ISO 14120:2015 specifica i requisiti generali per la progettazione, la costruzione, e la scelta dei ripari fornite per la protezione delle persone dai rischi meccanici, indica altri pericoli che potrebbero influenzare la progettazione e la costruzione di ripari, si applica alle protezioni per macchine che verranno realizzate dopo la pubblicazione.
I requisiti sono applicabili a ripari fissi o mobili.
La presente norma internazionale non comprende dispositivi di interblocco. Questi sono coperti nella norma ISO 14119.
ISO 14120:2015 non fornisce requisiti per i sistemi di protezione alla mobilità, come ROPS (rollover protective structures), FOPS (falling-object protective structures) e TOPS (tip over protective structures) o alla capacità delle macchine di sollevare carichi.
ISO 14120 – General requirements for design and construction of fixed and movable guards
Revision of ISO 14120
2015 an updated version of ISO 14120 will be published and it will replace the old standard EN 953. This new standard will also be harmonized. Transition period from the publishing date is one year. In the transition period you are free to choose which standard you will use as long your machinery is handed over before the transition period has ended. You have to choose one standard to use, either EN 953 or ISO 14120. It is not allowed to use booth standards.
ISO 14120 has not been revised since 1997 and many clauses needed updated wording for better understanding. Requirements for safety has been updated and tightened to comply with the Machinery Directive, the definitions and terms have been updated, validation and verification has a new table and the information of use is very clear with who can remove guards and what the manual shall include.
Type of standard
ISO 14120 is a type-B2 standard as stated in ISO 12100. Guards provide a risk reduction for both protection against unintended access and against ejected parts and substances. The guarding can also give protection against others hazards e.g. noise, fire, biological hazards, radiation.
Scope
ISO 14120 is an International Standard that specifies general requirements for the design, construction and selection of guards provided to protect persons from mechanical hazards. It indicates other hazards that can influence the design and construction of guards and it applies to guards for machinery which will be manufactured after it is published. The requirements are applicable if fixed and movable guards are used. This International Standard does not cover interlocking devices, these are covered in ISO 14119.
ISO 14120 does not provide requirements for special systems relating specifically to mobility or to the ability to lift loads such as ROPS (Rollover Protective Structures), FOPS (Falling-Object Protective Structures and TOPS (Tip over Protective Structures) are outside the scope of this standard
Some important updates to the standard
3.7 Tool
implement such as a key or wrench designed to open and close a fastener. Note to entry: An improvised implement such as a coin or a nail-file cannot be considered as a tool.
3.8 Use of a tool
action by a person under known and predetermined circumstances as part of a safe working procedure
4 Risk assessment
In order to select and design types of guards appropriate to particular machinery, it is important to assess the risk arising from the various hazards present at that machinery and the foreseeable categories of persons who can be exposed to the hazard(s) (see ISO 12100:2010, Clause 5).
5.1.3 Containment of ejected parts and other impacts
Where there is a foreseeable risk of
– ejection of parts (for example workpiece or broken tooling) from the machine
– impacts from parts of machinery
– impacts from the operator the guard shall, as far as practicable, be designed and constructed so as to contain and withstand such ejections and impacts.
5.2.4 Viewing
Where viewing of the process is required guards shall be designed and constructed to offer adequate viewing. This can eliminate the need for defeating them. See also 5.9.
5.3.9 Removal of fixed guards
Demountable fixed parts of guards shall only be removable with the use of a tool (see 3.8). See also 8.5 and 8.6.
NOTE 1 This is because operators may prefer to use an easily removable fixed guard instead of using an interlocked movable guard.
NOTE 2 The use of fastenings that can be released quickly from the inside of the guarded area should not be regarded as an alternative to providing an emergency exit. The emergency release of guards with interlocking/guard locking is dealt with in ISO 14119.See also Clause 6, Selection of types of guards.
5.3.10 Mounting of removable fixed guards
Fixed guards which are removable shall, where practicable, be unable to remain in place without their fixings.
5.3.12 Movable guards
The opening of movable guards shall require deliberate action. Where possible movable guards shall be attached to the machine or adjacent fixed elements so that they are retained, for example by hinges or slides, even when open. Such attachments shall only be removable with the use of a tool (see 3.8). Interlocked moveable guards shall be positioned relative to the hazard zone in accordance with ISO 13855.
5.4 Materials, rigidity and impact requirements
5.4.2 Impact and ejection resistance
Guards shall, as far as practicable, be designed and material selected to withstand and contain reasonably foreseeable impacts and ejections according to 5.1.3. Materials for viewing panels shall be selected with properties suited to resist the mass and velocity of the ejected object or material. Where guards are fitted with viewing panels, special consideration shall be given to the selection of materials and method of fixing them. Guards shall resist static and dynamic forces (pressure, impacts) according to the risk assessment.
NOTE The impact resistance depends e.g. on the properties of the material being used, its strength, the fixing and its ageing.
5.4.4 Secure fixing
Guards or parts of guards shall be secured by fixing points of adequate strength, spacing and number to remain secure under any foreseeable loading or impact. Fixing can be by means of mechanical fasteners or clamps, welded or bonded joints or other means suited to the application. See also 5.3.8.
5.12 Electrostatic properties
Materials of the guard that enclose or is placed in an environment containing dust, fibers or particles shall be selected to prevent accumulation. If there is a risk of static charge to a hazardous level, guards shall be designed in material with an electrical conductance high enough to avoid build-up of static charge or by other measures to prevent hazardous static charge. For consideration of ignition sources, see 5.1.7.
NOTE IEC /TR 61340-1 gives guidance on electrostatic problems and hazards.
5.13 Guards with electrically conductive parts
Where guards are made of electrically conductive material and used in electrically powered machines, they may need to be considered as ”extraneous conductive parts of the machine” according to IEC 60204-1:2005, clause 8.
5.19 Retained fastenings
When it is foreseen (e.g. maintenance) that the fixed guard will be removed, then the fastenings shall remain attached to the guard or to the machinery. The requirement does not necessarily apply to fixed guards that are only liable to be removed, for example, when the machinery is completely overhauled, is subject to major repairs or is dismantled for transfer to another site. For the same reason, it may not be necessary to apply the requirement for retained fastenings to the casings of machinery if,
– the manufacturer’s instructions specify that the repairs requiring removal of these casings are only to be carried out in a specialist repair workshop, and
– fastenings, as far as practicable, shall only be removable by the use of a tool.
See Annex A for examples of retained fastenings.
NOTE This requirement aims to reduce risks due to loss of one or more of the fixings when guards are removed, for example, for maintenance purposes. This can lead to the guards not being replaced, being only partially fixed in place or fixed with replacement fixings that do not have adequate strength, so that the guard cannot adequately perform its protective function, for example, where containment of ejected parts is necessary.
5.22 Colour
Attention can be drawn to the hazard while the guard is opened or left off by highlighting the hazard by the use of suitable colours. For example if a guard is painted the same colour as the machine then the hazardous parts is painted a contrasting bright colour. Care should be taken in the selection and combination of colours to avoid confusion, e.g. red and yellow in combination is normally used for emergency stop. When observation of the process is required, guards of perforate material should not be painted in bright colours, e.g. yellow, that might interfere with the viewing of the process.
NOTE For further information see EN 614-1.
6.2 Combination of different guards or of guards with other devices
It can be appropriate to use a combination of different types of guards. For example:
– if a machine has several hazard zones and access is required to one of them during the operating phase, the guards can consist of a fixed guard combined with an interlocking movable guard;
– if a perimeter fence is used to prevent access to the hazard zones of a machine, an interlocked gate would normally be required to provide safe access.
In a similar way, a combination of protective devices and guards can sometimes be required (see Figure 9).
EXAMPLE Where a mechanical feed device is used in conjunction with a fixed guard to feed workpieces into a machine (thereby removing the need for access to the hazard zone), a sensing protective device (see ISO 12100:2010, 3.28.5) can be required to protect against a secondary trapping or shearing hazard between the mechanical feed device and the fixed guard.
6.3 Selection of guards according to the number and size of the hazards
Where practicable hazards shall be guarded by enclosing guards. When enclosing guards are not practicable guards of the most appropriate type must be selected e.g. fixed guards (distance or perimeter), movable guards, adjustable guards (automatic or manual) (see 6.4). It is possible for a guard to protect multiple hazards and/or hazardous zones e.g. perimeter guarding with an interlocked access gate around an assembly of machines. If a guard protects multiple hazards then the guarding shall be appropriate for all the hazards.
NOTE 1 When a hazardous area is separated into different zones to allow access to stationary machinery in one zone when machinery is operating on other zones, access to a zone still in operation by accessing a safe zone should be prevented by the use of appropriate safeguarding.
NOTE 2 Other safeguarding measures outside of the scope of this standard might be more suited to the hazard(s) identified and the intended operation of the machine.
It can be beneficial to the production process to divide a guarded area into different zones, to enable actions (for example checking, adjustment) in one zone to be carried out without affecting machine operation in another zone. In this case, the guarding for each zone shall be in accordance with all the requirements of this International Standard
6.4.4.1 Where access is required only for machine setting, process correction or maintenance
The following types of guard should be used:
a) Movable guard, if the foreseeable frequency of access is high (e.g. more than once per week) or if removal or replacement of a fixed guard would be difficult. Movable guards shall be associated with an interlock or an interlock with guard locking (see ISO 14119);
b) Fixed guard only, if the foreseeable frequency of access is low (e.g. less than once per week), its replacement is easy and its removal and replacement are carried out under a safe system of work.
7.2 Verification and validation methods
Verification and validation can be satisfied by methods including but not limited to:
– Visual inspection (A);
– Practical tests (B);
– Measurement (C);
– Observation during operation (D);
– Review of task-based risk assessment (E);
– Review of specifications, layout and documentation (F).
– New table of verification and validation added.
8 Information for use
8.1 General
The instructions for use shall contain the required information about guards, their safety parameters and their functions (e.g. vertical or horizontal orientation), including installation and maintenance (see ISO 12100:2010, 6.4).
8.2 Guard hazards
Information shall be provided for any hazards associated with the guards themselves, for example mechanical hazards or flammability of materials and relevant test results.
8.3 Installation
Instructions shall be supplied for the correct installation of guards and associated equipment. When guards are to be attached to a structure, the instructions shall include requirements for fixing. This includes but is not limited to:
– fixing to a floor;
– assembling of movable guards;
– number and types of fixings;
– compliance with other relevant standards, e.g. ISO 13857 and ISO 14119.
NOTE When guards are designed to be fixed to a concrete floor, instructions for installation can refer to concrete classification. See for example EN 206-1 with classes C20/25 to C50/60 for compressive strength
8.5 Removal of guards
Information shall be provided indicating actions to be taken before guards are removed, for example machine power isolation, dissipation of stored energy and procedures for the removal of guards. The information shall also prescribe requirements on procedures for the removal of guards, including
– the appropriate use of a tool (see 3.9) and
– the safe working procedure.
NOTE See also ISO 14118 and IEC 60204-1:2005, 5.3 and 5.4.
– Includes new requirements.
8.6 Inspection and maintenance
Details shall be provided of inspections to be carried out and maintenance required for, including:
– loss of or damage to any part of the guard, especially where this leads to deterioration of safety performance, for example reduction of impact resistance from scratches to glazing materials;
– deformed or damaged part shall be repaired or replaced if the damage has negative influence on safety;
– replacement of wearing parts;
– correct operation of interlocks;
– degradation of jointing or fixing points;
– degradation by corrosion, temperature change, embrittlement or chemical attack;
– satisfactory operation and lubrication, if necessary, of moving parts;
– modification of safety distances and aperture sizes;
– degradation of acoustic performance, if applicable.
The information for use shall include requirements on the use of a tool (see 3.9).
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