EN 953-1997 pdf download.Safety of machineiy Guards Genenil requirements for the design and constmction of fixed and movable guards.
5.1.4 Containment of hazardous substances Where there is a foreseeable risk of emission from the machine of hazardous substances (e.g. coolant, vapours, gases, swarf sparks, hot or molten material, dust), the guard shall be designed to contain these as far as practicable and suitable extraction equipment may be needed (see EN 626-1).
If a guard forms part of an extraction system this function shall be considered in the design, selection of materials, construction and positioning of the guard.
5.1.5 Noise
Where a requirement has been es(abllsbe(l to reduce machine noise, guards shall be designed and constructed which will give the required noise reduction as well as providing protection agathst the other hazards present at the machine (reference:
CENITC 211). Guards acting as acoustic enclosures shall have adequately sealed joints to reduce the efltLSSiOIl of noise.
5.1.6 Radiation
Where there is a foreseeable risk of exposure to hazardous radiation, guards shall be designed and appropriate materials selected to protect. persons from the hazard. Examples include the use of darkened glazing to prevent weldflash or the elimination of openings in a guarol aroun(l a laser (reference:
CEN/rC 114!WG 13).
5.1.7 Explosion
Where there is foreseeable risk of explosion, guards shall be designed to contain or dissipate the released energy in a safe manner awl (lireetloti (e.g. by use of ‘explosion relief panels) (reference: EN 1127-1).
As far as practicable, movable guards shall be designed an(l j)OSit)Ofle(l such that, (hiring tiornial operation, they are prevented from closing when there are persons in the danger zone. Where this is not practicable, other means shall be used to prevent persons remaining undetected within the danger zone.
5.2.4 Viewing
To minimize the need to remove them, guards shall be designed and constnacte(l to offer adequate viewing of the process.
5.2.5 Ergonomic aspects
Guards shall be designed and constructed taking into account ergonomic principles (see also 3.6.1 and 3.6.2 of EN 292-2: 1991).
5.2.5.1 Size (1iU1 we?gbi
Removable sections of guards shall be designed to be of a suitable size and weight to permit ease of handling. Guards which cannot readily be moved or transported by hand shall be provided, or be capable of being provided with suitable attachment devices for transport by means of lifling gear The attaclunents or provisions can be, for instance:
– standard lifting appliances with slings, hooks,
eye1wdts or simply tapped holes for appliuice fixing;
— appliances for automatic grabbing with a lifting
hook, when securing is not possible from the
ground;
— lifting gear and appliances integrated into the guard;
an indication, on the guard itself and on some of its removable parts, or hi the information for use, of the value of their mass, expressed in kilograms (kg).
5.2.5.2 Opernting foires
Movable guards or removable sections of guards shall be designed to permit ease of operation.
The observance of ergonomic principles in designing guards contributes to increasing safety by reducing stress and the physical effort of the operator. This improves the performance and reliability of the operation, thereby reducing the probabihty of errors at all stages of machine use (see 3.11 of EN 292-1: 1991). Operating forces can be reduced by the use of devices such as springs, counterbalances or gas struts.
Where guard.s are 1o%ver operated they shall not be capable of causing injury (e.g. from contact pressure, force, speed, sharp edges). Where a guard i.s fitted with a protective device which automatically initiates re-opening of the guard, the force to prevent the guard closing shall not exceed 150 N. The kinetic energy of the guard shall not exceed 10 J. Where no such protective device is fitted these values shall be reduced to 75 N and 4 J respectively.
5.2.6 Intended use
Guards shall be designed so far as is practicable to take into account foreseeable use and reasonably foreseeable misuse (see 3.12 of EN 292-1: 1991).
5.3 Guard design aspects
5.3.1 General
All foreseeable aspects of guard operation shall be given proper consideration at the (lesign stage to ensure that the design and construction of the guard itself does not create a further hazard.EN 953-1997 pdf download.