 Mechanical controls

Mechanical controls activated more frequently than once per week (e.g. several times per month) shall be positioned at a maximum height of 1 800 mm from the servicing level.

Controls, dampers etc. which are to be rarely used (e.g. 4 times a year) shall be placed in positions where it is possible to establish access.

Also see 6.4.


5.7 Lighting

Not relevant.

5.8 Pneumatics

Pneumatic components of the extraction system shall meet the requirements of EN 983:1996.

Verification: By requiring confirmation from the manufacturer of the relevant components.

5.9 Hydraulics

Not relevant.



EN 12779:2004 (E)

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5.10 Vibration

Vibration can cause fatigue stress damage (e.g. on support structures).

Vibrating components of the extraction system shall be tested in accordance with the requirements of ISO 10816-1:1995 with measuring points in accordance with the requirements of 3.2 of ISO 10816-1:1995 (first section) and the test support structure in accordance with the requirements of 3.3.2 of ISO 10816-1:1995.

NOTE 1 The test can be carried out by the manufacturer.

The vibration velocity shall be declared and stated in the technical documentation for the component.

NOTE 2 Values for the vibration velocity for the fan depend on and are influenced by e.g. fan rotational speed, fan rest balance, support structure design, fan mass. Practical experience indicates that the vibration velocity can be expected to be between 5 mms-1 to 18 mms-1.

Foundation and fixation of vibrating components shall be designed in accordance with normal design practise and the calculations shall be based on the component weight and the vibration velocity normally expected.

NOTE 3 Flexible connections and supports with vibration dampers will normally lower vibration transmission.


5.11 Laser

Not relevant.

5.12 Static electricity

See 5.4.1.4.

5.13 Errors of fitting

Removable parts (e.g. fan, chain conveyor, rotary valves, screw conveyor, automatic blast gates) shall be designed such that that their assembly to or removal from the extraction system (e.g. maintenance and/or repair) does not lead to hazardous situations arising. Information regarding the removable parts shall be given (e.g. direction of movement or rotation).

5.14 Isolation

Electrical isolators shall be in accordance with the requirements of 5.3 of EN 60204-1:1997.

It shall be possible to isolate the pneumatic energy supply (e.g. a lockable valve). For means of isolation see EN 983:1996.

Where residual energy is stored (e.g. compressed air in a reservoir or pipe), a means for dumping residual pressure shall be provided (e.g. a valve).

Verification: By visual inspection, checking the relevant diagrams and requiring confirmation from the manufacturer of the relevant components.



EN 12779:2004 (E)

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5.15 Maintenance

The extraction system shall be equipped with inspection openings to allow the maintenance and inspection of all moving parts and the filter section (dust loaded and clean air parts) to be carried out safely in accordance with the requirements of 4.7 of EN ISO 12100-2:2003. The inspection openings can be positioned in an adjacent component if this is more convenient.

For openings in ducts and sections with a mesh or grate see 5.4.1.3.

For openings in silos see 5.4.1.7.

For requirements regarding the type of opening to be provided for access to moving parts see 5.3.7.

Any relevant information for maintenance shall be given by the manufacturerand the minimum information required is shown in 6.3.4.

Special maintenance tools shall be provided (e.g. probing sticks for silos and tension meters for belt drives).

Verification: By visual inspection of the extraction system, checking the relevant drawings, and checking the relevant clauses in the instruction handbook.

6 Information for use

6.1 General

See 6.3 of EN ISO 12100:2003.

6.2 Warning

6.2.1 Warning devices

The extraction system shall be provided with warning devices for activated fire gates (also see 5.4.3.1.2).

6.2.2 Warning signs

The following warnings shall be provided:

a) for the silo, filter and on explosion relief elements:

1) explosion hazard;

2) no sources of ignition allowed;

b) for blinds in silo door openings:

1) do not remove when under pressure;

c) at the platform entrance:

1) access for authorized personnel only;

d) on fan(s):

1) high noise level;

e) on guards:

1) "Moving parts".




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6.3 Marking

See 6.4 of EN ISO 12100-2:2003 and in addition the marking shall include the following:

a) name and address of the manufacturer;

b) designation of the series or type;

c) serial number;

d) year of construction.

On the silo, filter and explosion relief elements:

e) explosion hazard;

f) no sources of ignition allowed;

g) do not remove when under pressure (on blinds in silo door openings);

h) access for authorized personnel only (at platform entrance).

On fan(s):

i) high noise level (where applicable);

j) indication of the direction of rotation by an arrow.

On guards:

k) moving parts.

The marking shall be indicated in accordance with the requirements of ISO 7000:2004.


6.4 Instruction handbook

6.4.1 General

In addition to the requirements of 6.5 of EN ISO 121100-2:2003 the instruction handbook shall include the following:



EN 12779:2004 (E)

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6.4.2 Performance

6.4.2.1 Performance verification

The instruction handbook shall include recommendations for:

a) The frequency of performance verification;

b) performance measurements as shown in 5.4.3.1.1 and 5.4.3.1.3;

c) performance measurements after plant design modifications have been carried out;

d) recording of the measurements in 6.4.2.1 b) and c).

An example of the recording required is given in Annex C.

Verification : By checking the instruction handbook.

6.4.2.2 Performance documentation

The handbook shall include commissioning documentation as follows:

a) a drawing of the extraction system layout;

b) a list of the machines to be connected to the extraction system;

c) the required air flow and extraction vacuum for each machine;

d) a list of machines to be usedconcurrently;

e) the calculated maximum air flow for each duct section;

f) the measured air flow for each woodworking machine (see 5.4.3.1.3) at the extraction system maximum total air flow capacity. If concurrency factor is under 100 % measurements shall be performed for all significant combinations;

g) the indicator settings required in 5.4.3.1.2.

Verification: By checking the instruction handbook.

6.4.3 Explosion protection and safety systems

The instruction handbook shall include information on explosion related parameters and safety systems as follows:

a) the maximum Kst value;

b) the maximum surface temperature;

c) explosion relief systems;

d) explosion de-coupling systems;

e) ignition detection and extinguishing systems;

f) fire detection and fire fighting systems;

g) dry sprinkler water consumption rate and delivery pressure;

h) emergency shut down systems.




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6.4.4 Information for use

The instruction handbook shall include the following information:

a) a list of any residual risks (e.g. ignition sources);

b) any limitation on the material to be machined on the woodworking machines connected to the extraction system (see 5.4.1);

c) safe procedure for :

1) mode selection;

2) normal start and stop of system;

3) immediate re-start after an emergency situation.

d) nature and frequency of inspection tests;

e) residual dust content in the return air.

The instruction handbook shall contain information on the importance and frequency of performance measurement, dust concentration and function monitoring.


6.4.5 Maintenance practice

The manufacturer shall provide a maintenance scheme, which shall contain, as a minimum, the following information:

a) the nature and frequency of maintenance tasks to be carried out;

b) a list of maintenance operations to be carried out;

c) any training necessary for maintenance personnel;

d) a specification of maintenance operations which can be carried out by users (operators, etc.);

e) drawings and diagrams enabling maintenance personnel to carry out their task rationally;

f) a list of access openings for maintenance;

g) safe procedures for carrying out any maintenance work which involves particular risks (e.g. padlocking electrical main switch);

h) a procedure for fault finding;

i) a description of the safe working practices to be used during maintenance or system re-start after breakdown with special regard to the explosion/fire risks and unhealthy dust loads.

Information on the safe procedures for emptying the silo through the discharge door shall include information that:

j) all persons involved shall be instructed regarding the safety procedures including escape/rescue procedures and the use of special tools (see 5.15);

k) one person shall oversee/supervise the work;

l) suitable tools to be used shall be described, including personal protection equipment;

m) before work is started, the feed mechanism and the discharge system shall be shut down and unintentional start-up shall be prevented;

n) it is strictly forbidden to stand on piles of chips and dust.



EN 12779:2004 (E)

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6.4.6 Noise declaration

Noise emission levels shall be declared in the instruction handbook using the dual number form of declaration (see EN ISO 4871:1996) as follows:

a) maximum A-weighted sound pressure levels, LpAS, (or, if appropriate, the peak C-weighted sound pressure levels, LpCpeak, and the time-averaged A-weighted sound pressure levels, LpAeq) corrected for background noise;

b) associated measurement uncertainty (K).

K is the numeric value of the measurement uncertainty associated with the measured noise emission value.

Reference to the present standard and operating conditions for the extraction system used during noise measurement shall also be given.

NOTE 1 If the accuracy of the declared emission values is to be checked, the same method and the same operating conditions as those declared for measurement are to be used.

Example of declaration:

LpAS = measured value in accordance with EN 12779

Uncertainty K = 4 dB in accordance with EN 12779

NOTE 2 The sum of the measured noise emission value and its associated uncertainty represents an upper boundary of the range of values which is likely to occur in measurements performed in an environment with acoustical properties corresponding to the properties of the actual test site. When estimating the upper boundary for measurements performed in other environments the influence from the acoustic environment should also be taken into account (see 5.4.2.2.4).

The noise declaration shall be accompanied by following statement:

“The figures quoted are emission levels and are not necessarily working levels. Whilst there is a correlation between the emission and exposure levels, this cannot be used reliably to determine whether of not further precautions are required. Factors that influence the actual level of exposure of the work-force include the characteristics of the work room, the other sources of noise, etc. i.e. the number of machines and other adjacent processes. Also the permissible exposure level can vary from country to country. This information, however, will enable the user of the machine to make a better evaluation of the hazard and risk.”




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Annex A (informative)

Table with corresponding terms in English, French and German

This annex is common for English, French and German versions of this standard. The terminology provided is only applicable within the field of application of this standard.

ENGLISH FRENCH GERMAN Accumulation Accumulation Ansammlung Air filtration Filtration de L´air Luftfilterung Air flow Débit d’air Luftvolumenstrom Air flow capacity Capacité de debit d’air Luftvolumendurchsatz Air velocity Vitesse d’air Luftgeschwindigkeit Back pressure flap Clapet anti-retour Rückschlagklappe Bag filter Sac filtrant Schlauchfilter Bending Coude Bogen, Krümmer Bin Bac de réception Sammelbehälter Blast gate Trappe de fermeture Absperrschieber Blast wave Onde de pression Druckwelle Branch duct Collecteur secondaire Abzweigung Capture velocity Vitesse de captage Erfassungsgeschwindigkeit Chain conveyor Convoyeur à chaîne Kettenförderer Chips Copeaux Späne Chip and dust extraction system Installation d’extraction de Copeaux et

de poussiéres Absauganlage für Holzstaub und -späne

Clean air Air propre Reinluft Clean air part Partie en d’air propre Reinluftteil Cleaning cycle Cycle de nettoyage Reinigungsintervall oder

Reinigungszyklus Cleaning system Dispositif de nettoyage Reinigungssystem Concurrency factor Facteur de simultanéité Gleichzeitigkeitsfaktor Container Conteneur Container Control system Systèmes de commande Steuerung Conveying air Air de transport Förderluft Conveying air velocity Vitesse de transport Transportgeschwindingkeit Cyclone Cyclone Zyklon Damage control Contrôle de dommages Schadenbegrenzung Damper Volet de réglage Klappe Decoupling device Dispositif de découplage Entkopplungseinrichtung Detector Détecteur Detektor Differential pressure Pression différentielle Differenzdruck Discharge Décharge Entladung Dry sprinkler system Système de sprinkleurs antigel Trockenlöschsystem Duct Gaine Kanal/Leitung Duct diameter (round) Diamètre de gaine (rondes) Rohrdurchmesser Ducting (rectangular) Réseau de gaines (rectangulaires) Kanalsystem



EN 12779:2004 (E)

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ENGLISH FRENCH GERMAN Duct segment Tronçon de gaine Leitungsabschnitt Duct system Système de gaine Rohrleitungssystem Dust Poussières Holzstaub Dust alarm Alarme de poussières Staubalarm Dust load Charge de concentration en poussière Staubbeladung Dust loaded part Partie chargée en poussières Staubbelasteter Teil Emergency stop Arrêt d’urgence Not-aus Emptying system Dispositif de vidange Entleerungssystem Exhaust air Air évacué Abluft Explosion panel Panneau d’explosion Druckentlastungsfläche Explosion relief Volet anti-explosion Druckentlastungs-Einrichtungen Explosion relief element Elément de décharge Druckentlastungselement Explosion Venting Event d’explosion Explosionsableitung Extinguishing device Système d’extinction Löscheinrichtung Extraction efficiency Efficacité d’extraction Absaugwirkungsgrad Extraction hood Disposilif de captage Absaughaube Extraction hood design Conception de la buse de captage Haubengestaltung Extraction system Installation d’extraction Absauganlage Extraction vacuum Dépression d’extraction Absaugunterdruck Fan Ventilateur Ventilator Fan efficiency Efficacité du ventilateur Ventilatorwirkungsgrad Fan wheel Turbine Ventilatorlaufrad Filter sleeve Manche filtrante Filterschlauch Filter Filtre Filtereinheit Filter medium Média filtrant Filtermedium Filter hopper Corps de filtre Trichter Filter surface Surface du filtre Filteroberfläche Fire and explosion Incendie et explosion Brände und Explosionen Fire Incendie Brand Fire detection Détection incendie Branderkennung Fire fighting Lutte anti-incendie Feuerbekämpfung Fire gate Volet coupe-feu Brandschutzklappe Fire protecting door Porte coupe-feu Brandtür Fire protecting wall Mur coupe-feu Brandschutzmauer Fire zone Zone protegée Brandabschnitt Fixed guard Protecteur fixe Feststehende trennende

Schutzeinrichtung Fixed installation Installation fixe Ortsfest Anlage Flexible hose Gaines flexibles Flexibler Schlauch Flow control Contrôle de débit Kontrolle des LuftvolumenstromesGas Gaz Gas Grate Grille Rost Ground potential Potentiel du sol Ladung zur Erde Ignition detector Détecteur d’étincelles Funkendetektor Ignition extinguishing system Dispositif d’ extinction d’ étincelles Funkenlöschsystem Ignition source Source d’inflammation Zündquellen Ignition source Source d’inflammation Zündquellen Indicator Indicateur Anzeige



EN 12779:2004 (E)

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ENGLISH FRENCH GERMAN Inspection door Porte de visite Wartungsöffnung Leakage Fuite Undichtigkeit Main duct Collecteur principal Hauptleitung Material flow Débit matière Materialfluss Mesh Grillage Gitter Performance indication Indication de performance Leistungsanzeige Performance requirement Prescription de performance Anforderungen und Leistungen Plant design Conception de L’installation Anlagenplanung Poking Trinlage Stockern Poking opening Ouverture de tringlage Stockeröffnung Poking stick Perche de tringlage Stockerstab Potential difference Différence de potentiel Spannungsunterschiede Power consumption Consommation de puissance Energieverbrauch Pressure Pression Druck Pressure difference Pression différencielle Druckdifferenz Pressure loss Perte de charge Druckabfall Pressure loss indicator Capteur de perte de charge Druckverlustanzeige Re-circulation Recyclage Rückführung Regeneration Décolmatage Regeneration Regeneration period Durée de décolmatage Regenerationszeit Residual dust content Teneur résiduelle en poussières Reststaubgehalt Return air Air recyclé Rückluft Return air duct Gaine de recyclage Rückluftleitung Rotary valve Ecluse Zellenradschleuse Run-down time Temps d’ arrêt Auslaufzeit Running-in period Temps de fonctionnement Anlaufzeit Running-in period Temps de fonctionnement Anlaufzeit Screw conveyor Convoyeur à vis Schneckenförderer Separator Séparateur Abscheider Silo Silo Silo Silo discharge system Dispositif de déchargement du silo Siloentleerungssystem Silo filling system Díspositif de remplissage du silo Silobefüllungssystem oder

Silobeschickungssytem Sound pressure level Niveau de pression acoustique Schalldruckpegel Spark Etincelle Funk Spark detection Détecteur d’ étincelle Funkenerkennung Spark generation Production d’étincelles Funkenbildung Spark protection Protection contre les étincelles Funkenschutz Starting sequence Cycle de démarrage Einschaltvorgang Static electricity Electricité statique Statische Elektrizität Storage facility Installation de stockage Sammeleinrichtung Suction point Point d’aspiration Ansaugstelle Support Support Unterstützung Suspensions Suspensions Aufhängung Temperature Sensor Détecteur de température Temperaturfühler Transport system Dispositif de transport Fördersystem Vacuum (negative pressure) Dépression Vakuum Vacuum gauge Déprimomètre Unterdruckmessgerät



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ENGLISH FRENCH GERMAN Verification Verification Prüfung Water sprinkler Sprinkleur Sprinkleranlage Wood dust Poussières de bois Holzstaub Wood waste Déchets de bois Holzabfall Wood waste accumulation Accumulation de déchets de bois Holzabfallablagerung Wood waste bin Conteneur de déchets de bois Materialcontainer Woodworking machine Machines à bois Holzbearbeitungsmaschine



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Annex B (informative)

Relationship between airflow, vacuum, air velocity and power

consumption

This informative annex outlines the power consumption for chip and dust extraction systems.

The power consumption is calculated with respect to the major parameters as follows:

a) airflow;

b) pressure loss (in the duct system etc. and woodworking machines);

c) fan efficiency.

The calculated power consumption is to be considered as a guide.

The power consumption of the extraction system is mainly determined and influenced by the following parameters:

d) airflow Qa (m3h-1);

e) extraction vacuum at the outlet of the woodworking machine b (Pa);

f) pressure loss in flexible hoses (mainly length determined) c (Pa);

g) pressure loss in the duct system (mainly determined by velocity, length and number of bends) d (Pa);

h) pressure loss in the air filtration equipment e (Pa);

i) pressure loss in the duct system for filtered air f (Pa);

j) fan efficiency (%).



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d

e f

b

c

Figure B.1 — Pressure losses

The pressure loss (parameters f) to i)) also depends on the air velocity, system layout, filter design etc.

The pressure loss value (parameters f) to i)) is typically between 1 000 Pa and 4 000 Pa at an air velocity of 25 ms-1.

The calculations shown in Table B.1 are based on a pressure loss (parameters f) to i)) of 2 000 Pa.

Fan efficiency depends mainly on the airflow, differential pressure and the fan design. The efficiency will typically be in the range 60 % to 85 %. The calculations in Table B 1 are based upon a 75 % efficiency.

The airflow d) and the required extraction vacuum e) are determined by:

k) the woodworking process;

l) the design and position of the woodworking machine extraction hood(s);

m) the internal ducting of the woodworking machine.

The woodworking machine specifications include requirements regarding the air flow and the required extraction vacuum.

The power consumption is calculated for a set of corresponding figures for air flow and extraction vacuum. Results of the calculations are shown in Table B.1.

For the calculations used to establish the values shown in Table B.1 Equation 1 is used:

Power consumption = 7500036

)0002(×

+bQa kW (1)



EN 12779:2004 (E)

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If accurate data is available for the pressure loss (parameters f) to i))and/or the fan efficiencyEquation 2 can be used:

Power consumption = η×

++++00036

)( fedcbQa kW (2)

Table B.1 — Power consumption (kW) for chip and dust extraction systems

Extraction vacuum b

Airflow Qa(m3h-1)

(Pa) 1 000 2 000 5 000 10 000 20 000 50 000 10 000 4,4 8,9 22,2 44 89 222 5 000 2,6 5,2 13,0 26 52 130 3 000 1,9 3,7 9,3 18,5 37 93 2 000 1,5 3,0 7,4 14,8 30 74 1 500 1,3 2,6 6,5 13,0 26 65 1 000 1,1 2,2 5,6 11,1 22,2 56 500 0,9 1,9 4,6 9,3 18,5 46 0 0,7 1,5 3,7 7,4 14,8 37

(+ 500) 0,6 1,1 2,8 5,6 11,1 28 (+ 1 000) 0,4 0,7 1,9 3,7 7,4 18,5

The extraction vacuum (b) of almost all woodworking machines lies between 500 Pa and 2 000 Pa.

The shaded sector of Table B.1 is the normal sector.



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Annex C (informative)

Verification of performance measurement

The measurements are to be carried out for all significant combinations of machines designed to be in operation concurrently.

The scheme in this annex relates to following clauses of this standard:

a) plant design (5.4.3.1.1);

b) airflow measurement (5.4.3.1.3);

c) performance verification (6.3.1.1 ).

A typical form for recording the performance measurements is as follows:



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Performance verification

Name of person carrying out test: ………………………………………………………………………..

Company: ………………………………………………………………………..

Date of test: …………………………. Date of previous test : ………………………………………..

Location of Equipment: …………………………………………………………………………………..

Machine combination number: ……………………………………………………………………………..

Machine Design Measurement Test point Identifica-

tion

Type/model Duct diameter

(mm)

Air Flow (m3h-1)

Pressure (Pa)

Air velocity (ms-1)

Air flow (m3h-1)

Pressure (Pa)



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Annex D (normative)

Noise reduction at the design stage

D.1 Noise sources

The main sources of airborne noise for dust extraction systems are:

a) inlets of extraction hoods etc.;

b) leakage in the ducting system;

c) fans;

d) the filter regeneration system;

e) other moving parts of the extraction system;

f) collision between interior walls of the extraction system and large wood chips during their conveyance;

g) squeezing of chips between the interior walls of the extraction system and moving parts (e.g. between the screw itself and the wall of the screw conveyor;

h) conveying velocity in the ducting system.

D.2 Measures to reduce noise

Measures that can be introduced to reduce noise emission are:

a) to have smooth inner sides of the extraction system and no abrupt changes of air flow direction;

b) to avoid parts where the extraction velocity is high;

c) to minimise leakage especially where the static pressure/vacuum is higher than 500 Pa;

d) to make the fan wheel with low out of balance forces and to use a fan design that itself has low noise emission;

e) where possible to make the distance between moving parts and the walls large enough so that squeezing of chips rarely occurs;

f) to install air noise silencers in the extraction system;

g) to install sound insulation in the outer walls of the extraction system (eventually also at adjacent parts) at known noise source positions;

h) to have ducting bends with a large bend radius (1,5 x D or more wherever possible);

i) wherever possible to reduce the conveying air velocity.



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D.3 Impact from chips and dust

Noise emission information for the extraction system in this standard is given without taking into account the noise resulting from the impact of chips and dust being conveyed with the ducting system walls.

The level of impact from chips and dust being conveyed depends on several parameters (e.g. size and weight of chips, conveying velocity and ducting design). The impact between the chips and dust being conveyed and the ducting system can add up to 10 dB extra, and in some cases more, to the noise emission measured without chips and dust being conveyed in the ducting system.

The noise impact from chips and dust can be reduced by:

a) pre-separation of any larger wood pieces;

b) process change from (e.g. from sawing to moulding) to reduce wood piece size;

c) sound insulation of the duct bend outer walls and parts of the machine adjacent to ducts;

d) using duct bends with a large bending radius.



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Annex E (informative)

Air velocity and extraction hood design

E.1 Capture velocity and extraction hood design

The required capture velocity is complex to calculate and is influenced by the chip and dust particle size and weight as well as their velocity and direction.

The capture velocity is determined by the applied vacuum from the extraction system and the design of the extraction hood. The design of the extraction hood is therefore essential for extraction efficiency.

General rules for extraction hoods are:

a) its position shall be as close as possible to the machining process;

b) the airflow in the extraction hood shall be in the same direction as the chips leaving the tool;

c) airflow from the tool shall work together with the airflow in the extraction hood.

Guidance for the design of hoods for specific machines are included in machine specific standards.

E.2 Air velocity

Air velocity needed for transportation of normal wood waste is 20 ms-1 to 25 ms-1.

Greater velocities can be needed for special wood waste (e.g. wet saw dust).

NOTE Higher extraction velocities result in increased power consumption and noise levels.



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Figure E.1 — Design of extraction hoods



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Annex ZA (informative)

Clauses of this document addressing essential requirements or other

provisions of EU Directives

This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association to provide one means of conforming to Essential Requirements of the New Approach Directive Machinery 98/37/EC, amended by 98/79/EC.

Once this standard is cited in the Official Journal of the European Communities under that Directive and has been implemented as a national standard in at least one Member State, compliance with the normative clauses of this standard (except 5.4.3.1) confers, within the limits of the scope of this standard, a presumption of conformity with the relevant Essential Requirements of that Directive and associated EFTA regulations.

WARNING: Other requirements and other EU Directives may be applicable to the product(s) falling within the scope of this standard.



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Bibliography

[1] EN 1050:1996, Safety of machinery - Principles for risk assessment

[2] EN 1088:1995, Safety of Machinery - Interlocking devices associated with guards - Principles for design and selection.

[3] . EN 26184-1:1991, Explosion protection systems - Part 1: Determination of explosion indices of combustible dusts in air (ISO 6184-1:1985).

[4] EN ISO 4871:1996, Acoustics - Declaration and verification of noise emission values of machinery and equipment (ISO 4871:1996).

[5] HD 21.1 S4:2002, Cables of rated voltages up to and including 450/750 V and having thermoplastic insulation - Part 1: General requirements.

[6] Directive 89/336/EEC, Council Directive 89/336/EEC of 3 May 1989 on the approximation of the laws of the Member States relating to electromagnetic compatibility.

[7] Directive 94/9/EC, Equipment and protective systems intended for use in potentially explosive atmospheres.



Riproduzione vietata - Legge 22 aprile 1941 Nº 633 e successivi aggiornamenti.

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